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 /*
  * Copyright (C)2009-2015, 2017, 2020-2023 D. R. Commander.
  *                                         All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * - Redistributions of source code must retain the above copyright notice,
  *   this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright notice,
  *   this list of conditions and the following disclaimer in the documentation
  *   and/or other materials provided with the distribution.
  * - Neither the name of the libjpeg-turbo Project nor the names of its
  *   contributors may be used to endorse or promote products derived from this
  *   software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS",
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef __TURBOJPEG_H__
 #define __TURBOJPEG_H__
 
 #include <stddef.h>
 
 #if defined(_WIN32) && defined(DLLDEFINE)
 #define DLLEXPORT  __declspec(dllexport)
 #else
 #define DLLEXPORT
 #endif
 #define DLLCALL
 
 
 /**
  * @addtogroup TurboJPEG
  * TurboJPEG API.  This API provides an interface for generating, decoding, and
  * transforming planar YUV and JPEG images in memory.
  *
  * @anchor YUVnotes
  * YUV Image Format Notes
  * ----------------------
  * Technically, the JPEG format uses the YCbCr colorspace (which is technically
  * not a colorspace but a color transform), but per the convention of the
  * digital video community, the TurboJPEG API uses "YUV" to refer to an image
  * format consisting of Y, Cb, and Cr image planes.
  *
  * Each plane is simply a 2D array of bytes, each byte representing the value
  * of one of the components (Y, Cb, or Cr) at a particular location in the
  * image.  The width and height of each plane are determined by the image
  * width, height, and level of chrominance subsampling.  The luminance plane
  * width is the image width padded to the nearest multiple of the horizontal
  * subsampling factor (1 in the case of 4:4:4, grayscale, 4:4:0, or 4:4:1; 2 in
  * the case of 4:2:2 or 4:2:0; 4 in the case of 4:1:1.)  Similarly, the
  * luminance plane height is the image height padded to the nearest multiple of
  * the vertical subsampling factor (1 in the case of 4:4:4, 4:2:2, grayscale,
  * or 4:1:1; 2 in the case of 4:2:0 or 4:4:0; 4 in the case of 4:4:1.)  This is
  * irrespective of any additional padding that may be specified as an argument
  * to the various YUV functions.  The chrominance plane width is equal to the
  * luminance plane width divided by the horizontal subsampling factor, and the
  * chrominance plane height is equal to the luminance plane height divided by
  * the vertical subsampling factor.
  *
  * For example, if the source image is 35 x 35 pixels and 4:2:2 subsampling is
  * used, then the luminance plane would be 36 x 35 bytes, and each of the
  * chrominance planes would be 18 x 35 bytes.  If you specify a row alignment
  * of 4 bytes on top of this, then the luminance plane would be 36 x 35 bytes,
  * and each of the chrominance planes would be 20 x 35 bytes.
  *
  * @{
  */
 
 
 /**
  * The number of initialization options
  */
 #define TJ_NUMINIT  3
 
 /**
  * Initialization options.
  */
 enum TJINIT {
   /**
    * Initialize the TurboJPEG instance for compression.
    */
   TJINIT_COMPRESS,
   /**
    * Initialize the TurboJPEG instance for decompression.
    */
   TJINIT_DECOMPRESS,
   /**
    * Initialize the TurboJPEG instance for lossless transformation (both
    * compression and decompression.)
    */
   TJINIT_TRANSFORM
 };
 
 
 /**
  * The number of chrominance subsampling options
  */
 #define TJ_NUMSAMP  7
 
 /**
  * Chrominance subsampling options.
  * When pixels are converted from RGB to YCbCr (see #TJCS_YCbCr) or from CMYK
  * to YCCK (see #TJCS_YCCK) as part of the JPEG compression process, some of
  * the Cb and Cr (chrominance) components can be discarded or averaged together
  * to produce a smaller image with little perceptible loss of image clarity.
  * (The human eye is more sensitive to small changes in brightness than to
  * small changes in color.)  This is called "chrominance subsampling".
  */
 enum TJSAMP {
   /**
    * 4:4:4 chrominance subsampling (no chrominance subsampling).  The JPEG or
    * YUV image will contain one chrominance component for every pixel in the
    * source image.
    */
   TJSAMP_444,
   /**
    * 4:2:2 chrominance subsampling.  The JPEG or YUV image will contain one
    * chrominance component for every 2x1 block of pixels in the source image.
    */
   TJSAMP_422,
   /**
    * 4:2:0 chrominance subsampling.  The JPEG or YUV image will contain one
    * chrominance component for every 2x2 block of pixels in the source image.
    */
   TJSAMP_420,
   /**
    * Grayscale.  The JPEG or YUV image will contain no chrominance components.
    */
   TJSAMP_GRAY,
   /**
    * 4:4:0 chrominance subsampling.  The JPEG or YUV image will contain one
    * chrominance component for every 1x2 block of pixels in the source image.
    *
    * @note 4:4:0 subsampling is not fully accelerated in libjpeg-turbo.
    */
   TJSAMP_440,
   /**
    * 4:1:1 chrominance subsampling.  The JPEG or YUV image will contain one
    * chrominance component for every 4x1 block of pixels in the source image.
    * JPEG images compressed with 4:1:1 subsampling will be almost exactly the
    * same size as those compressed with 4:2:0 subsampling, and in the
    * aggregate, both subsampling methods produce approximately the same
    * perceptual quality.  However, 4:1:1 is better able to reproduce sharp
    * horizontal features.
    *
    * @note 4:1:1 subsampling is not fully accelerated in libjpeg-turbo.
    */
   TJSAMP_411,
   /**
    * 4:4:1 chrominance subsampling.  The JPEG or YUV image will contain one
    * chrominance component for every 1x4 block of pixels in the source image.
    * JPEG images compressed with 4:4:1 subsampling will be almost exactly the
    * same size as those compressed with 4:2:0 subsampling, and in the
    * aggregate, both subsampling methods produce approximately the same
    * perceptual quality.  However, 4:4:1 is better able to reproduce sharp
    * vertical features.
    *
    * @note 4:4:1 subsampling is not fully accelerated in libjpeg-turbo.
    */
   TJSAMP_441,
   /**
    * Unknown subsampling.  The JPEG image uses an unusual type of chrominance
    * subsampling.  Such images can be decompressed into packed-pixel images,
    * but they cannot be
    * - decompressed into planar YUV images,
    * - losslessly transformed if #TJXOPT_CROP is specified, or
    * - partially decompressed using a cropping region.
    */
   TJSAMP_UNKNOWN = -1
 };
 
 /**
  * MCU block width (in pixels) for a given level of chrominance subsampling.
  * MCU block sizes:
  * - 8x8 for no subsampling or grayscale
  * - 16x8 for 4:2:2
  * - 8x16 for 4:4:0
  * - 16x16 for 4:2:0
  * - 32x8 for 4:1:1
  * - 8x32 for 4:4:1
  */
 static const int tjMCUWidth[TJ_NUMSAMP]  = { 8, 16, 16, 8, 8, 32, 8 };
 
 /**
  * MCU block height (in pixels) for a given level of chrominance subsampling.
  * MCU block sizes:
  * - 8x8 for no subsampling or grayscale
  * - 16x8 for 4:2:2
  * - 8x16 for 4:4:0
  * - 16x16 for 4:2:0
  * - 32x8 for 4:1:1
  * - 8x32 for 4:4:1
  */
 static const int tjMCUHeight[TJ_NUMSAMP] = { 8, 8, 16, 8, 16, 8, 32 };
 
 
 /**
  * The number of pixel formats
  */
 #define TJ_NUMPF  12
 
 /**
  * Pixel formats
  */
 enum TJPF {
   /**
    * RGB pixel format.  The red, green, and blue components in the image are
    * stored in 3-sample pixels in the order R, G, B from lowest to highest
    * memory address within each pixel.
    */
   TJPF_RGB,
   /**
    * BGR pixel format.  The red, green, and blue components in the image are
    * stored in 3-sample pixels in the order B, G, R from lowest to highest
    * memory address within each pixel.
    */
   TJPF_BGR,
   /**
    * RGBX pixel format.  The red, green, and blue components in the image are
    * stored in 4-sample pixels in the order R, G, B from lowest to highest
    * memory address within each pixel.  The X component is ignored when
    * compressing and undefined when decompressing.
    */
   TJPF_RGBX,
   /**
    * BGRX pixel format.  The red, green, and blue components in the image are
    * stored in 4-sample pixels in the order B, G, R from lowest to highest
    * memory address within each pixel.  The X component is ignored when
    * compressing and undefined when decompressing.
    */
   TJPF_BGRX,
   /**
    * XBGR pixel format.  The red, green, and blue components in the image are
    * stored in 4-sample pixels in the order R, G, B from highest to lowest
    * memory address within each pixel.  The X component is ignored when
    * compressing and undefined when decompressing.
    */
   TJPF_XBGR,
   /**
    * XRGB pixel format.  The red, green, and blue components in the image are
    * stored in 4-sample pixels in the order B, G, R from highest to lowest
    * memory address within each pixel.  The X component is ignored when
    * compressing and undefined when decompressing.
    */
   TJPF_XRGB,
   /**
    * Grayscale pixel format.  Each 1-sample pixel represents a luminance
    * (brightness) level from 0 to the maximum sample value (255 for 8-bit
    * samples, 4095 for 12-bit samples, and 65535 for 16-bit samples.)
    */
   TJPF_GRAY,
   /**
    * RGBA pixel format.  This is the same as @ref TJPF_RGBX, except that when
    * decompressing, the X component is guaranteed to be equal to the maximum
    * sample value, which can be interpreted as an opaque alpha channel.
    */
   TJPF_RGBA,
   /**
    * BGRA pixel format.  This is the same as @ref TJPF_BGRX, except that when
    * decompressing, the X component is guaranteed to be equal to the maximum
    * sample value, which can be interpreted as an opaque alpha channel.
    */
   TJPF_BGRA,
   /**
    * ABGR pixel format.  This is the same as @ref TJPF_XBGR, except that when
    * decompressing, the X component is guaranteed to be equal to the maximum
    * sample value, which can be interpreted as an opaque alpha channel.
    */
   TJPF_ABGR,
   /**
    * ARGB pixel format.  This is the same as @ref TJPF_XRGB, except that when
    * decompressing, the X component is guaranteed to be equal to the maximum
    * sample value, which can be interpreted as an opaque alpha channel.
    */
   TJPF_ARGB,
   /**
    * CMYK pixel format.  Unlike RGB, which is an additive color model used
    * primarily for display, CMYK (Cyan/Magenta/Yellow/Key) is a subtractive
    * color model used primarily for printing.  In the CMYK color model, the
    * value of each color component typically corresponds to an amount of cyan,
    * magenta, yellow, or black ink that is applied to a white background.  In
    * order to convert between CMYK and RGB, it is necessary to use a color
    * management system (CMS.)  A CMS will attempt to map colors within the
    * printer's gamut to perceptually similar colors in the display's gamut and
    * vice versa, but the mapping is typically not 1:1 or reversible, nor can it
    * be defined with a simple formula.  Thus, such a conversion is out of scope
    * for a codec library.  However, the TurboJPEG API allows for compressing
    * packed-pixel CMYK images into YCCK JPEG images (see #TJCS_YCCK) and
    * decompressing YCCK JPEG images into packed-pixel CMYK images.
    */
   TJPF_CMYK,
   /**
    * Unknown pixel format.  Currently this is only used by #tj3LoadImage8(),
    * #tj3LoadImage12(), and #tj3LoadImage16().
    */
   TJPF_UNKNOWN = -1
 };
 
 /**
  * Red offset (in samples) for a given pixel format.  This specifies the number
  * of samples that the red component is offset from the start of the pixel.
  * For instance, if an 8-bit-per-component pixel of format TJPF_BGRX is stored
  * in `unsigned char pixel[]`, then the red component will be
  * `pixel[tjRedOffset[TJPF_BGRX]]`.  This will be -1 if the pixel format does
  * not have a red component.
  */
 static const int tjRedOffset[TJ_NUMPF] = {
   0, 2, 0, 2, 3, 1, -1, 0, 2, 3, 1, -1
 };
 /**
  * Green offset (in samples) for a given pixel format.  This specifies the
  * number of samples that the green component is offset from the start of the
  * pixel.  For instance, if an 8-bit-per-component pixel of format TJPF_BGRX is
  * stored in `unsigned char pixel[]`, then the green component will be
  * `pixel[tjGreenOffset[TJPF_BGRX]]`.  This will be -1 if the pixel format does
  * not have a green component.
  */
 static const int tjGreenOffset[TJ_NUMPF] = {
   1, 1, 1, 1, 2, 2, -1, 1, 1, 2, 2, -1
 };
 /**
  * Blue offset (in samples) for a given pixel format.  This specifies the
  * number of samples that the blue component is offset from the start of the
  * pixel.  For instance, if an 8-bit-per-component pixel of format TJPF_BGRX is
  * stored in `unsigned char pixel[]`, then the blue component will be
  * `pixel[tjBlueOffset[TJPF_BGRX]]`.  This will be -1 if the pixel format does
  * not have a blue component.
  */
 static const int tjBlueOffset[TJ_NUMPF] = {
   2, 0, 2, 0, 1, 3, -1, 2, 0, 1, 3, -1
 };
 /**
  * Alpha offset (in samples) for a given pixel format.  This specifies the
  * number of samples that the alpha component is offset from the start of the
  * pixel.  For instance, if an 8-bit-per-component pixel of format TJPF_BGRA is
  * stored in `unsigned char pixel[]`, then the alpha component will be
  * `pixel[tjAlphaOffset[TJPF_BGRA]]`.  This will be -1 if the pixel format does
  * not have an alpha component.
  */
 static const int tjAlphaOffset[TJ_NUMPF] = {
   -1, -1, -1, -1, -1, -1, -1, 3, 3, 0, 0, -1
 };
 /**
  * Pixel size (in samples) for a given pixel format
  */
 static const int tjPixelSize[TJ_NUMPF] = {
   3, 3, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4
 };
 
 
 /**
  * The number of JPEG colorspaces
  */
 #define TJ_NUMCS  5
 
 /**
  * JPEG colorspaces
  */
 enum TJCS {
   /**
    * RGB colorspace.  When compressing the JPEG image, the R, G, and B
    * components in the source image are reordered into image planes, but no
    * colorspace conversion or subsampling is performed.  RGB JPEG images can be
    * compressed from and decompressed to packed-pixel images with any of the
    * extended RGB or grayscale pixel formats, but they cannot be compressed
    * from or decompressed to planar YUV images.
    */
   TJCS_RGB,
   /**
    * YCbCr colorspace.  YCbCr is not an absolute colorspace but rather a
    * mathematical transformation of RGB designed solely for storage and
    * transmission.  YCbCr images must be converted to RGB before they can
    * actually be displayed.  In the YCbCr colorspace, the Y (luminance)
    * component represents the black & white portion of the original image, and
    * the Cb and Cr (chrominance) components represent the color portion of the
    * original image.  Originally, the analog equivalent of this transformation
    * allowed the same signal to drive both black & white and color televisions,
    * but JPEG images use YCbCr primarily because it allows the color data to be
    * optionally subsampled for the purposes of reducing network or disk usage.
    * YCbCr is the most common JPEG colorspace, and YCbCr JPEG images can be
    * compressed from and decompressed to packed-pixel images with any of the
    * extended RGB or grayscale pixel formats.  YCbCr JPEG images can also be
    * compressed from and decompressed to planar YUV images.
    */
   TJCS_YCbCr,
   /**
    * Grayscale colorspace.  The JPEG image retains only the luminance data (Y
    * component), and any color data from the source image is discarded.
    * Grayscale JPEG images can be compressed from and decompressed to
    * packed-pixel images with any of the extended RGB or grayscale pixel
    * formats, or they can be compressed from and decompressed to planar YUV
    * images.
    */
   TJCS_GRAY,
   /**
    * CMYK colorspace.  When compressing the JPEG image, the C, M, Y, and K
    * components in the source image are reordered into image planes, but no
    * colorspace conversion or subsampling is performed.  CMYK JPEG images can
    * only be compressed from and decompressed to packed-pixel images with the
    * CMYK pixel format.
    */
   TJCS_CMYK,
   /**
    * YCCK colorspace.  YCCK (AKA "YCbCrK") is not an absolute colorspace but
    * rather a mathematical transformation of CMYK designed solely for storage
    * and transmission.  It is to CMYK as YCbCr is to RGB.  CMYK pixels can be
    * reversibly transformed into YCCK, and as with YCbCr, the chrominance
    * components in the YCCK pixels can be subsampled without incurring major
    * perceptual loss.  YCCK JPEG images can only be compressed from and
    * decompressed to packed-pixel images with the CMYK pixel format.
    */
   TJCS_YCCK
 };
 
 
 /**
  * Parameters
  */
 enum TJPARAM {
   /**
    * Error handling behavior
    *
    * **Value**
    * - `0` *[default]* Allow the current compression/decompression/transform
    * operation to complete unless a fatal error is encountered.
    * - `1` Immediately discontinue the current
    * compression/decompression/transform operation if a warning (non-fatal
    * error) occurs.
    */
   TJPARAM_STOPONWARNING,
   /**
    * Row order in packed-pixel source/destination images
    *
    * **Value**
    * - `0` *[default]* top-down (X11) order
    * - `1` bottom-up (Windows, OpenGL) order
    */
   TJPARAM_BOTTOMUP,
   /**
    * JPEG destination buffer (re)allocation [compression, lossless
    * transformation]
    *
    * **Value**
    * - `0` *[default]* Attempt to allocate or reallocate the JPEG destination
    * buffer as needed.
    * - `1` Generate an error if the JPEG destination buffer is invalid or too
    * small.
    */
   TJPARAM_NOREALLOC,
   /**
    * Perceptual quality of lossy JPEG images [compression only]
    *
    * **Value**
    * - `1`-`100` (`1` = worst quality but best compression, `100` = best
    * quality but worst compression) *[no default; must be explicitly
    * specified]*
    */
   TJPARAM_QUALITY,
   /**
    * Chrominance subsampling level
    *
    * The JPEG or YUV image uses (decompression, decoding) or will use (lossy
    * compression, encoding) the specified level of chrominance subsampling.
    *
    * **Value**
    * - One of the @ref TJSAMP "chrominance subsampling options" *[no default;
    * must be explicitly specified for lossy compression, encoding, and
    * decoding]*
    */
   TJPARAM_SUBSAMP,
   /**
    * JPEG width (in pixels) [decompression only, read-only]
    */
   TJPARAM_JPEGWIDTH,
   /**
    * JPEG height (in pixels) [decompression only, read-only]
    */
   TJPARAM_JPEGHEIGHT,
   /**
    * JPEG data precision (bits per sample) [decompression only, read-only]
    *
    * The JPEG image uses the specified number of bits per sample.
    *
    * **Value**
    * - `8`, `12`, or `16`
    *
    * 12-bit data precision implies #TJPARAM_OPTIMIZE unless #TJPARAM_ARITHMETIC
    * is set.
    */
   TJPARAM_PRECISION,
   /**
    * JPEG colorspace
    *
    * The JPEG image uses (decompression) or will use (lossy compression) the
    * specified colorspace.
    *
    * **Value**
    * - One of the @ref TJCS "JPEG colorspaces" *[default for lossy compression:
    * automatically selected based on the subsampling level and pixel format]*
    */
   TJPARAM_COLORSPACE,
   /**
    * Chrominance upsampling algorithm [lossy decompression only]
    *
    * **Value**
    * - `0` *[default]* Use smooth upsampling when decompressing a JPEG image
    * that was compressed using chrominance subsampling.  This creates a smooth
    * transition between neighboring chrominance components in order to reduce
    * upsampling artifacts in the decompressed image.
    * - `1` Use the fastest chrominance upsampling algorithm available, which
    * may combine upsampling with color conversion.
    */
   TJPARAM_FASTUPSAMPLE,
   /**
    * DCT/IDCT algorithm [lossy compression and decompression]
    *
    * **Value**
    * - `0` *[default]* Use the most accurate DCT/IDCT algorithm available.
    * - `1` Use the fastest DCT/IDCT algorithm available.
    *
    * This parameter is provided mainly for backward compatibility with libjpeg,
    * which historically implemented several different DCT/IDCT algorithms
    * because of performance limitations with 1990s CPUs.  In the libjpeg-turbo
    * implementation of the TurboJPEG API:
    * - The "fast" and "accurate" DCT/IDCT algorithms perform similarly on
    * modern x86/x86-64 CPUs that support AVX2 instructions.
    * - The "fast" algorithm is generally only about 5-15% faster than the
    * "accurate" algorithm on other types of CPUs.
    * - The difference in accuracy between the "fast" and "accurate" algorithms
    * is the most pronounced at JPEG quality levels above 90 and tends to be
    * more pronounced with decompression than with compression.
    * - The "fast" algorithm degrades and is not fully accelerated for JPEG
    * quality levels above 97, so it will be slower than the "accurate"
    * algorithm.
    */
   TJPARAM_FASTDCT,
   /**
    * Optimized baseline entropy coding [lossy compression only]
    *
    * **Value**
    * - `0` *[default]* The JPEG image will use the default Huffman tables.
    * - `1` Optimal Huffman tables will be computed for the JPEG image.  For
    * lossless transformation, this can also be specified using
    * #TJXOPT_OPTIMIZE.
    *
    * Optimized baseline entropy coding will improve compression slightly
    * (generally 5% or less), but it will reduce compression performance
    * considerably.
    */
   TJPARAM_OPTIMIZE,
   /**
    * Progressive entropy coding
    *
    * **Value**
    * - `0` *[default for compression, lossless transformation]* The lossy JPEG
    * image uses (decompression) or will use (compression, lossless
    * transformation) baseline entropy coding.
    * - `1` The lossy JPEG image uses (decompression) or will use (compression,
    * lossless transformation) progressive entropy coding.  For lossless
    * transformation, this can also be specified using #TJXOPT_PROGRESSIVE.
    *
    * Progressive entropy coding will generally improve compression relative to
    * baseline entropy coding, but it will reduce compression and decompression
    * performance considerably.  Can be combined with #TJPARAM_ARITHMETIC.
    * Implies #TJPARAM_OPTIMIZE unless #TJPARAM_ARITHMETIC is also set.
    */
   TJPARAM_PROGRESSIVE,
   /**
    * Progressive JPEG scan limit for lossy JPEG images [decompression, lossless
    * transformation]
    *
    * Setting this parameter will cause the decompression and transform
    * functions to return an error if the number of scans in a progressive JPEG
    * image exceeds the specified limit.  The primary purpose of this is to
    * allow security-critical applications to guard against an exploit of the
    * progressive JPEG format described in
    * <a href="https://libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf" target="_blank">this report</a>.
    *
    * **Value**
    * - maximum number of progressive JPEG scans that the decompression and
    * transform functions will process *[default: `0` (no limit)]*
    *
    * @see #TJPARAM_PROGRESSIVE
    */
   TJPARAM_SCANLIMIT,
   /**
    * Arithmetic entropy coding
    *
    * **Value**
    * - `0` *[default for compression, lossless transformation]* The lossy JPEG
    * image uses (decompression) or will use (compression, lossless
    * transformation) Huffman entropy coding.
    * - `1` The lossy JPEG image uses (decompression) or will use (compression,
    * lossless transformation) arithmetic entropy coding.  For lossless
    * transformation, this can also be specified using #TJXOPT_ARITHMETIC.
    *
    * Arithmetic entropy coding will generally improve compression relative to
    * Huffman entropy coding, but it will reduce compression and decompression
    * performance considerably.  Can be combined with #TJPARAM_PROGRESSIVE.
    */
   TJPARAM_ARITHMETIC,
   /**
    * Lossless JPEG
    *
    * **Value**
    * - `0` *[default for compression]* The JPEG image is (decompression) or
    * will be (compression) lossy/DCT-based.
    * - `1` The JPEG image is (decompression) or will be (compression)
    * lossless/predictive.
    *
    * In most cases, compressing and decompressing lossless JPEG images is
    * considerably slower than compressing and decompressing lossy JPEG images,
    * and lossless JPEG images are much larger than lossy JPEG images.  Thus,
    * lossless JPEG images are typically used only for applications that require
    * mathematically lossless compression.  Also note that the following
    * features are not available with lossless JPEG images:
    * - Colorspace conversion (lossless JPEG images always use #TJCS_RGB,
    * #TJCS_GRAY, or #TJCS_CMYK, depending on the pixel format of the source
    * image)
    * - Chrominance subsampling (lossless JPEG images always use #TJSAMP_444)
    * - JPEG quality selection
    * - DCT/IDCT algorithm selection
    * - Progressive entropy coding
    * - Arithmetic entropy coding
    * - Compression from/decompression to planar YUV images
    * - Decompression scaling
    * - Lossless transformation
    *
    * @see #TJPARAM_LOSSLESSPSV, #TJPARAM_LOSSLESSPT
    */
   TJPARAM_LOSSLESS,
   /**
    * Lossless JPEG predictor selection value (PSV)
    *
    * **Value**
    * - `1`-`7` *[default for compression: `1`]*
    *
    * Lossless JPEG compression shares no algorithms with lossy JPEG
    * compression.  Instead, it uses differential pulse-code modulation (DPCM),
    * an algorithm whereby each sample is encoded as the difference between the
    * sample's value and a "predictor", which is based on the values of
    * neighboring samples.  If Ra is the sample immediately to the left of the
    * current sample, Rb is the sample immediately above the current sample, and
    * Rc is the sample diagonally to the left and above the current sample, then
    * the relationship between the predictor selection value and the predictor
    * is as follows:
    *
    * PSV | Predictor
    * ----|----------
    * 1   | Ra
    * 2   | Rb
    * 3   | Rc
    * 4   | Ra + Rb – Rc
    * 5   | Ra + (Rb – Rc) / 2
    * 6   | Rb + (Ra – Rc) / 2
    * 7   | (Ra + Rb) / 2
    *
    * Predictors 1-3 are 1-dimensional predictors, whereas Predictors 4-7 are
    * 2-dimensional predictors.  The best predictor for a particular image
    * depends on the image.
    *
    * @see #TJPARAM_LOSSLESS
    */
   TJPARAM_LOSSLESSPSV,
   /**
    * Lossless JPEG point transform (Pt)
    *
    * **Value**
    * - `0` through ***precision*** *- 1*, where ***precision*** is the JPEG
    * data precision in bits *[default for compression: `0`]*
    *
    * A point transform value of `0` is necessary in order to generate a fully
    * lossless JPEG image.  (A non-zero point transform value right-shifts the
    * input samples by the specified number of bits, which is effectively a form
    * of lossy color quantization.)
    *
    * @see #TJPARAM_LOSSLESS, #TJPARAM_PRECISION
    */
   TJPARAM_LOSSLESSPT,
   /**
    * JPEG restart marker interval in MCU blocks (lossy) or samples (lossless)
    * [compression only]
    *
    * The nature of entropy coding is such that a corrupt JPEG image cannot
    * be decompressed beyond the point of corruption unless it contains restart
    * markers.  A restart marker stops and restarts the entropy coding algorithm
    * so that, if a JPEG image is corrupted, decompression can resume at the
    * next marker.  Thus, adding more restart markers improves the fault
    * tolerance of the JPEG image, but adding too many restart markers can
    * adversely affect the compression ratio and performance.
    *
    * **Value**
    * - the number of MCU blocks or samples between each restart marker
    * *[default: `0` (no restart markers)]*
    *
    * Setting this parameter to a non-zero value sets #TJPARAM_RESTARTROWS to 0.
    */
   TJPARAM_RESTARTBLOCKS,
   /**
    * JPEG restart marker interval in MCU rows (lossy) or sample rows (lossless)
    * [compression only]
    *
    * See #TJPARAM_RESTARTBLOCKS for a description of restart markers.
    *
    * **Value**
    * - the number of MCU rows or sample rows between each restart marker
    * *[default: `0` (no restart markers)]*
    *
    * Setting this parameter to a non-zero value sets #TJPARAM_RESTARTBLOCKS to
    * 0.
    */
   TJPARAM_RESTARTROWS,
   /**
    * JPEG horizontal pixel density
    *
    * **Value**
    * - The JPEG image has (decompression) or will have (compression) the
    * specified horizontal pixel density *[default for compression: `1`]*.
    *
    * This value is stored in or read from the JPEG header.  It does not affect
    * the contents of the JPEG image.  Note that this parameter is set by
    * #tj3LoadImage8() when loading a Windows BMP file that contains pixel
    * density information, and the value of this parameter is stored to a
    * Windows BMP file by #tj3SaveImage8() if the value of #TJPARAM_DENSITYUNITS
    * is `2`.
    *
    * @see TJPARAM_DENSITYUNITS
    */
   TJPARAM_XDENSITY,
   /**
    * JPEG vertical pixel density
    *
    * **Value**
    * - The JPEG image has (decompression) or will have (compression) the
    * specified vertical pixel density *[default for compression: `1`]*.
    *
    * This value is stored in or read from the JPEG header.  It does not affect
    * the contents of the JPEG image.  Note that this parameter is set by
    * #tj3LoadImage8() when loading a Windows BMP file that contains pixel
    * density information, and the value of this parameter is stored to a
    * Windows BMP file by #tj3SaveImage8() if the value of #TJPARAM_DENSITYUNITS
    * is `2`.
    *
    * @see TJPARAM_DENSITYUNITS
    */
   TJPARAM_YDENSITY,
   /**
    * JPEG pixel density units
    *
    * **Value**
    * - `0` *[default for compression]* The pixel density of the JPEG image is
    * expressed (decompression) or will be expressed (compression) in unknown
    * units.
    * - `1` The pixel density of the JPEG image is expressed (decompression) or
    * will be expressed (compression) in units of pixels/inch.
    * - `2` The pixel density of the JPEG image is expressed (decompression) or
    * will be expressed (compression) in units of pixels/cm.
    *
    * This value is stored in or read from the JPEG header.  It does not affect
    * the contents of the JPEG image.  Note that this parameter is set by
    * #tj3LoadImage8() when loading a Windows BMP file that contains pixel
    * density information, and the value of this parameter is stored to a
    * Windows BMP file by #tj3SaveImage8() if the value is `2`.
    *
    * @see TJPARAM_XDENSITY, TJPARAM_YDENSITY
    */
   TJPARAM_DENSITYUNITS,
   /**
    * Memory limit for intermediate buffers
    *
    * **Value**
    * - the maximum amount of memory (in megabytes) that will be allocated for
    * intermediate buffers, which are used with progressive JPEG compression and
    * decompression, optimized baseline entropy coding, lossless JPEG
    * compression, and lossless transformation *[default: `0` (no limit)]*
    */
   TJPARAM_MAXMEMORY,
   /**
    * Image size limit [decompression, lossless transformation, packed-pixel
    * image loading]
    *
    * Setting this parameter will cause the decompression, transform, and image
    * loading functions to return an error if the number of pixels in the source
    * image exceeds the specified limit.  This allows security-critical
    * applications to guard against excessive memory consumption.
    *
    * **Value**
    * - maximum number of pixels that the decompression, transform, and image
    * loading functions will process *[default: `0` (no limit)]*
    */
   TJPARAM_MAXPIXELS
 };
 
 
 /**
  * The number of error codes
  */
 #define TJ_NUMERR  2
 
 /**
  * Error codes
  */
 enum TJERR {
   /**
    * The error was non-fatal and recoverable, but the destination image may
    * still be corrupt.
    */
   TJERR_WARNING,
   /**
    * The error was fatal and non-recoverable.
    */
   TJERR_FATAL
 };
 
 
 /**
  * The number of transform operations
  */
 #define TJ_NUMXOP  8
 
 /**
  * Transform operations for #tj3Transform()
  */
 enum TJXOP {
   /**
    * Do not transform the position of the image pixels
    */
   TJXOP_NONE,
   /**
    * Flip (mirror) image horizontally.  This transform is imperfect if there
    * are any partial MCU blocks on the right edge (see #TJXOPT_PERFECT.)
    */
   TJXOP_HFLIP,
   /**
    * Flip (mirror) image vertically.  This transform is imperfect if there are
    * any partial MCU blocks on the bottom edge (see #TJXOPT_PERFECT.)
    */
   TJXOP_VFLIP,
   /**
    * Transpose image (flip/mirror along upper left to lower right axis.)  This
    * transform is always perfect.
    */
   TJXOP_TRANSPOSE,
   /**
    * Transverse transpose image (flip/mirror along upper right to lower left
    * axis.)  This transform is imperfect if there are any partial MCU blocks in
    * the image (see #TJXOPT_PERFECT.)
    */
   TJXOP_TRANSVERSE,
   /**
    * Rotate image clockwise by 90 degrees.  This transform is imperfect if
    * there are any partial MCU blocks on the bottom edge (see
    * #TJXOPT_PERFECT.)
    */
   TJXOP_ROT90,
   /**
    * Rotate image 180 degrees.  This transform is imperfect if there are any
    * partial MCU blocks in the image (see #TJXOPT_PERFECT.)
    */
   TJXOP_ROT180,
   /**
    * Rotate image counter-clockwise by 90 degrees.  This transform is imperfect
    * if there are any partial MCU blocks on the right edge (see
    * #TJXOPT_PERFECT.)
    */
   TJXOP_ROT270
 };
 
 
 /**
  * This option will cause #tj3Transform() to return an error if the transform
  * is not perfect.  Lossless transforms operate on MCU blocks, whose size
  * depends on the level of chrominance subsampling used (see #tjMCUWidth and
  * #tjMCUHeight.)  If the image's width or height is not evenly divisible by
  * the MCU block size, then there will be partial MCU blocks on the right
  * and/or bottom edges.  It is not possible to move these partial MCU blocks to
  * the top or left of the image, so any transform that would require that is
  * "imperfect."  If this option is not specified, then any partial MCU blocks
  * that cannot be transformed will be left in place, which will create
  * odd-looking strips on the right or bottom edge of the image.
  */
 #define TJXOPT_PERFECT  (1 << 0)
 /**
  * This option will cause #tj3Transform() to discard any partial MCU blocks
  * that cannot be transformed.
  */
 #define TJXOPT_TRIM  (1 << 1)
 /**
  * This option will enable lossless cropping.  See #tj3Transform() for more
  * information.
  */
 #define TJXOPT_CROP  (1 << 2)
 /**
  * This option will discard the color data in the source image and produce a
  * grayscale destination image.
  */
 #define TJXOPT_GRAY  (1 << 3)
 /**
  * This option will prevent #tj3Transform() from outputting a JPEG image for
  * this particular transform.  (This can be used in conjunction with a custom
  * filter to capture the transformed DCT coefficients without transcoding
  * them.)
  */
 #define TJXOPT_NOOUTPUT  (1 << 4)
 /**
  * This option will enable progressive entropy coding in the JPEG image
  * generated by this particular transform.  Progressive entropy coding will
  * generally improve compression relative to baseline entropy coding (the
  * default), but it will reduce decompression performance considerably.
  * Can be combined with #TJXOPT_ARITHMETIC.  Implies #TJXOPT_OPTIMIZE unless
  * #TJXOPT_ARITHMETIC is also specified.
  */
 #define TJXOPT_PROGRESSIVE  (1 << 5)
 /**
  * This option will prevent #tj3Transform() from copying any extra markers
  * (including EXIF and ICC profile data) from the source image to the
  * destination image.
  */
 #define TJXOPT_COPYNONE  (1 << 6)
 /**
  * This option will enable arithmetic entropy coding in the JPEG image
  * generated by this particular transform.  Arithmetic entropy coding will
  * generally improve compression relative to Huffman entropy coding (the
  * default), but it will reduce decompression performance considerably.  Can be
  * combined with #TJXOPT_PROGRESSIVE.
  */
 #define TJXOPT_ARITHMETIC  (1 << 7)
 /**
  * This option will enable optimized baseline entropy coding in the JPEG image
  * generated by this particular transform.  Optimized baseline entropy coding
  * will improve compression slightly (generally 5% or less.)
  */
 #define TJXOPT_OPTIMIZE  (1 << 8)
 
 
 /**
  * Scaling factor
  */
 typedef struct {
   /**
    * Numerator
    */
   int num;
   /**
    * Denominator
    */
   int denom;
 } tjscalingfactor;
 
 /**
  * Cropping region
  */
 typedef struct {
   /**
    * The left boundary of the cropping region.  This must be evenly divisible
    * by the MCU block width (see #tjMCUWidth.)
    */
   int x;
   /**
    * The upper boundary of the cropping region.  For lossless transformation,
    * this must be evenly divisible by the MCU block height (see #tjMCUHeight.)
    */
   int y;
   /**
    * The width of the cropping region.  Setting this to 0 is the equivalent of
    * setting it to the width of the source JPEG image - x.
    */
   int w;
   /**
    * The height of the cropping region.  Setting this to 0 is the equivalent of
    * setting it to the height of the source JPEG image - y.
    */
   int h;
 } tjregion;
 
 /**
  * A #tjregion structure that specifies no cropping
  */
 static const tjregion TJUNCROPPED = { 0, 0, 0, 0 };
 
 /**
  * Lossless transform
  */
 typedef struct tjtransform {
   /**
    * Cropping region
    */
   tjregion r;
   /**
    * One of the @ref TJXOP "transform operations"
    */
   int op;
   /**
    * The bitwise OR of one of more of the @ref TJXOPT_ARITHMETIC
    * "transform options"
    */
   int options;
   /**
    * Arbitrary data that can be accessed within the body of the callback
    * function
    */
   void *data;
   /**
    * A callback function that can be used to modify the DCT coefficients after
    * they are losslessly transformed but before they are transcoded to a new
    * JPEG image.  This allows for custom filters or other transformations to be
    * applied in the frequency domain.
    *
    * @param coeffs pointer to an array of transformed DCT coefficients.  (NOTE:
    * this pointer is not guaranteed to be valid once the callback returns, so
    * applications wishing to hand off the DCT coefficients to another function
    * or library should make a copy of them within the body of the callback.)
    *
    * @param arrayRegion #tjregion structure containing the width and height of
    * the array pointed to by `coeffs` as well as its offset relative to the
    * component plane.  TurboJPEG implementations may choose to split each
    * component plane into multiple DCT coefficient arrays and call the callback
    * function once for each array.
    *
    * @param planeRegion #tjregion structure containing the width and height of
    * the component plane to which `coeffs` belongs
    *
    * @param componentID ID number of the component plane to which `coeffs`
    * belongs.  (Y, Cb, and Cr have, respectively, ID's of 0, 1, and 2 in
    * typical JPEG images.)
    *
    * @param transformID ID number of the transformed image to which `coeffs`
    * belongs.  This is the same as the index of the transform in the
    * `transforms` array that was passed to #tj3Transform().
    *
    * @param transform a pointer to a #tjtransform structure that specifies the
    * parameters and/or cropping region for this transform
    *
    * @return 0 if the callback was successful, or -1 if an error occurred.
    */
   int (*customFilter) (short *coeffs, tjregion arrayRegion,
                        tjregion planeRegion, int componentID, int transformID,
                        struct tjtransform *transform);
 } tjtransform;
 
 /**
  * TurboJPEG instance handle
  */
 typedef void *tjhandle;
 
 
 /**
  * Compute the scaled value of `dimension` using the given scaling factor.
  * This macro performs the integer equivalent of `ceil(dimension *
  * scalingFactor)`.
  */
 #define TJSCALED(dimension, scalingFactor) \
   (((dimension) * scalingFactor.num + scalingFactor.denom - 1) / \
    scalingFactor.denom)
 
 /**
  * A #tjscalingfactor structure that specifies a scaling factor of 1/1 (no
  * scaling)
  */
 static const tjscalingfactor TJUNSCALED = { 1, 1 };
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
 /**
  * Create a new TurboJPEG instance.
  *
  * @param initType one of the @ref TJINIT "initialization options"
  *
  * @return a handle to the newly-created instance, or NULL if an error occurred
  * (see #tj3GetErrorStr().)
  */
 DLLEXPORT tjhandle tj3Init(int initType);
 
 
 /**
  * Set the value of a parameter.
  *
  * @param handle handle to a TurboJPEG instance
  *
  * @param param one of the @ref TJPARAM "parameters"
  *
  * @param value value of the parameter (refer to @ref TJPARAM
  * "parameter documentation")
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr().)
  */
 DLLEXPORT int tj3Set(tjhandle handle, int param, int value);
 
 
 /**
  * Get the value of a parameter.
  *
  * @param handle handle to a TurboJPEG instance
  *
  * @param param one of the @ref TJPARAM "parameters"
  *
  * @return the value of the specified parameter, or -1 if the value is unknown.
  */
 DLLEXPORT int tj3Get(tjhandle handle, int param);
 
 
 /**
  * Compress an 8-bit-per-sample packed-pixel RGB, grayscale, or CMYK image into
  * an 8-bit-per-sample JPEG image.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * compression
  *
  * @param srcBuf pointer to a buffer containing a packed-pixel RGB, grayscale,
  * or CMYK source image to be compressed.  This buffer should normally be
  * `pitch * height` samples in size.  However, you can also use this parameter
  * to compress from a specific region of a larger buffer.
  *
  * @param width width (in pixels) of the source image
  *
  * @param pitch samples per row in the source image.  Normally this should be
  * <tt>width * #tjPixelSize[pixelFormat]</tt>, if the image is unpadded.
  * (Setting this parameter to 0 is the equivalent of setting it to
  * <tt>width * #tjPixelSize[pixelFormat]</tt>.)  However, you can also use this
  * parameter to specify the row alignment/padding of the source image, to skip
  * rows, or to compress from a specific region of a larger buffer.
  *
  * @param height height (in pixels) of the source image
  *
  * @param pixelFormat pixel format of the source image (see @ref TJPF
  * "Pixel formats".)
  *
  * @param jpegBuf address of a pointer to a byte buffer that will receive the
  * JPEG image.  TurboJPEG has the ability to reallocate the JPEG buffer to
  * accommodate the size of the JPEG image.  Thus, you can choose to:
  * -# pre-allocate the JPEG buffer with an arbitrary size using #tj3Alloc() and
  * let TurboJPEG grow the buffer as needed,
  * -# set `*jpegBuf` to NULL to tell TurboJPEG to allocate the buffer for you,
  * or
  * -# pre-allocate the buffer to a "worst case" size determined by calling
  * #tj3JPEGBufSize().  This should ensure that the buffer never has to be
  * re-allocated.  (Setting #TJPARAM_NOREALLOC guarantees that it won't be.)
  * .
  * If you choose option 1, then `*jpegSize` should be set to the size of your
  * pre-allocated buffer.  In any case, unless you have set #TJPARAM_NOREALLOC,
  * you should always check `*jpegBuf` upon return from this function, as it may
  * have changed.
  *
  * @param jpegSize pointer to a size_t variable that holds the size of the JPEG
  * buffer.  If `*jpegBuf` points to a pre-allocated buffer, then `*jpegSize`
  * should be set to the size of the buffer.  Upon return, `*jpegSize` will
  * contain the size of the JPEG image (in bytes.)  If `*jpegBuf` points to a
  * JPEG buffer that is being reused from a previous call to one of the JPEG
  * compression functions, then `*jpegSize` is ignored.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3Compress8(tjhandle handle, const unsigned char *srcBuf,
                            int width, int pitch, int height, int pixelFormat,
                            unsigned char **jpegBuf, size_t *jpegSize);
 
 /**
  * Compress a 12-bit-per-sample packed-pixel RGB, grayscale, or CMYK image into
  * a 12-bit-per-sample JPEG image.
  *
  * \details \copydetails tj3Compress8()
  */
 DLLEXPORT int tj3Compress12(tjhandle handle, const short *srcBuf, int width,
                             int pitch, int height, int pixelFormat,
                             unsigned char **jpegBuf, size_t *jpegSize);
 
 /**
  * Compress a 16-bit-per-sample packed-pixel RGB, grayscale, or CMYK image into
  * a 16-bit-per-sample lossless JPEG image.
  *
  * \details \copydetails tj3Compress8()
  */
 DLLEXPORT int tj3Compress16(tjhandle handle, const unsigned short *srcBuf,
                             int width, int pitch, int height, int pixelFormat,
                             unsigned char **jpegBuf, size_t *jpegSize);
 
 
 /**
  * Compress an 8-bit-per-sample unified planar YUV image into an
  * 8-bit-per-sample JPEG image.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * compression
  *
  * @param srcBuf pointer to a buffer containing a unified planar YUV source
  * image to be compressed.  The size of this buffer should match the value
  * returned by #tj3YUVBufSize() for the given image width, height, row
  * alignment, and level of chrominance subsampling (see #TJPARAM_SUBSAMP.)  The
  * Y, U (Cb), and V (Cr) image planes should be stored sequentially in the
  * buffer.  (Refer to @ref YUVnotes "YUV Image Format Notes".)
  *
  * @param width width (in pixels) of the source image.  If the width is not an
  * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate
  * buffer copy will be performed.
  *
  * @param align row alignment (in bytes) of the source image (must be a power
  * of 2.)  Setting this parameter to n indicates that each row in each plane of
  * the source image is padded to the nearest multiple of n bytes
  * (1 = unpadded.)
  *
  * @param height height (in pixels) of the source image.  If the height is not
  * an even multiple of the MCU block height (see #tjMCUHeight), then an
  * intermediate buffer copy will be performed.
  *
  * @param jpegBuf address of a pointer to a byte buffer that will receive the
  * JPEG image.  TurboJPEG has the ability to reallocate the JPEG buffer to
  * accommodate the size of the JPEG image.  Thus, you can choose to:
  * -# pre-allocate the JPEG buffer with an arbitrary size using #tj3Alloc() and
  * let TurboJPEG grow the buffer as needed,
  * -# set `*jpegBuf` to NULL to tell TurboJPEG to allocate the buffer for you,
  * or
  * -# pre-allocate the buffer to a "worst case" size determined by calling
  * #tj3JPEGBufSize().  This should ensure that the buffer never has to be
  * re-allocated.  (Setting #TJPARAM_NOREALLOC guarantees that it won't be.)
  * .
  * If you choose option 1, then `*jpegSize` should be set to the size of your
  * pre-allocated buffer.  In any case, unless you have set #TJPARAM_NOREALLOC,
  * you should always check `*jpegBuf` upon return from this function, as it may
  * have changed.
  *
  * @param jpegSize pointer to a size_t variable that holds the size of the JPEG
  * buffer.  If `*jpegBuf` points to a pre-allocated buffer, then `*jpegSize`
  * should be set to the size of the buffer.  Upon return, `*jpegSize` will
  * contain the size of the JPEG image (in bytes.)  If `*jpegBuf` points to a
  * JPEG buffer that is being reused from a previous call to one of the JPEG
  * compression functions, then `*jpegSize` is ignored.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3CompressFromYUV8(tjhandle handle,
                                   const unsigned char *srcBuf, int width,
                                   int align, int height,
                                   unsigned char **jpegBuf, size_t *jpegSize);
 
 
 /**
  * Compress a set of 8-bit-per-sample Y, U (Cb), and V (Cr) image planes into
  * an 8-bit-per-sample JPEG image.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * compression
  *
  * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
  * (or just a Y plane, if compressing a grayscale image) that contain a YUV
  * source image to be compressed.  These planes can be contiguous or
  * non-contiguous in memory.  The size of each plane should match the value
  * returned by #tj3YUVPlaneSize() for the given image width, height, strides,
  * and level of chrominance subsampling (see #TJPARAM_SUBSAMP.)  Refer to
  * @ref YUVnotes "YUV Image Format Notes" for more details.
  *
  * @param width width (in pixels) of the source image.  If the width is not an
  * even multiple of the MCU block width (see #tjMCUWidth), then an intermediate
  * buffer copy will be performed.
  *
  * @param strides an array of integers, each specifying the number of bytes per
  * row in the corresponding plane of the YUV source image.  Setting the stride
  * for any plane to 0 is the same as setting it to the plane width (see
  * @ref YUVnotes "YUV Image Format Notes".)  If `strides` is NULL, then the
  * strides for all planes will be set to their respective plane widths.  You
  * can adjust the strides in order to specify an arbitrary amount of row
  * padding in each plane or to create a JPEG image from a subregion of a larger
  * planar YUV image.
  *
  * @param height height (in pixels) of the source image.  If the height is not
  * an even multiple of the MCU block height (see #tjMCUHeight), then an
  * intermediate buffer copy will be performed.
  *
  * @param jpegBuf address of a pointer to a byte buffer that will receive the
  * JPEG image.  TurboJPEG has the ability to reallocate the JPEG buffer to
  * accommodate the size of the JPEG image.  Thus, you can choose to:
  * -# pre-allocate the JPEG buffer with an arbitrary size using #tj3Alloc() and
  * let TurboJPEG grow the buffer as needed,
  * -# set `*jpegBuf` to NULL to tell TurboJPEG to allocate the buffer for you,
  * or
  * -# pre-allocate the buffer to a "worst case" size determined by calling
  * #tj3JPEGBufSize().  This should ensure that the buffer never has to be
  * re-allocated.  (Setting #TJPARAM_NOREALLOC guarantees that it won't be.)
  * .
  * If you choose option 1, then `*jpegSize` should be set to the size of your
  * pre-allocated buffer.  In any case, unless you have set #TJPARAM_NOREALLOC,
  * you should always check `*jpegBuf` upon return from this function, as it may
  * have changed.
  *
  * @param jpegSize pointer to a size_t variable that holds the size of the JPEG
  * buffer.  If `*jpegBuf` points to a pre-allocated buffer, then `*jpegSize`
  * should be set to the size of the buffer.  Upon return, `*jpegSize` will
  * contain the size of the JPEG image (in bytes.)  If `*jpegBuf` points to a
  * JPEG buffer that is being reused from a previous call to one of the JPEG
  * compression functions, then `*jpegSize` is ignored.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3CompressFromYUVPlanes8(tjhandle handle,
                                         const unsigned char * const *srcPlanes,
                                         int width, const int *strides,
                                         int height, unsigned char **jpegBuf,
                                         size_t *jpegSize);
 
 
 /**
  * The maximum size of the buffer (in bytes) required to hold a JPEG image with
  * the given parameters.  The number of bytes returned by this function is
  * larger than the size of the uncompressed source image.  The reason for this
  * is that the JPEG format uses 16-bit coefficients, so it is possible for a
  * very high-quality source image with very high-frequency content to expand
  * rather than compress when converted to the JPEG format.  Such images
  * represent very rare corner cases, but since there is no way to predict the
  * size of a JPEG image prior to compression, the corner cases have to be
  * handled.
  *
  * @param width width (in pixels) of the image
  *
  * @param height height (in pixels) of the image
  *
  * @param jpegSubsamp the level of chrominance subsampling to be used when
  * generating the JPEG image (see @ref TJSAMP
  * "Chrominance subsampling options".)  #TJSAMP_UNKNOWN is treated like
  * #TJSAMP_444, since a buffer large enough to hold a JPEG image with no
  * subsampling should also be large enough to hold a JPEG image with an
  * arbitrary level of subsampling.  Note that lossless JPEG images always
  * use #TJSAMP_444.
  *
  * @return the maximum size of the buffer (in bytes) required to hold the
  * image, or 0 if the arguments are out of bounds.
  */
 DLLEXPORT size_t tj3JPEGBufSize(int width, int height, int jpegSubsamp);
 
 
 /**
  * The size of the buffer (in bytes) required to hold a unified planar YUV
  * image with the given parameters.
  *
  * @param width width (in pixels) of the image
  *
  * @param align row alignment (in bytes) of the image (must be a power of 2.)
  * Setting this parameter to n specifies that each row in each plane of the
  * image will be padded to the nearest multiple of n bytes (1 = unpadded.)
  *
  * @param height height (in pixels) of the image
  *
  * @param subsamp level of chrominance subsampling in the image (see
  * @ref TJSAMP "Chrominance subsampling options".)
  *
  * @return the size of the buffer (in bytes) required to hold the image, or 0
  * if the arguments are out of bounds.
  */
 DLLEXPORT size_t tj3YUVBufSize(int width, int align, int height, int subsamp);
 
 
 /**
  * The size of the buffer (in bytes) required to hold a YUV image plane with
  * the given parameters.
  *
  * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
  *
  * @param width width (in pixels) of the YUV image.  NOTE: this is the width of
  * the whole image, not the plane width.
  *
  * @param stride bytes per row in the image plane.  Setting this to 0 is the
  * equivalent of setting it to the plane width.
  *
  * @param height height (in pixels) of the YUV image.  NOTE: this is the height
  * of the whole image, not the plane height.
  *
  * @param subsamp level of chrominance subsampling in the image (see
  * @ref TJSAMP "Chrominance subsampling options".)
  *
  * @return the size of the buffer (in bytes) required to hold the YUV image
  * plane, or 0 if the arguments are out of bounds.
  */
 DLLEXPORT size_t tj3YUVPlaneSize(int componentID, int width, int stride,
                                  int height, int subsamp);
 
 
 /**
  * The plane width of a YUV image plane with the given parameters.  Refer to
  * @ref YUVnotes "YUV Image Format Notes" for a description of plane width.
  *
  * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
  *
  * @param width width (in pixels) of the YUV image
  *
  * @param subsamp level of chrominance subsampling in the image (see
  * @ref TJSAMP "Chrominance subsampling options".)
  *
  * @return the plane width of a YUV image plane with the given parameters, or 0
  * if the arguments are out of bounds.
  */
 DLLEXPORT int tj3YUVPlaneWidth(int componentID, int width, int subsamp);
 
 
 /**
  * The plane height of a YUV image plane with the given parameters.  Refer to
  * @ref YUVnotes "YUV Image Format Notes" for a description of plane height.
  *
  * @param componentID ID number of the image plane (0 = Y, 1 = U/Cb, 2 = V/Cr)
  *
  * @param height height (in pixels) of the YUV image
  *
  * @param subsamp level of chrominance subsampling in the image (see
  * @ref TJSAMP "Chrominance subsampling options".)
  *
  * @return the plane height of a YUV image plane with the given parameters, or
  * 0 if the arguments are out of bounds.
  */
 DLLEXPORT int tj3YUVPlaneHeight(int componentID, int height, int subsamp);
 
 
 /**
  * Encode an 8-bit-per-sample packed-pixel RGB or grayscale image into an
  * 8-bit-per-sample unified planar YUV image.  This function performs color
  * conversion (which is accelerated in the libjpeg-turbo implementation) but
  * does not execute any of the other steps in the JPEG compression process.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * compression
  *
  * @param srcBuf pointer to a buffer containing a packed-pixel RGB or grayscale
  * source image to be encoded.  This buffer should normally be `pitch * height`
  * bytes in size.  However, you can also use this parameter to encode from a
  * specific region of a larger buffer.
  *
  * @param width width (in pixels) of the source image
  *
  * @param pitch bytes per row in the source image.  Normally this should be
  * <tt>width * #tjPixelSize[pixelFormat]</tt>, if the image is unpadded.
  * (Setting this parameter to 0 is the equivalent of setting it to
  * <tt>width * #tjPixelSize[pixelFormat]</tt>.)  However, you can also use this
  * parameter to specify the row alignment/padding of the source image, to skip
  * rows, or to encode from a specific region of a larger packed-pixel image.
  *
  * @param height height (in pixels) of the source image
  *
  * @param pixelFormat pixel format of the source image (see @ref TJPF
  * "Pixel formats".)
  *
  * @param dstBuf pointer to a buffer that will receive the unified planar YUV
  * image.  Use #tj3YUVBufSize() to determine the appropriate size for this
  * buffer based on the image width, height, row alignment, and level of
  * chrominance subsampling (see #TJPARAM_SUBSAMP.)  The Y, U (Cb), and V (Cr)
  * image planes will be stored sequentially in the buffer.  (Refer to
  * @ref YUVnotes "YUV Image Format Notes".)
  *
  * @param align row alignment (in bytes) of the YUV image (must be a power of
  * 2.)  Setting this parameter to n will cause each row in each plane of the
  * YUV image to be padded to the nearest multiple of n bytes (1 = unpadded.)
  * To generate images suitable for X Video, `align` should be set to 4.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3EncodeYUV8(tjhandle handle, const unsigned char *srcBuf,
                             int width, int pitch, int height, int pixelFormat,
                             unsigned char *dstBuf, int align);
 
 
 /**
  * Encode an 8-bit-per-sample packed-pixel RGB or grayscale image into separate
  * 8-bit-per-sample Y, U (Cb), and V (Cr) image planes.  This function performs
  * color conversion (which is accelerated in the libjpeg-turbo implementation)
  * but does not execute any of the other steps in the JPEG compression process.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * compression
  *
  * @param srcBuf pointer to a buffer containing a packed-pixel RGB or grayscale
  * source image to be encoded.  This buffer should normally be `pitch * height`
  * bytes in size.  However, you can also use this parameter to encode from a
  * specific region of a larger buffer.
  *
  *
  * @param width width (in pixels) of the source image
  *
  * @param pitch bytes per row in the source image.  Normally this should be
  * <tt>width * #tjPixelSize[pixelFormat]</tt>, if the image is unpadded.
  * (Setting this parameter to 0 is the equivalent of setting it to
  * <tt>width * #tjPixelSize[pixelFormat]</tt>.)  However, you can also use this
  * parameter to specify the row alignment/padding of the source image, to skip
  * rows, or to encode from a specific region of a larger packed-pixel image.
  *
  * @param height height (in pixels) of the source image
  *
  * @param pixelFormat pixel format of the source image (see @ref TJPF
  * "Pixel formats".)
  *
  * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
  * (or just a Y plane, if generating a grayscale image) that will receive the
  * encoded image.  These planes can be contiguous or non-contiguous in memory.
  * Use #tj3YUVPlaneSize() to determine the appropriate size for each plane
  * based on the image width, height, strides, and level of chrominance
  * subsampling (see #TJPARAM_SUBSAMP.)  Refer to @ref YUVnotes
  * "YUV Image Format Notes" for more details.
  *
  * @param strides an array of integers, each specifying the number of bytes per
  * row in the corresponding plane of the YUV image.  Setting the stride for any
  * plane to 0 is the same as setting it to the plane width (see @ref YUVnotes
  * "YUV Image Format Notes".)  If `strides` is NULL, then the strides for all
  * planes will be set to their respective plane widths.  You can adjust the
  * strides in order to add an arbitrary amount of row padding to each plane or
  * to encode an RGB or grayscale image into a subregion of a larger planar YUV
  * image.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3EncodeYUVPlanes8(tjhandle handle, const unsigned char *srcBuf,
                                   int width, int pitch, int height,
                                   int pixelFormat, unsigned char **dstPlanes,
                                   int *strides);
 
 
 /**
  * Retrieve information about a JPEG image without decompressing it, or prime
  * the decompressor with quantization and Huffman tables.  If a JPEG image is
  * passed to this function, then the @ref TJPARAM "parameters" that describe
  * the JPEG image will be set when the function returns.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param jpegBuf pointer to a byte buffer containing a JPEG image or an
  * "abbreviated table specification" (AKA "tables-only") datastream.  Passing a
  * tables-only datastream to this function primes the decompressor with
  * quantization and Huffman tables that can be used when decompressing
  * subsequent "abbreviated image" datastreams.  This is useful, for instance,
  * when decompressing video streams in which all frames share the same
  * quantization and Huffman tables.
  *
  * @param jpegSize size of the JPEG image or tables-only datastream (in bytes)
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3DecompressHeader(tjhandle handle,
                                   const unsigned char *jpegBuf,
                                   size_t jpegSize);
 
 
 /**
  * Returns a list of fractional scaling factors that the JPEG decompressor
  * supports.
  *
  * @param numScalingFactors pointer to an integer variable that will receive
  * the number of elements in the list
  *
  * @return a pointer to a list of fractional scaling factors, or NULL if an
  * error is encountered (see #tj3GetErrorStr().)
  */
 DLLEXPORT tjscalingfactor *tj3GetScalingFactors(int *numScalingFactors);
 
 
 /**
  * Set the scaling factor for subsequent lossy decompression operations.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param scalingFactor #tjscalingfactor structure that specifies a fractional
  * scaling factor that the decompressor supports (see #tj3GetScalingFactors()),
  * or <tt>#TJUNSCALED</tt> for no scaling.  Decompression scaling is a function
  * of the IDCT algorithm, so scaling factors are generally limited to multiples
  * of 1/8.  If the entire JPEG image will be decompressed, then the width and
  * height of the scaled destination image can be determined by calling
  * #TJSCALED() with the JPEG width and height (see #TJPARAM_JPEGWIDTH and
  * #TJPARAM_JPEGHEIGHT) and the specified scaling factor.  When decompressing
  * into a planar YUV image, an intermediate buffer copy will be performed if
  * the width or height of the scaled destination image is not an even multiple
  * of the MCU block size (see #tjMCUWidth and #tjMCUHeight.)  Note that
  * decompression scaling is not available (and the specified scaling factor is
  * ignored) when decompressing lossless JPEG images (see #TJPARAM_LOSSLESS),
  * since the IDCT algorithm is not used with those images.  Note also that
  * #TJPARAM_FASTDCT is ignored when decompression scaling is enabled.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr().)
  */
 DLLEXPORT int tj3SetScalingFactor(tjhandle handle,
                                   tjscalingfactor scalingFactor);
 
 
 /**
  * Set the cropping region for partially decompressing a lossy JPEG image into
  * a packed-pixel image
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param croppingRegion #tjregion structure that specifies a subregion of the
  * JPEG image to decompress, or <tt>#TJUNCROPPED</tt> for no cropping.  The
  * left boundary of the cropping region must be evenly divisible by the scaled
  * MCU block width (<tt>#TJSCALED(#tjMCUWidth[subsamp], scalingFactor)</tt>,
  * where `subsamp` is the level of chrominance subsampling in the JPEG image
  * (see #TJPARAM_SUBSAMP) and `scalingFactor` is the decompression scaling
  * factor (see #tj3SetScalingFactor().)  The cropping region should be
  * specified relative to the scaled image dimensions.  Unless `croppingRegion`
  * is <tt>#TJUNCROPPED</tt>, the JPEG header must be read (see
  * #tj3DecompressHeader()) prior to calling this function.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr().)
  */
 DLLEXPORT int tj3SetCroppingRegion(tjhandle handle, tjregion croppingRegion);
 
 
 /**
  * Decompress an 8-bit-per-sample JPEG image into an 8-bit-per-sample
  * packed-pixel RGB, grayscale, or CMYK image.  The @ref TJPARAM "parameters"
  * that describe the JPEG image will be set when this function returns.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param jpegBuf pointer to a byte buffer containing the JPEG image to
  * decompress
  *
  * @param jpegSize size of the JPEG image (in bytes)
  *
  * @param dstBuf pointer to a buffer that will receive the packed-pixel
  * decompressed image.  This buffer should normally be
  * `pitch * destinationHeight` samples in size.  However, you can also use this
  * parameter to decompress into a specific region of a larger buffer.  NOTE:
  * If the JPEG image is lossy, then `destinationHeight` is either the scaled
  * JPEG height (see #TJSCALED(), #TJPARAM_JPEGHEIGHT, and
  * #tj3SetScalingFactor()) or the height of the cropping region (see
  * #tj3SetCroppingRegion().)  If the JPEG image is lossless, then
  * `destinationHeight` is the JPEG height.
  *
  * @param pitch samples per row in the destination image.  Normally this should
  * be set to <tt>destinationWidth * #tjPixelSize[pixelFormat]</tt>, if the
  * destination image should be unpadded.  (Setting this parameter to 0 is the
  * equivalent of setting it to
  * <tt>destinationWidth * #tjPixelSize[pixelFormat]</tt>.)  However, you can
  * also use this parameter to specify the row alignment/padding of the
  * destination image, to skip rows, or to decompress into a specific region of
  * a larger buffer.  NOTE: If the JPEG image is lossy, then `destinationWidth`
  * is either the scaled JPEG width (see #TJSCALED(), #TJPARAM_JPEGWIDTH, and
  * #tj3SetScalingFactor()) or the width of the cropping region (see
  * #tj3SetCroppingRegion().)  If the JPEG image is lossless, then
  * `destinationWidth` is the JPEG width.
  *
  * @param pixelFormat pixel format of the destination image (see @ref
  * TJPF "Pixel formats".)
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3Decompress8(tjhandle handle, const unsigned char *jpegBuf,
                              size_t jpegSize, unsigned char *dstBuf, int pitch,
                              int pixelFormat);
 
 /**
  * Decompress a 12-bit-per-sample JPEG image into a 12-bit-per-sample
  * packed-pixel RGB, grayscale, or CMYK image.
  *
  * \details \copydetails tj3Decompress8()
  */
 DLLEXPORT int tj3Decompress12(tjhandle handle, const unsigned char *jpegBuf,
                               size_t jpegSize, short *dstBuf, int pitch,
                               int pixelFormat);
 
 /**
  * Decompress a 16-bit-per-sample lossless JPEG image into a 16-bit-per-sample
  * packed-pixel RGB, grayscale, or CMYK image.
  *
  * \details \copydetails tj3Decompress8()
  */
 DLLEXPORT int tj3Decompress16(tjhandle handle, const unsigned char *jpegBuf,
                               size_t jpegSize, unsigned short *dstBuf,
                               int pitch, int pixelFormat);
 
 
 /**
  * Decompress an 8-bit-per-sample JPEG image into an 8-bit-per-sample unified
  * planar YUV image.  This function performs JPEG decompression but leaves out
  * the color conversion step, so a planar YUV image is generated instead of a
  * packed-pixel image.  The @ref TJPARAM "parameters" that describe the JPEG
  * image will be set when this function returns.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param jpegBuf pointer to a byte buffer containing the JPEG image to
  * decompress
  *
  * @param jpegSize size of the JPEG image (in bytes)
  *
  * @param dstBuf pointer to a buffer that will receive the unified planar YUV
  * decompressed image.  Use #tj3YUVBufSize() to determine the appropriate size
  * for this buffer based on the scaled JPEG width and height (see #TJSCALED(),
  * #TJPARAM_JPEGWIDTH, #TJPARAM_JPEGHEIGHT, and #tj3SetScalingFactor()), row
  * alignment, and level of chrominance subsampling (see #TJPARAM_SUBSAMP.)  The
  * Y, U (Cb), and V (Cr) image planes will be stored sequentially in the
  * buffer.  (Refer to @ref YUVnotes "YUV Image Format Notes".)
  *
  * @param align row alignment (in bytes) of the YUV image (must be a power of
  * 2.)  Setting this parameter to n will cause each row in each plane of the
  * YUV image to be padded to the nearest multiple of n bytes (1 = unpadded.)
  * To generate images suitable for X Video, `align` should be set to 4.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3DecompressToYUV8(tjhandle handle,
                                   const unsigned char *jpegBuf,
                                   size_t jpegSize,
                                   unsigned char *dstBuf, int align);
 
 
 /**
  * Decompress an 8-bit-per-sample JPEG image into separate 8-bit-per-sample Y,
  * U (Cb), and V (Cr) image planes.  This function performs JPEG decompression
  * but leaves out the color conversion step, so a planar YUV image is generated
  * instead of a packed-pixel image.  The @ref TJPARAM "parameters" that
  * describe the JPEG image will be set when this function returns.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param jpegBuf pointer to a byte buffer containing the JPEG image to
  * decompress
  *
  * @param jpegSize size of the JPEG image (in bytes)
  *
  * @param dstPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
  * (or just a Y plane, if decompressing a grayscale image) that will receive
  * the decompressed image.  These planes can be contiguous or non-contiguous in
  * memory.  Use #tj3YUVPlaneSize() to determine the appropriate size for each
  * plane based on the scaled JPEG width and height (see #TJSCALED(),
  * #TJPARAM_JPEGWIDTH, #TJPARAM_JPEGHEIGHT, and #tj3SetScalingFactor()),
  * strides, and level of chrominance subsampling (see #TJPARAM_SUBSAMP.)  Refer
  * to @ref YUVnotes "YUV Image Format Notes" for more details.
  *
  * @param strides an array of integers, each specifying the number of bytes per
  * row in the corresponding plane of the YUV image.  Setting the stride for any
  * plane to 0 is the same as setting it to the scaled plane width (see
  * @ref YUVnotes "YUV Image Format Notes".)  If `strides` is NULL, then the
  * strides for all planes will be set to their respective scaled plane widths.
  * You can adjust the strides in order to add an arbitrary amount of row
  * padding to each plane or to decompress the JPEG image into a subregion of a
  * larger planar YUV image.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3DecompressToYUVPlanes8(tjhandle handle,
                                         const unsigned char *jpegBuf,
                                         size_t jpegSize,
                                         unsigned char **dstPlanes,
                                         int *strides);
 
 
 /**
  * Decode an 8-bit-per-sample unified planar YUV image into an 8-bit-per-sample
  * packed-pixel RGB or grayscale image.  This function performs color
  * conversion (which is accelerated in the libjpeg-turbo implementation) but
  * does not execute any of the other steps in the JPEG decompression process.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param srcBuf pointer to a buffer containing a unified planar YUV source
  * image to be decoded.  The size of this buffer should match the value
  * returned by #tj3YUVBufSize() for the given image width, height, row
  * alignment, and level of chrominance subsampling (see #TJPARAM_SUBSAMP.)  The
  * Y, U (Cb), and V (Cr) image planes should be stored sequentially in the
  * source buffer.  (Refer to @ref YUVnotes "YUV Image Format Notes".)
  *
  * @param align row alignment (in bytes) of the YUV source image (must be a
  * power of 2.)  Setting this parameter to n indicates that each row in each
  * plane of the YUV source image is padded to the nearest multiple of n bytes
  * (1 = unpadded.)
  *
  * @param dstBuf pointer to a buffer that will receive the packed-pixel decoded
  * image.  This buffer should normally be `pitch * height` bytes in size.
  * However, you can also use this parameter to decode into a specific region of
  * a larger buffer.
  *
  * @param width width (in pixels) of the source and destination images
  *
  * @param pitch bytes per row in the destination image.  Normally this should
  * be set to <tt>width * #tjPixelSize[pixelFormat]</tt>, if the destination
  * image should be unpadded.  (Setting this parameter to 0 is the equivalent of
  * setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>.)  However, you can
  * also use this parameter to specify the row alignment/padding of the
  * destination image, to skip rows, or to decode into a specific region of a
  * larger buffer.
  *
  * @param height height (in pixels) of the source and destination images
  *
  * @param pixelFormat pixel format of the destination image (see @ref TJPF
  * "Pixel formats".)
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3DecodeYUV8(tjhandle handle, const unsigned char *srcBuf,
                             int align, unsigned char *dstBuf, int width,
                             int pitch, int height, int pixelFormat);
 
 
 /**
  * Decode a set of 8-bit-per-sample Y, U (Cb), and V (Cr) image planes into an
  * 8-bit-per-sample packed-pixel RGB or grayscale image.  This function
  * performs color conversion (which is accelerated in the libjpeg-turbo
  * implementation) but does not execute any of the other steps in the JPEG
  * decompression process.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * decompression
  *
  * @param srcPlanes an array of pointers to Y, U (Cb), and V (Cr) image planes
  * (or just a Y plane, if decoding a grayscale image) that contain a YUV image
  * to be decoded.  These planes can be contiguous or non-contiguous in memory.
  * The size of each plane should match the value returned by #tj3YUVPlaneSize()
  * for the given image width, height, strides, and level of chrominance
  * subsampling (see #TJPARAM_SUBSAMP.)  Refer to @ref YUVnotes
  * "YUV Image Format Notes" for more details.
  *
  * @param strides an array of integers, each specifying the number of bytes per
  * row in the corresponding plane of the YUV source image.  Setting the stride
  * for any plane to 0 is the same as setting it to the plane width (see
  * @ref YUVnotes "YUV Image Format Notes".)  If `strides` is NULL, then the
  * strides for all planes will be set to their respective plane widths.  You
  * can adjust the strides in order to specify an arbitrary amount of row
  * padding in each plane or to decode a subregion of a larger planar YUV image.
  *
  * @param dstBuf pointer to a buffer that will receive the packed-pixel decoded
  * image.  This buffer should normally be `pitch * height` bytes in size.
  * However, you can also use this parameter to decode into a specific region of
  * a larger buffer.
  *
  * @param width width (in pixels) of the source and destination images
  *
  * @param pitch bytes per row in the destination image.  Normally this should
  * be set to <tt>width * #tjPixelSize[pixelFormat]</tt>, if the destination
  * image should be unpadded.  (Setting this parameter to 0 is the equivalent of
  * setting it to <tt>width * #tjPixelSize[pixelFormat]</tt>.)  However, you can
  * also use this parameter to specify the row alignment/padding of the
  * destination image, to skip rows, or to decode into a specific region of a
  * larger buffer.
  *
  * @param height height (in pixels) of the source and destination images
  *
  * @param pixelFormat pixel format of the destination image (see @ref TJPF
  * "Pixel formats".)
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3DecodeYUVPlanes8(tjhandle handle,
                                   const unsigned char * const *srcPlanes,
                                   const int *strides, unsigned char *dstBuf,
                                   int width, int pitch, int height,
                                   int pixelFormat);
 
 
 /**
  * Losslessly transform a JPEG image into another JPEG image.  Lossless
  * transforms work by moving the raw DCT coefficients from one JPEG image
  * structure to another without altering the values of the coefficients.  While
  * this is typically faster than decompressing the image, transforming it, and
  * re-compressing it, lossless transforms are not free.  Each lossless
  * transform requires reading and performing entropy decoding on all of the
  * coefficients in the source image, regardless of the size of the destination
  * image.  Thus, this function provides a means of generating multiple
  * transformed images from the same source or applying multiple transformations
  * simultaneously, in order to eliminate the need to read the source
  * coefficients multiple times.
  *
  * @param handle handle to a TurboJPEG instance that has been initialized for
  * lossless transformation
  *
  * @param jpegBuf pointer to a byte buffer containing the JPEG source image to
  * transform
  *
  * @param jpegSize size of the JPEG source image (in bytes)
  *
  * @param n the number of transformed JPEG images to generate
  *
  * @param dstBufs pointer to an array of n byte buffers.  `dstBufs[i]` will
  * receive a JPEG image that has been transformed using the parameters in
  * `transforms[i]`.  TurboJPEG has the ability to reallocate the JPEG
  * destination buffer to accommodate the size of the transformed JPEG image.
  * Thus, you can choose to:
  * -# pre-allocate the JPEG destination buffer with an arbitrary size using
  * #tj3Alloc() and let TurboJPEG grow the buffer as needed,
  * -# set `dstBufs[i]` to NULL to tell TurboJPEG to allocate the buffer for
  * you, or
  * -# pre-allocate the buffer to a "worst case" size determined by calling
  * #tj3JPEGBufSize() with the transformed or cropped width and height and the
  * level of subsampling used in the source image.  Under normal circumstances,
  * this should ensure that the buffer never has to be re-allocated.  (Setting
  * #TJPARAM_NOREALLOC guarantees that it won't be.)  Note, however, that there
  * are some rare cases (such as transforming images with a large amount of
  * embedded EXIF or ICC profile data) in which the transformed JPEG image will
  * be larger than the worst-case size, and #TJPARAM_NOREALLOC cannot be used in
  * those cases.
  * .
  * If you choose option 1, then `dstSizes[i]` should be set to the size of your
  * pre-allocated buffer.  In any case, unless you have set #TJPARAM_NOREALLOC,
  * you should always check `dstBufs[i]` upon return from this function, as it
  * may have changed.
  *
  * @param dstSizes pointer to an array of n size_t variables that will receive
  * the actual sizes (in bytes) of each transformed JPEG image.  If `dstBufs[i]`
  * points to a pre-allocated buffer, then `dstSizes[i]` should be set to the
  * size of the buffer.  Upon return, `dstSizes[i]` will contain the size of the
  * transformed JPEG image (in bytes.)
  *
  * @param transforms pointer to an array of n #tjtransform structures, each of
  * which specifies the transform parameters and/or cropping region for the
  * corresponding transformed JPEG image.
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr()
  * and #tj3GetErrorCode().)
  */
 DLLEXPORT int tj3Transform(tjhandle handle, const unsigned char *jpegBuf,
                            size_t jpegSize, int n, unsigned char **dstBufs,
                            size_t *dstSizes, const tjtransform *transforms);
 
 
 /**
  * Destroy a TurboJPEG instance.
  *
  * @param handle handle to a TurboJPEG instance.  If the handle is NULL, then
  * this function has no effect.
  */
 DLLEXPORT void tj3Destroy(tjhandle handle);
 
 
 /**
  * Allocate a byte buffer for use with TurboJPEG.  You should always use this
  * function to allocate the JPEG destination buffer(s) for the compression and
  * transform functions unless you are disabling automatic buffer (re)allocation
  * (by setting #TJPARAM_NOREALLOC.)
  *
  * @param bytes the number of bytes to allocate
  *
  * @return a pointer to a newly-allocated buffer with the specified number of
  * bytes.
  *
  * @see tj3Free()
  */
 DLLEXPORT void *tj3Alloc(size_t bytes);
 
 
 /**
  * Load an 8-bit-per-sample packed-pixel image from disk into memory.
  *
  * @param handle handle to a TurboJPEG instance
  *
  * @param filename name of a file containing a packed-pixel image in Windows
  * BMP or PBMPLUS (PPM/PGM) format.  Windows BMP files require 8-bit-per-sample
  * data precision.  If the data precision of the PBMPLUS file does not match
  * the target data precision, then upconverting or downconverting will be
  * performed.
  *
  * @param width pointer to an integer variable that will receive the width (in
  * pixels) of the packed-pixel image
  *
  * @param align row alignment (in samples) of the packed-pixel buffer to be
  * returned (must be a power of 2.)  Setting this parameter to n will cause all
  * rows in the buffer to be padded to the nearest multiple of n samples
  * (1 = unpadded.)
  *
  * @param height pointer to an integer variable that will receive the height
  * (in pixels) of the packed-pixel image
  *
  * @param pixelFormat pointer to an integer variable that specifies or will
  * receive the pixel format of the packed-pixel buffer.  The behavior of this
  * function will vary depending on the value of `*pixelFormat` passed to the
  * function:
  * - @ref TJPF_UNKNOWN : The packed-pixel buffer returned by this function will
  * use the most optimal pixel format for the file type, and `*pixelFormat` will
  * contain the ID of that pixel format upon successful return from this
  * function.
  * - @ref TJPF_GRAY : Only PGM files and 8-bit-per-pixel BMP files with a
  * grayscale colormap can be loaded.
  * - @ref TJPF_CMYK : The RGB or grayscale pixels stored in the file will be
  * converted using a quick & dirty algorithm that is suitable only for testing
  * purposes.  (Proper conversion between CMYK and other formats requires a
  * color management system.)
  * - Other @ref TJPF "pixel formats" : The packed-pixel buffer will use the
  * specified pixel format, and pixel format conversion will be performed if
  * necessary.
  *
  * @return a pointer to a newly-allocated buffer containing the packed-pixel
  * image, converted to the chosen pixel format and with the chosen row
  * alignment, or NULL if an error occurred (see #tj3GetErrorStr().)  This
  * buffer should be freed using #tj3Free().
  */
 DLLEXPORT unsigned char *tj3LoadImage8(tjhandle handle, const char *filename,
                                        int *width, int align, int *height,
                                        int *pixelFormat);
 
 /**
  * Load a 12-bit-per-sample packed-pixel image from disk into memory.
  *
  * \details \copydetails tj3LoadImage8()
  */
 DLLEXPORT short *tj3LoadImage12(tjhandle handle, const char *filename,
                                 int *width, int align, int *height,
                                 int *pixelFormat);
 
 /**
  * Load a 16-bit-per-sample packed-pixel image from disk into memory.
  *
  * \details \copydetails tj3LoadImage8()
  */
 DLLEXPORT unsigned short *tj3LoadImage16(tjhandle handle, const char *filename,
                                          int *width, int align, int *height,
                                          int *pixelFormat);
 
 
 /**
  * Save an 8-bit-per-sample packed-pixel image from memory to disk.
  *
  * @param handle handle to a TurboJPEG instance
  *
  * @param filename name of a file to which to save the packed-pixel image.  The
  * image will be stored in Windows BMP or PBMPLUS (PPM/PGM) format, depending
  * on the file extension.  Windows BMP files require 8-bit-per-sample data
  * precision.
  *
  * @param buffer pointer to a buffer containing a packed-pixel RGB, grayscale,
  * or CMYK image to be saved
  *
  * @param width width (in pixels) of the packed-pixel image
  *
  * @param pitch samples per row in the packed-pixel image.  Setting this
  * parameter to 0 is the equivalent of setting it to
  * <tt>width * #tjPixelSize[pixelFormat]</tt>.
  *
  * @param height height (in pixels) of the packed-pixel image
  *
  * @param pixelFormat pixel format of the packed-pixel image (see @ref TJPF
  * "Pixel formats".)  If this parameter is set to @ref TJPF_GRAY, then the
  * image will be stored in PGM or 8-bit-per-pixel (indexed color) BMP format.
  * Otherwise, the image will be stored in PPM or 24-bit-per-pixel BMP format.
  * If this parameter is set to @ref TJPF_CMYK, then the CMYK pixels will be
  * converted to RGB using a quick & dirty algorithm that is suitable only for
  * testing purposes.  (Proper conversion between CMYK and other formats
  * requires a color management system.)
  *
  * @return 0 if successful, or -1 if an error occurred (see #tj3GetErrorStr().)
  */
 DLLEXPORT int tj3SaveImage8(tjhandle handle, const char *filename,
                             const unsigned char *buffer, int width, int pitch,
                             int height, int pixelFormat);
 
 /**
  * Save a 12-bit-per-sample packed-pixel image from memory to disk.
  *
  * \details \copydetails tj3SaveImage8()
  */
 DLLEXPORT int tj3SaveImage12(tjhandle handle, const char *filename,
                              const short *buffer, int width, int pitch,
                              int height, int pixelFormat);
 
 /**
  * Save a 16-bit-per-sample packed-pixel image from memory to disk.
  *
  * \details \copydetails tj3SaveImage8()
  */
 DLLEXPORT int tj3SaveImage16(tjhandle handle, const char *filename,
                              const unsigned short *buffer, int width,
                              int pitch, int height, int pixelFormat);
 
 
 /**
  * Free a byte buffer previously allocated by TurboJPEG.  You should always use
  * this function to free JPEG destination buffer(s) that were automatically
  * (re)allocated by the compression and transform functions or that were
  * manually allocated using #tj3Alloc().
  *
  * @param buffer address of the buffer to free.  If the address is NULL, then
  * this function has no effect.
  *
  * @see tj3Alloc()
  */
 DLLEXPORT void tj3Free(void *buffer);
 
 
 /**
  * Returns a descriptive error message explaining why the last command failed.
  *
  * @param handle handle to a TurboJPEG instance, or NULL if the error was
  * generated by a global function (but note that retrieving the error message
  * for a global function is thread-safe only on platforms that support
  * thread-local storage.)
  *
  * @return a descriptive error message explaining why the last command failed.
  */
 DLLEXPORT char *tj3GetErrorStr(tjhandle handle);
 
 
 /**
  * Returns a code indicating the severity of the last error.  See
  * @ref TJERR "Error codes".
  *
  * @param handle handle to a TurboJPEG instance
  *
  * @return a code indicating the severity of the last error.  See
  * @ref TJERR "Error codes".
  */
 DLLEXPORT int tj3GetErrorCode(tjhandle handle);
 
 
 /* Backward compatibility functions and macros (nothing to see here) */
 
 /* TurboJPEG 1.0+ */
 
 #define NUMSUBOPT  TJ_NUMSAMP
 #define TJ_444  TJSAMP_444
 #define TJ_422  TJSAMP_422
 #define TJ_420  TJSAMP_420
 #define TJ_411  TJSAMP_420
 #define TJ_GRAYSCALE  TJSAMP_GRAY
 
 #define TJ_BGR  1
 #define TJ_BOTTOMUP  TJFLAG_BOTTOMUP
 #define TJ_FORCEMMX  TJFLAG_FORCEMMX
 #define TJ_FORCESSE  TJFLAG_FORCESSE
 #define TJ_FORCESSE2  TJFLAG_FORCESSE2
 #define TJ_ALPHAFIRST  64
 #define TJ_FORCESSE3  TJFLAG_FORCESSE3
 #define TJ_FASTUPSAMPLE  TJFLAG_FASTUPSAMPLE
 
 #define TJPAD(width)  (((width) + 3) & (~3))
 
 DLLEXPORT unsigned long TJBUFSIZE(int width, int height);
 
 DLLEXPORT int tjCompress(tjhandle handle, unsigned char *srcBuf, int width,
                          int pitch, int height, int pixelSize,
                          unsigned char *dstBuf, unsigned long *compressedSize,
                          int jpegSubsamp, int jpegQual, int flags);
 
 DLLEXPORT int tjDecompress(tjhandle handle, unsigned char *jpegBuf,
                            unsigned long jpegSize, unsigned char *dstBuf,
                            int width, int pitch, int height, int pixelSize,
                            int flags);
 
 DLLEXPORT int tjDecompressHeader(tjhandle handle, unsigned char *jpegBuf,
                                  unsigned long jpegSize, int *width,
                                  int *height);
 
 DLLEXPORT int tjDestroy(tjhandle handle);
 
 DLLEXPORT char *tjGetErrorStr(void);
 
 DLLEXPORT tjhandle tjInitCompress(void);
 
 DLLEXPORT tjhandle tjInitDecompress(void);
 
 /* TurboJPEG 1.1+ */
 
 #define TJ_YUV  512
 
 DLLEXPORT unsigned long TJBUFSIZEYUV(int width, int height, int jpegSubsamp);
 
 DLLEXPORT int tjDecompressHeader2(tjhandle handle, unsigned char *jpegBuf,
                                   unsigned long jpegSize, int *width,
                                   int *height, int *jpegSubsamp);
 
 DLLEXPORT int tjDecompressToYUV(tjhandle handle, unsigned char *jpegBuf,
                                 unsigned long jpegSize, unsigned char *dstBuf,
                                 int flags);
 
 DLLEXPORT int tjEncodeYUV(tjhandle handle, unsigned char *srcBuf, int width,
                           int pitch, int height, int pixelSize,
                           unsigned char *dstBuf, int subsamp, int flags);
 
 /* TurboJPEG 1.2+ */
 
 #define TJFLAG_BOTTOMUP  2
 #define TJFLAG_FORCEMMX  8
 #define TJFLAG_FORCESSE  16
 #define TJFLAG_FORCESSE2  32
 #define TJFLAG_FORCESSE3  128
 #define TJFLAG_FASTUPSAMPLE  256
 #define TJFLAG_NOREALLOC  1024
 
 DLLEXPORT unsigned char *tjAlloc(int bytes);
 
 DLLEXPORT unsigned long tjBufSize(int width, int height, int jpegSubsamp);
 
 DLLEXPORT unsigned long tjBufSizeYUV(int width, int height, int subsamp);
 
 DLLEXPORT int tjCompress2(tjhandle handle, const unsigned char *srcBuf,
                           int width, int pitch, int height, int pixelFormat,
                           unsigned char **jpegBuf, unsigned long *jpegSize,
                           int jpegSubsamp, int jpegQual, int flags);
 
 DLLEXPORT int tjDecompress2(tjhandle handle, const unsigned char *jpegBuf,
                             unsigned long jpegSize, unsigned char *dstBuf,
                             int width, int pitch, int height, int pixelFormat,
                             int flags);
 
 DLLEXPORT int tjEncodeYUV2(tjhandle handle, unsigned char *srcBuf, int width,
                            int pitch, int height, int pixelFormat,
                            unsigned char *dstBuf, int subsamp, int flags);
 
 DLLEXPORT void tjFree(unsigned char *buffer);
 
 DLLEXPORT tjscalingfactor *tjGetScalingFactors(int *numscalingfactors);
 
 DLLEXPORT tjhandle tjInitTransform(void);
 
 DLLEXPORT int tjTransform(tjhandle handle, const unsigned char *jpegBuf,
                             unsigned long jpegSize, int n,
                             unsigned char **dstBufs, unsigned long *dstSizes,
                             tjtransform *transforms, int flags);
 
 /* TurboJPEG 1.2.1+ */
 
 #define TJFLAG_FASTDCT  2048
 #define TJFLAG_ACCURATEDCT  4096
 
 /* TurboJPEG 1.4+ */
 
 DLLEXPORT unsigned long tjBufSizeYUV2(int width, int align, int height,
                                       int subsamp);
 
 DLLEXPORT int tjCompressFromYUV(tjhandle handle, const unsigned char *srcBuf,
                                 int width, int align, int height, int subsamp,
                                 unsigned char **jpegBuf,
                                 unsigned long *jpegSize, int jpegQual,
                                 int flags);
 
 DLLEXPORT int tjCompressFromYUVPlanes(tjhandle handle,
                                       const unsigned char **srcPlanes,
                                       int width, const int *strides,
                                       int height, int subsamp,
                                       unsigned char **jpegBuf,
                                       unsigned long *jpegSize, int jpegQual,
                                       int flags);
 
 DLLEXPORT int tjDecodeYUV(tjhandle handle, const unsigned char *srcBuf,
                           int align, int subsamp, unsigned char *dstBuf,
                           int width, int pitch, int height, int pixelFormat,
                           int flags);
 
 DLLEXPORT int tjDecodeYUVPlanes(tjhandle handle,
                                 const unsigned char **srcPlanes,
                                 const int *strides, int subsamp,
                                 unsigned char *dstBuf, int width, int pitch,
                                 int height, int pixelFormat, int flags);
 
 DLLEXPORT int tjDecompressHeader3(tjhandle handle,
                                   const unsigned char *jpegBuf,
                                   unsigned long jpegSize, int *width,
                                   int *height, int *jpegSubsamp,
                                   int *jpegColorspace);
 
 DLLEXPORT int tjDecompressToYUV2(tjhandle handle, const unsigned char *jpegBuf,
                                  unsigned long jpegSize, unsigned char *dstBuf,
                                  int width, int align, int height, int flags);
 
 DLLEXPORT int tjDecompressToYUVPlanes(tjhandle handle,
                                       const unsigned char *jpegBuf,
                                       unsigned long jpegSize,
                                       unsigned char **dstPlanes, int width,
                                       int *strides, int height, int flags);
 
 DLLEXPORT int tjEncodeYUV3(tjhandle handle, const unsigned char *srcBuf,
                            int width, int pitch, int height, int pixelFormat,
                            unsigned char *dstBuf, int align, int subsamp,
                            int flags);
 
 DLLEXPORT int tjEncodeYUVPlanes(tjhandle handle, const unsigned char *srcBuf,
                                 int width, int pitch, int height,
                                 int pixelFormat, unsigned char **dstPlanes,
                                 int *strides, int subsamp, int flags);
 
 DLLEXPORT int tjPlaneHeight(int componentID, int height, int subsamp);
 
 DLLEXPORT unsigned long tjPlaneSizeYUV(int componentID, int width, int stride,
                                        int height, int subsamp);
 
 DLLEXPORT int tjPlaneWidth(int componentID, int width, int subsamp);
 
 /* TurboJPEG 2.0+ */
 
 #define TJFLAG_STOPONWARNING  8192
 #define TJFLAG_PROGRESSIVE  16384
 
 DLLEXPORT int tjGetErrorCode(tjhandle handle);
 
 DLLEXPORT char *tjGetErrorStr2(tjhandle handle);
 
 DLLEXPORT unsigned char *tjLoadImage(const char *filename, int *width,
                                      int align, int *height, int *pixelFormat,
                                      int flags);
 
 DLLEXPORT int tjSaveImage(const char *filename, unsigned char *buffer,
                           int width, int pitch, int height, int pixelFormat,
                           int flags);
 
 /* TurboJPEG 2.1+ */
 
 #define TJFLAG_LIMITSCANS  32768
 
 /**
  * @}
  */
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif

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