include/QtWidgets/qsizepolicy.h

0001 // Copyright (C) 2016 The Qt Company Ltd.
0002 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
0003
0004 #ifndef QSIZEPOLICY_H
0005 #define QSIZEPOLICY_H
0006
0007 #include <QtWidgets/qtwidgetsglobal.h>
0008 #include <QtCore/qobject.h>
0009 #include <QtCore/qalgorithms.h>
0010 #include <QtCore/qhashfunctions.h>
0011
0012 QT_BEGIN_NAMESPACE
0013
0014 class QVariant;
0015 class QSizePolicy;
0016
0017 class Q_WIDGETS_EXPORT QSizePolicy
0018 {
0019     Q_GADGET
0020
0021 public:
0022     enum PolicyFlag {
0023         GrowFlag = 1,
0024         ExpandFlag = 2,
0025         ShrinkFlag = 4,
0026         IgnoreFlag = 8
0027     };
0028
0029     enum Policy {
0030         Fixed = 0,
0031         Minimum = GrowFlag,
0032         Maximum = ShrinkFlag,
0033         Preferred = GrowFlag | ShrinkFlag,
0034         MinimumExpanding = GrowFlag | ExpandFlag,
0035         Expanding = GrowFlag | ShrinkFlag | ExpandFlag,
0036         Ignored = ShrinkFlag | GrowFlag | IgnoreFlag
0037     };
0038     Q_ENUM(Policy)
0039
0040     enum ControlType {
0041         DefaultType      = 0x00000001,
0042         ButtonBox        = 0x00000002,
0043         CheckBox         = 0x00000004,
0044         ComboBox         = 0x00000008,
0045         Frame            = 0x00000010,
0046         GroupBox         = 0x00000020,
0047         Label            = 0x00000040,
0048         Line             = 0x00000080,
0049         LineEdit         = 0x00000100,
0050         PushButton       = 0x00000200,
0051         RadioButton      = 0x00000400,
0052         Slider           = 0x00000800,
0053         SpinBox          = 0x00001000,
0054         TabWidget        = 0x00002000,
0055         ToolButton       = 0x00004000
0056     };
0057     Q_DECLARE_FLAGS(ControlTypes, ControlType)
0058     Q_FLAG(ControlTypes)
0059
0060     constexpr QSizePolicy() noexcept : data(0) { }
0061
0062     constexpr QSizePolicy(Policy horizontal, Policy vertical, ControlType type = DefaultType) noexcept
0063         : bits{0, 0, quint32(horizontal), quint32(vertical),
0064                type == DefaultType ? 0 : toControlTypeFieldValue(type), 0, 0, 0}
0065     {}
0066     constexpr Policy horizontalPolicy() const noexcept { return static_cast<Policy>(bits.horPolicy); }
0067     constexpr Policy verticalPolicy() const noexcept { return static_cast<Policy>(bits.verPolicy); }
0068     ControlType controlType() const noexcept;
0069
0070     constexpr void setHorizontalPolicy(Policy d) noexcept { bits.horPolicy = d; }
0071     constexpr void setVerticalPolicy(Policy d) noexcept { bits.verPolicy = d; }
0072     void setControlType(ControlType type) noexcept;
0073
0074     // ### Qt 7: consider making Policy a QFlags and removing these casts
0075     constexpr Qt::Orientations expandingDirections() const noexcept {
0076         return ( (verticalPolicy()   & static_cast<Policy>(ExpandFlag)) ? Qt::Vertical   : Qt::Orientations() )
0077              | ( (horizontalPolicy() & static_cast<Policy>(ExpandFlag)) ? Qt::Horizontal : Qt::Orientations() ) ;
0078     }
0079
0080     constexpr void setHeightForWidth(bool b) noexcept { bits.hfw = b;  }
0081     constexpr bool hasHeightForWidth() const noexcept { return bits.hfw; }
0082     constexpr void setWidthForHeight(bool b) noexcept { bits.wfh = b;  }
0083     constexpr bool hasWidthForHeight() const noexcept { return bits.wfh; }
0084
0085     constexpr bool operator==(const QSizePolicy& s) const noexcept { return data == s.data; }
0086     constexpr bool operator!=(const QSizePolicy& s) const noexcept { return data != s.data; }
0087
0088     friend Q_DECL_CONST_FUNCTION size_t qHash(QSizePolicy key, size_t seed = 0) noexcept { return qHash(key.data, seed); }
0089
0090     operator QVariant() const;
0091
0092     constexpr int horizontalStretch() const noexcept { return static_cast<int>(bits.horStretch); }
0093     constexpr int verticalStretch() const noexcept { return static_cast<int>(bits.verStretch); }
0094     constexpr void setHorizontalStretch(int stretchFactor) { bits.horStretch = static_cast<quint32>(qBound(0, stretchFactor, 255)); }
0095     constexpr void setVerticalStretch(int stretchFactor) { bits.verStretch = static_cast<quint32>(qBound(0, stretchFactor, 255)); }
0096
0097     constexpr bool retainSizeWhenHidden() const noexcept { return bits.retainSizeWhenHidden; }
0098     constexpr void setRetainSizeWhenHidden(bool retainSize) noexcept { bits.retainSizeWhenHidden = retainSize; }
0099
0100     constexpr void transpose() noexcept { *this = transposed(); }
0101     [[nodiscard]] constexpr QSizePolicy transposed() const noexcept
0102     {
0103         return QSizePolicy(bits.transposed());
0104     }
0105
0106 private:
0107 #ifndef QT_NO_DATASTREAM
0108     friend Q_WIDGETS_EXPORT QDataStream &operator<<(QDataStream &, const QSizePolicy &);
0109     friend Q_WIDGETS_EXPORT QDataStream &operator>>(QDataStream &, QSizePolicy &);
0110 #endif
0111     constexpr QSizePolicy(int i) noexcept : data(i) { }
0112     struct Bits;
0113     constexpr explicit QSizePolicy(Bits b) noexcept : bits(b) { }
0114
0115     static constexpr quint32 toControlTypeFieldValue(ControlType type) noexcept
0116     {
0117         /*
0118           The control type is a flag type, with values 0x1, 0x2, 0x4, 0x8, 0x10,
0119           etc. In memory, we pack it onto the available bits (CTSize) in
0120           setControlType(), and unpack it here.
0121
0122           Example:
0123
0124           0x00000001 maps to 0
0125           0x00000002 maps to 1
0126           0x00000004 maps to 2
0127           0x00000008 maps to 3
0128           etc.
0129         */
0130
0131         return qCountTrailingZeroBits(static_cast<quint32>(type));
0132     }
0133
0134     struct Bits {
0135         quint32 horStretch : 8;
0136         quint32 verStretch : 8;
0137         quint32 horPolicy : 4;
0138         quint32 verPolicy : 4;
0139         quint32 ctype : 5;
0140         quint32 hfw : 1;
0141         quint32 wfh : 1;
0142         quint32 retainSizeWhenHidden : 1;
0143
0144         constexpr Bits transposed() const noexcept
0145         {
0146             return {verStretch, // \ swap
0147                     horStretch, // /
0148                     verPolicy, // \ swap
0149                     horPolicy, // /
0150                     ctype,
0151                     hfw, // \ don't swap (historic behavior)
0152                     wfh, // /
0153                     retainSizeWhenHidden};
0154         }
0155     };
0156     union {
0157         Bits bits;
0158         quint32 data;
0159     };
0160 };
0161
0162 Q_DECLARE_TYPEINFO(QSizePolicy, Q_PRIMITIVE_TYPE);
0163
0164 Q_DECLARE_OPERATORS_FOR_FLAGS(QSizePolicy::ControlTypes)
0165 Q_DECLARE_MIXED_ENUM_OPERATORS(int, QSizePolicy::Policy, QSizePolicy::PolicyFlag)
0166
0167 #ifndef QT_NO_DATASTREAM
0168 Q_WIDGETS_EXPORT QDataStream &operator<<(QDataStream &, const QSizePolicy &);
0169 Q_WIDGETS_EXPORT QDataStream &operator>>(QDataStream &, QSizePolicy &);
0170 #endif
0171
0172 #ifndef QT_NO_DEBUG_STREAM
0173 Q_WIDGETS_EXPORT QDebug operator<<(QDebug dbg, const QSizePolicy &);
0174 #endif
0175
0176 QT_END_NAMESPACE
0177
0178 #endif // QSIZEPOLICY_H