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The QSizePolicy class is a layout attribute describing horizontal and vertical resizing policy. More...
#include <QSizePolicy>
The QSizePolicy class is a layout attribute describing horizontal and vertical resizing policy.
The size policy of a widget is an expression of its willingness to be resized in various ways.
Widgets that reimplement QWidget::sizePolicy() return a QSizePolicy that describes the horizontal and vertical resizing policy they prefer when being laid out.
QSizePolicy contains two independent SizeType objects and two stretch factors; one describes the widgets's horizontal size policy, and the other describes its vertical size policy. It also contains a flag to indicate whether the height and width of its preferred size are related.
The horizontal and vertical SizeTypes are set in the usual constructor and can be queried using a variety of functions.
The hasHeightForWidth() flag indicates whether the widget's sizeHint() is width-dependent (such as a word-wrapping label) or not.
See also QSizePolicy::SizeType.
This enum type describes in which directions a widget can make use of extra space. There are four possible values:
QSizePolicy::NoDirection | the widget cannot make use of extra space in any direction. |
QSizePolicy::Horizontally | the widget can usefully be wider than the sizeHint(). |
QSizePolicy::Vertically | the widget can usefully be taller than the sizeHint(). |
QSizePolicy::BothDirections | the widget can usefully be both wider and taller than the sizeHint(). |
The per-dimension sizing types used when constructing a QSizePolicy are:
QSizePolicy::Fixed | the QWidget::sizeHint() is the only acceptable alternative, so the widget can never grow or shrink (e.g. the vertical direction of a push button). |
QSizePolicy::Minimum | the sizeHint() is minimal, and sufficient. The widget can be expanded, but there is no advantage to it being larger (e.g. the horizontal direction of a push button). |
QSizePolicy::Maximum | the sizeHint() is a maximum. The widget can be shrunk any amount without detriment if other widgets need the space (e.g. a separator line). |
QSizePolicy::Preferred | the sizeHint() is best, but the widget can be shrunk and still be useful. The widget can be expanded, but there is no advantage to it being larger than sizeHint() (the default QWidget policy). |
QSizePolicy::Expanding | the sizeHint() is a sensible size, but the widget can be shrunk and still be useful. The widget can make use of extra space, so it should get as much space as possible (e.g. the horizontal direction of a slider). |
QSizePolicy::MinimumExpanding | the sizeHint() is minimal, and sufficient. The widget can make use of extra space, so it should get as much space as possible (e.g. the horizontal direction of a slider). |
QSizePolicy::Ignored | the sizeHint() is ignored. The widget will get as much space as possible. |
The SizeType typedef can store a combination of SizeTypeFlag values.
Constructs a minimally initialized QSizePolicy.
It constructs a QSizePolicy with independent horizontal and vertical sizing types, hor and ver respectively. These sizing types affect how the widget is treated by the layout engine.
Use setHeightForWidth() if the preferred height of the widget is dependent on the width of the widget (for example, a QLabel with line wrapping).
See also horizontalData(), verticalData(), and setHeightForWidth().
Returns whether this layout can make use of more space than sizeHint(). A value of Qt::Vertical or Qt::Horizontal means that it wants to grow in only one dimension, whereas BothDirections means that it wants to grow in both dimensions.
mayShrinkVertically() mayGrowVertically()
See also mayShrinkHorizontally() and mayGrowHorizontally().
Returns true if the widget's preferred height depends on its width; otherwise returns false.
See also setHeightForWidth().
Returns the horizontal component of the size policy.
See also setHorizontalData(), verticalData(), and horizontalStretch().
Returns the horizontal stretch factor of the size policy.
See also setHorizontalStretch() and verticalStretch().
Returns true if the widget can sensibly be wider than its sizeHint(); otherwise returns false.
See also mayGrowVertically() and mayShrinkHorizontally().
Returns true if the widget can sensibly be taller than its sizeHint(); otherwise returns false.
See also mayGrowHorizontally() and mayShrinkVertically().
Returns true if the widget can sensibly be narrower than its sizeHint(); otherwise returns false.
See also mayShrinkVertically() and mayGrowHorizontally().
Returns true if the widget can sensibly be shorter than its sizeHint(); otherwise returns false.
See also mayShrinkHorizontally() and mayGrowVertically().
Sets the hasHeightForWidth() flag to b.
See also hasHeightForWidth().
Sets the horizontal component of the size policy to size type d.
See also horizontalData() and setVerticalData().
Sets the horizontal stretch factor of the size policy to sf.
See also horizontalStretch() and setVerticalStretch().
Sets the vertical component of the size policy to size type d.
See also verticalData() and setHorizontalData().
Sets the vertical stretch factor of the size policy to sf.
See also verticalStretch() and setHorizontalStretch().
Swaps the horizontal and vertical policies and stretches.
Returns the vertical component of the size policy.
See also setVerticalData(), horizontalData(), and verticalStretch().
Returns the vertical stretch factor of the size policy.
See also setVerticalStretch() and horizontalStretch().
Returns true if this policy is different from s; otherwise returns false.
See also operator==().
Returns true if this policy is equal to s; otherwise returns false.
See also operator!=().
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