Home · All Classes · Modules

QSizePolicy Class Reference
[QtGui module]

The QSizePolicy class is a layout attribute describing horizontal and vertical resizing policy. More...

Types

Methods

Special Methods


Detailed Description

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, and affects how the widget is treated by the layout engine. Each widget returns a QSizePolicy that describes the horizontal and vertical resizing policy it prefers when being laid out. You can change this for a specific widget by changing its QWidget.sizePolicy property.

QSizePolicy contains two independent QSizePolicy.Policy values 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 policies can be set in the constructor, and altered using the setHorizontalPolicy() and setVerticalPolicy() functions. The stretch factors can be set using the setHorizontalStretch() and setVerticalStretch() functions. The flag indicating whether the widget's sizeHint() is width-dependent (such as a menu bar or a word-wrapping label) can be set using the setHeightForWidth() function.

The current size policies and stretch factors be retrieved using the horizontalPolicy(), verticalPolicy(), horizontalStretch() and verticalStretch() functions. Alternatively, use the transpose() function to swap the horizontal and vertical policies and stretches. The hasHeightForWidth() function returns the current status of the flag indicating the size hint dependencies.

Use the expandingDirections() function to determine whether the associated widget can make use of more space than its sizeHint() function indicates, as well as find out in which directions it can expand.

Finally, the QSizePolicy class provides operators comparing this size policy to a given policy, as well as a QVariant operator storing this QSizePolicy as a QVariant object.


Type Documentation

QSizePolicy.ControlType

This enum specifies the different types of widgets in terms of layout interaction:

Constant Value Description
QSizePolicy.DefaultType 0x00000001 The default type, when none is specified.
QSizePolicy.ButtonBox 0x00000002 A QDialogButtonBox instance.
QSizePolicy.CheckBox 0x00000004 A QCheckBox instance.
QSizePolicy.ComboBox 0x00000008 A QComboBox instance.
QSizePolicy.Frame 0x00000010 A QFrame instance.
QSizePolicy.GroupBox 0x00000020 A QGroupBox instance.
QSizePolicy.Label 0x00000040 A QLabel instance.
QSizePolicy.Line 0x00000080 A QFrame instance with QFrame.HLine or QFrame.VLine.
QSizePolicy.LineEdit 0x00000100 A QLineEdit instance.
QSizePolicy.PushButton 0x00000200 A QPushButton instance.
QSizePolicy.RadioButton 0x00000400 A QRadioButton instance.
QSizePolicy.Slider 0x00000800 A QAbstractSlider instance.
QSizePolicy.SpinBox 0x00001000 A QAbstractSpinBox instance.
QSizePolicy.TabWidget 0x00002000 A QTabWidget instance.
QSizePolicy.ToolButton 0x00004000 A QToolButton instance.

This enum was introduced or modified in Qt 4.3.

The ControlTypes type is a typedef for QFlags<ControlType>. It stores an OR combination of ControlType values.

See also setControlType() and controlType().

QSizePolicy.Policy

This enum describes the various per-dimension sizing types used when constructing a QSizePolicy.

Constant Value Description
QSizePolicy.Fixed 0 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 GrowFlag 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). It cannot be smaller than the size provided by sizeHint().
QSizePolicy.Maximum ShrinkFlag 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). It cannot be larger than the size provided by sizeHint().
QSizePolicy.Preferred GrowFlag | ShrinkFlag 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 GrowFlag | ShrinkFlag | ExpandFlag 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 horizontal slider).
QSizePolicy.MinimumExpanding GrowFlag | ExpandFlag 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 horizontal slider).
QSizePolicy.Ignored ShrinkFlag | GrowFlag | IgnoreFlag The sizeHint() is ignored. The widget will get as much space as possible.

See also PolicyFlag, setHorizontalPolicy(), and setVerticalPolicy().

QSizePolicy.PolicyFlag

These flags are combined together to form the various Policy values:

Constant Value Description
QSizePolicy.GrowFlag 1 The widget can grow beyond its size hint if necessary.
QSizePolicy.ExpandFlag 2 The widget should get as much space as possible.
QSizePolicy.ShrinkFlag 4 The widget can shrink below its size hint if necessary.
QSizePolicy.IgnoreFlag 8 The widget's size hint is ignored. The widget will get as much space as possible.

See also Policy.


Method Documentation

QSizePolicy.__init__ (self)

Constructs a QSizePolicy object with Fixed as its horizontal and vertical policies.

The policies can be altered using the setHorizontalPolicy() and setVerticalPolicy() functions. Use the setHeightForWidth() function if the preferred height of the widget is dependent on the width of the widget (for example, a QLabel with line wrapping).

See also setHorizontalStretch() and setVerticalStretch().

QSizePolicy.__init__ (self, Policy horizontal, Policy vertical)

Constructs a QSizePolicy object with the given horizontal and vertical policies, and DefaultType as the control type.

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 setHorizontalStretch() and setVerticalStretch().

QSizePolicy.__init__ (self, Policy horizontal, Policy vertical, ControlType type)

Constructs a QSizePolicy object with the given horizontal and vertical policies, and the specified control type.

Use setHeightForWidth() if the preferred height of the widget is dependent on the width of the widget (for example, a QLabel with line wrapping).

This function was introduced in Qt 4.3.

See also setHorizontalStretch(), setVerticalStretch(), and controlType().

QSizePolicy.__init__ (self, QVariant variant)

QSizePolicy.__init__ (self, QSizePolicy)

ControlType QSizePolicy.controlType (self)

Returns the control type associated with the widget for which this size policy applies.

This function was introduced in Qt 4.3.

See also setControlType().

Qt.Orientations QSizePolicy.expandingDirections (self)

Returns whether a widget can make use of more space than the QWidget.sizeHint() function indicates.

A value of Qt.Horizontal or Qt.Vertical means that the widget can grow horizontally or vertically (i.e., the horizontal or vertical policy is Expanding or MinimumExpanding), whereas Qt.Horizontal | Qt.Vertical means that it can grow in both dimensions.

See also horizontalPolicy() and verticalPolicy().

bool QSizePolicy.hasHeightForWidth (self)

Returns true if the widget's preferred height depends on its width; otherwise returns false.

See also setHeightForWidth().

bool QSizePolicy.hasWidthForHeight (self)

Returns true if the widget's width depends on its height; otherwise returns false.

This function was introduced in Qt 4.8.

See also setWidthForHeight().

Policy QSizePolicy.horizontalPolicy (self)

Returns the horizontal component of the size policy.

See also setHorizontalPolicy(), verticalPolicy(), and horizontalStretch().

int QSizePolicy.horizontalStretch (self)

Returns the horizontal stretch factor of the size policy.

See also setHorizontalStretch(), verticalStretch(), and horizontalPolicy().

QSizePolicy.setControlType (self, ControlType type)

Sets the control type associated with the widget for which this size policy applies to type.

The control type specifies the type of the widget for which this size policy applies. It is used by some styles, notably QMacStyle, to insert proper spacing between widgets. For example, the Mac OS X Aqua guidelines specify that push buttons should be separated by 12 pixels, whereas vertically stacked radio buttons only require 6 pixels.

This function was introduced in Qt 4.3.

See also controlType() and QStyle.layoutSpacing().

QSizePolicy.setHeightForWidth (self, bool b)

Sets the flag determining whether the widget's preferred height depends on its width, to dependent.

See also hasHeightForWidth() and setWidthForHeight().

QSizePolicy.setHorizontalPolicy (self, Policy d)

Sets the horizontal component to the given policy.

See also horizontalPolicy(), setVerticalPolicy(), and setHorizontalStretch().

QSizePolicy.setHorizontalStretch (self, int stretchFactor)

Sets the horizontal stretch factor of the size policy to the given stretchFactor.

See also horizontalStretch(), setVerticalStretch(), and setHorizontalPolicy().

QSizePolicy.setVerticalPolicy (self, Policy d)

Sets the vertical component to the given policy.

See also verticalPolicy(), setHorizontalPolicy(), and setVerticalStretch().

QSizePolicy.setVerticalStretch (self, int stretchFactor)

Sets the vertical stretch factor of the size policy to the given stretchFactor.

See also verticalStretch(), setHorizontalStretch(), and setVerticalPolicy().

QSizePolicy.setWidthForHeight (self, bool b)

Sets the flag determining whether the widget's width depends on its height, to dependent.

This is only supported for QGraphicsLayout's subclasses. It is not possible to have a layout with both height-for-width and width-for-height constraints at the same time.

This function was introduced in Qt 4.8.

See also hasWidthForHeight() and setHeightForWidth().

QSizePolicy.transpose (self)

Swaps the horizontal and vertical policies and stretches.

Policy QSizePolicy.verticalPolicy (self)

Returns the vertical component of the size policy.

See also setVerticalPolicy(), horizontalPolicy(), and verticalStretch().

int QSizePolicy.verticalStretch (self)

Returns the vertical stretch factor of the size policy.

See also setVerticalStretch(), horizontalStretch(), and verticalPolicy().

bool QSizePolicy.__eq__ (self, QSizePolicy s)

bool QSizePolicy.__ne__ (self, QSizePolicy s)


PyQt 4.12.1 for X11Copyright © Riverbank Computing Ltd and The Qt Company 2015Qt 4.8.7