class QIconEngine¶

The QIconEngine class provides an abstract base class for QIcon renderers. More…

Synopsis¶

Methods¶

def __init__()

Virtual methods¶

def actualSize()
def addFile()
def addPixmap()
def availableSizes()
def clone()
def iconName()
def isNull()
def key()
def paint()
def pixmap()
def read()
def scaledPixmap()
def write()

Note

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Detailed Description¶

An icon engine provides the rendering functions for a QIcon . Each icon has a corresponding icon engine that is responsible for drawing the icon with a requested size, mode and state.

The icon is rendered by the paint() function, and the icon can additionally be obtained as a pixmap with the pixmap() function (the default implementation simply uses paint() to achieve this). The addPixmap() function can be used to add new pixmaps to the icon engine, and is used by QIcon to add specialized custom pixmaps.

The paint() , pixmap() , and addPixmap() functions are all virtual, and can therefore be reimplemented in subclasses of QIconEngine .

See also

QIconEnginePlugin

class IconEngineHook¶

These enum values are used for virtual_hook() to allow additional queries to icon engine without breaking binary compatibility.

Constant

Description

QIconEngine.IsNullHook

Allow to query if this engine represents a null icon. The data argument of the virtual_hook() is a pointer to a bool that can be set to true if the icon is null. This enum value was added in Qt 5.7.

QIconEngine.ScaledPixmapHook

Provides a way to get a pixmap that is scaled according to the given scale (typically equal to the device pixel ratio). The data argument of the virtual_hook() function is a ScaledPixmapArgument pointer that contains both the input and output arguments. This enum value was added in Qt 5.9.

See also

virtual_hook()

Constant	Description
QIconEngine.IsNullHook	Allow to query if this engine represents a null icon. The `data` argument of the `virtual_hook()` is a pointer to a bool that can be set to true if the icon is null. This enum value was added in Qt 5.7.
QIconEngine.ScaledPixmapHook	Provides a way to get a pixmap that is scaled according to the given scale (typically equal to the device pixel ratio). The `data` argument of the `virtual_hook()` function is a `ScaledPixmapArgument` pointer that contains both the input and output arguments. This enum value was added in Qt 5.9.

__init__()¶

Constructs the icon engine.

__init__(other)

Parameters:: other – QIconEngine

actualSize(size, mode, state)¶

Parameters:

size – QSize
mode – Mode
state – State

Return type:

QSize

Returns the actual size of the icon the engine provides for the requested size, mode and state. The default implementation returns the given size.

The returned size is in device-independent pixels (This is relevant for high-dpi pixmaps).

addFile(fileName, size, mode, state)¶

Parameters:

fileName – str
size – QSize
mode – Mode
state – State

Called by addFile() . Adds a specialized pixmap from the file with the given fileName, size, mode and state. The default pixmap-based engine stores any supplied file names, and it loads the pixmaps on demand instead of using scaled pixmaps if the size of a pixmap matches the size of icon requested. Custom icon engines that implement scalable vector formats are free to ignores any extra files.

addPixmap(pixmap, mode, state)¶

Parameters:

pixmap – QPixmap
mode – Mode
state – State

Called by addPixmap() . Adds a specialized pixmap for the given mode and state. The default pixmap-based engine stores any supplied pixmaps, and it uses them instead of scaled pixmaps if the size of a pixmap matches the size of icon requested. Custom icon engines that implement scalable vector formats are free to ignores any extra pixmaps.

availableSizes([mode=QIcon.Normal[, state=QIcon.Off]])¶

Parameters:

mode – Mode
state – State

Return type:

.list of QSize

Returns sizes of all images that are contained in the engine for the specific mode and state.

abstract clone()¶

Return type:: QIconEngine

Reimplement this method to return a clone of this icon engine.

iconName()¶

Return type:: str

Returns the name used to create the engine, if available.

isNull()¶

Return type:: bool

Returns true if this icon engine represent a null QIcon .

Note

If the icon engine does not reimplement this function, the actual work is done by the virtual_hook() method, hence this method depends on icon engine support and may not work with all icon engines.

key()¶

Return type:: str

Returns a key that identifies this icon engine.

abstract paint(painter, rect, mode, state)¶

Parameters:

painter – QPainter
rect – QRect
mode – Mode
state – State

Uses the given painter to paint the icon with the required mode and state into the rectangle rect.

pixmap(size, mode, state)¶

Parameters:

size – QSize
mode – Mode
state – State

Return type:

QPixmap

Returns the icon as a pixmap with the required size, mode, and state. The default implementation creates a new pixmap and calls paint() to fill it.

read(in)¶

Parameters:: in – QDataStream
Return type:: bool

Reads icon engine contents from the QDataStream in. Returns true if the contents were read; otherwise returns false.

QIconEngine ‘s default implementation always return false.

scaledPixmap(size, mode, state, scale)¶

Parameters:

size – QSize
mode – Mode
state – State
scale – float

Return type:

QPixmap

Returns a pixmap for the given size, mode, state and scale.

The scale argument is typically equal to the device pixel ratio of the display. The size is given in device-independent pixels.

Note

If the icon engine does not reimplement this function, the actual work is done by the virtual_hook() method, hence this method depends on icon engine support and may not work with all icon engines.

Note

Some engines may cast scale to an integer.