The QIconEngine class provides an abstract base class for QIcon renderers. 更多...
| 头： | #include <QIconEngine> |
| qmake: | QT += gui |
| class | AvailableSizesArgument |
| class | ScaledPixmapArgument |
| enum | IconEngineHook { AvailableSizesHook, IconNameHook, IsNullHook, ScaledPixmapHook } |
| QIconEngine () | |
| virtual | ~QIconEngine () |
| virtual QSize | actualSize (const QSize & size , QIcon::Mode mode , QIcon::State state ) |
| virtual void | addFile (const QString & fileName , const QSize & size , QIcon::Mode mode , QIcon::State state ) |
| virtual void | addPixmap (const QPixmap & pixmap , QIcon::Mode mode , QIcon::State state ) |
| virtual QList<QSize> | availableSizes (QIcon::Mode mode = QIcon::Normal, QIcon::State state = QIcon::Off) const |
| virtual QIconEngine * | clone () const = 0 |
| virtual QString | iconName () const |
| bool | isNull () const |
| virtual QString | key () const |
| virtual void | paint (QPainter * painter , const QRect & rect , QIcon::Mode mode , QIcon::State state ) = 0 |
| virtual QPixmap | pixmap (const QSize & size , QIcon::Mode mode , QIcon::State state ) |
| virtual bool | read (QDataStream & in ) |
| QPixmap | scaledPixmap (const QSize & size , QIcon::Mode mode , QIcon::State state , qreal scale ) |
| virtual void | virtual_hook (int id , void * data ) |
| virtual bool | write (QDataStream & out ) const |
The QIconEngine class provides an abstract base class for QIcon renderers.
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 ()，和 addPixmap () functions are all virtual, and can therefore be reimplemented in subclasses of QIconEngine .
另请参阅 QIconEnginePlugin .
These enum values are used for virtual_hook () to allow additional queries to icon engine without breaking binary compatibility.
| 常量 | 值 | 描述 |
|---|---|---|
QIconEngine::AvailableSizesHook
|
1
|
Allows to query the sizes of the contained pixmaps for pixmap-based engines. The data argument of the virtual_hook () function is a AvailableSizesArgument pointer that should be filled with icon sizes. Engines that work in terms of a scalable, vectorial format normally return an empty list. |
QIconEngine::IconNameHook
|
2
|
Allows to query the name used to create the icon, for example when instantiating an icon using QIcon::fromTheme (). |
QIconEngine::IsNullHook
|
3
|
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
|
4
|
Provides a way to get a pixmap that is scaled according to the given scale (typically equal to the 设备像素比率 )。 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. |
该枚举在 Qt 4.5 引入或被修改。
另请参阅 virtual_hook ().
Constructs the icon engine.
该函数在 Qt 5.6 引入。
[虚拟]
QIconEngine::
~QIconEngine
()
Destroys the icon engine.
[虚拟]
QSize
QIconEngine::
actualSize
(const
QSize
&
size
,
QIcon::Mode
mode
,
QIcon::State
state
)
Returns the actual size of the icon the engine provides for the requested size , mode and state . The default implementation returns the given size .
[虚拟]
void
QIconEngine::
addFile
(const
QString
&
fileName
, const
QSize
&
size
,
QIcon::Mode
mode
,
QIcon::State
state
)
Called by QIcon::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.
[虚拟]
void
QIconEngine::
addPixmap
(const
QPixmap
&
pixmap
,
QIcon::Mode
mode
,
QIcon::State
state
)
Called by QIcon::addPixmap (). Adds a specialized pixmap 为给定 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.
[虚拟]
QList
<
QSize
> QIconEngine::
availableSizes
(
QIcon::Mode
mode
= QIcon::Normal,
QIcon::State
state
= QIcon::Off) const
Returns sizes of all images that are contained in the engine for the specific mode and state .
注意： This is a helper method and 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.
该函数在 Qt 4.5 引入。
[pure virtual]
QIconEngine
*QIconEngine::
clone
() const
Reimplement this method to return a clone of this icon engine.
[虚拟]
QString
QIconEngine::
iconName
() const
返回用于创建引擎的名称，若可用。
注意： This is a helper method and 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.
该函数在 Qt 4.7 引入。
Returns true if this icon engine represent a null QIcon .
注意： This is a helper method and 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.
该函数在 Qt 5.7 引入。
[虚拟]
QString
QIconEngine::
key
() const
Returns a key that identifies this icon engine.
[pure virtual]
void
QIconEngine::
paint
(
QPainter
*
painter
, const
QRect
&
rect
,
QIcon::Mode
mode
,
QIcon::State
state
)
Uses the given painter to paint the icon with the required mode and state 到矩形 rect .
[虚拟]
QPixmap
QIconEngine::
pixmap
(const
QSize
&
size
,
QIcon::Mode
mode
,
QIcon::State
state
)
Returns the icon as a pixmap with the required size , mode ，和 state . The default implementation creates a new pixmap and calls paint () to fill it.
[虚拟]
bool
QIconEngine::
read
(
QDataStream
&
in
)
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.
Returns a pixmap for the given size , mode , state and scale .
The scale argument is typically equal to the 设备像素比率 of the display.
注意： This is a helper method and 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.
注意： Some engines may cast scale to an integer.
该函数在 Qt 5.9 引入。
另请参阅 ScaledPixmapArgument .
[虚拟]
void
QIconEngine::
virtual_hook
(
int
id
,
void
*
data
)
Additional method to allow extending QIconEngine without adding new virtual methods (and without breaking binary compatibility). The actual action and format of data depends on id argument which is in fact a constant from IconEngineHook 枚举。
该函数在 Qt 4.5 引入。
另请参阅 IconEngineHook .
[虚拟]
bool
QIconEngine::
write
(
QDataStream
&
out
) const
Writes the contents of this engine to the
QDataStream
out
。返回
true
if the contents were written; otherwise returns
false
.
QIconEngine 's default implementation always return false.