QPaintEngine class provides an abstract definition of how QPainter 绘制到给定设备在给定平台。 更多...
| 头： | #include <QPaintEngine> |
| qmake: | QT += gui |
| enum | DirtyFlag { DirtyPen, DirtyBrush, DirtyBrushOrigin, DirtyFont, ..., AllDirty } |
| flags | DirtyFlags |
| enum | PaintEngineFeature { AlphaBlend, Antialiasing, BlendModes, BrushStroke, ..., AllFeatures } |
| flags | PaintEngineFeatures |
| enum | PolygonDrawMode { OddEvenMode, WindingMode, ConvexMode, PolylineMode } |
| enum | Type { X11, Windows, MacPrinter, CoreGraphics, ..., Direct2D } |
| QPaintEngine (PaintEngineFeatures caps = PaintEngineFeatures()) | |
| virtual | ~QPaintEngine () |
| virtual bool | begin (QPaintDevice * pdev ) = 0 |
| virtual void | drawEllipse (const QRectF & rect ) |
| virtual void | drawEllipse (const QRect & rect ) |
| virtual void | drawImage (const QRectF & rectangle , const QImage & image , const QRectF & sr , Qt::ImageConversionFlags flags = Qt::AutoColor) |
| virtual void | drawLines (const QLineF * lines , int lineCount ) |
| virtual void | drawLines (const QLine * lines , int lineCount ) |
| virtual void | drawPath (const QPainterPath & path ) |
| virtual void | drawPixmap (const QRectF & r , const QPixmap & pm , const QRectF & sr ) = 0 |
| virtual void | drawPoints (const QPointF * points , int pointCount ) |
| virtual void | drawPoints (const QPoint * points , int pointCount ) |
| virtual void | drawPolygon (const QPointF * points , int pointCount , PolygonDrawMode mode ) |
| virtual void | drawPolygon (const QPoint * points , int pointCount , PolygonDrawMode mode ) |
| virtual void | drawRects (const QRectF * rects , int rectCount ) |
| virtual void | drawRects (const QRect * rects , int rectCount ) |
| virtual void | drawTextItem (const QPointF & p , const QTextItem & textItem ) |
| virtual void | drawTiledPixmap (const QRectF & rect , const QPixmap & pixmap , const QPointF & p ) |
| virtual bool | end () = 0 |
| bool | hasFeature (PaintEngineFeatures feature ) const |
| bool | isActive () const |
| QPaintDevice * | paintDevice () const |
| QPainter * | painter () const |
| void | setActive (bool state ) |
| virtual Type | type () const = 0 |
| virtual void | updateState (const QPaintEngineState & state ) = 0 |
QPaintEngine class provides an abstract definition of how QPainter 绘制到给定设备在给定平台。
Qt provides several premade implementations of QPaintEngine for the different painter backends we support. The primary paint engine provided is the raster paint engine, which contains a software rasterizer which supports the full feature set on all supported platforms. This is the default for painting on QWidget 基类如在 Windows、X11 及 macOS，它是后端为描绘在 QImage and it is used as a fallback for paint engines that do not support a certain capability. In addition we provide QPaintEngine implementations for OpenGL (accessible through QGLWidget) and printing (which allows using QPainter 去绘制在 QPrinter 对象)。
若想要使用 QPainter to draw to a different backend, one must subclass QPaintEngine and reimplement all its virtual functions. The QPaintEngine implementation is then made available by subclassing QPaintDevice 和重实现虚函数 QPaintDevice::paintEngine ().
QPaintEngine is created and owned by the QPaintDevice 创建了它。
另请参阅 QPainter , QPaintDevice::paintEngine ()，和 描绘系统 .
| 常量 | 值 | 描述 |
|---|---|---|
QPaintEngine::DirtyPen
|
0x0001
|
钢笔脏且需要更新。 |
QPaintEngine::DirtyBrush
|
0x0002
|
笔刷脏且需要更新。 |
QPaintEngine::DirtyBrushOrigin
|
0x0004
|
The brush origin is dirty and needs to updated. |
QPaintEngine::DirtyFont
|
0x0008
|
The font is dirty and needs to be updated. |
QPaintEngine::DirtyBackground
|
0x0010
|
The background is dirty and needs to be updated. |
QPaintEngine::DirtyBackgroundMode
|
0x0020
|
The background mode is dirty and needs to be updated. |
QPaintEngine::DirtyTransform
|
0x0040
|
The transform is dirty and needs to be updated. |
QPaintEngine::DirtyClipRegion
|
0x0080
|
The clip region is dirty and needs to be updated. |
QPaintEngine::DirtyClipPath
|
0x0100
|
The clip path is dirty and needs to be updated. |
QPaintEngine::DirtyHints
|
0x0200
|
The render hints is dirty and needs to be updated. |
QPaintEngine::DirtyCompositionMode
|
0x0400
|
The composition mode is dirty and needs to be updated. |
QPaintEngine::DirtyClipEnabled
|
0x0800
|
Whether clipping is enabled or not is dirty and needs to be updated. |
QPaintEngine::DirtyOpacity
|
0x1000
|
The constant opacity has changed and needs to be updated as part of the state change in QPaintEngine::updateState (). |
QPaintEngine::AllDirty
|
0xffff
|
Convenience enum used internally. |
这些类型用于 QPainter 以触发各种状态的惰性更新在 QPaintEngine 使用 QPaintEngine::updateState ().
描绘引擎必须更新每脏点状态。
The DirtyFlags type is a typedef for QFlags <DirtyFlag>. It stores an OR combination of DirtyFlag values.
This enum is used to describe the features or capabilities that the paint engine has. If a feature is not supported by the engine, QPainter will do a best effort to emulate that feature through other means and pass on an alpha blended QImage to the engine with the emulated results. Some features cannot be emulated: AlphaBlend and PorterDuff.
| 常量 | 值 | 描述 |
|---|---|---|
QPaintEngine::AlphaBlend
|
0x00000080
|
引擎可以 Alpha 融合原语。 |
QPaintEngine::Antialiasing
|
0x00000400
|
The engine can use antialising to improve the appearance of rendered primitives. |
QPaintEngine::BlendModes
|
0x00008000
|
引擎支持融合模式。 |
QPaintEngine::BrushStroke
|
0x00000800
|
The engine supports drawing strokes that contain brushes as fills, not just solid colors (e.g. a dashed gradient line of width 2). |
QPaintEngine::ConicalGradientFill
|
0x00000040
|
The engine supports conical gradient fills. |
QPaintEngine::ConstantOpacity
|
0x00001000
|
The engine supports the feature provided by QPainter::setOpacity (). |
QPaintEngine::LinearGradientFill
|
0x00000010
|
The engine supports linear gradient fills. |
QPaintEngine::MaskedBrush
|
0x00002000
|
The engine is capable of rendering brushes that has a texture with an alpha channel or a mask. |
QPaintEngine::ObjectBoundingModeGradients
|
0x00010000
|
The engine has native support for gradients with coordinate mode QGradient::ObjectBoundingMode . Otherwise, if QPaintEngine::PatternTransform is supported, object bounding mode gradients are converted to gradients with coordinate mode QGradient::LogicalMode and a brush transform for the coordinate mapping. |
QPaintEngine::PainterPaths
|
0x00000200
|
The engine has path support. |
QPaintEngine::PaintOutsidePaintEvent
|
0x20000000
|
The engine is capable of painting outside of paint events. |
QPaintEngine::PatternBrush
|
0x00000008
|
The engine is capable of rendering brushes with the brush patterns specified in Qt::BrushStyle . |
QPaintEngine::PatternTransform
|
0x00000002
|
The engine has support for transforming brush patterns. |
QPaintEngine::PerspectiveTransform
|
0x00004000
|
The engine has support for performing perspective transformations on primitives. |
QPaintEngine::PixmapTransform
|
0x00000004
|
The engine can transform pixmaps, including rotation and shearing. |
QPaintEngine::PorterDuff
|
0x00000100
|
The engine supports Porter-Duff operations |
QPaintEngine::PrimitiveTransform
|
0x00000001
|
The engine has support for transforming drawing primitives. |
QPaintEngine::RadialGradientFill
|
0x00000020
|
The engine supports radial gradient fills. |
QPaintEngine::RasterOpModes
|
0x00020000
|
The engine supports bitwise raster operations. |
QPaintEngine::AllFeatures
|
0xffffffff
|
All of the above features. This enum value is usually used as a bit mask. |
PaintEngineFeatures 类型是 typedef 对于 QFlags <PaintEngineFeature>. It stores an OR combination of PaintEngineFeature values.
| 常量 | 值 | 描述 |
|---|---|---|
QPaintEngine::OddEvenMode
|
0
|
The polygon should be drawn using OddEven fill rule. |
QPaintEngine::WindingMode
|
1
|
The polygon should be drawn using Winding fill rule. |
QPaintEngine::ConvexMode
|
2
|
The polygon is a convex polygon and can be drawn using specialized algorithms where available. |
QPaintEngine::PolylineMode
|
3
|
Only the outline of the polygon should be drawn. |
| 常量 | 值 | 描述 |
|---|---|---|
QPaintEngine::X11
|
0
|
|
QPaintEngine::Windows
|
1
|
|
QPaintEngine::MacPrinter
|
4
|
|
QPaintEngine::CoreGraphics
|
3
|
macOS 的 Quartz2D (CoreGraphics) |
QPaintEngine::QuickDraw
|
2
|
macOS 的 QuickDraw |
QPaintEngine::QWindowSystem
|
5
|
Qt for Embedded Linux |
QPaintEngine::PostScript
|
6
|
(No longer supported) |
QPaintEngine::OpenGL
|
7
|
|
QPaintEngine::Picture
|
8
|
QPicture format |
QPaintEngine::SVG
|
9
|
SVG (可伸缩向量图形) XML 格式 |
QPaintEngine::Raster
|
10
|
|
QPaintEngine::Direct3D
|
11
|
仅 Windows，基于 Direct3D 的引擎 |
QPaintEngine::Pdf
|
12
|
PDF (便携式文档格式) |
QPaintEngine::OpenVG
|
13
|
|
QPaintEngine::User
|
50
|
第一用户类型 ID |
QPaintEngine::MaxUser
|
100
|
最后用户类型 ID |
QPaintEngine::OpenGL2
|
14
|
|
QPaintEngine::PaintBuffer
|
15
|
|
QPaintEngine::Blitter
|
16
|
|
QPaintEngine::Direct2D
|
17
|
仅 Windows，基于 Direct2D 的引擎 |
创建描绘引擎采用的特征集指定通过 caps .
[virtual]
QPaintEngine::
~QPaintEngine
()
销毁描绘引擎。
[pure virtual]
bool
QPaintEngine::
begin
(
QPaintDevice
*
pdev
)
Reimplement this function to initialise your paint engine when painting is to start on the paint device pdev . Return true if the initialization was successful; otherwise return false.
[virtual]
void
QPaintEngine::
drawEllipse
(const
QRectF
&
rect
)
Reimplement this function to draw the largest ellipse that can be contained within rectangle rect .
默认实现调用 drawPolygon ().
[virtual]
void
QPaintEngine::
drawEllipse
(const
QRect
&
rect
)
The default implementation of this function calls the floating point version of this function
[virtual]
void
QPaintEngine::
drawImage
(const
QRectF
&
rectangle
, const
QImage
&
image
, const
QRectF
&
sr
,
Qt::ImageConversionFlags
flags
= Qt::AutoColor)
Reimplement this function to draw the part of the image specified by the sr rectangle in the given rectangle using the given conversion flags flags , to convert it to a pixmap.
[virtual]
void
QPaintEngine::
drawLines
(const
QLineF
*
lines
,
int
lineCount
)
The default implementation splits the list of lines in lines into lineCount separate calls to drawPath () 或 drawPolygon () depending on the feature set of the paint engine.
[virtual]
void
QPaintEngine::
drawLines
(const
QLine
*
lines
,
int
lineCount
)
这是重载函数。
The default implementation converts the first lineCount lines in lines 到 QLineF and calls the floating point version of this function.
[virtual]
void
QPaintEngine::
drawPath
(const
QPainterPath
&
path
)
The default implementation ignores the path and does nothing.
[pure virtual]
void
QPaintEngine::
drawPixmap
(const
QRectF
&
r
, const
QPixmap
&
pm
, const
QRectF
&
sr
)
Reimplement this function to draw the part of the pm specified by the sr rectangle in the given r .
[virtual]
void
QPaintEngine::
drawPoints
(const
QPointF
*
points
,
int
pointCount
)
绘制第一 pointCount points in the buffer points
[virtual]
void
QPaintEngine::
drawPoints
(const
QPoint
*
points
,
int
pointCount
)
绘制第一 pointCount points in the buffer points
The default implementation converts the first pointCount QPoints in points to QPointFs and calls the floating point version of drawPoints .
[virtual]
void
QPaintEngine::
drawPolygon
(const
QPointF
*
points
,
int
pointCount
,
PolygonDrawMode
mode
)
Reimplement this virtual function to draw the polygon defined by the pointCount first points in points , using mode mode .
注意： At least one of the drawPolygon() functions must be reimplemented.
[virtual]
void
QPaintEngine::
drawPolygon
(const
QPoint
*
points
,
int
pointCount
,
PolygonDrawMode
mode
)
这是重载函数。
Reimplement this virtual function to draw the polygon defined by the pointCount first points in points , using mode mode .
注意： At least one of the drawPolygon () functions must be reimplemented.
[virtual]
void
QPaintEngine::
drawRects
(const
QRectF
*
rects
,
int
rectCount
)
绘制第一 rectCount rectangles in the buffer rects . The default implementation of this function calls drawPath () 或 drawPolygon () depending on the feature set of the paint engine.
[virtual]
void
QPaintEngine::
drawRects
(const
QRect
*
rects
,
int
rectCount
)
这是重载函数。
The default implementation converts the first rectCount rectangles in the buffer rects 到 QRectF and calls the floating point version of this function.
[virtual]
void
QPaintEngine::
drawTextItem
(const
QPointF
&
p
, const
QTextItem
&
textItem
)
This function draws the text item textItem 在位置 p . The default implementation of this function converts the text to a QPainterPath and paints the resulting path.
[virtual]
void
QPaintEngine::
drawTiledPixmap
(const
QRectF
&
rect
, const
QPixmap
&
pixmap
, const
QPointF
&
p
)
重实现此函数以绘制 pixmap 以给定 rect , starting at the given p . The pixmap will be drawn repeatedly until the rect is filled.
[pure virtual]
bool
QPaintEngine::
end
()
Reimplement this function to finish painting on the current paint device. Return true if painting was finished successfully; otherwise return false.
返回
true
若描绘引擎支持指定
feature
；否则返回
false
.
返回
true
if the paint engine is actively drawing; otherwise returns
false
.
另请参阅 setActive ().
Returns the device that this engine is painting on, if painting is active; otherwise returns 0.
返回描绘引擎的描绘器。
将描绘引擎的活动状态设为 state .
另请参阅 isActive ().
[pure virtual]
Type
QPaintEngine::
type
() const
重实现此函数以返回描绘引擎 Type .
[pure virtual]
void
QPaintEngine::
updateState
(const
QPaintEngineState
&
state
)
Reimplement this function to update the state of a paint engine.
When implemented, this function is responsible for checking the paint engine's current state and update the properties that are changed. Use the QPaintEngineState::state () function to find out which properties that must be updated, then use the corresponding get function to retrieve the current values for the given properties.
另请参阅 QPaintEngineState .