The QCustomRasterPaintDevice class is provided to activate hardware accelerated paint engines in Qt for Embedded Linux. 更多...
| 头： | #include <QCustomRasterPaintDevice> |
| Since: | Qt 4.2 |
| 继承： | QPaintDevice |
该类在开发且可能改变。
| QCustomRasterPaintDevice (QWidget * widget ) | |
| virtual int | bytesPerLine () const |
| virtual QImage::Format | format () const |
| virtual void * | memory () const |
| virtual int | metric (PaintDeviceMetric m ) const |
The QCustomRasterPaintDevice class is provided to activate hardware accelerated paint engines in Qt for Embedded Linux.
注意，此类只可用于 Qt for Embedded Linux .
在 Qt for Embedded Linux , painting is a pure software implementation. But starting with Qt 4.2, it is possible to add an accelerated graphics driver to take advantage of available hardware resources.
Hardware acceleration is accomplished by creating a custom screen driver, accelerating the copying from memory to the screen, and implementing a custom paint engine accelerating the various painting operations. Then a custom paint device (derived from the QCustomRasterPaintDevice class) and a custom window surface (derived from QWSWindowSurface) must be implemented to make Qt for Embedded Linux aware of the accelerated driver.
见 Adding an Accelerated Graphics Driver to Qt for Embedded Linux 文档编制了解细节。
另请参阅 QRasterPaintEngine and QPaintDevice .
Constructs a custom raster based paint device for the given top-level widget .
[虚拟]
int
QCustomRasterPaintDevice::
bytesPerLine
() const
Returns the number of bytes per line in the framebuffer. Note that this number might be larger than the framebuffer width.
[虚拟]
QImage::Format
QCustomRasterPaintDevice::
format
() const
Returns the format of the device's memory buffet.
默认格式为 QImage::Format_ARGB32_Premultiplied . The only other valid format is QImage::Format_RGB16 .
[虚拟]
void
* QCustomRasterPaintDevice::
memory
() const
Returns a pointer to the paint device's memory buffer, or 0 if no such buffer exists.
[虚拟]
int
QCustomRasterPaintDevice::
metric
(
PaintDeviceMetric
m
) const
重实现自 QPaintDevice::metric ().