about image operation:bitblt

[iGoo]

Hi,folks:

I QT4,We can use QLabel::setPixmap to render an image.

Can I use windows raw api bitblt to draw the image?How?
what's the difference(in efficiency),then

typeproto:

BOOL BitBlt(
  HDC hdcDest, // handle to destination DC
  int nXDest,  // x-coord of destination upper-left corner
  int nYDest,  // y-coord of destination upper-left corner
  int nWidth,  // width of destination rectangle
  int nHeight, // height of destination rectangle
  HDC hdcSrc,  // handle to source DC
  int nXSrc,   // x-coordinate of source upper-left corner
  int nYSrc,   // y-coordinate of source upper-left corner
  DWORD dwRop  // raster operation code
);

BOOL BitBlt(
  HDC hdcDest, // handle to destination DC
  int nXDest,  // x-coord of destination upper-left corner
  int nYDest,  // y-coord of destination upper-left corner
  int nWidth,  // width of destination rectangle
  int nHeight, // height of destination rectangle
  HDC hdcSrc,  // handle to source DC
  int nXSrc,   // x-coordinate of source upper-left corner
  int nYSrc,   // y-coordinate of source upper-left corner
  DWORD dwRop  // raster operation code
);

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I think the KEY is how get the coordinate "hdcDest"


Any advice will be appreciated.

Thanks in advance.

[wysota]

If you're using Qt3, you can use bitBlt from Qt. If you're using Qt4 I don't think you should use native WinAPI calls to do the drawing, because Qt uses a backing store and this would probably ruin it.

Maybe you should just try to improve the efficiency of the rendering itself? For example by making as less conversions between classes as possible (especially QImage <=> QPixmap).