PALM 实现离屏与局部刷新

 终于是搞定了PALM的离屏与局部刷新了，但由于PALM OS本身的问题效果并不是很明显

 

/******************************************************************************
 * 函数：InitBitmap
 * 功能：创建一个图位并得到位图数据区  

 * 参数：
 * 返回：
 * 修改：
 ******************************************************************************/
static Int16 InitBitmap()
{
 UInt32 deep = 16;
 UInt8  ena = 1;
 UInt16 err;
 Err error;

    // Set coordinate system to native.
    oldCoord = WinSetCoordinateSystem(kCoordinatesStandard);
    //Set depth 
    error = WinScreenMode(winScreenModeSet, NULL, NULL, &deep,&ena ); 
    // Create a nativeFormat offscreen window.
    winH = WinCreateOffscreenWindow(LCDWIDTH, LCDHEIGHT, screenFormat, &error);//nativeFormat
    if (error)
    {
  // Restore the old coordinate system.
  WinSetCoordinateSystem(oldCoord);
  return;
 }
 
 bmpP = WinGetBitmap(winH);
 // Set the density of the bitmap to low first.
 testDep = BmpGetBitDepth(bmpP);
 BmpSetDensity(bmpP, kDensityLow);
 bitBuffer = BmpGetBits(bmpP); 
 BmpGetDimensions(bmpP, &bmw, &bmh, &bmrb); 

 return 1;
}
 /******************************************************************************
 * 函数：UpdateBitmapData
 * 功能：更新位图数据区
 * 参数：
 * 返回：
 * 修改：
 ******************************************************************************/
Int16 UpdateBitmapData()
{
 int x,  y,  width,  height;

 if (CHandleEvent(hm,_TIMER, 0, 0))
 {

  if (CGetUpdateRect(hm,&x, &y, &width, &height))
  {

{
 UInt32 WinVersion;
 RectangleType rect;
 Err error;

 // Get the window version.
 FtrGet(sysFtrCreator, sysFtrNumWinVersion, &WinVersion);
 // If doesn't support high density, draw the bitmap here.
 if (WinVersion < 4)
 {
     WinPaintBitmap (bmpP, 0, 0);
  return;
 }
 else
 {
     UInt32 density;
     // Get the density of the screen.
     error = WinScreenGetAttribute(winScreenDensity, &density);
     if (!error && (density != kDensityDouble))
     {
     WinDrawBitmap (bmpP, 0, 0);
   return;   
     }
     else
     {
   // Set the draw window to the offscreen window.
   oldWinH = WinSetDrawWindow(winH);

  
   rect.topLeft.x = x;
   rect.topLeft.y = y;
   rect.extent.x = width;
   rect.extent.y = height;

   // Draw the bitmap on the offscreen window.
   WinDrawBitmap(bmpP, 0, 0);     
   // Set the density of the bitmap to double.
   BmpSetDensity(bmpP, kDensityDouble);
   // Set the draw window back to main window.
   WinSetDrawWindow(oldWinH); 
   // Copy the bitmap from the offscreen window to main window
   WinCopyRectangle(winH, oldWinH, &rect, x, y, winPaint);
   // Restore the coordinate system.
   WinSetCoordinateSystem(oldCoord);
     }

 }
}
  }
 }
 
 return 0;
}