symbian中的图像合并

24位色和1位色mask图合并为32位真彩色图片。

 struct col   //24位的像素点定义
  {
  TUint8 g;
  TUint8 b;
  TUint8 r;
  };
 
 struct cola   //32位的像素点定义
 {
  TUint8 g;
  TUint8 b;
  TUint8 r;
  TUint8 a;    //透明度 alpha, 用于图像合成

};

/*

Note：The alpha channel is normally used as an opacity channel. If a pixel has a value of 0% in its alpha channel, it is fully transparent (and, thus, invisible), whereas a value of 100% in the alpha channel gives a fully opaque pixel (traditional digital images). Values between 0% and 100% make it possible for pixels to show through a background like a glass (translucency), an effect not possible with simple binary (transparent or opaque) transparency. It allows easy image compositing. Alpha channel values can be expressed as a percentage, integer, or real number between 0 and 1 like RGB parameters.

*/

bitmap;24C

True colour display mode (24 bpp)

mask;1   

Monochrome display mode (1 bpp)

bitmap3->Create(bitmap->SizeInPixels(), EColor16MA);

/*

EColor16MA:Display mode with alpha (24bpp colour plus 8bpp alpha)

*/

bitmap->LockHeap();

bitmap3->LockHeap();

mask->LockHeap();

TSize s = bitmap->SizeInPixels();

 TInt scan = CFbsBitmap::ScanLineLength(bitmap->SizeInPixels().iWidth, bitmap->DisplayMode());
 TInt scan3 = CFbsBitmap::ScanLineLength(bitmap3->SizeInPixels().iWidth, bitmap3->DisplayMode());
 TInt scanm = CFbsBitmap::ScanLineLength(mask->SizeInPixels().iWidth, mask->DisplayMode());

 col* bit = (col*)bitmap->DataAddress();
 cola* bita = (cola*)bitmap3->DataAddress();
 TUint8* bitm = (TUint8*)mask->DataAddress();
 for (TInt i = 0; i < s.iHeight; i++)
  {
  TUint8* temp = bitm;
  for (TInt j = 0, m = 0; j < s.iWidth; j++, m++)
   {
   Mem::Copy((void*)&(bita[j]), &bit[j], sizeof(col));
   
   
   bita[j].a = (((*temp)>>m) & 1) == 0 ? 255 : 0;
   if (m == 7)
    {
    temp++;
    m = -1;
    }
   }
  bit = (col*)((TUint8*)(bit) + scan);
  bita = (cola*)((TUint8*)(bita) + scan3);
  bitm = bitm + scanm;
  }

 

bitmap->UnlockHeap();

bitmap3->UnlockHeap();

mask->UnlockHeap();