Thread: Transparency function not working

I am making a transparency function in GDI. The way it works is by making a mask image, which is a monochrome bitmap where all white areas is where the image is transparent and black where it is not. The color image's transparent color (this case 255,0,255) is set to black. The mask image is blitted to the window's DC, using the SRCAND (Boolean AND) raster operation, and then the color image is blitted on top of that using the SRCPAINT (Boolean OR) operation. Here is the code:

Code:

__declspec(dllexport) void
_NebGDI::DrawSpriteEx(HBITMAP hbitmap, HDC hdcTarget, int X, int Y, DWORD dwRaster)
{
  HBITMAP hbmMask;
  HDC hdcMem, hdcMem2;
  HBITMAP hbmOld, hbmOld2;
  BITMAP bmp;

  GetObject(hbitmap, sizeof(BITMAP), &bmp);
  hbmMask = CreateBitmap(bmp.bmWidth, bmp.bmHeight, 1,1, NULL);

  hdcMem = CreateCompatibleDC(0);
  hdcMem2= CreateCompatibleDC(0);

  hbmOld = (HBITMAP)SelectObject(hdcMem, hbitmap);
  hbmOld2= (HBITMAP)SelectObject(hdcMem2, hbmMask);

  SetBkColor(hdcMem, RGB(255,0,255));

  BitBlt(hdcMem2, 0, 0, bmp.bmWidth, bmp.bmHeight, hdcMem, 0, 0, SRCCOPY);
  BitBlt(hdcMem, 0, 0, bmp.bmWidth, bmp.bmHeight, hdcMem2, 0, 0, SRCINVERT);

  SelectObject(hdcMem, hbmMask);
  BitBlt(hdcTarget, X, Y, bmp.bmWidth, bmp.bmHeight, hdcMem, 0, 0, SRCAND);  
  SelectObject(hdcMem, hbitmap);
  BitBlt(hdcTarget, X, Y, bmp.bmWidth, bmp.bmHeight, hdcMem, 0, 0, SRCPAINT);

  SelectObject(hdcMem, hbmOld);
  SelectObject(hdcMem2, hbmOld2);

  DeleteDC(hdcMem);
  DeleteDC(hdcMem2);
  DeleteObject(hbmMask);
}

oops. The question is, why isn't it working?

I figured it out