Method CopyScaled

rEFIt_UEFI/libeg/XImage.cpp:201–231

sizes remain as were assumed input image is large enough?

//sizes remain as were assumed input image is large enough?
void XImage::CopyScaled(const XImage& Image, float scale)
{
  int SrcWidth = (int)Image.GetWidth(); //because Source[] requires int argument, why not long long int?

  int Pixel = sizeof(EFI_GRAPHICS_OUTPUT_BLT_PIXEL);
  int Row = SrcWidth * sizeof(EFI_GRAPHICS_OUTPUT_BLT_PIXEL);
  int W = (int)GetWidth();
  int H = (int)GetHeight();

  const XArray<EFI_GRAPHICS_OUTPUT_BLT_PIXEL>& Source = Image.GetData();

  for (INTN y = 0; y < H; y++) //destination coordinates
  {
    int ly = (int)(y / scale); //integer part of src coord
    float dy = y - ly * scale; //fractional part
    for (INTN x = 0; x < W; x++)
    {
      int lx = (int)(x / scale);
      float dx = x - lx * scale;
      int a01 = (lx == 0) ? 0 : -Pixel;
      int a10 = (ly == 0) ? 0 : -Row;
      int a21 = (lx == W - 1) ? 0 : Pixel;
      int a12 = (ly == H - 1) ? 0 : Row;
      EFI_GRAPHICS_OUTPUT_BLT_PIXEL& dst = *GetPixelPtr(x, y);
      dst.Blue = Smooth(&Source[lx + ly * SrcWidth].Blue, a01, a10, a21, a12, dx, dy, scale);
      dst.Green = Smooth(&Source[lx + ly * SrcWidth].Green, a01, a10, a21, a12, dx, dy, scale);
      dst.Red = Smooth(&Source[lx + ly * SrcWidth].Red, a01, a10, a21, a12, dx, dy, scale);
      dst.Reserved = Source[lx + ly * SrcWidth].Reserved;
    }
  }
}

/* Place Top image over this image at PosX,PosY
 * Lowest means final image is opaque