private static Rectangle TrimTransparentFindHeight(UnsafeBitmap unsafeBitmap, Rectangle rect)
{
for (int y = rect.Height - 1; y >= rect.Y; y--)
{
for (int x = rect.X; x < rect.Width; x++)
{
if (unsafeBitmap.GetPixel(x, y).Alpha > 0)
{
rect.Height = y - rect.Y + 1;
return(rect);
}
}
}
return(rect);
}
private static Rectangle TrimTransparentFindY(UnsafeBitmap unsafeBitmap, Rectangle rect)
{
for (int y = rect.Y; y < rect.Height; y++)
{
for (int x = rect.X; x < rect.Width; x++)
{
if (unsafeBitmap.GetPixel(x, y).Alpha > 0)
{
rect.Y = y;
return(rect);
}
}
}
return(rect);
}
private static Rectangle TrimTransparentFindWidth(UnsafeBitmap unsafeBitmap, Rectangle rect)
{
for (int x = rect.Width - 1; x >= rect.X; x--)
{
for (int y = rect.Y; y < rect.Height; y++)
{
if (unsafeBitmap.GetPixel(x, y).Alpha > 0)
{
rect.Width = x - rect.X + 1;
return(rect);
}
}
}
return(rect);
}
private static Bitmap CreateTransparentImage(Bitmap whiteBackground, Bitmap blackBackground)
{
if (whiteBackground != null && blackBackground != null && whiteBackground.Size == blackBackground.Size)
{
Bitmap result = new Bitmap(whiteBackground.Width, whiteBackground.Height, PixelFormat.Format32bppArgb);
using (UnsafeBitmap whiteBitmap = new UnsafeBitmap(whiteBackground, true, ImageLockMode.ReadOnly))
using (UnsafeBitmap blackBitmap = new UnsafeBitmap(blackBackground, true, ImageLockMode.ReadOnly))
using (UnsafeBitmap resultBitmap = new UnsafeBitmap(result, true, ImageLockMode.WriteOnly))
{
int pixelCount = blackBitmap.PixelCount;
for (int i = 0; i < pixelCount; i++)
{
ColorBgra white = whiteBitmap.GetPixel(i);
ColorBgra black = blackBitmap.GetPixel(i);
double alpha = (black.Red - white.Red + 255) / 255.0;
if (alpha == 1)
{
resultBitmap.SetPixel(i, white);
}
else if (alpha > 0)
{
white.Blue = (byte)(black.Blue / alpha);
white.Green = (byte)(black.Green / alpha);
white.Red = (byte)(black.Red / alpha);
white.Alpha = (byte)(255 * alpha);
resultBitmap.SetPixel(i, white);
}
}
}
return(result);
}
return(whiteBackground);
}
private static void TrimShadow(Bitmap bitmap)
{
int sizeLimit = 10;
int alphaLimit = 200;
using (UnsafeBitmap unsafeBitmap = new UnsafeBitmap(bitmap, true))
{
for (int i = 0; i < sizeLimit; i++)
{
int y = i;
int width = bitmap.Width;
// Left top
for (int x = 0; x < sizeLimit; x++)
{
if (unsafeBitmap.GetPixel(x, y).Alpha < alphaLimit)
{
unsafeBitmap.ClearPixel(x, y);
}
else
{
break;
}
}
// Right top
for (int x = width - 1; x > width - sizeLimit - 1; x--)
{
if (unsafeBitmap.GetPixel(x, y).Alpha < alphaLimit)
{
unsafeBitmap.ClearPixel(x, y);
}
else
{
break;
}
}
y = bitmap.Height - i - 1;
// Left bottom
for (int x = 0; x < sizeLimit; x++)
{
if (unsafeBitmap.GetPixel(x, y).Alpha < alphaLimit)
{
unsafeBitmap.ClearPixel(x, y);
}
else
{
break;
}
}
// Right bottom
for (int x = width - 1; x > width - sizeLimit - 1; x--)
{
if (unsafeBitmap.GetPixel(x, y).Alpha < alphaLimit)
{
unsafeBitmap.ClearPixel(x, y);
}
else
{
break;
}
}
}
}
}