public static WriteableBitmap ConvertToGrayScale(ZoomBorder border, BitmapImage source, Int32Rect roi)
{
WriteableBitmap wb = new WriteableBitmap(source);
int[] grayPixels = new int[wb.PixelWidth * wb.PixelHeight];
int widthInBytes = 4 * wb.PixelWidth;
wb.CopyPixels(grayPixels, widthInBytes, 0);
//foreach (int x in index)
for (int x = 0; x < wb.PixelWidth * wb.PixelHeight; x++)
{
// get the pixel
int pixel = grayPixels[x];
// get the component
int red = (pixel & 0x00FF0000) >> 16;
int blue = (pixel & 0x0000FF00) >> 8;
int green = (pixel & 0x000000FF);
// get the average
int average = (byte)((red + blue + green) / 3);
// assign the gray values keep the alpha
unchecked
{
grayPixels[x] = (int)((pixel & 0xFF000000) | (average << 16) | (average << 8) | average);
}
}
if (roi.Height > 0 && roi.Width > 0)
{
roi = RoiToPixel(border, source, roi);
wb.WritePixels(roi, grayPixels, widthInBytes, (roi.Y * source.PixelWidth) + roi.X);
}
else
{
wb.WritePixels(new Int32Rect(0, 0, wb.PixelWidth, wb.PixelHeight), grayPixels, widthInBytes, 0);
}
return(wb);
}
