// Copy Pixels from the bitmap source into a PixelColor array, i.e., flattens out those pixels into one huge array
public static unsafe void CopyPixelsEx(this BitmapSource source, PixelColor[] pixels, int stride, int offset)
{
fixed (PixelColor* buffer = &pixels[0])
source.CopyPixels(
new System.Windows.Int32Rect(0, 0, source.PixelWidth, source.PixelHeight),
(IntPtr)(buffer + offset),
pixels.Length * sizeof(PixelColor),
stride);
}
public static void WritePixels(this WriteableBitmap bitmap, PixelColor[,] pixels, int x, int y)
{
int width = pixels.GetLength(0);
int height = pixels.GetLength(1);
bitmap.WritePixels(new System.Windows.Int32Rect(0, 0, width, height), pixels, width * 4 /* bpp of incoming pixels */, x, y);
}
// Given three images, return an image that highlights the differences in common betwen the main image and the first image,
// and the main image and a second image.
//public static PixelBitmap Difference(PixelBitmap mainImg, PixelBitmap img1, PixelBitmap img2, byte threshold)
public static PixelBitmap Difference(BitmapSource mainImgBM, BitmapSource img1BM, BitmapSource img2BM, byte threshold)
{
PixelBitmap mainImg = new PixelBitmap((BitmapSource)mainImgBM);
PixelBitmap img1 = new PixelBitmap((BitmapSource)img1BM);
PixelBitmap img2 = new PixelBitmap((BitmapSource)img2BM);
// if images are not same size , use the smaller of their dimensions
int width = Math.Min(mainImg.Width, img1.Width);
width = Math.Min(width, img2.Width);
int height = Math.Min(mainImg.Height, img1.Height);
height = Math.Min(height, img2.Height);
PixelColor[] pixelColor = new PixelColor[width * height]; //CHECK THIS - BOUNDS MAY NOT BE RIGHT
for (int i = 0; i < pixelColor.Length; i++)
{
byte b1 = (byte)Math.Abs(mainImg.Pixels[i].Blue - img1.Pixels[i].Blue);
byte b2 = (byte)Math.Abs(mainImg.Pixels[i].Blue - img2.Pixels[i].Blue);
byte b = PixelBitmap.TempCalc(threshold, b1, b2);
byte g1 = (byte)Math.Abs(mainImg.Pixels[i].Green - img1.Pixels[i].Green);
byte g2 = (byte)Math.Abs(mainImg.Pixels[i].Green - img2.Pixels[i].Green);
byte g = PixelBitmap.TempCalc(threshold, g1, g2);
byte r1 = (byte)Math.Abs(mainImg.Pixels[i].Red - img1.Pixels[i].Red);
byte r2 = (byte)Math.Abs(mainImg.Pixels[i].Red - img2.Pixels[i].Red);
byte r = PixelBitmap.TempCalc(threshold, r1, r2);
byte a = byte.MaxValue; // opaque
var diff = (byte)(b / 3 + g / 3 + r / 3);
var pixel = new PixelColor() { Alpha = a, Red = diff, Blue = diff, Green = diff };
pixelColor[i] = pixel;
}
return new PixelBitmap() { Width = width, Height = height, Pixels = pixelColor };
}
// Copy pixels form a source into the PixelColor array
unsafe void copyPixels(BitmapSource source, PixelColor[] pixels, int stride, int offset)
{
// fixed holds the item in memory while I am working on it
fixed (PixelColor* buffer = &pixels[0])
{
source.CopyPixels(
new System.Windows.Int32Rect(0, 0, source.PixelWidth, source.PixelHeight),
(IntPtr)(buffer + offset),
pixels.Length * sizeof(PixelColor),
stride);
}
}
// Given two images, return an image containing the visual difference between them
public static PixelBitmap operator -(PixelBitmap image1, PixelBitmap image2)
{
// if image1 is not same size as image2, use the smaller of their dimensions
int width = Math.Min (image1.Width, image2.Width) ;
int height = Math.Min (image1.Height, image2.Height);
//PixelColor[] pixelColor = new PixelColor[image1.Pixels.Length];
PixelColor[] pixelColor = new PixelColor[width * height];
for (int i = 0; i < pixelColor.Length; i++)
{
byte b = (byte) Math.Abs(image1.Pixels[i].Blue - image2.Pixels[i].Blue);
byte g = (byte)Math.Abs(image1.Pixels[i].Green - image2.Pixels[i].Green);
byte r = (byte)Math.Abs(image1.Pixels[i].Red - image2.Pixels[i].Red);
byte a = byte.MaxValue; // opaque
byte diff = (byte)(b / 3 + g / 3 + r / 3); // Average the differences
// Add that pixel to the image
PixelColor pixel = new PixelColor() { Alpha = a, Red = diff, Blue = diff, Green = diff };
pixelColor[i] = pixel;
}
return new PixelBitmap() { Width = width, Height = height, Pixels = pixelColor };
}
