Re: Sepia tone image filter for Java

After spending hours searching the web and not finding an answer, I
finally put together a function to create sepia images with Java.
This function produces amazing results, I'm very happy with it. I
hope it saves everyone time...

(You'll need your image to be in a BufferedImage object. The web has
plenty of tutorials for that.)

/**
   *
   * @param img Image to modify
   * @param sepiaIntensity From 0-255, 30 produces nice results
   * @throws Exception
   */
public static void applySepiaFilter(BufferedImage img, int
sepiaIntensity) throws Exception
{
  // Play around with this. 20 works well and was recommended
  // by another developer. 0 produces black/white image
  int sepiaDepth = 20;

  int w = img.getWidth();
  int h = img.getHeight();

  WritableRaster raster = img.getRaster();

  // We need 3 integers (for R,G,B color values) per pixel.
  int[] pixels = new int[w*h*3];
  raster.getPixels(0, 0, w, h, pixels);

  // Process 3 ints at a time for each pixel. Each pixel has 3 RGB
colors in array
  for (int i=0;i<pixels.length; i+=3)
  {
    int r = pixels[i];
    int g = pixels[i+1];
    int b = pixels[i+2];

    int gry = (r + g + b) / 3;
    r = g = b = gry;
    r = r + (sepiaDepth * 2);
    g = g + sepiaDepth;

    if (r>255) r=255;
    if (g>255) g=255;
    if (b>255) b=255;

    // Darken blue color to increase sepia effect
    b-= sepiaIntensity;

    // normalize if out of bounds
    if (b<0) b=0;
    if (b>255) b=255;

    pixels[i] = r;
    pixels[i+1]= g;
    pixels[i+2] = b;
  }
  raster.setPixels(0, 0, w, h, pixels);
}