Convert bitmap to sepia in android

Question

Is there any way to convert a Bitmap to sepia? I know to convert to grayScale is to set the setSaturation in ColorMatrix. But what about Sepia?

Answer 1

If you have instance of image then you can use ColorMartix to draw it in Sepia. Let me describe way how you can do this using Drawable.

public static void setSepiaColorFilter(Drawable drawable) {
  if (drawable == null)
    return;

  final ColorMatrix matrixA = new ColorMatrix();
  // making image B&W
  matrixA.setSaturation(0);

  final ColorMatrix matrixB = new ColorMatrix();
  // applying scales for RGB color values
  matrixB.setScale(1f, .95f, .82f, 1.0f);
  matrixA.setConcat(matrixB, matrixA);

  final ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrixA);
  drawable.setColorFilter(filter);
}

Sample project was moved from Bitbucket to GitHub. Please check Release section to download APK binary to test without compiling.

Answer 2

I know the answer, but maybe if some have other better solution..

public Bitmap toSephia(Bitmap bmpOriginal)
{        
    int width, height, r,g, b, c, gry;
    height = bmpOriginal.getHeight();
    width = bmpOriginal.getWidth();
    int depth = 20;

    Bitmap bmpSephia = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bmpSephia);
    Paint paint = new Paint();
    ColorMatrix cm = new ColorMatrix();
    cm.setScale(.3f, .3f, .3f, 1.0f);   
    ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
    paint.setColorFilter(f);
    canvas.drawBitmap(bmpOriginal, 0, 0, paint);
    for(int x=0; x < width; x++) {
        for(int y=0; y < height; y++) {
            c = bmpOriginal.getPixel(x, y);

            r = Color.red(c);
            g = Color.green(c);
            b = Color.blue(c);

            gry = (r + g + b) / 3;
            r = g = b = gry;

            r = r + (depth * 2);
            g = g + depth;

            if(r > 255) {
              r = 255;
            }
            if(g > 255) {
              g = 255;
            }
            bmpSephia.setPixel(x, y, Color.rgb(r, g, b));
        }
    }      
    return bmpSephia;
}

Answer 3

I've improved on the OP's answer. This runs competitively fast when compared to the ColorMatrix method, but producing a nicer brown tone. (in my opinion)

public Bitmap toSepiaNice(Bitmap color) {
    int red, green, blue, pixel, gry;
    int height = color.getHeight();
    int width = color.getWidth();
    int depth = 20;

    Bitmap sepia = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

    int[] pixels = new int[width * height];
    color.getPixels(pixels, 0, width, 0, 0, width, height);
    for (int i = 0; i < pixels.length; i++) {
        pixel = pixels[i];

        red = (pixel >> 16) & 0xFF;
        green = (pixel >> 8) & 0xFF;
        blue = pixel & 0xFF;

        red = green = blue = (red + green + blue) / 3;

        red += (depth * 2);
        green += depth;

        if (red > 255)
            red = 255;
        if (green > 255)
            green = 255;
        pixels[i] = (0xFF << 24) | (red << 16) | (green << 8) | blue;
    }
    sepia.setPixels(pixels, 0, width, 0, 0, width, height);
    return sepia;
}