ImageUtil

ImageUtil.java

public class ImageUtil {

    public static void setColorFilter(ImageView imageView, int color) {
        final float r = Color.red(color) / 255f;
        final float g = Color.green(color) / 255f;
        final float b = Color.blue(color) / 255f;
        final float a = Color.alpha(color) / 255f;
        setColorFilter(imageView, r, g, b, a);
    }

    public static void setColorFilter(ImageView imageView, float r, float g, float b, float a) {
        /*
         * 5x4 matrix for transforming the color+alpha components of a Bitmap.
         * The matrix is stored in a single array, and its treated as follows:
         * [  a, b, c, d, e,
         *   f, g, h, i, j,
         *   k, l, m, n, o,
         *   p, q, r, s, t ]
         *
         * When applied to a color [r, g, b, a], the resulting color is computed
         * as (after clamping)
         * R' = a*R + b*G + c*B + d*A + e;
         * G' = f*R + g*G + h*B + i*A + j;
         * B' = k*R + l*G + m*B + n*A + o;
         * A' = p*R + q*G + r*B + s*A + t;
         */
        float[] colorMatrix = { //
                r, 0, 0, 0, 0,  //red
                0, g, 0, 0, 0, //green
                0, 0, b, 0, 0,  //blue
                0, 0, 0, a, 0    //alpha
        };

        ColorFilter colorFilter = new ColorMatrixColorFilter(colorMatrix);
        imageView.setColorFilter(colorFilter);
    }

}