How do I recolor an image? (see images)

Question

How do I achieve this kind of color replacement programmatically?

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So this i

Answer 1

If any Android devs end up looking at this, this is what I came up with to gray scale and tint an image using CodesInChaos's formula and the android graphics classes ColorMatrix and ColorMatrixColorFilter.

Thanks for the help!

public static ColorFilter getColorFilter(Context context) {
    final int tint = ContextCompat.getColor(context, R.color.tint);

    final float R = Color.red(tint);
    final float G = Color.green(tint);
    final float B = Color.blue(tint);

    final float Rs = R / 255;
    final float Gs = G / 255;
    final float Bs = B / 255;

    // resultColor = oldColor + (1 - oldColor/255) * tintColor
    final float[] colorTransform = {
            1, -Rs, 0, 0, R,
            1, -Gs, 0, 0, G,
            1, -Bs, 0, 0, B,
            0, 0, 0, 0.9f, 0};

    final ColorMatrix grayMatrix = new ColorMatrix();
    grayMatrix.setSaturation(0f);
    grayMatrix.postConcat(new ColorMatrix(colorTransform));
    return new ColorMatrixColorFilter(grayMatrix);
}

The ColorFilter can then be applied to an ImageView

imageView.setColorFilter(getColorFilter(imageView.getContext()));