Blender modes for android

Blender.java

package com.example.blendmodes;

import android.graphics.Bitmap;
import android.util.Log;

public class Blender {

    private static final String TAG = Blender.class.getSimpleName();

    public static Bitmap performBlending(Bitmap source, Bitmap destination, int mode) {
        return performBlending(source, destination, mode, 1F);
    }

    public static Bitmap performBlending(Bitmap source, Bitmap destination, int mode, float alpha) {
        int width = source.getWidth();
        int height = source.getHeight();
        int srcPixels[] = new int[width * height];;
        int destPixels[] = new int[width * height];
        int resultPixels[] = new int[width * height];
        int aS = 0, rS = 0, gS = 0, bS = 0;
        int rgbS = 0;
        int aD = 0, rD = 0, gD = 0, bD = 0;
        int rgbD = 0;

        try
        {
            source.getPixels(srcPixels, 0, width, 0, 0, width, height);
            destination.getPixels(destPixels, 0, width, 0, 0, width, height);
            source.recycle();
            destination.recycle();
        }
        catch(IllegalArgumentException e) {
        }
        catch(ArrayIndexOutOfBoundsException e) {
        }

        if (mode == Mode.SOFT_LIGHT || mode == Mode.OVERLAY) {
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    rgbS = srcPixels[y * width + x];
                    aS = (rgbS >> 24) & 0xff;
                    rS = (rgbS >> 16) & 0xff;
                    gS = (rgbS >> 8) & 0xff;
                    bS = (rgbS) & 0xff;

                    rgbD = destPixels[y * width + x];
                    aD = (rgbD >> 24) & 0xff;
                    rD = (rgbD >> 16) & 0xff;
                    gD = (rgbD >> 8) & 0xff;
                    bD = (rgbD) & 0xff;

                    rS = blendByte(rD, rS, mode);
                    gS = blendByte(gD, gS, mode);
                    bS = blendByte(bD, bS, mode);
                    aS = aS + aD - Math.round((aS * aD) / 255f);

                    resultPixels[y * width + x] = ((int) aS << 24) | ((int) rS << 16) | ((int) gS << 8) | (int) bS;
                }
            }
        } else {
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    rgbS = srcPixels[y * width + x];
                    aS = (rgbS >> 24) & 0xff;
                    rS = (rgbS >> 16) & 0xff;
                    gS = (rgbS >> 8) & 0xff;
                    bS = (rgbS) & 0xff;
                    Color S = new Color(aS, rS, gS, bS);

                    rgbD = destPixels[y * width + x];
                    aD = (rgbD >> 24) & 0xff;
                    rD = (rgbD >> 16) & 0xff;
                    gD = (rgbD >> 8) & 0xff;
                    bD = (rgbD) & 0xff;
                    Color D = new Color(aD, rD, gD, bD);

                    Color resultColor = setLum(D, lum(S));

                    rS = resultColor.r;
                    gS = resultColor.g;
                    bS = resultColor.b;
                    aS = aS + aD - Math.round((aS * aD) / 255f);

                    resultPixels[y * width + x] = ((int) aS << 24) | ((int) rS << 16) | ((int) gS << 8) | (int) bS;
                }
            }
        }

        return Bitmap.createBitmap(resultPixels, width, height, source.getConfig());
    }

    private static int blendByte(int colChannelDest, int colChannelSrc, int mode) {
        int result = 0;
        switch (mode) {
            case Mode.SOFT_LIGHT:
                result = softLightBlendByte(colChannelDest, colChannelSrc);
                break;
            case Mode.OVERLAY:
                result = overlayBlendByte(colChannelDest, colChannelSrc);
        }
        return result;
    }

    /** http://stackoverflow.com/questions/5919663/how-does-photoshop-blend-two-images-together */
    private static int softLightBlendByte(int A, int B) {
        return ((int) ( (B < 128) ? (2*((A>>1)+64))*((float)B/255) : (255-(2*(255-((A>>1)+64))*(float)(255-B)/255))));
    }

    /** http://stackoverflow.com/questions/5919663/how-does-photoshop-blend-two-images-together */
    private static int overlayBlendByte(int A, int B) {
        return (((B < 128) ? (2 * A * B / 255) : (255 - 2 * (255 - A) * (255 - B) / 255)));
    }

    private static Color setLum(Color c, int l) {
        int d = l - lum(c);
        c.r += d;
        c.g += d;
        c.b += d;

        return clipColor(c);
    }

    private static int lum(Color c) {
        return (int) Math.round((0.3 * c.r) + (0.59 * c.g) + (0.11 * c.b));
    }

    private static Color clipColor(Color c) {
        int l = lum(c);
        int n = Math.min(Math.min(c.r, c.g), c.b);
        int x = Math.max(Math.max(c.r, c.g), c.b);
        Color resCol = new Color();

        resCol.r = clipChannel(c.r, l, n, x);
        resCol.g = clipChannel(c.g, l, n, x);
        resCol.b = clipChannel(c.b, l, n, x);

        return clamp(resCol, 0, 255);
    }

    private static int clipChannel(int ch, int l, int n, int x) {
        ch = (n < 0) ? l + (((ch - l) * l) / (l - n)) : ch;
        ch = (x > 255) ? l + (((ch - l) * (255 - l)) / (x - l)) : ch;
        return ch;
    }

    public static Color clamp(Color c, int min, int max) {
        c.r = clamp(c.r, min, max);
        c.g = clamp(c.g, min, max);
        c.b = clamp(c.b, min, max);
        return c;
    }

    public static int clamp(int c, int min, int max) {
        if (c < min) {
//            Log.d(TAG, "Clamped: " + c + " > " + min);
            return min;
        }
        else if(c > max) {
//            Log.d(TAG, "Clamped: " + c + " > " + max);
            return max;
        }
        else return c;
    }

    public static class Mode {

        public static final int SOFT_LIGHT = 42;
        public static final int OVERLAY = 43;
        public static final int COLOR = 44;
    }

    private static class Color {
        public int a;
        public int r;
        public int g;
        public int b;

        public Color() {
            new Color(0, 0, 0, 0);
        }

        public Color(int a, int r, int g, int b) {
            this.a = a;
            this.r = r;
            this.g = g;
            this.b = b;
        }
    }
}