Java tutorial
//package com.java2s; //License from project: Apache License import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.ColorMatrix; import android.graphics.ColorMatrixColorFilter; import android.graphics.Paint; public class Main { public static Bitmap greyScale(Bitmap source) { int width = source.getWidth(); int height = source.getHeight(); Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); ColorMatrix saturation = new ColorMatrix(); saturation.setSaturation(0f); Paint paint = new Paint(); paint.setColorFilter(new ColorMatrixColorFilter(saturation)); canvas.drawBitmap(source, 0, 0, paint); source.recycle(); if (source != bitmap) { source.recycle(); } return bitmap; } }