java - 如何将一张普通图片转成64级灰度图片？

问题描述

如何将一张普通图片转成64级灰度图片？在Java或者Android平台上。

问题解答

public static Bitmap convertGreyImg(Bitmap img) {int width = img.getWidth(); //获取位图的宽int height = img.getHeight(); //获取位图的高int[] pixels = new int[width * height]; //通过位图的大小创建像素点数组img.getPixels(pixels, 0, width, 0, 0, width, height);int alpha = 0xFF << 24;for (int i = 0; i < height; i++) { for (int j = 0; j < width; j++) {int original = pixels[width * i + j];int red = ((original & 0x00FF0000) >> 16);int green = ((original & 0x0000FF00) >> 8);int blue = (original & 0x000000FF);int grey = (int) ((float) red * 0.3 + (float) green * 0.59 + (float) blue * 0.11);grey = alpha | (grey << 16) | (grey << 8) | grey;pixels[width * i + j] = grey; }}Bitmap result = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);result.setPixels(pixels, 0, width, 0, 0, width, height);return result; }

参考资料:Android实现图片相似度

去看下Android的这个类ColorMatrixAndroid的矩阵(一)：ColorMatrix