問題描述

如何將一張普通圖片轉成64級灰度圖片？在Java或者Android平臺上。

問題解答

public static Bitmap convertGreyImg(Bitmap img) {int width = img.getWidth(); //獲取位圖的寬int height = img.getHeight(); //獲取位圖的高int[] pixels = new int[width * height]; //通過位圖的大小創建像素點數組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; }

參考資料:Android實現圖片相似度

去看下Android的這個類ColorMatrixAndroid的矩陣(一)：ColorMatrix