public class FastBlur{public static Bitmap doBlur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {// This is a compromise between Gaussian Blur and Box blur// 這是一個妥協于高斯模糊和方形模糊的產物// It creates much better looking blurs than Box Blur, but is// 他不但看上去的模糊效果比方形模糊更好，而且實現速度比高斯模糊要快// 7x faster than my Gaussian Blur implementation.// I called it Stack Blur because this describes best how this// 我叫他堆棧模糊，因為他很好的闡述了過濾器是如何在內存中工作的。// filter works internally: it creates a kind of moving stack// of colors whilst scanning through the image. Thereby it// 他實現了在移動顏色的棧的同時對圖片進行掃描。// just has to add one new block of color to the right side// 其實它只是在棧的右邊添加了一個新的顏色塊，然后移除了最左邊的顏色。// of the stack and remove the leftmost color. The remaining// 在棧最上層模塊的剩余顏色塊由他們所處的區域是屬于棧右邊還是左邊來決定是增加還是刪除// colors on the topmost layer of the stack are either added on// or reduced by one, depending on if they are on the right or// on the left side of the stack.//// If you are using this algorithm in your code please add// the following line:// 如果你在你的代碼中使用這個算法，請添加下面這行// Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>// 堆棧模糊算法由Mario Klingemann <mario@quasimondo.com>所創作Bitmap bitmap;if (canReuseInBitmap) {bitmap = sentBitmap;} else {//決定圖片像素點的存儲，即用圖片查看器看圖片屬性時候的位深參數。bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);}if (radius < 1) {return (null);}int w = bitmap.getWidth();int h = bitmap.getHeight();int[] pix = new int[w * h];bitmap.getPixels(pix, 0, w, 0, 0, w, h);int wm = w - 1;int hm = h - 1;int wh = w * h;int div = radius + radius + 1;int r[] = new int[wh];int g[] = new int[wh];int b[] = new int[wh];int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;int vmin[] = new int[Math.max(w, h)];int divsum = (div + 1) >> 1;divsum *= divsum;int dv[] = new int[256 * divsum];for (i = 0; i < 256 * divsum; i++) {dv[i] = (i / divsum);}yw = yi = 0;int[][] stack = new int[div][3];int stackpointer;int stackstart;int[] sir;int rbs;int r1 = radius + 1;int routsum, goutsum, boutsum;int rinsum, ginsum, binsum;for (y = 0; y < h; y++) {rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;for (i = -radius; i <= radius; i++) {p = pix[yi + Math.min(wm, Math.max(i, 0))];sir = stack[i + radius];sir[0] = (p & 0xff0000) >> 16;sir[1] = (p & 0x00ff00) >> 8;sir[2] = (p & 0x0000ff);rbs = r1 - Math.abs(i);rsum += sir[0] * rbs;gsum += sir[1] * rbs;bsum += sir[2] * rbs;if (i > 0) {rinsum += sir[0];ginsum += sir[1];binsum += sir[2];} else {routsum += sir[0];goutsum += sir[1];boutsum += sir[2];}}stackpointer = radius;for (x = 0; x < w; x++) {r[yi] = dv[rsum];g[yi] = dv[gsum];b[yi] = dv[bsum];rsum -= routsum;gsum -= goutsum;bsum -= boutsum;stackstart = stackpointer - radius + div;sir = stack[stackstart % div];routsum -= sir[0];goutsum -= sir[1];boutsum -= sir[2];if (y == 0) {vmin[x] = Math.min(x + radius + 1, wm);}p = pix[yw + vmin[x]];sir[0] = (p & 0xff0000) >> 16;sir[1] = (p & 0x00ff00) >> 8;sir[2] = (p & 0x0000ff);rinsum += sir[0];ginsum += sir[1];binsum += sir[2];rsum += rinsum;gsum += ginsum;bsum += binsum;stackpointer = (stackpointer + 1) % div;sir = stack[(stackpointer) % div];routsum += sir[0];goutsum += sir[1];boutsum += sir[2];rinsum -= sir[0];ginsum -= sir[1];binsum -= sir[2];yi++;}yw += w;}for (x = 0; x < w; x++) {rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;yp = -radius * w;for (i = -radius; i <= radius; i++) {yi = Math.max(0, yp) + x;sir = stack[i + radius];sir[0] = r[yi];sir[1] = g[yi];sir[2] = b[yi];rbs = r1 - Math.abs(i);rsum += r[yi] * rbs;gsum += g[yi] * rbs;bsum += b[yi] * rbs;if (i > 0) {rinsum += sir[0];ginsum += sir[1];binsum += sir[2];} else {routsum += sir[0];goutsum += sir[1];boutsum += sir[2];}if (i < hm) {yp += w;}}yi = x;stackpointer = radius;for (y = 0; y < h; y++) {// Preserve alpha channel: ( 0xff000000 & pix[yi] )pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];rsum -= routsum;gsum -= goutsum;bsum -= boutsum;stackstart = stackpointer - radius + div;sir = stack[stackstart % div];routsum -= sir[0];goutsum -= sir[1];boutsum -= sir[2];if (x == 0) {vmin[y] = Math.min(y + r1, hm) * w;}p = x + vmin[y];sir[0] = r[p];sir[1] = g[p];sir[2] = b[p];rinsum += sir[0];ginsum += sir[1];binsum += sir[2];rsum += rinsum;gsum += ginsum;bsum += binsum;stackpointer = (stackpointer + 1) % div;sir = stack[stackpointer];routsum += sir[0];goutsum += sir[1];boutsum += sir[2];rinsum -= sir[0];ginsum -= sir[1];binsum -= sir[2];yi += w;}}bitmap.setPixels(pix, 0, w, 0, 0, w, h);return (bitmap);}}public class MainActivity extends AppCompatActivity {//這個方法不會oom/** 在addOnPreDrawListener中來調用blur方法是為了能夠在onCreate中獲取控件尺寸，通過scaleFactor和radius兩個參數，來控制Blur的程度。* */@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);final ImageView imageView = (ImageView) findViewById(R.id.img);final Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.back1);imageView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {@Overridepublic boolean onPreDraw() {blur(bitmap, imageView);return true;}});}private void blur(Bitmap bkg, View view) {long startMs = System.currentTimeMillis();float scaleFactor = 8;float radius = 20;Bitmap overlay = Bitmap.createBitmap((int) (view.getMeasuredWidth() / scaleFactor),(int) (view.getMeasuredHeight() / scaleFactor),Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(overlay);canvas.translate(-view.getLeft() / scaleFactor, -view.getTop()/ scaleFactor);canvas.scale(1 / scaleFactor, 1 / scaleFactor);Paint paint = new Paint();paint.setFlags(Paint.FILTER_BITMAP_FLAG);canvas.drawBitmap(bkg, 0, 0, paint);overlay = FastBlur.doBlur(overlay, (int) radius, true);view.setBackground(new BitmapDrawable(getResources(), overlay));}}