1. 程式人生 > >Android 高斯模糊效果從319ms到3ms的優化實現

Android 高斯模糊效果從319ms到3ms的優化實現

之前做過高斯模糊的的效果,不過依賴一個三方庫,今天看到了一篇文章,一個類檔案就能解決,感覺竊喜,分享給大家。

使用:

Glide.with(getActivity()).load(mUser.avatarUrl).asBitmap().into(new SimpleTarget<Bitmap>() {
                                @Override
                                public void onResourceReady(Bitmap resource, GlideAnimation<? super
Bitmap> glideAnimation) { if(resource != null) { StackBlurManager stackBlurManager = new StackBlurManager(resource); Bitmap bitmap = stackBlurManager.process(20); mUserContainer.setBackground(new
BitmapDrawable(getResources(),bitmap)); } } });

使用簡單方便。

正文開始。

我要做的效果就是自定義image大小,自定義高斯模糊的區域,這樣才算我要的效果。

先上圖分別是優化前和優化後的,大家可想這個優化的作用多麼巨大,我直接把這個效果的顯示耗時在介面繪製出來了,下面圖片中的單位打錯了額,是ms。

3ms VS 209ms
這裡寫圖片描述

這裡寫圖片描述

4ms VS 197ms
這裡寫圖片描述

這裡寫圖片描述

說下實現吧,那個演算法我就沒有怎麼研究了,直接是個演算法類,直接把要模糊的Bitmap傳進去返回的就是模糊後的。程式碼如下:

public class FastBlur {

    public static Bitmap doBlur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {

        // Stack Blur v1.0 from
        // http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
        //
        // Java Author: Mario Klingemann <mario at="" quasimondo.com="">
        // http://incubator.quasimondo.com
        // created Feburary 29, 2004
        // Android port : Yahel Bouaziz <yahel at="" kayenko.com="">
        // http://www.kayenko.com
        // ported april 5th, 2012

        // This is a compromise between Gaussian Blur and Box blur
        // It creates much better looking blurs than Box Blur, but is
        // 7x faster than my Gaussian Blur implementation.
        //
        // I called it Stack Blur because this describes best how this
        // filter works internally: it creates a kind of moving stack
        // of colors whilst scanning through the image. Thereby it
        // just has to add one new block of color to the right side
        // of the stack and remove the leftmost color. The remaining
        // 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:
        //
        // Stack Blur Algorithm by Mario Klingemann <[email protected]>

        Bitmap bitmap;
        if (canReuseInBitmap) {
            bitmap = sentBitmap;
        } else {
            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);
    }
}

接下來就是在程式碼中去用了。

先上優化前的方法:因為下面紅字部分那句的程式碼把我坑慘了,原來用了matrix,在新建的時候還是要用matrix前的大小,我也是暈的不要不要的了。。。

還有注意要根據演示區域的大小,縮放bitmap的大小後再剪裁,再模糊。
這裡順便熟悉了canvas,drawBitmap,放大縮小的一些方法

public void test(View v) {

        Bitmap srcbitmap = BitmapFactory.decodeResource(getResources(),
                R.drawable.meitu);
        long t1 = System.currentTimeMillis();
        imageView.setBackground(new BitmapDrawable(getResources(), srcbitmap));// 設定大背景

        Bitmap backBitmap = Bitmap.createBitmap(textView.getMeasuredWidth(),// 設定需高斯模糊的背景
                textView.getMeasuredHeight(), Config.RGB_565);

        float f1 = (float) imageView.getMeasuredWidth()
                / (float) srcbitmap.getWidth();
        float f2 = (float) imageView.getMeasuredHeight()
                / (float) srcbitmap.getHeight();
        Matrix matrix = new Matrix();
        matrix.postScale(f1, f2);
        Bitmap desBitmap = Bitmap.createBitmap(srcbitmap, 0, 0,
                srcbitmap.getWidth(), srcbitmap.getHeight(), matrix, true); //因為作為背景的bmp已經縮放,那麼需要剪裁的bmp也要縮放----------這裡3/4引數是坑

        Bitmap lastBitmap = Bitmap.createBitmap(desBitmap, textView.getLeft(),
                textView.getTop(), textView.getMeasuredWidth(),
                textView.getMeasuredHeight()); // 根據模糊的區域剪裁

        Canvas canvas = new Canvas(backBitmap);
        canvas.drawBitmap(lastBitmap, 0, 0, new Paint());
        backBitmap = FastBlur.doBlur(backBitmap, (int) 20, true);
        textView.setBackground(new BitmapDrawable(getResources(), backBitmap));
        long t2 = System.currentTimeMillis();

        textView.setText((t2 - t1) + "S");// 319S

    }

下面是優化後的方法:
其實現原理是反正效果也是模糊的,先把圖片弄小模糊,再把模糊放大,這樣就減少了演算法的複雜度

public void test2(View v) {

        int rad = 8;

        Bitmap srcbitmap = BitmapFactory.decodeResource(getResources(),
                R.drawable.meitu);
        long t1 = System.currentTimeMillis();
        imageView.setBackground(new BitmapDrawable(getResources(), srcbitmap));// 設定大背景

        Bitmap backBitmap = Bitmap.createBitmap(textView.getMeasuredWidth()/rad,// 設定需高斯模糊的背景
                textView.getMeasuredHeight()/rad, Config.RGB_565);

        float f1 = (float) imageView.getMeasuredWidth()
                / (float) srcbitmap.getWidth();
        float f2 = (float) imageView.getMeasuredHeight()
                / (float) srcbitmap.getHeight();
        Matrix matrix = new Matrix();
        matrix.postScale(f1/8, f2/8);
        Bitmap desBitmap = Bitmap.createBitmap(srcbitmap, 0, 0,
                srcbitmap.getWidth(), srcbitmap.getHeight(), matrix, true); // 因為作為背景的bmp已經縮放,那麼需要剪裁的bmp也要縮放----------這裡3/4引數是坑

        Bitmap lastBitmap = Bitmap.createBitmap(desBitmap, textView.getLeft()/8,
                textView.getTop()/8, textView.getMeasuredWidth()/8,
                textView.getMeasuredHeight()/8); // 根據模糊的區域剪裁

        Canvas canvas = new Canvas(backBitmap);
        canvas.drawBitmap(lastBitmap, 0, 0, new Paint());
        backBitmap = FastBlur.doBlur(backBitmap, (int) 2, true);
        canvas.scale(1/rad, 1/rad);
        textView.setBackground(new BitmapDrawable(getResources(), backBitmap));
        long t2 = System.currentTimeMillis();

        textView.setText((t2 - t1) + "S");// 2S

    }