android 图片毛玻璃效果

本博客主要作为作者自己的笔记，学习自http://www.jianshu.com/p/7ae7dfe47a70

网上实现毛玻璃效果大致分为两种，一种是java实现，一种是c实现。一般来说，java实现效率没有c实现效率高，本次使用的是复制过来的java代码，效果参考http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html。
如果图片非常大，那么处理的时间就会比较长，影响用户体验，所以可以先将图片缩小在模糊化，效果也会更加明显。
本人学习效果：
原图

缩放倍率2 模糊程度10

缩放倍率2 模糊程度20

缩放倍率2 模糊程度50

缩放倍率8 模糊程度20

为了使用方便，重新对其进行封装，代码如下

package com.example.photoblurdemo.utils;import android.graphics.Bitmap;import android.os.Build;import android.util.Log;/***  类说明：处理bitmap，使bitmap模糊化（毛玻璃效果）*  created by liuxiong on 2017/1/12**/public class BlurBitmapUtils {    /**    * 方法说明:  先将图片进行缩放处理，再对图片进行毛玻璃效果处理    * @param  scaleRatio 缩放倍率    * @param  blurRadius 模糊程度    * @param  bitmap 资源图片    *@author liuxiong    *@time 2017/1/12 11:26    */    public static Bitmap blurBitmap(int scaleRatio,int blurRadius,Bitmap bitmap){        if(bitmap==null){          return null;        }        if(scaleRatio<2){ //缩放比例小于2会崩            scaleRatio=2;        }        if(blurRadius<1){            blurRadius=1;        }        Bitmap scaledBitmap = Bitmap.createScaledBitmap(                bitmap,                bitmap.getWidth()/ scaleRatio,                bitmap.getHeight()/ scaleRatio,                false        );  //毛玻璃边缘有没有锯齿都没关系，所以设为false        return bitmap = doBlur(scaledBitmap, blurRadius, true);    }    /**    * 方法说明:  先将图片进行缩放处理，使图片小于maxSize时，再对图片进行毛玻璃效果处理    * @param  bitmap 资源图片    * @param  blurRadius 模糊程度    * @param  maxSize 图片最大的内存大小    *@author liuxiong    *@time 2017/1/12 11:31    */    public static Bitmap blurBitmap(Bitmap bitmap,int blurRadius,int maxSize){        if(bitmap==null){            return null;        }        if(blurRadius<0){            blurRadius=0;        }        if(maxSize<50*1024){            maxSize=50*1024;        }        long size = getBitmapsize(bitmap);        Log.d("----","-----size="+size);        int scaleRatio=1;        if(size>maxSize){            scaleRatio= (int) ((float)size/maxSize+0.5);        }       return blurBitmap(scaleRatio,blurRadius,bitmap);    }    /**    * 方法说明:  获取bitmap的大小    * @param  bitmap 资源图片    *@author liuxiong    *@time 2017/1/12 11:35    */    public static long getBitmapsize(Bitmap bitmap){        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR1) {            return bitmap.getByteCount();        }        // Pre HC-MR1        return bitmap.getRowBytes() * bitmap.getHeight();    }    /**    * 方法说明:  将图片进行毛玻璃效果处理（java算法）    * @param  sentBitmap 资源图片    * @param  radius 模糊程度    * @param  canReuseInBitmap 是否重用    *@author liuxiong    *@time 2017/1/12 11:23    */    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 <[e-mail]>        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);        Log.d("-----","-----size="+getBitmapsize(bitmap));        return (bitmap);    }}

缩放比例小于2好像会造成崩溃，本人菜鸟没找到原因，activity代码如下

package com.example.photoblurdemo;import android.content.res.Resources;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.drawable.BitmapDrawable;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.text.TextUtils;import android.view.View;import android.widget.EditText;import android.widget.ImageView;import com.example.photoblurdemo.utils.BlurBitmapUtils;import java.io.InputStream;public class MainActivity extends AppCompatActivity {    private ImageView mIv;    private EditText mEtRadius;    private EditText mEdRatio;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mIv = (ImageView) findViewById(R.id.iv_photo);        mEdRatio = (EditText) findViewById(R.id.et_scale_ratio);        mEtRadius = (EditText) findViewById(R.id.et_blur_radius);    }    public void onClick(View view){        String ratio = mEdRatio.getText().toString().trim();        String radius = mEtRadius.getText().toString().trim();        if(TextUtils.isEmpty(ratio)){            ratio="0";        }        if(TextUtils.isEmpty(radius)){            radius="0";        }        Resources r = getResources();        InputStream is = r.openRawResource(R.drawable.beauty_girls);        BitmapDrawable bmpDraw = new BitmapDrawable(is);        Bitmap bmp = bmpDraw.getBitmap();//        bmp= BlurBitmapUtils.blurBitmap(1, 8, bmp);//        bmp= BlurBitmapUtils.blurBitmap(bmp,Integer.parseInt(ratio),100*1024);        bmp= BlurBitmapUtils.blurBitmap(Integer.valueOf(ratio),Integer.valueOf(radius),bmp);        mIv.setImageBitmap(bmp);    }}