毛玻璃背景效果

在正常的开发中，经常会遇到打开一个界面，只打开的一半，这种情况，背景怎么去处理？

其实使用毛玻璃虚化是最方便的处理方法。

这个首先就需要获取到，这个时候背景图片的截图。可以通过DrawCache来获取。

view.setDrawingCacheEnabled(true);//设置能否缓存图片信息（drawing cache）

view.buildDrawingCache();//如果能够缓存图片，则创建图片缓存Bitmap bitmap = view.getDrawingCache();//如果图片已经缓存，返回一个bitmap

Bitmap bitmap1 = FastBlurUtils.toBlur(bitmap, 5);　　　　//这个方法就是把得到的bitmap缓存，转换为毛玻璃的效果，具体方法直接上代码，拿去就可以使用。  参数 5 增大，可以得到更高程度的虚化，不过会导致CPU更加intensiveiv.setImageBitmap(bitmap1)；

mChatListView.destroyDrawingCache();//使用完之后，释放缓存占用的资源

Glide通过transform也可以转化为毛玻璃效果，但是试了几次都没有成功。

 .bitmapTransform(new CropCircleTransformation(this))　　　　//这个是转换为圆形。   添加下面这个依赖库，  可以进行很多的图片转换

.bitmapTransform(new BlurTransformation(context, 25), new CropCircleTransformation(context))　　　　//对图片进行虚化和圆形裁剪，两个效果一起加上，就这样使用，用“，”隔开就可以了

compile ‘jp.wasabeef:glide-transformations:2.0.2‘

这个类可以直接拿去使用

public class FastBlurUtils {    /**     * 根据imagepath获取bitmap     */    /**     * 得到本地或者网络上的bitmap url - 网络或者本地图片的绝对路径,比如:     * <p>     * A.网络路径: url="http://blog.foreverlove.us/girl2.png" ;     * <p>     * B.本地路径:url="file://mnt/sdcard/photo/image.png";     * <p>     * C.支持的图片格式 ,png, jpg,bmp,gif等等     *     * @param url     * @return     */    public static int IO_BUFFER_SIZE = 2 * 1024;

public static Bitmap GetUrlBitmap(String url, int scaleRatio) {        int blurRadius = 8;//通常设置为8就行。        if (scaleRatio <= 0) {            scaleRatio = 10;        }

Bitmap originBitmap = null;        InputStream in = null;        BufferedOutputStream out = null;        try {            in = new BufferedInputStream(new URL(url).openStream(), IO_BUFFER_SIZE);            final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();            out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);            copy(in, out);            out.flush();            byte[] data = dataStream.toByteArray();            originBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);

Bitmap scaledBitmap = Bitmap.createScaledBitmap(originBitmap,                    originBitmap.getWidth() / scaleRatio,                    originBitmap.getHeight() / scaleRatio,                    false);            Bitmap blurBitmap = doBlur(scaledBitmap, blurRadius, true);            return blurBitmap;        } catch (IOException e) {            e.printStackTrace();            return null;        }    }

private static void copy(InputStream in, OutputStream out)            throws IOException {        byte[] b = new byte[IO_BUFFER_SIZE];        int read;        while ((read = in.read(b)) != -1) {            out.write(b, 0, read);        }    }

//    把本地图片毛玻璃化    public static Bitmap toBlur(Bitmap originBitmap, int scaleRatio) {        //        int scaleRatio = 10;        // 增大scaleRatio缩放比，使用一样更小的bitmap去虚化可以到更好的得模糊效果，而且有利于占用内存的减小；        int blurRadius = 5;//通常设置为8就行。        //增大blurRadius，可以得到更高程度的虚化，不过会导致CPU更加intensive

/* 其中前三个参数很明显，其中宽高我们可以选择为原图尺寸的1/10；        第四个filter是指缩放的效果，filter为true则会得到一个边缘平滑的bitmap，        反之，则会得到边缘锯齿、pixelrelated的bitmap。        这里我们要对缩放的图片进行虚化，所以无所谓边缘效果，filter=false。*/        if (scaleRatio <= 0) {            scaleRatio = 10;        }        Bitmap scaledBitmap = Bitmap.createScaledBitmap(originBitmap,                originBitmap.getWidth() / scaleRatio,                originBitmap.getHeight() / scaleRatio,                false);        Bitmap blurBitmap = doBlur(scaledBitmap, blurRadius, true);        return blurBitmap;    }

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