毛玻璃背景效果

Posted 2020-10-05 wlwqnj

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intensive
iv.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);
    }
}