Android背景模糊话模糊、高斯模糊（FastBlur）

朱雀 2022-05-26 06:45 1416阅读 0赞

### 一、添加FastBlur工具类： ###

/**
     * Created by Lee on 2018/4/26.
     */
    
    import android.graphics.Bitmap;
    
    public class FastBlur {
    
        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);
        }
    }
    er

### 二、布局文件 ###

三、编写Activity使用工具类

import android.annotation.SuppressLint;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Canvas;
    import android.graphics.Paint;
    import android.graphics.Rect;
    import android.graphics.drawable.BitmapDrawable;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.util.Log;
    import android.view.View;
    import android.view.ViewTreeObserver;
    import android.view.Window;
    
    /**
     * Created by www44 on 2018/4/26.
     */
    
    public class FastBlurActivity extends AppCompatActivity {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            final Bitmap bmp1 = BitmapFactory.decodeResource(getResources(), R.drawable.bg);
    
            findViewById(R.id.content).getViewTreeObserver().addOnPreDrawListener(
                    new ViewTreeObserver.OnPreDrawListener() {
                        @Override
                        public boolean onPreDraw() {
    //                        blur(bmp1, findViewById(R.id.content)); applyBlur();
                            return true;
                        }
                    });
        }
    
        private void applyBlur() {
            View view = getWindow().getDecorView();
            view.setDrawingCacheEnabled(true);
            view.buildDrawingCache(true);
            /**
             * 获取当前窗口快照，相当于截屏
             */
            Bitmap bmp1 = view.getDrawingCache();
    //        final Bitmap bmp1 = BitmapFactory.decodeResource(getResources(), R.drawable.bg);
            int height = getOtherHeight();
            /**
             * 除去状态栏和标题栏
             */
            Bitmap bmp2 = Bitmap.createBitmap(bmp1, 0, height,bmp1.getWidth(), bmp1.getHeight() - height);
            blur(bmp2, findViewById(R.id.content));
        }
    
        @SuppressLint("NewApi")
        private void blur(Bitmap bkg, View view) {
            long startMs = System.currentTimeMillis();
            float scaleFactor = 8;//图片缩放比例；
            float radius = 20;//模糊程度
    
            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));
            /**
             * 打印高斯模糊处理时间，如果时间大约16ms，用户就能感到到卡顿，时间越长卡顿越明显，如果对模糊完图片要求不高，可是将scaleFactor设置大一些。
             */
            Log.i("jerome", "blur time:" + (System.currentTimeMillis() - startMs));
        }
    
        /**
         * 获取系统状态栏和软件标题栏，部分软件没有标题栏，看自己软件的配置；
         * @return
         */
        private int getOtherHeight() {
            Rect frame = new Rect();
            getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
            int statusBarHeight = frame.top;
            int contentTop = getWindow().findViewById(Window.ID_ANDROID_CONTENT).getTop();
            int titleBarHeight = contentTop - statusBarHeight;
            return statusBarHeight + titleBarHeight;
        }
    }

参阅：http://gqdy365.iteye.com/blog/2193913

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[70]: /images/20220526/c5cf86b5a9a34a7d9755e6cd45c9ec1e.png