Android 毛玻璃效果的實現

robert_chao發表於2016-05-31

Android 毛玻璃效果,主要找到了3中實現方案,

1、如果系統的api在16以上,可以使用系統提供的方法直接處理圖片

if (VERSION.SDK_INT > 16) {
            Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);            
            final RenderScript rs = RenderScript.create(context);
            final Allocation input = Allocation.createFromBitmap(rs, sentBitmap, Allocation.MipmapControl.MIPMAP_NONE,
                    Allocation.USAGE_SCRIPT);
            final Allocation output = Allocation.createTyped(rs, input.getType());
            final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
            script.setRadius(radius /* e.g. 3.f */);
            script.setInput(input);
            script.forEach(output);
            output.copyTo(bitmap);
            return bitmap;
        }



2、 如果Api條件不滿足,可以使用如下方法

  @SuppressLint("NewApi")
    public static Bitmap fastblur(Context context, Bitmap sentBitmap, int radius) {       
        Bitmap 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];
//        Log.e("pix", w + " " + h + " " + pix.length);
        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 temp = 256 * divsum;
        int dv[] = new int[temp];
        for (i = 0; i < temp; 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);
    }

3、以上方法都存在一個問題,效能較低,下面提供一個C實現

static int* StackBlur(int* pix, int w, int h, int radius) {
    int wm = w - 1;
    int hm = h - 1;
    int wh = w * h;
    int div = radius + radius + 1;    int *r = (int *)malloc(wh * sizeof(int));
    int *g = (int *)malloc(wh * sizeof(int));
    int *b = (int *)malloc(wh * sizeof(int));
    int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
    int *vmin = (int *)malloc(MAX(w,h) * sizeof(int));
    int divsum = (div + 1) >> 1;
    divsum *= divsum;
    int *dv = (int *)malloc(256 * divsum * sizeof(int));
    for (i = 0; i < 256 * divsum; i++) {
        dv[i] = (i / divsum);
    }
    yw = yi = 0;
    int(*stack)[3] = (int(*)[3])malloc(div * 3 * sizeof(int));
    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 + (MIN(wm, MAX(i, 0)))];
            sir = stack[i + radius];
            sir[0] = (p & 0xff0000) >> 16;
            sir[1] = (p & 0x00ff00) >> 8;
            sir[2] = (p & 0x0000ff);
            rbs = r1 - 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] = 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 = MAX(0, yp) + x;
            sir = stack[i + radius];
            sir[0] = r[yi];
            sir[1] = g[yi];
            sir[2] = b[yi];
            rbs = r1 - 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] = 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;
        }
    }
    free(r);
    free(g);
    free(b);
    free(vmin);
    free(dv);
    free(stack);
    return(pix);
}



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