使用 Renderscript 的 android 模糊问题

Question

我正在使用以下代码为我的 imageview 构建模糊背景。

public class BlurBuilder {
    private static final float BITMAP_SCALE = 0.2f;
    private static final float BLUR_RADIUS = 25f;

    public static Bitmap blur(Context context, Bitmap image) {
        int width = Math.round(image.getWidth() * BITMAP_SCALE);
        int height = Math.round(image.getHeight() * BITMAP_SCALE);

        Bitmap inputBitmap = Bitmap.createScaledBitmap(image, width, height, false);
        Bitmap outputBitmap = Bitmap.createBitmap(inputBitmap);

        RenderScript rs = RenderScript.create(context);
        ScriptIntrinsicBlur theIntrinsic = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
        Allocation tmpIn = Allocation.createFromBitmap(rs, inputBitmap);
        Allocation tmpOut = Allocation.createFromBitmap(rs, outputBitmap);
        theIntrinsic.setRadius(BLUR_RADIUS);
        theIntrinsic.setInput(tmpIn);
        theIntrinsic.forEach(tmpOut);
        tmpOut.copyTo(outputBitmap);

        return outputBitmap;
    }
}

Blur 在大多数情况下都构建得很好，但随着时间的推移会变得很糟糕，最终我的应用程序崩溃而没有任何崩溃日志。在模拟器上运行时，经过严格测试，我看到以下错误：

09-01 15:05:03.230 4624-9758/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
09-01 15:05:03.238 4624-9781/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
09-01 15:05:03.242 4624-10128/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
09-01 15:05:03.242 4624-9610/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
09-01 15:05:03.242 4624-9781/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
09-01 15:05:03.250 4624-9767/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
09-01 15:05:03.254 4624-9758/? E/RenderScript: rsAssert failed: ret == bytes || mShutdown, in frameworks/rs/rsFifoSocket.cpp at 83
... (same error - many more times and then crash)

我对此有以下疑问：

1. 我正在为渲染脚本使用以下 gradle 配置：

   compileSdkVersion 23 buildToolsVersion "23.0.3"

   默认配置 { 应用程序ID“包” minSdkVersion 19 targetSdkVersion 23 multiDexEnabled 真 renderscriptTargetApi 19 renderscriptSupportModeEnabled true }

renderscript 库的推荐版本是多少？ 我应该从android.support.v8.renderscript.Allocation orandroid.renderscript`包中导入依赖项吗？

1. 不使用renderscript库可以实现模糊效果吗？

Answer 1

花了一天多的时间，我想出了以下几点：

1. 应用程序崩溃，因为 Renderscript 库抛出异常。这通常发生在处理能力较低的设备中。此异常不是 Java 异常，无法捕获。

2. 使用以下代码以另一种方式发出模糊（不使用渲染脚本库）：

   public static Bitmap fastblur(Bitmap sentBitmap) {
   
   int radius = (int) BLUR_RADIUS;
   
   int width = Math.round(sentBitmap.getWidth() * BITMAP_SCALE);
   int height = Math.round(sentBitmap.getHeight() * BITMAP_SCALE);
   sentBitmap = Bitmap.createScaledBitmap(sentBitmap, width, height, false);
   
   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 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;
       }
   }
   
   Log.e("pix", w + " " + h + " " + pix.length);
   bitmap.setPixels(pix, 0, w, 0, 0, w, h);
   
   return (bitmap);
   }