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Issues with android blur using Renderscript


I am using following code for building blurred background for my imageview.

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 is built fine for most times, but get bad over time, eventually my app crashes without any crash log. Upon running on emulator, I have seen the following error after severe testing:

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)

I have following queries in this regard:

  1. I am using following gradle config for renderscript:

    compileSdkVersion 23 buildToolsVersion "23.0.3"

    defaultConfig { applicationId "package " minSdkVersion 19 targetSdkVersion 23 multiDexEnabled true renderscriptTargetApi 19 renderscriptSupportModeEnabled true }

What is the recommended version of renderscript library ? Should I import dependencies from android.support.v8.renderscript.Allocation orandroid.renderscript` package ?

  1. Can I achieve the blur effect without using renderscript library ?

Solution

  • After spending more than a day, I figured out the following:

    1. App is crashing because there is an exception being thrown by Renderscript library. This usually happens often in devices with low processing power. This exception is not a Java exception, cannot be caught.

    2. Use the following code for another way to issue blur (without using renderscript library):

      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);
      }