import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.util.Log;
import android.view.View;
import android.view.ViewTreeObserver; public class FastBlur { public static void applyBlur(final View v) {
v.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
@Override
public boolean onPreDraw() {
v.getViewTreeObserver().removeOnPreDrawListener(this);
v.buildDrawingCache();
Bitmap bmp = v.getDrawingCache();
blur(bmp, v);
return true;
}
});
} public static void blur(Bitmap bkg, View view) {
long startMs = System.currentTimeMillis();
float scaleFactor = 1;
float radius = 20;
scaleFactor = 8;
radius = 2; 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.setBackgroundDrawable(new BitmapDrawable(view.getResources(), overlay));
Log.e("TAG", System.currentTimeMillis() - startMs + "ms");
} 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);
}
}