所以我想尽可能快模糊的图像尽可能（即时感觉）， 作为活动的需要，因为我preSS的模糊按钮进行更新。

So I'm trying to blur an image as fast as possible(instant feel like), as the activity needs to be updated as I press the Blur button.

我遇到的问题是，我无法找到工作的速度不够快，一个模糊... 注意：该模糊，preferably高斯模糊，并不需要将所有最优质的..

The problem I am having is that, I cannot find a Blur that works quick enough... Note: The blur, preferably a Gaussian blur, doesn't need to be the best quality at all..

我尝试了下，但它需要几秒钟，反正是有这个code可以作出在质量上牺牲更快的运行？还是有什么其他的选择吗？ 我会去了解一下GPU的东西，但这种模糊是真的只是关系到用户界面的效果，只有发生在我preSS打开一个透明的活性大小作为一个小盒子......

I tried out the following, but it takes a few seconds, is there anyway this code could be made to run quicker in sacrifice of quality ? Or are there any other alternatives? I would look into GPU stuff, but this blur is really just an effect related to the UI and only happens when I press open a transparent activity sized as a small box...

任何想法？

static Bitmap fastblur(Bitmap sentBitmap, int radius, int fromX, int fromY,
    int width, int height) {

// Stack Blur v1.0 from
// http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
//
// Java Author: Mario Klingemann <mario at quasimondo.com>
// http://incubator.quasimondo.com
// created Feburary 29, 2004
// Android port : Yahel Bouaziz <yahel at kayenko.com>
// http://www.kayenko.com
// ported april 5th, 2012

// This is a compromise between Gaussian Blur and Box blur
// It creates much better looking blurs than Box Blur, but is
// 7x faster than my Gaussian Blur implementation.
//
// I called it Stack Blur because this describes best how this
// filter works internally: it creates a kind of moving stack
// of colors whilst scanning through the image. Thereby it
// just has to add one new block of color to the right side
// of the stack and remove the leftmost color. The remaining
// colors on the topmost layer of the stack are either added on
// or reduced by one, depending on if they are on the right or
// on the left side of the stack.
//
// If you are using this algorithm in your code please add
// the following line:
//
// Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>

Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);

if (radius < 1) {
    return (null);
}

int w = width;
int h = height;

int[] pix = new int[w * h];

bitmap.getPixels(pix, 0, w, fromX, fromY, 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;

int originRadius = radius;
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;
}

radius = originRadius;

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++) {
        pix[yi] = 0xff000000 | (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, fromX, fromY, w, h);

return (bitmap);

}

推荐答案

尽量缩小图像2，4，8，...时间，然后重新将其放大。这就是快。在renderscript否则实现它。

Try to scale down the image 2, 4, 8, ... times and then scale it up again. That is fast. Otherwise implement it in renderscript.

如果您想了解更多比缩放，你可以看看renderscript这个code段。它确实同类bluring在另一个回答给出的。同样的算法也可以使用Java来实现，并且是对方的回答的最优化。这code模糊一行。模糊的位图，你应该为所有行，然后在相同的所有列调用这个（你需要重新实现它来处理列）。要快速模糊只是做一次。如果你想有一个更好看的模糊做了好几遍。我通常只做两次。

If you want more than the scaling you can look at this code snippet in renderscript. It does the same kind of bluring as given in another answer. The same algorithm can be implemented in Java and is an optimization of the other answer. This code blurs one line. To blur a bitmap you should invoke this for all lines and then the same for all columns (you need to reimplement it to handle columns). To get a quick blur just do this once. If you want a better looking blur do it several times. I usually only do it twice.

这样做的原因一条线是，我试图并行算法，这给了一些改进，并在renderscript非常简单。我引用下面的code在所有平行线，然后在相同的所有列。

The reason for doing one line is that I tried to parallelize the algorithm, that gave some improvement and is really simple in renderscript. I invoked the below code for all lines in parallel, and then the same for all columns.

int W = 8;
uchar4 *in;
uchar4 *out;    

int N;
float invN;    

uint32_t nx;
uint32_t ny;    

void init_calc() {
  N = 2*W+1;
  invN = 1.0f/N;    

  nx = rsAllocationGetDimX(rsGetAllocation(in));
  ny = rsAllocationGetDimY(rsGetAllocation(in));
}    

void root(const ushort *v_in) {
  float4 sum = 0;    

  uchar4 *head = in + *v_in * nx;
  uchar4 *tail = head;
  uchar4 *p = out + *v_in * nx;    

  uchar4 *hpw = head + W;
  uchar4 *hpn = head + N;
  uchar4 *hpx = head + nx;
  uchar4 *hpxmw = head + nx - W - 1;    

  while (head < hpw) {
      sum += rsUnpackColor8888(*head++);
  }    

  while (head < hpn) {
      sum += rsUnpackColor8888(*head++);
      *p++ = rsPackColorTo8888(sum*invN);
  }    

  while (head < hpx) {
    sum += rsUnpackColor8888(*head++);
    sum -= rsUnpackColor8888(*tail++);
    *p++ = rsPackColorTo8888(sum*invN);
  }    

  while (tail < hpxmw) {
      sum -= rsUnpackColor8888(*tail++);
      *p++ = rsPackColorTo8888(sum*invN);
  }
}

下面是垂直bluring：

Here is for the vertical bluring:

int W = 8;
uchar4 *in;
uchar4 *out;    

int N;
float invN;    

uint32_t nx;
uint32_t ny;    

void init_calc() {
  N = 2*W+1;
  invN = 1.0f/N;    

  nx = rsAllocationGetDimX(rsGetAllocation(in));
  ny = rsAllocationGetDimY(rsGetAllocation(in));
}    

void root(const ushort *v_in) {
  float4 sum = 0;    

  uchar4 *head = in + *v_in;
  uchar4 *tail = head;
  uchar4 *hpw = head + nx*W;
  uchar4 *hpn = head + nx*N;
  uchar4 *hpy = head + nx*ny;
  uchar4 *hpymw = head + nx*(ny-W-1);    

  uchar4 *p = out + *v_in;    

  while (head < hpw) {
      sum += rsUnpackColor8888(*head);
      head += nx;
  }    

  while (head < hpn) {
      sum += rsUnpackColor8888(*head);
      *p = rsPackColorTo8888(sum*invN);
      head += nx;
      p += nx;
  }    

  while (head < hpy) {
      sum += rsUnpackColor8888(*head);
      sum -= rsUnpackColor8888(*tail);
      *p = rsPackColorTo8888(sum*invN);
      head += nx;
      tail += nx;
      p += nx;
  }    

  while (tail < hpymw) {
      sum -= rsUnpackColor8888(*tail);
      *p = rsPackColorTo8888(sum*invN);
      tail += nx;
      p += nx;
  }
}

这里是Java code调用到RS code：

And here is the Java code that calls into the rs code:

private RenderScript mRS;
private ScriptC_horzblur mHorizontalScript;
private ScriptC_vertblur mVerticalScript;
private ScriptC_blur mBlurScript;

private Allocation alloc1;
private Allocation alloc2;

private void hblur(int radius, Allocation index, Allocation in, Allocation out) {
    mHorizontalScript.set_W(radius);
    mHorizontalScript.bind_in(in);
    mHorizontalScript.bind_out(out);
    mHorizontalScript.invoke_init_calc();
    mHorizontalScript.forEach_root(index);
}

private void vblur(int radius, Allocation index, Allocation in, Allocation out) {
    mHorizontalScript.set_W(radius);
    mVerticalScript.bind_in(in);
    mVerticalScript.bind_out(out);
    mVerticalScript.invoke_init_calc();
    mVerticalScript.forEach_root(index);
}

Bitmap blur(Bitmap org, int radius) {
    Bitmap out = Bitmap.createBitmap(org.getWidth(), org.getHeight(), org.getConfig());

    blur(org, out, radius);

    return out;
}

private Allocation createIndex(int size) {
    Element element = Element.U16(mRS);
    Allocation allocation = Allocation.createSized(mRS, element, size);
    short[] rows = new short[size];
    for (int i = 0; i < rows.length; i++) rows[i] = (short)i;
    allocation.copyFrom(rows);

    return allocation;
}

private void blur(Bitmap src, Bitmap dst, int r) {
    Allocation alloc1 = Allocation.createFromBitmap(mRS, src);
    Allocation alloc2 = Allocation.createTyped(mRS, alloc1.getType());

    Allocation hIndexAllocation = createIndex(alloc1.getType().getY());
    Allocation vIndexAllocation = createIndex(alloc1.getType().getX());

    // Iteration 1
    hblur(r, hIndexAllocation, alloc1, alloc2);
    vblur(r, vIndexAllocation, alloc2, alloc1);
    // Iteration 2
    hblur(r, hIndexAllocation, alloc1, alloc2);
    vblur(r, vIndexAllocation, alloc2, alloc1);
    // Add more iterations if you like or simply make a loop
    alloc1.copyTo(dst);
}