视图级别的 Android 模糊

Question

我正在整个互联网上寻找一种在 LinearLayout 后面获得漂亮模糊的方法。 那里有很多库（android-stackblur / BlurBehind / ...），但它们大多在 Activity 级别模糊，或者需要模糊图像。

让事情变得复杂的是我使用视频作为背景，并且在 LinearLayout 的底部有一些按钮，如果我可以在 LinearLayout 上实现模糊效果会很棒。

有用的库有什么提示吗？

Answer 1

我要做一张GoogleMap的模糊图片，我用的是fastblur算法，是下一个：

public static Bitmap fastblur(Bitmap sentBitmap, int radius)
{

// 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 = 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);
}

我认为视频是不同的，但对于地图，您可以拍摄快照并返回位图：

private void captureMapScreen()
{
    SnapshotReadyCallback callback = new SnapshotReadyCallback()
    {

    @Override
    public void onSnapshotReady(Bitmap snapshot)
    {
        final Bitmap snap = snapshot;

        Thread thread = new Thread(new Runnable()
        {

        @Override
        public void run()
        {
            Bitmap blurTemplate = Bitmap.createScaledBitmap(snap, snap.getWidth() / 10, snap.getHeight() / 10, false);

            final Bitmap image = MyApplication.fastblur(blurTemplate, 8);

            getActivity().runOnUiThread(new Runnable()
            {

            @Override
            public void run()
            {
                v_blur.setBackgroundDrawable(new BitmapDrawable(getActivity().getResources(), image));

            }
            });

        }
        });
        thread.start();
    }
    };

    map.snapshot(callback);

}

您可以尝试获取视频的快照，然后尝试我上面所说的。并非所有设备都以相同的方式工作，例如华为设备在快照方面有点棘手。

希望对你有帮助。