如何使用没有任何瑕疵的Renderscript模糊效果？ [英] How to use the Renderscript blurring effect without artifacts?

问题描述

有很多地方（包括 这里 ），以展示如何使用Renderscript来模糊的图像，因为这样的：

There are plenty of places (including here) to show how to use Renderscript to blur images, as such:

@TargetApi(VERSION_CODES.JELLY_BEAN_MR1)
public static Bitmap renderScriptBlur(Context context, Bitmap srcBitmap, @FloatRange(from = 0.0f, to = 25.0f) float radius) {
    if (srcBitmap == null)
        return null;
    Bitmap outputBitmap = null;
    RenderScript rs = null;
    try {
        rs = RenderScript.create(context);
        outputBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), Bitmap.Config.ARGB_8888);
        final Canvas canvas = new Canvas(outputBitmap);
        canvas.drawBitmap(srcBitmap, 0, 0, null);
        Allocation overlayAlloc = Allocation.createFromBitmap(rs, outputBitmap);
        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
        blur.setInput(overlayAlloc);
        blur.setRadius(radius);
        blur.forEach(overlayAlloc);
        overlayAlloc.copyTo(outputBitmap);
        return outputBitmap;
    } catch (Exception ex) {
        if (outputBitmap != null)
            outputBitmap.recycle();
        return srcBitmap;
    } finally {
        if (rs != null)
            rs.destroy();
    }
}

问题

通常它的伟大工程，但使用一些图像和/或半径的设置时，输出图像具有文物看起来像扫描线：

The problem

Usually it works great, but when using some images and/or radius-settings, the output image has artifacts that look like scan-lines:

我发现有一个更好的解决方案，模糊（如 这里 ）但它们不使用Renderscript并且也缓慢和存储器消耗。

I've found that there is a nicer blurring solutions (like here), but they don't use Renderscript and are also slow and memory-consuming.

我也试图让输入图像小，但输出仍然有扫描线的文物。

I've also tried to make the input image smaller, but the output still has scanlines artifacts.

最后，我也报这个， < STRONG>这里 。

Finally, I've also reported about this, here.

时有可能使用Renderscript模糊图像，而这些Artifcats？这有什么错我写的？

Is it possible to use Renderscript to blur images without those Artifcats? Is there anything wrong with what I wrote?

推荐答案

的问题是与我所使用的算法。由于 此github上 项目，我发现这个问题（这可能是没有使用正确的类型FOT分配），并使用了更好的方法：

The problem was with the algorithm I used. Thanks to this github project, I've found the issue (which is probably not using the correct type fot the allocation) and used a nicer approach:

private static final AtomicReference<RenderScript> sRenderscript = new AtomicReference<>();


public static Bitmap blur(Context context, Bitmap bitmap) {
    return blur(context, bitmap, 4, false, false);
}

public static Bitmap blur(Context context, Bitmap bitmap, float radius) {
    return blur(context, bitmap, radius, false, false);
}

public static Bitmap blur(Context context, Bitmap bitmapOriginal, @FloatRange(from = 0.0f, to = 25.0f) float radius, boolean overrideOriginal, boolean recycleOriginal) {
    if (bitmapOriginal == null || bitmapOriginal.isRecycled())
        return null;
    RenderScript rs = sRenderscript.get();
    if (rs == null)
        if (!sRenderscript.compareAndSet(null, rs = RenderScript.create(context)) && rs != null)
            rs.destroy();
        else
            rs = sRenderscript.get();
    final Bitmap inputBitmap = bitmapOriginal.getConfig() == Config.ARGB_8888 ? bitmapOriginal : bitmapOriginal.copy(Config.ARGB_8888, true);
    final Bitmap outputBitmap = overrideOriginal ? bitmapOriginal : Bitmap.createBitmap(bitmapOriginal.getWidth(), bitmapOriginal.getHeight(), Config.ARGB_8888);
    final Allocation input = Allocation.createFromBitmap(rs, inputBitmap);
    final Allocation output = Allocation.createTyped(rs, input.getType());
    final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
    script.setRadius(radius);
    script.setInput(input);
    script.forEach(output);
    if (recycleOriginal && !overrideOriginal)
        bitmapOriginal.recycle();
    output.copyTo(outputBitmap);
    return outputBitmap;
}

现在这一切工作得很好。

Now it all works nicely.

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