动态壁纸渐变带：是否可以使用 ARGB_8888 或抖动来修复？

Question

我正在创建一个动态壁纸，并在每个画布上绘画 Runnable.run() 调用改变颜色，我希望放一个 顶部的渐变，但我创建的渐变是条带 可怕的是。经过几天的谷歌搜索，我想出了两个解决方案： 将抖动设置为 true 将画布位图设置为 ARGB_8888

我尝试在 getWallpaper() 访问器和 Paint 对象，但它没有帮助（我看不到 任何抖动）所以我尝试更改画布位图，但我 不确定如何实际显示它

// _canvasBmp = Bitmap.createBitmap(metrics.widthPixels, metrics.heightPixels, Bitmap.Config.ARGB_8888);

_shadowPaint.setStyle(Paint.Style.FILL);
_shadowPaint.setShader(new RadialGradient(metrics.widthPixels / 2,
metrics.heightPixels / 2, metrics.heightPixels / 2, 0x00000000,0x33000000, Shader.TileMode.CLAMP));
_shadowPaint.setDither(true); // this hasn't seemed to have done anything to fix the banding

// my main rendering method is this (based on the Google live wallpaper example)
void drawFrame()
{
   final SurfaceHolder holder = getSurfaceHolder();

   Canvas c = null;
   try
   {
           c = holder.lockCanvas();
           // c.setBitmap(_canvasBmp);// this was my attempt to update the bitmap to one that was ARGB_8888 but it didn't render at all

           if (c != null)
           {
                   // draw something
                   drawBackground(c);
                   drawTouchPoint(c);
                   drawShading(c);
                   drawBorder(c);

                   getWallpaper().setDither(true); // yet another attempt to get some kind of dithering going to no avail
           }
   }
   finally
   {
           if (c != null)
                   holder.unlockCanvasAndPost(c);
   }

   _handler.removeCallbacks(_drawClock); // _drawClock is the Runnable object

   if (_isVisible)
   {
           _handler.postDelayed(_drawClock, 1000 / 25);
   }
}


private void drawShading(Canvas c)
{
    c.drawRect(_screenBounds, _shadowPaint); // _screenBounds is a Rect set to the _metrics width and height
}

提前感谢您的时间

Answer 1

在您的 PinupEngine 类中...

@Override
public void onCreate(SurfaceHolder surfaceHolder) {
  super.onCreate(surfaceHolder);
  surfaceHolder.setFormat(android.graphics.PixelFormat.RGBA_8888);
}

我发现，位图像素类型越大，LiveWallpaper 绘制速度就越慢。我预计它也会使用更多的内存（超过双倍）。如果可以的话，尝试限制 RGBA_8888 的使用可能是值得的。我认为默认值是 RGB_565，对此不确定。