Png图片的透明部分穿透测试

       private void Window_MouseMove(object sender, MouseEventArgs e)
{
           NavBtnList.Clear();

                Point mouseP = e.GetPosition(this);

                VisualTreeHelper.HitTest(this, new HitTestFilterCallback(HitFilter),

                    new HitTestResultCallback(HitResult), new PointHitTestParameters(mouseP));



                if (NavBtnList.Count > 0)

                {

                    for (int k = 0; k < NavBtnList.Count; k++)

                    {

                        IconBtn element = NavBtnList[k] as IconBtn;



                        DrawingVisual drawingVisual = new DrawingVisual();

                        using (DrawingContext context = drawingVisual.RenderOpen())

                        {

                            VisualBrush brush = new VisualBrush(element) { Stretch = Stretch.None };

                            context.DrawRectangle(brush, null,

                                new Rect(0, 0, element.ActualWidth, element.ActualHeight));

                            context.Close();

                        }



                        //dpi可以自己设定

                        // 获取dpi方法：PresentationSource.FromVisual(this).CompositionTarget.TransformToDevice

                        RenderTargetBitmap bitmap = new RenderTargetBitmap((int)element.ActualWidth,

                            (int)element.ActualHeight, 96, 96, PixelFormats.Pbgra32);

                        bitmap.Render(drawingVisual);



                        Point p = this.TranslatePoint(mouseP, element); //全局坐标转为局部坐标point



                        //获取鼠标下像素颜色值

                        var c = getImagePointColor((bitmap as BitmapSource), (int)p.X, (int)p.Y);

                        if (c != Convert16ToColor("#00000000"))

                        {

                            if (element.IsEnabled)

                            {

                            }

                            break;



                        }

                        bitmap.Clear();

                    }
}

 1         //鼠标按下获得所有IconBtnFrame 存储在NavBtnList里

 2         List<IconBtn> NavBtnList = new List<IconBtn>();

 3 

 4         public HitTestFilterBehavior HitFilter(DependencyObject dObject)

 5         {

 6             if (dObject is IconBtn)

 7             {

 8                 NavBtnList.Add(dObject as IconBtn);

 9             }

10             return HitTestFilterBehavior.Continue;

11         }

12 

13         public HitTestResultBehavior HitResult(HitTestResult result)

14         {

15             return HitTestResultBehavior.Continue;

16         }