WPF Canvas 以鼠标指针为中心缩放

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XMAL:   <Canvas     x:Name="mCanvas"     MouseWheel="mCanvas_MouseWheel"     Background="Wheat" > <Canvas.RenderTransform>     <TransformGroup>         <ScaleTransform x:Name="mScaleTf" ScaleX="1.0" CenterX="0"></ScaleTransform>                <TranslateTransform x:Name="mTranslateTf" X="10" Y="20"></TranslateTransform>     </TransformGroup> </Canvas.RenderTransform> </Canvas>   ------------------------------------------------------------------------------------------------------   Code:   private void mCanvas_MouseWheel(object sender, MouseWheelEventArgs e) {              Point zoomCenter = e.GetPosition(this.mCanvas);//参数必须是this.mCanvas, e.GetPosition和RenderTransform有关?               //或者:             //Point screenPos = e.GetPosition(this);             //Point zoomCenter = this.mCanvas.RenderTransform.Inverse.Transform(screenPos);               Point pt = this.mCanvas.RenderTransform.Inverse.Transform(zoomCenter);             this.mTranslateTf.X = (zoomCenter.X - pt.X) * this.mScaleTf.ScaleX ;             this.mTranslateTf.Y = (zoomCenter.Y - pt.Y) * this.mScaleTf.ScaleY;             this.mScaleTf.CenterX = zoomCenter.X;             this.mScaleTf.CenterY = zoomCenter.Y;             this.mScaleTf.ScaleX += e.Delta / 1000.0;             this.mScaleTf.ScaleY += e.Delta / 1000.0;               Console.WriteLine("MouseWheel : " + zoomCenter.ToString());   }   或者   private void mCanvas_MouseWheel(object sender, MouseWheelEventArgs e) {     Point mousePos = e.GetPosition(this);       //oldCenter : untransformed and transformed     Point untransformedOldCenter = new Point(this.mScaleTf.CenterX, this.mScaleTf.CenterY);     Point transformedOldCenter = this.mScaleTf.Transform(untransformedOldCenter);       //newCenter : untransformed and transformed     Point untransformedNewCenter = this.mCanvas.RenderTransform.Inverse.Transform(mousePos);     Point transformedNewCenter = mousePos;       double adjustX = transformedNewCenter.X - transformedOldCenter.X - untransformedNewCenter.X + untransformedOldCenter.X;       //update transforms     this.mTranslateTf.X = adjustX;     this.mScaleTf.CenterX = untransformedNewCenter.X;     this.mScaleTf.ScaleX += 0.1; }