问题：图像旋转然后移动，发现移动距离出现错误，位置跳跃问题。

前端关键代码：

<Viewbox x:Name="imageview" Width="480" Height="480" Stretch="Fill" >
	<Image x:Name="MyImage" Width="480" Height="480" Source="/Viewer;component/Images/p29.png"  HorizontalAlignment="Center" VerticalAlignment="Center" RenderTransformOrigin="0.5,0.5" SnapsToDevicePixels="True" Stretch="Fill" 
			PreviewMouseLeftButtonDown="PreviewMouseLeftButtonDown" PreviewMouseMove="PreviewMouseMove" PreviewMouseLeftButtonUp="PreviewMouseLeftButtonUp">
		<Image.RenderTransform>
			<TransformGroup>
				<SkewTransform/>
				<RotateTransform x:Name="RotateAngle" Angle="{Binding RotateValue ,ElementName=RotateBtn}"/>
				<TranslateTransform/>
			</TransformGroup>
		</Image.RenderTransform>
	</Image>
</Viewbox>

后台逻辑主要代码：

Point m_offset = new Point(0, 0);
bool m_isDrag = false;
private void PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
	FrameworkElement el = (FrameworkElement)sender;
	m_offset = e.GetPosition(el);
	m_isDrag = true;
}

private void PreviewMouseMove(object sender, MouseEventArgs e)
{
	if (m_isDrag && e.LeftButton == MouseButtonState.Pressed)
	{
		this.imageview.Cursor = Cursors.SizeAll;
		Point p = e.GetPosition((FrameworkElement)sender);
		double x = imageview.Margin.Left + (p.X - m_offset.X);
		double y = imageview.Margin.Top + (p.Y - m_offset.Y);
		if (Math.Abs(x) > 10 || Math.Abs(y) > 10)
		{
			imageview.Margin = new Thickness(x, y, 0, 0);
		}
	}
}

private void PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
	if (m_isDrag)
	{
		m_isDrag = false;
	}
	this.imageview.Cursor = Cursors.Arrow;
}

分析原因：这是由于坐标系不统一造成的。图像旋转中心点会随之改变，平移坐标x，y移动方向会发生旋转改变，会影响平移的偏移值。为了方便理解画了张图，图像旋转图如下：

方法一：对图像旋转，不对图像移动，移动操作放在其上一层控件上。

<Viewbox x:Name="imageview" Width="480" Height="480" Stretch="Fill" StretchDirection="Both">
	<Border HorizontalAlignment="Stretch" VerticalAlignment="Stretch" PreviewMouseLeftButtonDown="PreviewMouseLeftButtonDown" PreviewMouseMove="PreviewMouseMove" PreviewMouseLeftButtonUp="PreviewMouseLeftButtonUp">
		<Image x:Name="MyImage" Width="480" Height="480" Source="/Viewer;component/Images/p29.png"  HorizontalAlignment="Center" VerticalAlignment="Center" RenderTransformOrigin="0.5,0.5" SnapsToDevicePixels="True" Stretch="Fill" >
			<Image.RenderTransform>
				<TransformGroup>
					<SkewTransform/>
					<RotateTransform x:Name="RotateAngle" Angle="{Binding RotateValue ,ElementName=RotateBtn}"/>
					<TranslateTransform/>
				</TransformGroup>
			</Image.RenderTransform>
		</Image>
	</Border>
</Viewbox>

方法二：对图像旋转、平移，对其坐标旋转。

private void PreviewMouseMove(object sender, MouseEventArgs e)
{
	if (this.ZommBtn.ZoomValue <= 100.0)
		return;
	if (m_isDrag && e.LeftButton == MouseButtonState.Pressed)
	{
		this.imageview.Cursor = Cursors.SizeAll;
		Point p = e.GetPosition((FrameworkElement)sender);
		Point ptChange = RotateAngle.Transform(new Point((p.X - m_offset.X), (p.Y - m_offset.Y)));
		double x = imageview.Margin.Left + ptChange.X;
		double y = imageview.Margin.Top + ptChange.Y;
		if (Math.Abs(x) > 10 || Math.Abs(y) > 10)
		{
			imageview.Margin = new Thickness(x, y, 0, 0);
		}
	}
}