Setting the layout transfrom of image without creating a new matrixtransform

Question

I have the following code for xaml:
         <Grid Name="navigationGrid" Grid.RowSpan="2">
        <ScrollViewer Name="scrollViewer" Grid.Row="0"
                      HorizontalScrollBarVisibility="Hidden"  VerticalScrollBarVisibility="Hidden"
                      k:KinectRegion.IsHorizontalRailEnabled="true"
                      k:KinectRegion.IsVerticalRailEnabled="true"
                      k:KinectRegion.ZoomMode="Enabled" LayoutUpdated="scrollViewer_LayoutUpdated" >
            <Image Name="navigationImage" RenderTransformOrigin="0.5, 0.5"/>
        </ScrollViewer>
       </Grid>
Now I would like to change the zoom of the image manually i.e. suppose to a zoom value Z , so I do the following:
      System.Windows.Media.Matrix m = navigationImage.LayoutTransform.Value;
       m.ScaleAtPrepend(Z / m.M11), Z / m.M11, m.M21, m.M22);                      //Z is the zoom value
       navigationImage.LayoutTransform = new System.Windows.Media.MatrixTransform(m);
But after performing layoutTransform on the image, I am now not being able to use the kinect zoom gesture. I guess it is due to assigning new LayoutTransform.
So instead of new System.Windows.Media.MatrixTransform(m); I would like something like navigationImage.LayoutTransform.SetValue(ScaleTransform.ScaleXProperty, Z / m.M11); but this gives me an error
"Cannot set a property on object 'Identity' because it is in a read-only state."  So my question is how to set new value to layoutTransform.

Answer 1

Hi Samprit,
In my experience, if you want to zoom an image,
ScaleTransform is the simplest way:
<Image Source="{Binding ImageSource}">
<Image.RenderTransform>
<ScaleTransform x:Name="scale" ScaleX="{Binding Value, ElementName=slider1}" ScaleY="{Binding Value, ElementName=slider1}" CenterX="0.5" CenterY="0.5"/>
</Image.RenderTransform>
</Image>
<Slider Grid.Row="1" Name="slider1" Maximum="1" Minimum="0" Value="1" TickPlacement="Both" />
From code behind, changing the ScaleTransform.ScaleX/ScaleY property to adjust the zoom level.
>>But after performing layoutTransform on the image, I am now not being able to use the kinect zoom gesture. I guess it is due to assigning new LayoutTransform.
I think this question is more related to Kinect SDK, the Kinect for Windows SDKs forum is a better place to get more accurate help:
https://social.msdn.microsoft.com/Forums/en-US/home?category=kinectsdks
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