WPF Zoom but keeping some items width, height and position - wpf

Question

What I want to get is any way for making zoom on a collection of controls but keep the width, height and position for a subset of this controls. I have seen the question How to keep element size while WPF zoom in and out?, seems very much to what I want, but is not answered and also is not very explicit so a will improve the question.
Currently I'm using the Zoombox control that comes with the WPF Toolkit extended for .net framework 4.0, but I can change it. The structure that I have is the following:
<Border x:Name="drawRegionBorder" Grid.Column="1" Grid.Row="1" d:LayoutOverrides="Width, Height" BorderThickness="1" CornerRadius="4" BorderBrush="{StaticResource BorderBrush}" >
<xctk:Zoombox x:Name="zoomBox">
<Grid x:Name="drawRegion" Height="{Binding Height}" Width="{Binding Width}" HorizontalAlignment="Left" VerticalAlignment="Top" Background="{DynamicResource DrawBackgroundBrush}">
<Image Source="{Binding Image}" ... />
<ListBox x:Name="points" ItemsSource="{Binding Points}">
<ListBox.Template>
<ControlTemplate>
<Canvas IsItemsHost="True"/>
</ControlTemplate>
</ListBox.Template>
</ListBox>
<ListBox x:Name="paths" ItemsSource="{Binding SomePaths}">
<ListBox.Template>
<ControlTemplate>
<Canvas IsItemsHost="True"/>
</ControlTemplate>
</ListBox.Template>
</ListBox>
<!--... Others ...-->
</Grid>
</xctk:Zoombox>
</Border>
What I have here, are several list boxes, inside a grid, and the items panel for each list box is a Canvas, so each child (but the image) will be located inside a canvas and also each child will set the Canvas.X and Canvas.Y properties. So what I want, is any way of make the zoom (zoom-in or zoom-out), and keep the size of poitns (ellipsed) or paths...
Due the zoom, is a wpf's scale transformation, I suppose maybe a way for doing this when the zoom-in, make the zoom-out to the control I want to keep the size, and viceversa.
An example of the spected behavior is the blend designer, for instance when you zoom in a grid with rows and columns, the columns indicators keeps the original size, some thing like that is what I want for my points and paths.
I will appreciate any solution, maybe library, attached property, behavior or code.
Thaknks

Answer 1

The Blend designer uses Adorners for its manipulators. The sizes are calculated according to zoom the current zoom. If you're interested in using a similar technique, it's actually not that hard to do the calculation yourself.
You would create an adorner set to the Bounds of your control, then apply a scale factor according to the zoom in the designer. So if you zoom by 2.0, then you apply a RenderTransform of Scale 2.0 to your zoomed control, while calculating your adorner to be 2.0 of the ActualWidth and ActualHeight of the zoomed control (because those two properties do not take into account RenderTransformations). The nice thing is that since everything uses doubles, you get pixel perfect precision when doing this kind of calculation.
By using this approach, you gain the ability to zoom your main controls, while your manipulators simply scale to the zoomed controls, but maintain their control size throughout.
This tutorial is a good starting point. In the OnRender method is where you'd want to apply the scaling factor (by calculating the bounds of your adorner based on the UIElement's ActualWidth/Height, then multiplying by your scaling factor). How you apply your adorner depends a lot on application context - if you're doing a designer, then you'd want to apply the adorners in a design canvas or upon item selection.

Answer 2

I had made a research and found some useful things, for instace, if you are working with Adorners you can override the GetDesiredTransform in order to set what transform to do you want your adorner to do, here you can make null the transform made to your adorner. For more details see How to exclude scaleTransform from GeneralTransform in Adorner GetDesiredTransform method. In Msdn. But I think that if I want make it on controls I need to control the transform by my self.