MaxWitdh of Path - wpf

Question

I'm developing an app and I'm facing the same problem.
For some reason, Path does not stretch to the entire area of ​​the program window (I programmatically stretch the application window to two screens), but the Path seems to have its own limit Width. Here is the markup of the Path itself
<Grid >
<InkCanvas Name="inkCanvas"
Cursor="Cross"
UseCustomCursor="True"
EditingMode="{Binding EditingMode}">
<InkCanvas.InputBindings>
<KeyBinding Command="{Binding CloseAppCommand}"
Key="Esc"/>
<KeyBinding Command="{Binding DrawModeCommand}"
Key="F1"/>
</InkCanvas.InputBindings>
<i:Interaction.Behaviors>
<if:MouseBehaviour MouseX="{Binding MouseX, Mode=OneWayToSource}"
MouseY="{Binding MouseY, Mode=OneWayToSource}" />
</i:Interaction.Behaviors>
<InkCanvas.Background>
<ImageBrush ImageSource="{Binding Screenshot.Source}"></ImageBrush>
</InkCanvas.Background>
<Path Stroke="Black" Fill="Green" Opacity=".3">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Exclude">
<CombinedGeometry.Geometry1>
<RectangleGeometry Rect="{Binding BlackoutRect.Rect}" >
</RectangleGeometry>
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<RectangleGeometry Rect="{Binding SelectionRect.Rect}" >
</RectangleGeometry>
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
</InkCanvas>
</Grid>
As a result, we see the following picture:
https://imgur.com/nqbqHFO
For example, if we specify Width="300px" for the path
<Path Stroke="Black" Fill="Green" Opacity=".3" Width="300px"...
, then the width of the green area on the screen above will actually be 300px, but if you specify for example 300000px, the picture will be the same as on the screen above. That is, I concluded that the Path element has a maximum width (by the way, if you specify MaxWitdh="30000px", then nothing will change anyway and it will be the same as in the screenshot above)
Hence the main question of this thread: How to change the maximum size of a Path element?

Answer 1

An InkCanvas does not stretch its child elements.
You could add a Panel that performs the desired layout, and bind its Width and Height to the ActualWidth and ActualHeight of the parent InkCanvas:
<InkCanvas ...>
...
<Grid Width="{Binding ActualWidth,
RelativeSource={RelativeSource AncestorType=InkCanvas}}"
Height="{Binding ActualHeight,
RelativeSource={RelativeSource AncestorType=InkCanvas}}">
<Path Stretch="Uniform" ...>
...
</Path>
</Grid>
</InkCanvas>