Continuous (Edge-to-Edge) Rectangles in WPF overlaps each other - wpf

Question

I am using WPF component in my project in which there is a feature of creating rectangles with the input given as a list containing <x,y> for aligning rectangle over a canvas. I have given 0.5 stroke thickness to the rectangle but not any margin or border between the plotting but still these rectangles are not aligning smoothly , you can see the image attached.
enter image description here
Code
<ItemsControl ItemsSource="{Binding RectangleData}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas Height="{Binding ActualHeight, ElementName=8}"
Width="{Binding ActualWidth, ElementName=myPlotRect}"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.Style>
<Style>
<Setter Property="Canvas.Right" Value="0"/>
<Setter Property="Canvas.Bottom" Value="0"/>
</Style>
</ItemsControl.Style>
<ItemsControl.ItemContainerStyle >
<Style>
</Style>
</ItemsControl.ItemContainerStyle>
<ItemsControl.ItemTemplate>
<DataTemplate DataType="plotLineViewModel:RectangleDataType">
<Canvas Height="{Binding ActualHeight, ElementName=PlotArea}">
<Rectangle Fill= "Blue"
HorizontalAlignment="Left"
VerticalAlignment="Top"
Opacity=".6" Stroke="Grey" StrokeThickness="0.5"
Height ="{Binding Path=ActualHeight, ElementName=RectangleData}">
<Canvas.Left>
<MultiBinding Converter="{StaticResource ChartViewXCordinateConverter}" >
<Binding Path="ActualWidth" ElementName="RectangleData" />
<Binding Path="Location.X" />
<Binding Path="DataContext.XAxisMax" ElementName="XPosition"/>
<Binding Path="DataContext.XAxisMin" ElementName="XPosition"/>
</MultiBinding>
</Canvas.Left>
<Rectangle.Width>
<MultiBinding Converter="{StaticResource ChartViewXCordinateConverter}" >
<Binding Path="ActualWidth" ElementName="RectangleData" />
<Binding Path="Width" />
<Binding Path="DataContext.XAxisMax" ElementName="XPosition" />
<Binding Path="DataContext.XAxisMin" ElementName="XPosition"/>
</MultiBinding>
</Rectangle.Width>
</Rectangle>
</Canvas>
</DataTemplate>
</ItemsControl.ItemTemplate>
Here below i am trying stackpanel approach but the gaps are not coming properly?
enter image description here
enter image description here
Below is the code with StackPanel:
<ItemsControl.ItemTemplate>
<DataTemplate DataType="plotLineViewModel:HighLightRectType">
<StackPanel Orientation="Horizontal" Height="{Binding ActualHeight, ElementName=PlotArea}">
<!--<TextBlock Name="TextBlock1" TextAlignment="Center" Style="{StaticResource AxisValueStyle}" Text="{Binding Path=Label}" >
<Canvas.Left>
<MultiBinding Converter="{StaticResource HighlightRectTextPositionCalculator}" >
<Binding Path="Label" />
<Binding Path="Width" />
<Binding Path="Location.X" />
<Binding Path="ActualWidth" ElementName="myPlotRectangle" />
<Binding Path="DataContext.XAxisMax" ElementName="XPosition"/>
<Binding Path="DataContext.XAxisMin" ElementName="XPosition"/>
</MultiBinding>
</Canvas.Left>
<Canvas.Top>-30</Canvas.Top>
</TextBlock>-->
<StackPanel.Margin>
<MultiBinding Converter="{StaticResource ChartViewXCordinateConverter}" >
<Binding Path="ActualWidth" ElementName="myPlotRectangle" />
<Binding Path="Location.X" />
<Binding Path="DataContext.XAxisMax" ElementName="XPosition"/>
<Binding Path="DataContext.XAxisMin" ElementName="XPosition"/>
<Binding RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType={x:Type ItemsControl}}" Path="DataContext.IsScalingRequired" />
</MultiBinding>
</StackPanel.Margin>
<Rectangle Fill= "{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ItemsControl}}, Path=DataContext.FrameOverlayColor}"
HorizontalAlignment="Left"
VerticalAlignment="Top"
Opacity=".6"
Height ="{Binding Path=ActualHeight, ElementName=myPlotRectangle}">
<!--<Canvas.Left>
<MultiBinding Converter="{StaticResource ChartViewXCordinateConverter}" >
<Binding Path="ActualWidth" ElementName="myPlotRectangle" />
<Binding Path="Location.X" />
<Binding Path="DataContext.XAxisMax" ElementName="XPosition"/>
<Binding Path="DataContext.XAxisMin" ElementName="XPosition"/>
</MultiBinding>
</Canvas.Left>-->
<Rectangle.Width>
<MultiBinding Converter="{StaticResource ChartViewXCordinateConverter}" >
<Binding Path="ActualWidth" ElementName="myPlotRectangle" />
<Binding Path="Width" />
<Binding Path="DataContext.XAxisMax" ElementName="XPosition" />
<Binding Path="DataContext.XAxisMin" ElementName="XPosition"/>
</MultiBinding>
</Rectangle.Width>
</Rectangle>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>