When I place the following code in a Window or UserControl, the image is displayed with its native width and height. Is there a way to automatically scale outer canvas to proportions of the containing window while retaining the proper aspect ratio for the window?
<Canvas Background="AliceBlue">
<Canvas.LayoutTransform>
<ScaleTransform ScaleX="1" ScaleY="1"/>
</Canvas.LayoutTransform>
<Image Source="ImageName.jpg" HorizontalAlignment="Center" VerticalAlignment="Center"/>
<Canvas Canvas.Top="20" Canvas.Left="20" Width="20" Height="20" Background="Salmon"/>
</Canvas>
A Canvas never resizes its child elements. Put the Image control in a Grid instead, then probably put the whole thing in a Viewbox:
<Viewbox>
<Grid>
<Image Stretch="None" Source="ImageName.jpg" .../>
<Canvas Margin="20,20,0,0" Width="20" Height="20" Background="Salmon"/>
</Grid>
</Viewbox>
Wrap your Canvas in a ViewBox.
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WPF Clipping Problem
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Closed 5 years ago.
I try to rotate an image in a ScrollViewer (WPF), but the entire image needs to remain visible. The corners of the image are cut off, if rotation angle is for example 45. I tried setting the Width and Height of the image by calculation the surrounding rectangle of the rotated image. It works, but not if the rotation angle is over 45.
<Grid>
<ScrollViewer ScrollViewer.HorizontalScrollBarVisibility="Visible" Margin="0,0,0,0">
<Image x:Name="image" RenderTransformOrigin="0.5,0.5" Margin="0,0,0,0" MouseDown="image_MouseDown" MouseRightButtonDown="image_MouseRightButtonDown" MouseLeftButtonDown="image_MouseLeftButtonDown">
<Image.RenderTransform>
<TransformGroup>
<ScaleTransform x:Name="scal"/>
<SkewTransform/>
<RotateTransform Angle="90" x:Name="rot"/>
<TranslateTransform/>
</TransformGroup>
</Image.RenderTransform>
</Image>
</ScrollViewer>
</Grid>
Use a ViewBox in the following structure:
<ScrollViewer Width="100" Height="100" Background="Black" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
<Viewbox Width="100" Height="100">
<Border Width="100" Height="100" Background="Red" >
<Border.LayoutTransform>
<RotateTransform Angle="30" />
</Border.LayoutTransform>
</Border>
</Viewbox>
</ScrollViewer>
Note that you should set the size of the ViewBox and the inner Control (in your case the Image) equal to the size of the ScrollViewer. The ViewBox will adjust the size of the inner Control, in such a way that the ScrollBars are never Visible.
Note that I used a red Border, you can add the image.
Edit
Just checked it. You do not need to set the Widths, but just the size of inner Control. In other words, this works too:
<ScrollViewer Background="Black" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
<Viewbox>
<Border Width="1" Height="1" Background="Red" >
<Border.LayoutTransform>
<RotateTransform Angle="30" />
</Border.LayoutTransform>
</Border>
</Viewbox>
</ScrollViewer>
When i draw items in canvas, the position is take from top of the item inside canvas:
<Canvas Name="cnvMain"
Width="80"
Height="80">
<Ellipse Canvas.Top="20"
Canvas.Left="40"
Width="40"
Height="40"
Fill="Gray" />
</Canvas>
Now what i would need is to take the measurement from the bottom of the element, like this:
In the end i would like to be able to set the distance from the bottom of the Ellipse to the top of the Canvas.
NB: Ellipse can sometimes not be a circle and flipping it upside down is not an option. Also i dont know the height before runtime so setting negative margin in xaml will not work also.
(Picture and example xaml taken from: http://weblogs.asp.net/psheriff/centering-text-within-a-wpf-shape-using-a-canvas)
If you want to specify the distance of the bottom of the Ellipse to the bottom of the Canvas, you could replace Canvas.Top by Canvas.Bottom:
<Ellipse Canvas.Bottom="20" Canvas.Left="40" Width="40" Height="40" Fill="Gray"/>
For the distance from the bottom of the Ellipse to the top of the Canvas, you may specify a negative Margin:
<Ellipse Canvas.Top="20" Canvas.Left="40" Width="40" Height="40" Fill="Gray"
Margin="0,-40,0,0"/>
or an appropriate RenderTransform:
<Ellipse Canvas.Top="20" Canvas.Left="40" Width="40" Height="40" Fill="Gray">
<Ellipse.RenderTransform>
<ScaleTransform ScaleY="-1"/>
</Ellipse.RenderTransform>
</Ellipse>
In order to invert the y direction of the whole Canvas coordinate system, you may apply a RenderTransform to the Canvas:
<Canvas ... RenderTransformOrigin="0,0.5">
<Canvas.RenderTransform>
<ScaleTransform ScaleY="-1"/>
</Canvas.RenderTransform>
...
</Canvas>
Edit: You may also put the Ellipse in another Canvas with zero Height, and attach it to the lower Canvas border:
<Canvas Canvas.Top="20" Canvas.Left="40" Width="0" Height="0">
<Ellipse Canvas.Bottom="0" Width="40" Height="40" Fill="Gray"/>
</Canvas>
I have the following controls in xaml:
<Canvas Height="500" Width="500" Name="canPreview" VerticalAlignment="top" Grid.Row="1" Grid.RowSpan="3" MouseLeftButtonDown="canPreview_MouseLeftButtonDown"
MouseLeftButtonUp="canPreview_MouseLeftButtonUp" MouseLeave="canPreview_MouseLeave" MouseMove="canPreview_MouseMove"
Height="{Binding Path=ActualHeight, ElementName=imgPreview}" Width="{Binding Path=ActualWidth, ElementName=imgPreview}">
<Rectangle Name="recSelection" StrokeThickness="2" Stroke="Black" Fill="Transparent" Opacity=".5" Height="100" Width="100" />
</Canvas>
And for some reason the Canvas events only fire when the mouse pointer is above the rectangle. Any idea what is going on?
Set the background color of the Canvas; you can't click something that isn't drawn.
You can use the Transparent brush if you do not want to see the canvas, it will be clickable.
I am declaring this Grid Splitter:
<GridSplitter HorizontalAlignment="Right" VerticalAlignment="Stretch" Grid.Column="1" Grid.RowSpan="1" Grid.Row="1" Width="5" Background="#FFBCBCBC" ResizeBehavior="PreviousAndNext">
</GridSplitter>
It is a vertical grid splitter and I want to draw some text using RotateTransform so the text runs from top to bottom. I am having trouble getting it to work.
This should render the text as rotated.
<TextBlock Text="Testing" HorizontalAlignment="Center" VerticalAlignment="Center" IsHitTestVisible="False">
<TextBlock.LayoutTransform>
<RotateTransform Angle="90" />
</TextBlock.LayoutTransform>
</TextBlock>
You would then need to include it after your GridSplitter in the same column. The IsHitTestVisible is just in case it interferes with the mouse.
EDIT: Just to be clear, this would be a child of the Grid, not the GridSplitter. It would simply render on top of the GridSplitter.
I am perplexed with an issue that I am experiencing, using ScaleTransform. I have a Grid with a fixed width and height. The grid contains one child, a Rectangle. The Rectangle's Fill is a VisualBrush whose Visual binds to a canvas outside of the grid, whose dimensions are rather large. On the rectangle, I use a ScaleTransform, with ScaleX and ScaleY both being set to 0.18. Essentially, I am trying to scale the Rectangle's visual down to fit within my grid. What appears to be happening is that the Grid itself is being scaled down, resulting in a much smaller result than what I want. I have included the code below. Just as a point of reference, the height and width that the rectangle binds do are essentially 900 by 600, respectively. Any pointers as to what I might be doing wrong would be greatly appreciated.
<Grid Height="225" Width="200" Grid.Row="0" HorizontalAlignment="Left" VerticalAlignment="Top" x:Name="PART_Content">
<Rectangle Height="{Binding Path=ActualHeight}" Width="{Binding Path=ActualWidth}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<Rectangle.Fill>
<VisualBrush Visual="{Binding}"/>
</Rectangle.Fill>
<Rectangle.RenderTransform>
<ScaleTransform ScaleX="0.183" ScaleY="0.183"/>
</Rectangle.RenderTransform>
</Rectangle>
</Grid>
Can you post the XAML for the Canvas element? I tried the following and I am getting the behavior you are going for (the rectangle is scaled and the grid is sized correctly)
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid ShowGridLines="True" Height="225" Width="200" Grid.Row="0" HorizontalAlignment="Left" VerticalAlignment="Top" x:Name="PART_Content">
<Rectangle Height="{Binding Path=ActualHeight}" Width="{Binding Path=ActualWidth}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<Rectangle.Fill>
<VisualBrush Visual="{Binding ElementName=theCanvas}"/>
</Rectangle.Fill>
<Rectangle.RenderTransform>
<ScaleTransform ScaleX="0.183" ScaleY="0.183"/>
</Rectangle.RenderTransform>
</Rectangle>
</Grid>
<Canvas x:Name="theCanvas" Grid.Row="1">
<Rectangle Fill="Brown" Height="300" Width="300" />
</Canvas>
</Grid>
What is ActualWidth and ActualHeight? Unless I am mistaken the ActualHeight and ActualWidth properties as they normally mean in WPF are not DP's and you cannot bind to them. As has been pointed out below these are readonly dependency properties. Assuming this is in a CustomControl style Binding should be changed to TemplateBinding first.
I removed the bindings and essentially created a static version of your XAML which looks just fine. Since you have Part_Content defined for the grid, I am curious, is this xaml part of a custom control style? Is the code of the CustomControl manipulating the grid via PART_Content?
<Grid Height="225" Width="200" Grid.Row="0" HorizontalAlignment="Left" VerticalAlignment="Top" x:Name="PART_Content" Background="Red">
<Rectangle Height="225"
Width="200"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Fill="Blue">
<Rectangle.RenderTransform>
<ScaleTransform ScaleX="0.183" ScaleY="0.183"/>
</Rectangle.RenderTransform>
</Rectangle>
</Grid>