CODEWITHSUNDEEP
wpfxamlsizezoomingscaletransform
slavka
slavka

Reputation: 119

How I can determine control size, after applying ScaleTransform?

How I can determine actual width and actual height of control, after applying the transformation?

For example, I think that following XAML-code should show size something like 400x400 (for example, on the pic. red rectangle, which width 400), but width and height equals 200.

What am I doing wrong?

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    x:Class="VisualCad.Components.TempVisualTests.MainWindow"
    mc:Ignorable="d"
    x:Name="MyWin"
    Title="MainWindow" WindowState="Maximized" Height="500" Width="500">

    <Grid>
        <Rectangle Width="400" Height="5" Fill="Red" Margin="0,20,0,0" VerticalAlignment="Top"/>

        <Canvas x:Name="MyCanvas" Width="200" Height="200">
            <Canvas.RenderTransform>
                <ScaleTransform CenterX="100" CenterY="100" ScaleX="2" ScaleY="2" />
            </Canvas.RenderTransform>

            <StackPanel>
                <TextBlock Text="{Binding Path=RenderSize, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Canvas}}, StringFormat='Render size: {0}'}" />
                <TextBlock Text="{Binding Path=ActualWidth, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Canvas}}, StringFormat='ActualWidth: {0}'}" />
                <TextBlock Text="{Binding Path=ActualHeight, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Canvas}}, StringFormat='ActualHeight: {0}'}" />
            </StackPanel>
        </Canvas>
    </Grid>
</Window>

Upvotes: 3

Views: 2273

Answers (2)

Maxim
Maxim

Reputation: 2128

This code works for me:

var parent = element.Parent as UIElement;

Point bottomLeft = element.TranslatePoint(new Point(0, 0), parent);
Point topRight = element.TranslatePoint(new Point(element.ActualWidth, element.ActualHeight), parent);

var renderWidth = topRight.X - bottomLeft.X;
var renderHeight = topRight.Y - bottomLeft.Y;

Upvotes: 4

mm8
mm8

Reputation: 169150

How I can determine actual width and actual height of control, after applying the transformation?

You need to calculate the width and height yourself. It should be pretty straight-forward though:

double width = MyCanvas.ActualWidth;
double height = MyCanvas.ActualHeight;

ScaleTransform st = MyCanvas.RenderTransform as ScaleTransform;
if(st != null)
{
    width *= st.ScaleX;
    height *= st.ScaleY;
}

There is no property that will return this size for you. Tranformations don't affect the ActualWidth and ActualHeight properties.

Upvotes: 1

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