CODEWITHSUNDEEP
winrt-xaml
MilkBottle
MilkBottle

Reputation: 4332

How to keep rotating image or canvas

This code only fire once to rotate the canvas. Why it does not rotate when user press the rotate button second time?

--update with button

<AppBarButton x:Name="CamRotate90" Margin="0,2,2,0" Width="90" Height="90" FontSize="16"  Label="Rotate-Right" Icon="Rotate" Click="CamRotate90_Click">
</AppBarButton>




<Canvas  x:Name="canvas" Margin="231,28,321,111" Width="700" Height="525" Grid.Row="0" Grid.RowSpan="3" Grid.Column="0">
    <Image Canvas.Top="0" Canvas.Left="0" Margin="0" x:Name="preview" Width="700" Height="525"  Stretch="UniformToFill" >
    </Image>
 </Canvas>


 private void CamRotate90_Click(object sender, RoutedEventArgs e)
        {

            CompositeTransform ct = new CompositeTransform();
            ct.CenterX = canvas.ActualWidth / 2;
            ct.CenterY = canvas.ActualHeight/2;
            ct.Rotation = 90;

            canvas.RenderTransform = ct;          


        }

Upvotes: 0

Views: 270

Answers (1)

Rob Caplan - MSFT
Rob Caplan - MSFT

Reputation: 21919

Instead of replacing the RenderTransform each time create the RenderTransform once and reuse it:

Xaml:

<Canvas x:Name="canvas" Margin="231,28,321,111" Width="700" Height="525" Grid.Row="0" Grid.RowSpan="3" Grid.Column="0">
    <Canvas.RenderTransform>
        <CompositeTransform />
    </Canvas.RenderTransform>
    <Image Canvas.Top="0" Canvas.Left="0" Margin="0" x:Name="preview" Width="700" Height="525"  Stretch="UniformToFill" >
    </Image>
</Canvas>

Code:

private void CamRotate90_Click(object sender, RoutedEventArgs e)
{
    CompositeTransform ct = canvas.RenderTransform as CompositeTransform;
    if (ct != null) // Just to make sure
    {
        ct.CenterX = canvas.ActualWidth / 2;
        ct.CenterY = canvas.ActualHeight / 2;
        ct.Rotation += 90;
    }
}

Upvotes: 0

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