Image manipulation and scroll bars in WPF

[Peter O'Hanlon]

Has anybody played around with DeltaManipulation on an image inside a ScrollViewer in WPF? What I'm trying to do is pan and zoom an image using touch, but when the user changes the pan or zoom, the scrollbars don't change size/position to match?

This is a WPF 4.5 app.

My XAML

    <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
        <Image 
            Source="{Binding PreviewImage}" 
            HorizontalAlignment="Stretch" 
            x:Name="scaleImage" 
            ManipulationDelta="scaleImage_ManipulationDelta_1" 
            ManipulationStarting="scaleImage_ManipulationStarting_1"
            ManipulationCompleted="scaleImage_ManipulationCompleted_1"
            VerticalAlignment="Stretch" 
            IsManipulationEnabled="True"
            RenderTransformOrigin="0.5,0.5" Stretch="Fill" >
            <Image.RenderTransform>
                <MatrixTransform>
                </MatrixTransform>
            </Image.RenderTransform>
        </Image>
    </ScrollViewer>

My code

        private void scaleImage_ManipulationDelta_1(object sender, ManipulationDeltaEventArgs e)
        {
 
            Matrix rectsMatrix = ((MatrixTransform)scaleImage.RenderTransform).Matrix;
            ManipulationDelta manipDelta = e.DeltaManipulation;
            Point rectManipOrigin = rectsMatrix.Transform(new Point(scaleImage.ActualWidth / 2, scaleImage.ActualHeight / 2));
 
            rectsMatrix.ScaleAt(manipDelta.Scale.X, manipDelta.Scale.Y, rectManipOrigin.X, rectManipOrigin.Y);
            rectsMatrix.Translate(manipDelta.Translation.X, manipDelta.Translation.Y);
            ((MatrixTransform)scaleImage.RenderTransform).Matrix = rectsMatrix;// (MatrixTransform)(new MatrixTransform(rectsMatrix).GetAsFrozen());
            e.Handled = true;
 
        }
 
        private void scaleImage_ManipulationStarting_1(object sender, ManipulationStartingEventArgs e)
        {
            e.ManipulationContainer = this;
            e.Handled = true;
        }

--
Peter O'Hanlon

[Sacha's Gmail]

You can control the scrollviewer yourself have a look at my metro panorama control at codeproject it has that code in it

Sent from my iPhone

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[Peter O'Hanlon]

Cheers mate. I wondered if I would have to do that.

---

From: Sacha's Gmail
Sent: 28/02/2013 08:08
To: wpf-di...@googlegroups.com
Subject: Re: [WPF Disciples] Image manipulation and scroll bars in WPF

[Sacha's Gmail]

Think so

Sent from my iPhone