Visibility change of Shapes in a WPF Canvas

Question

Is there any event that can be raised when a shape in a Canvas(which has zoom and pan controls using Translatetransform/ScaleTransform) becomes visible/invisible when the canvas is panned or zoomed?

Any leads on ways to do this will be helpful and is appreciated. Thanks!

score 1 · Accepted Answer · answered Nov 04 '11 at 04:28

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I assume you mean a canvas inside a scrollviewer? No, there is no such event as the canvas is unaware of the visible part. As far as the canvas is concerned everything is always visible.

You should be able to do this yourself by listening to scale,pan changes and then checking the visible viewport of the scrollviewer against your objects in your canvas.

answered Nov 04 '11 at 04:28

Patrick Klug

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I have >10,000 shapes in the canvas. Checking against them will not be efficient. – Sam Nov 06 '11 at 01:08
I doubt that this will be an issue. Even if you need to check all 10.000 Rect's it should be fast enough. – Patrick Klug Nov 07 '11 at 04:18

Visibility change of Shapes in a WPF Canvas

1 Answers1