If you have used the Deep Zoom Composer to generate a Silverlight project, then one thing you may notice is that your users can zoom out so far that they can't see anything! It is actually quite easy to lose the image completely and not be able to get back to seeing anything. Alternatively you may want to restrict how far they can zoom in too, so they don't start to see "blocky" images.
A simple fix for this is to modify the Zoom method in Page.Xaml.cs with the following:
public void Zoom(double zoom, Point pointToZoom)
{
bool zoomingIn = zoom > 1;
bool zoomingOut = zoom < 1;
double minViewportWidth = 0.05;
double maxViewportWidth = 1;
if (msi.ViewportWidth < minViewportWidth && zoomingIn)
{
return;
}
if (msi.ViewportWidth > maxViewportWidth && zoomingOut)
{
return;
}
Point logicalPoint = this.msi.ElementToLogicalPoint(pointToZoom);
this.msi.ZoomAboutLogicalPoint(zoom, logicalPoint.X, logicalPoint.Y);
}
This still allows users who are quick with the mouse wheel to take effect of the spring zoom and go a little further than defined but it does offers a simple solution to a common problem.
Cheers
Ian
posted @ Saturday, August 16, 2008 7:58 AM