private static void ContentOffsetY_PropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
ScrollBox c = (ScrollBox)o;
c.UpdateTranslationY();
if (!c.disableContentFocusSync)
{
//
// Normally want to automatically update content focus when content offset changes.
// Although this is disabled using 'disableContentFocusSync' when content offset changes due to in-progress zooming.
//
c.UpdateContentZoomFocusY();
}
if (c.ContentOffsetYChanged != null)
{
//
// Raise an event to let users of the control know that the content offset has changed.
//
c.ContentOffsetYChanged(c, EventArgs.Empty);
}
if (!c.disableScrollOffsetSync && c.scrollOwner != null)
{
//
// Notify the owning ScrollViewer that the scrollbar offsets should be updated.
//
c.scrollOwner.InvalidateScrollInfo();
}
}
private static object Zoom_Coerce(DependencyObject d, object baseValue)
{
ScrollBox c = (ScrollBox)d;
double value = (double)baseValue;
value = Math.Min(Math.Max(value, c.MinimumZoom), c.MaximumZoom);
return(value);
}
private static void Zoom_PropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
ScrollBox c = (ScrollBox)o;
if (c.contentScaleTransform != null)
{
//
// Update the content scale transform whenever 'Zoom' changes.
//
c.contentScaleTransform.ScaleX = c.Zoom;
c.contentScaleTransform.ScaleY = c.Zoom;
}
//
// Update the size of the viewport in content coordinates.
//
c.UpdateContentViewportSize();
if (c.enableContentOffsetUpdateFromScale)
{
try
{
//
// Disable content focus syncronization. We are about to update content offset whilst zooming
// to ensure that the viewport is focused on our desired content focus point. Setting this
// to 'true' stops the automatic update of the content focus when content offset changes.
//
c.disableContentFocusSync = true;
//
// Whilst zooming in or out keep the content offset up-to-date so that the viewport is always
// focused on the content focus point (and also so that the content focus is locked to the
// viewport focus point - this is how the google maps style zooming works).
//
double viewportOffsetX = c.ViewportZoomFocusX - (c.ViewportWidth / 2);
double viewportOffsetY = c.ViewportZoomFocusY - (c.ViewportHeight / 2);
double contentOffsetX = viewportOffsetX / c.Zoom;
double contentOffsetY = viewportOffsetY / c.Zoom;
c.ContentOffsetX = (c.ContentZoomFocusX - (c.ContentViewportWidth / 2)) - contentOffsetX;
c.ContentOffsetY = (c.ContentZoomFocusY - (c.ContentViewportHeight / 2)) - contentOffsetY;
}
finally
{
c.disableContentFocusSync = false;
}
}
if (c.ZoomChanged != null)
{
c.ZoomChanged(c, EventArgs.Empty);
}
if (c.scrollOwner != null)
{
c.scrollOwner.InvalidateScrollInfo();
}
}
private static object ContentOffsetY_Coerce(DependencyObject d, object baseValue)
{
ScrollBox c = (ScrollBox)d;
double value = (double)baseValue;
double minOffsetY = 0.0;
double maxOffsetY = Math.Max(0.0, c.unScaledExtent.Height - c.constrainedContentViewportHeight);
value = Math.Min(Math.Max(value, minOffsetY), maxOffsetY);
return(value);
}
private static void MinOrMaximumZoom_PropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
ScrollBox c = (ScrollBox)o;
c.Zoom = Math.Min(Math.Max(c.Zoom, c.MinimumZoom), c.MaximumZoom);
}
