/// <summary>
/// Zoom to the specified scale and move the specified focus point to the center of the viewport.
/// </summary>
private void AnimatedZoomPointToViewportCenter(double newContentScale, Point contentZoomFocus, EventHandler callback)
{
newContentScale = Math.Min(Math.Max(newContentScale, MinContentScale), MaxContentScale);
AnimationHelper.CancelAnimation(this, ContentZoomFocusXProperty);
AnimationHelper.CancelAnimation(this, ContentZoomFocusYProperty);
AnimationHelper.CancelAnimation(this, ViewportZoomFocusXProperty);
AnimationHelper.CancelAnimation(this, ViewportZoomFocusYProperty);
ContentZoomFocusX = contentZoomFocus.X;
ContentZoomFocusY = contentZoomFocus.Y;
ViewportZoomFocusX = (ContentZoomFocusX - ContentOffsetX) * ContentScale;
ViewportZoomFocusY = (ContentZoomFocusY - ContentOffsetY) * ContentScale;
//
// When zooming about a point make updates to ContentScale also update content offset.
//
enableContentOffsetUpdateFromScale = true;
if (ContentScale == newContentScale)
{
ContentScale *= 1.0000000001; // Change the scale slightly so our animation still works.
}
AnimationHelper.StartAnimation(this, ContentScaleProperty, newContentScale, AnimationDuration,
delegate(object sender, EventArgs e)
{
enableContentOffsetUpdateFromScale = false;
if (callback != null)
{
callback(this, EventArgs.Empty);
}
});
double newViewportZoomFocusX = ViewportWidth / 2;
double newViewportZoomFocusY = ViewportHeight / 2;
if (newViewportZoomFocusY == ViewportZoomFocusY)
{
ViewportZoomFocusY += 1;
}
if (newViewportZoomFocusX == ViewportZoomFocusX)
{
ViewportZoomFocusX += 1;
}
AnimationHelper.StartAnimation(this, ViewportZoomFocusXProperty, newViewportZoomFocusX, AnimationDuration);
AnimationHelper.StartAnimation(this, ViewportZoomFocusYProperty, newViewportZoomFocusY, AnimationDuration);
}
/// <summary>
/// Zoom in/out centered on the specified point (in content coordinates).
/// The focus point is kept locked to it's on screen position (ala google maps).
/// </summary>
public void ZoomAboutPoint(double newContentScale, Point contentZoomFocus)
{
newContentScale = Math.Min(Math.Max(newContentScale, MinContentScale), MaxContentScale);
double screenSpaceZoomOffsetX = (contentZoomFocus.X - ContentOffsetX) * ContentScale;
double screenSpaceZoomOffsetY = (contentZoomFocus.Y - ContentOffsetY) * ContentScale;
double contentSpaceZoomOffsetX = screenSpaceZoomOffsetX / newContentScale;
double contentSpaceZoomOffsetY = screenSpaceZoomOffsetY / newContentScale;
double newContentOffsetX = contentZoomFocus.X - contentSpaceZoomOffsetX;
double newContentOffsetY = contentZoomFocus.Y - contentSpaceZoomOffsetY;
AnimationHelper.CancelAnimation(this, ContentScaleProperty);
AnimationHelper.CancelAnimation(this, ContentOffsetXProperty);
AnimationHelper.CancelAnimation(this, ContentOffsetYProperty);
this.ContentScale = newContentScale;
this.ContentOffsetX = newContentOffsetX;
this.ContentOffsetY = newContentOffsetY;
}