/// <summary>
/// Applies the computed scale to the image control.
/// </summary>
private static void ApplyScale(Image image, ImageZoomerSettings settings)
{
((CompositeTransform)image.RenderTransform).ScaleX = settings.TotalImageScale;
((CompositeTransform)image.RenderTransform).ScaleY = settings.TotalImageScale;
}
/// <summary>
/// Checks that dragging by the given amount won't result in empty space around the image
/// </summary>
private static bool IsDragValid(double scaleDelta, Point translateDelta, Image image, ImageZoomerSettings settings, out bool bounce)
{
if (settings.ImagePosition.X + translateDelta.X < image.ActualWidth * 0.33 || settings.ImagePosition.Y + translateDelta.Y < image.ActualHeight * 0.33)
{
bounce = true;
return true;
}
if ((image.ActualWidth * settings.TotalImageScale * scaleDelta) + (settings.ImagePosition.X + translateDelta.X) < image.ActualWidth * 1.33)
{
bounce = true;
return true;
}
if ((image.ActualHeight * settings.TotalImageScale * scaleDelta) + (settings.ImagePosition.Y + translateDelta.Y) < image.ActualHeight * 1.33)
{
bounce = true;
return true;
}
if ((image.ActualWidth * settings.TotalImageScale * scaleDelta) + (settings.ImagePosition.X + translateDelta.X) < image.ActualWidth)
{
bounce = false;
return false;
}
if ((image.ActualHeight * settings.TotalImageScale * scaleDelta) + (settings.ImagePosition.Y + translateDelta.Y) < image.ActualHeight)
{
bounce = false;
return false;
}
bounce = false;
return true;
}
private static void ApplyPosition(Image image, ImageZoomerSettings settings)
{
((CompositeTransform)image.RenderTransform).TranslateX = settings.ImagePosition.X;
((CompositeTransform)image.RenderTransform).TranslateY = settings.ImagePosition.Y;
}
/// <summary>
/// Updates the scaling factor by multiplying the delta.
/// </summary>
private static void UpdateImageScale(double scaleFactor, Image image, ImageZoomerSettings settings)
{
settings.TotalImageScale *= scaleFactor;
ApplyScale(image, settings);
}
private static void UpdateImagePosition(Point delta, Image image, ImageZoomerSettings settings)
{
var newPosition = new Point(settings.ImagePosition.X + delta.X, settings.ImagePosition.Y + delta.Y);
if (newPosition.X > 0) newPosition.X = 0;
if (newPosition.Y > 0) newPosition.Y = 0;
if ((image.ActualWidth * settings.TotalImageScale) + newPosition.X < image.ActualWidth)
newPosition.X = image.ActualWidth - (image.ActualWidth * settings.TotalImageScale);
if ((image.ActualHeight * settings.TotalImageScale) + newPosition.Y < image.ActualHeight)
newPosition.Y = image.ActualHeight - (image.ActualHeight * settings.TotalImageScale);
settings.ImagePosition = newPosition;
ApplyPosition(image, settings);
}
/// <summary>
/// Resets the zoom to its original scale and position
/// </summary>
private static void ResetImagePosition(Image image, ImageZoomerSettings settings)
{
settings.TotalImageScale = 1;
settings.ImagePosition = new Point(0, 0);
ApplyScale(image, settings);
ApplyPosition(image, settings);
}
/// <summary>
/// Tells if the scaling is inside the desired range
/// </summary>
private static bool IsScaleValid(double scaleDelta, ImageZoomerSettings settings)
{
return (settings.TotalImageScale * scaleDelta >= 1) && (settings.TotalImageScale * scaleDelta <= settings.MAX_IMAGE_ZOOM);
}