Increase in Memory allocation after Zoom-In and Zoom-Out operation on a Grid control

Shilpa Neema 0

I am having a GRID control which contains one ImageControl and corresponding Height/Intensity/Color image thumbnails. Now I am performing a simple operation of Zooming In and then again Zooming out my GRID. For this Zoom-In and Zoom-Out Operation I am using "ScaleTransform" property of Grid control.

Now even after Zooming out the image to previous Zoom value, there is increase in Memory allocation in system.Thus performing this operation multiple times results in quite a good amount of increased memory. On checking with one of the Memory Profiler tool, it has been observed that this increase is related to few WPF controls (For eg: EffectiveValueEntry[], MenuItem, Border, TextBlock, Paths etc)

Can someone provide any solution for this issue.

Hui Liu-MSFT 40,661 Reputation points Microsoft Vendor

2023-05-23T02:20:46.5466667+00:00
Hi,@Shilpa Neema. Welcome Microsoft Q&A. For the issue of increased memory allocation when zooming in and out of images multiple times, this may be due to preserving visual elements and resources. The ScaleTransform property affects the rendering of visual elements, but does not necessarily release resources associated with the previous scale state.

To address this issue and minimize memory allocation, you could try the following approaches:

Clear the visual tree: After zooming out, explicitly clear the visual tree of the grid or the container that holds the image and thumbnail controls. This will help release the resources associated with the previous zoomed state. You can achieve this by removing the child elements from the container and then adding them again.

For example:

private void ZoomOutButton_Click(object sender, RoutedEventArgs e) { ScaleTransform.ScaleX = Math.Max(ScaleTransform.ScaleX / 1.2, originalScaleX); ScaleTransform.ScaleY = Math.Max(ScaleTransform.ScaleY / 1.2, originalScaleY); ClearRenderTransform(MainGrid); } private void ClearRenderTransform(Visual visual) { if (visual is UIElement uiElement) { uiElement.RenderTransform = null; uiElement.InvalidateVisual(); } for (int i = 0; i < VisualTreeHelper.GetChildrenCount(visual); i++) { Visual child = VisualTreeHelper.GetChild(visual, i) as Visual; ClearRenderTransform(child); } }

Dispose of unused resources: If you're working with resources such as images, make sure to dispose of them properly when they are no longer needed. Use using blocks or explicitly call the Dispose method to release resources. This ensures that memory is freed up when zooming in and out.