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BeginUpdate Method

Summary

Stops the viewer from being updated if any change is applied. This is useful to increase the control's speed efficiency.

Syntax

Java

Objective-C

WinRT C#

public virtual void BeginUpdate()

Public Overridable Sub BeginUpdate()

public virtual void BeginUpdate()

- (void)beginUpdate

public void beginUpdate()

function Leadtools.Controls.ImageViewer.BeginUpdate()

Remarks

The BeginUpdate method will cause the control to not update the image viewing transformation or invalidate the display when any changes to the control's properties or the image is applied. When the user calls the EndUpdate method, the viewer will then update the transformation and invalidate the display to show all the changes that have been made.

For better visual results and for speed efficiency, it is recommended you surround multiple calls that will cause a render or transformation change between BeginUpdate and EndUpdate.

Calls to BeginUpdate and EndUpdate are accumulative. Each call to BeginUpdate must be matched with a corresponding call to EndUpdate or else updates to the transform won't be applied.

To determine if the control will currently update the transform and invalidate, use CanUpdate.

Example

WinRT C#

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Controls; 
 
public void BeginUpdateExample() 
{ 
   // Disable updating 
   _viewer.BeginUpdate(); 
   // Flip 
   _viewer.Flip = true; 
   // Zoom 
   _viewer.Zoom(ImageViewerSizeMode.None, 2, _viewer.ImageControlCenter); 
   // Scroll 
   _viewer.ScrollBy(new Point(100, 100)); 
 
   // Show the results 
   _viewer.EndUpdate(); 
}