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ImageViewerInteractiveMode Class

Summary

Represents the base class for the rich user experience features of an ImageViewer

Syntax

Java

Objective-C

WinRT C#

public abstract class ImageViewerInteractiveMode

Public MustInherit Class ImageViewerInteractiveMode

public sealed class ImageViewerInteractiveMode

iOS: 
@interface LTImageViewerInteractiveMode : NSObject <LTInteractiveServiceDelegate, LTInteractiveServiceBasicDelegate, UIGestureRecognizerDelegate, NSCoding> 
macOS: 
@interface LTImageViewerInteractiveMode : NSObject <LTInteractiveServiceMouseDelegate, NSCoding>

public abstract class ImageViewerInteractiveMode

function Leadtools.Controls.ImageViewerInteractiveMode()

Remarks

ImageViewerInteractiveMode works with the InteractiveService object of the ImageViewer to provide rich user interface experience when the user interacts with the viewer using mouse or touch.

ImageViewerInteractiveMode is a base abstract class, you can derive your own class to handle custom interaction with the viewer. Out of the box, LEADTOOLS provide the following implementations:

Class	Description
ImageViewerPanZoomInteractiveMode	Supports panning and zooming with the mouse and multi-touch.
ImageViewerZoomToInteractiveMode	Zooms to image rectangle created by the user using mouse or touch.
ImageViewerMagnifyGlassInteractiveMode	Magnifies the portion of the image under the mouse or touch.
ImageViewerCenterAtInteractiveMode	Centers the image inside the user based on user mouse click or touch tap.
ImageViewerRubberBandInteractiveMode	Draws a temporary rectangle on top of the image using the mouse or touch. Can be used to perform any extra functionality such as drawing a region of interest for a user-defined operation.

To use an interactive mode, you create an instance of any of the derived classes and assign it to the viewer using one of the following methods:

ImageViewer.DefaultInteractiveMode: Assigns the interactive mode to be set as the default one.
ImageViewer.TouchInteractiveMode: Assigns the interactive mode in devices that support touch.
ImageViewer.MouseWheelInteractiveMode: Assigns the interactive mode to the mouse wheel.

Example

WinRT C#

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Controls; 
 
// RotateInteractiveMode 
[TestClass] 
public class ImageViewerRotateInteractiveMode : ImageViewerInteractiveMode 
{ 
   public ImageViewerRotateInteractiveMode() 
   { 
   } 
   public override string Name 
   { 
      get { return "Rotate"; } 
   } 
 
   public override string ToString() 
   { 
      return Name; 
   } 
 
   // Called by the base class when the mode is started 
   public override void Start(ImageViewer viewer) 
   { 
      base.Start(viewer); 
 
      // add EventHandlers to the DragStarted, DragDelta and DragCompleted events 
      base.InteractiveService.DragStarted += InteractiveService_DragStarted; 
      base.InteractiveService.DragDelta += InteractiveService_DragDelta; 
      base.InteractiveService.DragCompleted += InteractiveService_DragCompleted; 
   } 
 
   // Called by the base class when the mode is stopped 
   public override void Stop(ImageViewer viewer) 
   { 
      // Check if we have started 
      if (IsStarted) 
      { 
         // remove EventHandlers from events 
         base.InteractiveService.DragStarted -= InteractiveService_DragStarted; 
         base.InteractiveService.DragDelta -= InteractiveService_DragDelta; 
         base.InteractiveService.DragCompleted -= InteractiveService_DragCompleted; 
 
         // Always call base class stop method 
         base.Stop(viewer); 
      } 
   } 
 
   // Called when the user starts a drag operation 
   void InteractiveService_DragStarted(object sender, InteractiveDragStartedEventArgs e) 
   { 
 
      if (!this.CanStartWork(e)) 
      { 
         return; 
      } 
 
      // Inform whoever is listening that we have started working 
      this.OnWorkStarted(EventArgs.Empty); 
 
 
   } 
 
   // Called when the user is dragging 
   void InteractiveService_DragDelta(object sender, InteractiveDragDeltaEventArgs e) 
   { 
      // If we are not working (for example, the user has not clicked the mouse button yet), then 
      // nothing to do 
      if (!this.IsWorking) 
      { 
         return; 
      } 
 
      // Perform our operation, get the change of the drag, then increase 
      // or decrease the current rotation angle based on direction 
      var viewer = this.ImageViewerControl; 
      var change = e.Change; 
      var delta = 4; 
      if (change.X < 0) 
      { 
         viewer.RotateAngle = viewer.RotateAngle - delta; 
      } 
      else if (change.X > 0) 
      { 
         viewer.RotateAngle = viewer.RotateAngle + delta; 
      } 
 
   } 
 
   // Called when the user has stopped dragging 
   void InteractiveService_DragCompleted(object sender, InteractiveDragCompletedEventArgs e) 
   { 
      if (!this.IsWorking) 
      { 
         return; 
      } 
 
      // Inform whoever is listening that we have stoped working 
      this.OnWorkCompleted(EventArgs.Empty); 
   } 
} 
 
//set InteractiveMode in new ImageViewer 
ImageViewer InteractiveModeExample() 
{ 
   Uri imageUrl = new Uri("ms-appx:///Assets/PngImage2.png"); 
 
   // Create the viewer 
   var viewer = new Leadtools.Controls.ImageViewer(); 
 
   // Set the image Source 
   viewer.Source = new BitmapImage(imageUrl); 
 
   // Set Rotate as our interactive mode 
   viewer.DefaultInteractiveMode = new ImageViewerRotateInteractiveMode(); 
 
   return viewer; 
}