Changed Event

Summary

Occurs when the image data or attributes has changed.

Syntax

Objective-C

C++

Java

public event EventHandler<RasterImageChangedEventArgs> Changed

Public Event Changed As EventHandler(Of RasterImageChangedEventArgs)

extern NSString *const LTRasterImageChangedNotification 
extern NSString *const LTRasterImageChangedNotificationFlags

synchronized public void addChangedListener(RasterImageChangedListener listener) 
synchronized public void removeChangedListener(RasterImageChangedListener listener)

public: 
event EventHandler<RasterImageChangedEventArgs^>^ Changed

Event Data

The event handler receives an argument of type RasterImageChangedEventArgs containing data related to this event. The following RasterImageChangedEventArgs properties provide information specific to this event.

Property	Description
Flags	Gets the flags for the Changed event.

Remarks

When the data or attributes of a RasterImage object changes, the Changed event is fired with information of what has changed. For example, you can subscribe to this event to get notified when the RasterImage object has been changed and need to be updated in your user interface by re-painting it.

For more information, refer to RasterImageChangedEventArgs.

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Dicom; 
using Leadtools.Drawing; 
using Leadtools.Controls; 
using Leadtools.Svg; 
 
 
public void ChangedExample() 
{ 
	RasterCodecs codecs = new RasterCodecs(); 
 
	string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); 
 
	// Load the image 
	RasterImage img = codecs.Load(srcFileName); 
 
	// Subscribe to the Changed event of this image 
	img.Changed += new EventHandler<RasterImageChangedEventArgs>(img_Changed); 
 
	// Call a few methods and image processing commands that changes the image 
	Console.WriteLine("Calling FlipViewPerspective"); 
	img.FlipViewPerspective(true); 
 
	Console.WriteLine("Calling RotateViewPerspective"); 
	img.RotateViewPerspective(90); 
 
	Console.WriteLine("Calling FlipCommand"); 
	FlipCommand flip = new FlipCommand(true); 
	flip.Run(img); 
 
	// Now disable firing the events and call the methods again 
	Console.WriteLine("Disabling the events"); 
	img.DisableEvents(); 
 
	Console.WriteLine("Calling FlipViewPerspective"); 
	img.FlipViewPerspective(true); 
 
	Console.WriteLine("Calling RotateViewPerspective"); 
	img.RotateViewPerspective(90); 
 
	Console.WriteLine("Calling FlipCommand while"); 
	flip.Run(img); 
 
	// Re-enable the events and fire it manually 
	Console.WriteLine("Re-enabling the events"); 
	img.EnableEvents(); 
 
	Console.WriteLine("Firing the event manually"); 
	RasterImageChangedFlags flags = RasterImageChangedFlags.Data | RasterImageChangedFlags.ViewPerspective; 
	RasterImageChangedEventArgs e = new RasterImageChangedEventArgs(flags); 
 
	img.OnChanged(e); 
 
	// Clean up 
	img.Changed -= new EventHandler<RasterImageChangedEventArgs>(img_Changed); 
	img.Dispose(); 
	codecs.Dispose(); 
} 
 
void img_Changed(object sender, RasterImageChangedEventArgs e) 
{ 
	// Show the changed flags 
	Console.WriteLine("Changed: {0}", e.Flags); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS21\Resources\Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Controls 
Imports Leadtools.Dicom 
Imports Leadtools.Drawing 
Imports Leadtools.Svg 
 
Public Sub ChangedExample() 
   Dim codecs As RasterCodecs = New RasterCodecs() 
 
   Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp") 
 
   ' Load the image 
   Dim img As RasterImage = codecs.Load(srcFileName) 
 
   ' Subscribe to the Changed event of this image 
   AddHandler img.Changed, AddressOf img_Changed 
 
   ' Call a few methods and image processing commands that changes the image 
   Console.WriteLine("Calling FlipViewPerspective") 
   img.FlipViewPerspective(True) 
 
   Console.WriteLine("Calling RotateViewPerspective") 
   img.RotateViewPerspective(90) 
 
   Console.WriteLine("Calling FlipCommand") 
   Dim flip As FlipCommand = New FlipCommand(True) 
   flip.Run(img) 
 
   ' Now disable firing the events and call the methods again 
   Console.WriteLine("Disabling the events") 
   img.DisableEvents() 
 
   Console.WriteLine("Calling FlipViewPerspective") 
   img.FlipViewPerspective(True) 
 
   Console.WriteLine("Calling RotateViewPerspective") 
   img.RotateViewPerspective(90) 
 
   Console.WriteLine("Calling FlipCommand while") 
   flip.Run(img) 
 
   ' Re-enable the events and fire it manually 
   Console.WriteLine("Re-enabling the events") 
   img.EnableEvents() 
 
   Console.WriteLine("Firing the event manually") 
   Dim flags As RasterImageChangedFlags = RasterImageChangedFlags.Data Or RasterImageChangedFlags.ViewPerspective 
   Dim e As RasterImageChangedEventArgs = New RasterImageChangedEventArgs(flags) 
 
   img.OnChanged(e) 
 
   ' Clean up 
   RemoveHandler img.Changed, AddressOf img_Changed 
   img.Dispose() 
   codecs.Dispose() 
End Sub 
 
Private Sub img_Changed(ByVal sender As Object, ByVal e As RasterImageChangedEventArgs) 
   ' Show the changed flags 
   Console.WriteLine("Changed: {0}", e.Flags) 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\LEADTOOLS21\Resources\Images" 
End Class

Requirements

Target Platforms

Reference

RasterImage Class

RasterImage Members

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Help Version 21.0.2021.7.2