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ViewerToImageRectangle Method

Summary

Converts a rectangle in viewer coordinates to image coordinates.

Syntax

C++/CLI

C++

public Rectangle ViewerToImageRectangle( 
   Rectangle rect, 
   bool accountForViewPerspective 
)

public: 
Rectangle ViewerToImageRectangle(  
   Rectangle rect, 
   bool accountForViewPerspective 
)

public:  
   Rectangle^ ViewerToImageRectangle( 
      Rectangle^ rect, 
      bool accountForViewPerspective 
   )

Parameters

rect
The rectangle in viewer coordinates.

accountForViewPerspective
true to return the coordinates in the current Image view perspective. false to return the coordinates in top-left view perspective.

Return Value

A System.Drawing.Rectangle object containing the rectangle coordinates.

Remarks

This method converts a rectangle from viewer (physical) to image (logical) coordinates. The viewer coordinates is what you are currently seeing on the screen. It contains the current scale and scroll values (as well as any padding if set). For example, when you use the RasterViewerInteractiveMode.UserRectangle, the value obtained from the RasterViewerRectangleEventArgs.Rectangle parameter to the InteractiveUserRectangle event is in physical coordinates. If you need to convert this value to image coordinates (for example, to use it as a region or to find the exact pixel coordinate of this rectangle in the image) then you should use the ViewerToImageRectangle method.

When accountForViewPerspective is set to true, the return rectangle value is in the same view perspective as the current image (RasterImage.ViewPerspective) which might not be necessary in top-left coordinates. If this value is false, the return value is always in top-left coordinates.

To convert a rectangle from image (logical) to viewer (physical) coordinates, use the ImageToViewerRectangle method.

To convert a point from image to viewer coordinates and back, use ImageToViewerPoint and ViewerToImagePoint.

Example

using Leadtools.WinForms; 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Drawing; 
 
public void InteractiveUserRectangleExample(RasterImageViewer viewer) 
{ 
   // Set the interactive mode of the viewer to user-defined rectangle 
   viewer.InteractiveMode = RasterViewerInteractiveMode.UserRectangle; 
 
   // Subscribe to the InteractiveUserRectangle event to know when the user has finished drawing a new rectangle 
   viewer.InteractiveUserRectangle += new EventHandler<RasterViewerRectangleEventArgs>(viewer_InteractiveUserRectangle); 
} 
 
private void viewer_InteractiveUserRectangle(object sender, RasterViewerRectangleEventArgs e) 
{ 
   // Check the status of the event 
   if (e.Status == RasterViewerInteractiveStatus.End && !e.Cancel) 
   { 
      // The user has finished drawing a new rectangle (and the operation has not been canceled) 
 
      // Get the rectangle and convert it to image coordinates (with view-perspective) 
      RasterImageViewer viewer = sender as RasterImageViewer; 
      Rectangle rect = e.Rectangle; 
 
      // The user rectangle might have negative width or height (if the user starts the drawing from 
      // bottom-left corner for example), check for that 
      if (rect.Left > rect.Right) 
         rect = Rectangle.FromLTRB(rect.Right, rect.Top, rect.Left, rect.Bottom); 
      if (rect.Top > rect.Bottom) 
         rect = Rectangle.FromLTRB(rect.Left, rect.Bottom, rect.Right, rect.Top); 
 
      // Account for the view perspective of the image 
      rect = viewer.ViewerToImageRectangle(rect, true); 
 
      // Set this as the region and invert the colors 
      RasterImage image = viewer.Image; 
 
      LeadRect ltRect = new LeadRect(rect.Left, rect.Top, rect.Width, rect.Height); 
      image.AddRectangleToRegion(null, ltRect, RasterRegionCombineMode.Set); 
 
      InvertCommand cmd = new InvertCommand(); 
      cmd.Run(image); 
 
      // Remove the region 
      image.MakeRegionEmpty(); 
   } 
}

Requirements

Target Platforms