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PaintOverlay(RasterImage,IntPtr,int,LeadRect,LeadRect,LeadRect,LeadRect,RasterPaintProperties) Method

Summary
Paints the overlay at the specified index. Use this method to paint overlays that are not automatically painted.
Syntax
C#
C++/CLI
Python

Parameters

image
The source image.

hdc
The destination device context where the image will be displayed.

index
The index of the overlay used for painting. The overlay should have an image. If the overlay is embedded into an image bitplane, make sure you create an overlay image prior to calling this method. This index is zero-based.

srcRect
Rectangle which determines the portion of the image to paint.

srcClipRect
Rectangle which further clips the source image.

destRect
Rectangle which determines where the image is placed, and how it is scaled.

destClipRect
Rectangle which clips the image display.

properties
Options for the display.

Remarks

This method will paint an overlay image. For more information on the paint rectangles, see Paint(RasterImage,Graphics,LeadRect,RasterPaintProperties).

Paint(RasterImage,Graphics,LeadRect,RasterPaintProperties) will paint all the overlays that have RasterOverlayAttributes.AutoPaint set to true. The overlays are painted in ascending index order: overlay 0 is painted first, then overlay 1, etc.

Use this method to manually paint an overlay. For example, to change the order in which the overlays are painted, set the RasterOverlayAttributes.AutoPaint property of the overlay to false then call PaintOverlay(RasterImage,Graphics,Int32,LeadRect,LeadRect,LeadRect,LeadRect,RasterPaintProperties) directly.

To temporarily make an overlay top-most, call PaintOverlay(RasterImage,Graphics,Int32,LeadRect,LeadRect,LeadRect,LeadRect,RasterPaintProperties) after Paint(RasterImage,Graphics,LeadRect,RasterPaintProperties). To permanently make an overlay top-most, change its index and give it the highest defined index.

The overlay image's 1 pixels are painted with the color set in the RasterOverlayAttributes.Color property of the overlay. The overlay image's 0 pixels are considered transparent.

For more information on the overlay attributes, including the RasterOverlayAttributes.AutoPaint property and the RasterOverlayAttributes.Color property, refer to Leadtools.RasterOverlayAttributes, Overlay Overview, and RasterImage and GDI/GDI+.

Example
C#
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
 
 
public void PaintOverlayExample() 
{ 
   PaintOverlayForm f = new PaintOverlayForm(); 
   f.ShowDialog(); 
} 
 
class PaintOverlayForm : Form 
{ 
   private RasterImage image; 
   private RasterPaintProperties props; 
 
   public PaintOverlayForm() 
   { 
      // Load the image 
      RasterCodecs codecs = new RasterCodecs(); 
 
      image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir,"DICOM", "Image2.dcm")); 
 
      using (RasterImage overlay = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif"))) 
      { 
         ResizeCommand cmd = new ResizeCommand(); 
         using (RasterImage destImage = new RasterImage(RasterMemoryFlags.Conventional, image.Width, image.Height, 1, RasterByteOrder.Bgr, image.ViewPerspective, null, IntPtr.Zero, 0)) 
         { 
            cmd.Flags = RasterSizeFlags.FavorBlack; 
            cmd.DestinationImage = destImage; 
            cmd.Run(overlay); 
            image.SetOverlayImage(0, destImage, RasterGetSetOverlayImageMode.Copy); 
         } 
      } 
 
      RasterOverlayAttributes attributes = image.GetOverlayAttributes(0, 
         RasterGetSetOverlayAttributesFlags.Color | 
         RasterGetSetOverlayAttributesFlags.Flags | 
         RasterGetSetOverlayAttributesFlags.Origin | 
         RasterGetSetOverlayAttributesFlags.BitIndex); 
 
      attributes.AutoPaint = false; 
      attributes.Color = new RasterColor(255, 0, 0); 
 
      image.UpdateOverlayAttributes( 
         0, 
         attributes, 
         RasterGetSetOverlayAttributesFlags.Color | 
         RasterGetSetOverlayAttributesFlags.Flags | 
         RasterGetSetOverlayAttributesFlags.Origin | 
         RasterGetSetOverlayAttributesFlags.BitIndex); 
 
      Text = "PaintOverlay Example"; 
      props = RasterPaintProperties.Default; 
      props.UsePaintPalette = true; 
   } 
 
   protected override void Dispose(bool disposing) 
   { 
      // Clean up 
      if (disposing) 
      { 
         image.Dispose(); 
      } 
 
      base.Dispose(disposing); 
   } 
 
   protected override void OnPaint(PaintEventArgs e) 
   { 
      // Draw the image fit and center on this form 
      LeadRect destRect = LeadRect.FromLTRB(ClientRectangle.Left, ClientRectangle.Top, ClientRectangle.Right, ClientRectangle.Bottom); 
      destRect = RasterImage.CalculatePaintModeRectangle( 
         image.ImageWidth, 
         image.ImageHeight, 
         destRect, 
         RasterPaintSizeMode.Fit, 
         RasterPaintAlignMode.Center, 
         RasterPaintAlignMode.Center); 
      RasterImagePainter.Paint(image, e.Graphics, LeadRect.Empty, destRect, props); 
      RasterImagePainter.PaintOverlay(image, e.Graphics, 0, LeadRect.Empty, LeadRect.Empty, destRect, LeadRect.Empty, props); 
 
      base.OnPaint(e); 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
} 
Requirements

Target Platforms

Help Version 22.0.2023.3.31
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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Drawing Assembly

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.