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BackgroundColor Property

Summary

Color to use to fill the background area.

Syntax
C#
C++/CLI
public Color BackgroundColor { get; set; } 
public:  
   property System::Drawing::Color^ BackgroundColor 
   { 
      System::Drawing::Color^ get() 
      void set(System::Drawing::Color^ value) 
   } 

Property Value

The color to use to fill the background area. Default value is "Transparent".

Remarks

The default value of "Transparent" will instruct RenderRedirect to not erase the background of the target control during rendering. Otherwise, set this value to the desired color. For more information, refer to Image Viewer Rendering.

Example
C#
using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public ImageViewerForm _form = new ImageViewerForm(); 
public ImageViewer _imageViewer; 
public PictureBox redirectRenderControl; 
 
public void ImageViewerRedirectRenderExample() 
{ 
   // Get the ImageViewer control from the form 
   _imageViewer = _form.ImageViewer; 
 
   // Load an image 
   using (var codecs = new RasterCodecs()) 
      _imageViewer.Image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "cannon.jpg")); 
 
   // PanZoom Interactive Mode 
   _imageViewer.DefaultInteractiveMode = new ImageViewerPanZoomInteractiveMode(); 
 
   // Separate Form with PictureBox control 
   Form redirectRenderForm = new Form(); 
   redirectRenderControl = new PictureBox(); 
   redirectRenderControl.Width = 400; 
   redirectRenderControl.Dock = DockStyle.Fill; 
   redirectRenderForm.Controls.Add(redirectRenderControl); 
   redirectRenderForm.Show(); 
 
   // Invalidate on double-click 
   bool renderView = false; 
   redirectRenderControl.DoubleClick += (sender, e) => 
   { 
      renderView = !renderView; 
      redirectRenderControl.Invalidate(); 
   }; 
 
             
   redirectRenderControl.Paint += (sender, e) => 
   { 
      if (_imageViewer.Image == null) 
         return; 
 
      // Get PictureBox Graphics object 
      Graphics graphics = e.Graphics; 
 
      // Destination rectangle in PictureBox 
      int margin = 20; 
      LeadRect destRect = LeadRect.Create(margin, margin, redirectRenderControl.ClientSize.Width - margin * 2, redirectRenderControl.ClientSize.Height - margin * 2); 
      LeadRect clipRect = destRect; 
 
      // Source rectangle 
      Debug.WriteLine(_imageViewer.ViewSize); 
 
      // RenderRedirect Options 
      ImageViewerRenderRedirectOptions options = new ImageViewerRenderRedirectOptions(); 
      options.BackgroundColor = Color.Transparent; 
 
      // Try to get item from the viewer 
      ImageViewerItem item = null; 
      if (!renderView) 
         item = _imageViewer.Items[0]; 
      LeadRectD sourceRect = LeadRectD.Empty; 
 
      if (item == null) 
         sourceRect = _imageViewer.GetViewBounds(true, false); 
      else 
      { 
         sourceRect = _imageViewer.GetItemViewBounds(item, ImageViewerItemPart.Image, false); 
         options.RenderBackgrounds = false; 
         options.RenderBorders = false; 
         options.RenderItemStates = false; 
         options.RenderShadows = false; 
         options.RenderText = false; 
      } 
 
      // Transformation Matrix (represents rotation, zooming...etc)  
      Debug.WriteLine(_imageViewer.ViewTransform); 
      options.CreateTransform(_imageViewer, destRect, sourceRect, ControlSizeMode.FitAlways, ControlAlignment.Center, ControlAlignment.Center); 
      clipRect = options.Transform.TransformRect(sourceRect).ToLeadRect(); 
 
      // Redirect rendering to the PictureBox Graphics object (Outlined with a black rectangle) 
      _imageViewer.RenderRedirect(graphics, options, clipRect); 
      graphics.DrawRectangle(Pens.Black, destRect.X, destRect.Y, destRect.Width + 1, destRect.Height + 1); 
 
      // Calculate visible view 
      LeadRectD rect; 
      if (item == null) 
         rect = _imageViewer.GetViewBounds(true, true); 
      else 
         rect = _imageViewer.GetItemViewBounds(item, ImageViewerItemPart.Image, true); 
 
      LeadPointD[] points = 
      { 
            LeadPointD.Create(rect.Left, rect.Top), 
            LeadPointD.Create(rect.Right, rect.Bottom) 
      }; 
 
      options.Transform.TransformPoints(points); 
 
      double xmin = points[0].X; 
      double ymin = points[0].Y; 
      double xmax = xmin; 
      double ymax = ymin; 
 
      for (int i = 1; i < points.Length; i++) 
      { 
         if (points[i].X < xmin) xmin = points[i].X; 
         if (points[i].X > xmax) xmax = points[i].X; 
         if (points[i].Y < ymin) ymin = points[i].Y; 
         if (points[i].Y > ymax) ymax = points[i].Y; 
      } 
 
      // Draw yellow rectangle showing visible part of the view 
      LeadRectD bounds = LeadRectD.FromLTRB(xmin, ymin, xmax, ymax); 
      RectangleF rc = new RectangleF((float)bounds.X, (float)bounds.Y, (float)bounds.Width, (float)bounds.Height); 
      graphics.DrawRectangle(Pens.Yellow, rc.X, rc.Y, rc.Width - 1, rc.Height - 1); 
   }; 
 
   _imageViewer.RedirectRender += (sender, e) => 
   { 
      redirectRenderControl.Invalidate(); 
   }; 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
} 
Requirements

Target Platforms

Help Version 23.0.2024.2.29
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Leadtools.Controls Assembly

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