Transform Property

Summary

Transformation to use when rendering.

Syntax

C++/CLI

public LeadMatrix Transform { get; set; }

public:  
   property LeadMatrix^ Transform 
   { 
      LeadMatrix^ get() 
      void set(LeadMatrix^ value) 
   }

Property Value

The transformation to use when rendering. Default value is Identity.

Remarks

Use this value to control the offset, scale and rotation to use when redirecting the rendering of ImageViewer to an external control. The helper method CreateTransform can be used to easily create a transformation matrix for common scenarios such as rendering a thumbnail of the content of the viewer.

For more information, refer to Image Viewer Rendering.

Example

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public void TestRedirectRender() 
{ 
   PictureBox control = new PictureBox(); 
   control.Width = 400; 
   control.Dock = DockStyle.Right; 
   control.BringToFront(); 
   _imageViewer.BringToFront(); 
 
   bool renderView = false; 
 
   control.DoubleClick += (sender, e) => 
   { 
      renderView = !renderView; 
      control.Invalidate(); 
   }; 
 
   control.Paint += (sender, e) => 
   { 
      Graphics graphics = e.Graphics; 
 
      int delta = 20; 
      LeadRect destRect = LeadRect.Create(delta, delta, control.ClientSize.Width - delta * 2, control.ClientSize.Height - delta * 2); 
      LeadRect clipRect = destRect; 
 
      ImageViewerRenderRedirectOptions options = new ImageViewerRenderRedirectOptions(); 
 
      ImageViewerItem item = null; 
      if (!renderView) 
         item = _imageViewer.Items[0]; 
 
      LeadRectD sourceRect; 
 
      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; 
      } 
 
      options.CreateTransform(_imageViewer, destRect, sourceRect, ControlSizeMode.FitAlways, ControlAlignment.Center, ControlAlignment.Center); 
      clipRect = options.Transform.TransformRect(sourceRect).ToLeadRect(); 
 
      _imageViewer.RenderRedirect(graphics, options, clipRect); 
 
      graphics.DrawRectangle(Pens.Black, destRect.X, destRect.Y, destRect.Width + 1, destRect.Height + 1); 
 
      // Now lets find out how much of the view is visible (something pan window would do) 
      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; 
      } 
 
      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) => 
   { 
      control.Invalidate(); 
   }; 
}

Requirements

Target Platforms

Reference

ImageViewerRenderRedirectOptions Class

ImageViewerRenderRedirectOptions Members

Leadtools.Controls Namespace

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Help Version 22.0.2023.1.24