GetTransformWithDpi Method

using Leadtools.WinForms; 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Drawing; 
 
class MyForm4 : Form 
{ 
 
   private RasterImageViewer _viewer; 
   // Are we currently rubber banding 
   private bool isRubberBanding; 
   // The current rubberband rectangle 
   private Rectangle rubberBandingRectangle; 
   // Flag to indicates if the rubber band rectangle is drawn 
   private bool isRubberBandingRectangleDrawn; 
   // Did we clicp the cursor? 
   private bool isCursorClipped; 
   private Rectangle saveClipRectangle; 
 
   public MyForm4(string title) 
   { 
      Text = title; 
      Size = new Size(750, 450); 
 
      // Create the raster viewer 
      _viewer = new RasterImageViewer(); 
      _viewer.DoubleBuffer = true; 
      _viewer.Dock = DockStyle.Fill; 
 
      // Load an image into the viewer 
      RasterCodecs codecs = new RasterCodecs(); 
      _viewer.Image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Sample1.cmp")); 
      codecs.Dispose(); 
 
      Controls.Add(_viewer); 
      _viewer.BringToFront(); 
      StartRubberBanding(); 
   } 
 
   // Call this to start rubber banding on the viewer 
   private void StartRubberBanding() 
   { 
      // Subclass to the event we need 
      _viewer.MouseDown += new MouseEventHandler(_viewer_MouseDown); 
      _viewer.MouseMove += new MouseEventHandler(_viewer_MouseMove); 
      _viewer.MouseUp += new MouseEventHandler(_viewer_MouseUp); 
      _viewer.LostFocus += new EventHandler(_viewer_LostFocus); 
   } 
 
   // Call this to stop rubber banding on the viewer 
   private void StopRubberBanding() 
   { 
      // Un-subclass to the events 
      _viewer.MouseDown -= new MouseEventHandler(_viewer_MouseDown); 
      _viewer.MouseMove -= new MouseEventHandler(_viewer_MouseMove); 
      _viewer.MouseUp -= new MouseEventHandler(_viewer_MouseUp); 
      _viewer.LostFocus -= new EventHandler(_viewer_LostFocus); 
 
      isRubberBanding = false; 
      rubberBandingRectangle = Rectangle.Empty; 
      isRubberBandingRectangleDrawn = false; 
      isCursorClipped = false; 
      saveClipRectangle = Rectangle.Empty; 
   } 
 
   // Begins the rubber banding operation 
   private void BeginRubberBanding(int x, int y) 
   { 
      rubberBandingRectangle = Rectangle.FromLTRB(x, y, x, y); 
 
      isRubberBanding = true; 
      _viewer.Capture = true; 
 
      // Clip the cursor 
      ClipCursor(true); 
 
      DrawRubberBandRectangle(); 
   } 
 
   // Ends the rubber banding 
   private void EndRubberBanding() 
   { 
      _viewer.Capture = false; 
      isRubberBanding = false; 
 
      if (isRubberBandingRectangleDrawn) 
         DrawRubberBandRectangle(); 
 
      if (isCursorClipped) 
         ClipCursor(false); 
   } 
 
   private void ClipCursor(bool clip) 
   { 
      if (clip) 
      { 
         Rectangle rect = Rectangle.Intersect(FixRectangle(_viewer.PhysicalViewRectangle), _viewer.ClientRectangle); 
         rect = _viewer.RectangleToScreen(rect); 
         Control parent = _viewer.Parent; 
         while (parent != null) 
         { 
            rect = Rectangle.Intersect(rect, _viewer.Parent.RectangleToScreen(_viewer.Parent.ClientRectangle)); 
            if (parent is Form) 
            { 
               Form form = parent as Form; 
               if (form.IsMdiChild) 
               { 
                  if (form.Owner != null) 
                     rect = Rectangle.Intersect(rect, form.Owner.RectangleToScreen(form.Owner.ClientRectangle)); 
                  else if (form.Parent != null) 
                     rect = Rectangle.Intersect(rect, form.Parent.RectangleToScreen(form.Parent.ClientRectangle)); 
               } 
            } 
 
            parent = parent.Parent; 
         } 
 
         rect.Height += 1; 
         rect.Width += 1; 
 
         saveClipRectangle = Cursor.Clip; 
         Cursor.Clip = rect; 
         isCursorClipped = true; 
      } 
      else 
      { 
         Cursor.Clip = saveClipRectangle; 
         isCursorClipped = false; 
         saveClipRectangle = Rectangle.Empty; 
      } 
   } 
 
   private static Rectangle FixRectangle(Rectangle rect) 
   { 
      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); 
 
      return rect; 
   } 
 
   // Draws the rubberband rectangle on the viewer 
   private void DrawRubberBandRectangle() 
   { 
      Rectangle rect = FixRectangle(rubberBandingRectangle); 
      rect.Width++; 
      rect.Height++; 
      rect = _viewer.RectangleToScreen(rect); 
      ControlPaint.DrawReversibleFrame(rect, Color.Transparent, FrameStyle.Thick); 
 
      isRubberBandingRectangleDrawn = !isRubberBandingRectangleDrawn; 
   } 
 
   private void _viewer_MouseDown(object sender, MouseEventArgs e) 
   { 
      _viewer.Focus(); 
 
      // Cancel rubber banding if it is on 
      if (isRubberBanding) 
         EndRubberBanding(); 
      else 
      { 
         if (_viewer.IsImageAvailable && e.Button == MouseButtons.Left) 
         { 
            // See if we click is on the image 
            Rectangle rect = _viewer.PhysicalViewRectangle; 
            if (rect.Contains(e.X, e.Y)) 
            { 
               // Start the rubber banding 
               BeginRubberBanding(e.X, e.Y); 
            } 
         } 
      } 
   } 
 
   private void _viewer_MouseMove(object sender, MouseEventArgs e) 
   { 
      if (isRubberBanding) 
      { 
         DrawRubberBandRectangle(); 
 
         rubberBandingRectangle = Rectangle.FromLTRB( 
            rubberBandingRectangle.Left, 
            rubberBandingRectangle.Top, 
            e.X, 
            e.Y); 
 
         DrawRubberBandRectangle(); 
      } 
   } 
 
   private void _viewer_MouseUp(object sender, MouseEventArgs e) 
   { 
      if (isRubberBanding) 
      { 
         // Save the rubberband rectangle 
         Rectangle rect = rubberBandingRectangle; 
 
         EndRubberBanding(); 
 
         // First, convert the rectangle to image coordinates 
 
         rect = FixRectangle(rect); 
 
         // Must be at least 1 pixel in size 
         if (rect.Width > 1 && rect.Height > 1) 
         { 
            // Get the transform matrix 
            // This works even if the UseDpi property of the viewer is set to true 
            using (Matrix transform = _viewer.GetTransformWithDpi()) 
            { 
               Transformer t = new Transformer(transform); 
               rect = Rectangle.Round(t.RectangleToLogical(rect)); 
               LeadRect lrect = new LeadRect(rect.Left, rect.Top, rect.Width, rect.Height); 
 
               lrect = _viewer.Image.RectangleToImage(RasterViewPerspective.TopLeft, lrect); 
 
               // Add this rectangle as a region 
               // Note: no conversion or xform is needed 
               _viewer.Image.AddRectangleToRegion(null, lrect, RasterRegionCombineMode.Set); 
            } 
         } 
      } 
   } 
 
   private void _viewer_LostFocus(object sender, EventArgs e) 
   { 
      if (isRubberBanding) 
      { 
         EndRubberBanding(); 
      } 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
}