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ControlSizeMode Enumeration

Summary

Determines how the control displays the image and the automatic adjustments of the display rectangles.

Syntax
C#
C++/CLI
public enum ControlSizeMode 
public enum class ControlSizeMode sealed 
Members

0

None

(0) No special sizing

1

ActualSize

(1) Use the image actual size

2

Fit

(2) Fit the image into the viewing area while maintaining the aspect ratio. If the image size is smaller than the viewing area, no resizing is done.

3

FitAlways

(3) Always fit the image into the viewing area while maintaining the aspect ratio even if the image size is smaller than the viewing area (in which case, the image will be scaled up).

4

FitWidth

(4) Fit the image width to be the size of the width of the viewing area while maintaining the aspect ratio.

5

FitHeight

(5) Fit the image height to be the size of the height of the viewing area while maintaining the aspect ratio.

6

Stretch

(6) Fit the image to fill the viewing area. Aspect ratio might not be maintained.

Remarks

ControlSizeMode is used by the ImageViewer.Zoom and ImageViewerItem.Zoom methods.

Example
C#
using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public void ImageViewerZoom_Example() 
{ 
   // Create the form that holds the ImageViewer 
   new MyForm2().ShowDialog(); 
} 
 
class MyForm2 : Form 
{ 
   public MyForm2() 
   { 
      this.Size = new Size(800, 800); 
   } 
 
   // LEADTOOLS ImageViewer to be used with this example 
   private ImageViewer _imageViewer; 
   // Ratio to use when the user zooms in or out. Change this if another value is needed, 
   // for example, 2.0 will zoom the viewer in by 200% and out by 50% each time 
   private const double _zoomRatio = 1.2; 
 
   protected override void OnLoad(EventArgs e) 
   { 
      // Create a panel to the top 
      var panel = new Panel(); 
      panel.Dock = DockStyle.Top; 
      panel.BorderStyle = BorderStyle.FixedSingle; 
      this.Controls.Add(panel); 
 
      // Add a combo box for the zoom values 
      var zoomComboBox = new ComboBox(); 
      zoomComboBox.Name = "zoomComboBox"; 
      zoomComboBox.Location = new Point(8, 8); 
      zoomComboBox.DropDownStyle = ComboBoxStyle.DropDown; 
 
      // Add default zoom values 
      zoomComboBox.Items.AddRange(new string[] 
      { 
         "10%", "25%", "50%", "75%", "100%", "125%", "200%", "400%", "800%", 
         "1600%", "2400%", "3200%", "6400%", "Actual Size", "Fit Page", "Fit Width", "Fit Height" 
      }); 
      panel.Controls.Add(zoomComboBox); 
 
      // Add zoom in and out buttons 
      var zoomInButton = new Button(); 
      zoomInButton.Text = "+"; 
      zoomInButton.Location = new Point(zoomComboBox.Right + 8, zoomComboBox.Top - 1); 
      panel.Controls.Add(zoomInButton); 
      var zoomOutButton = new Button(); 
      zoomOutButton.Text = "-"; 
      zoomOutButton.Location = new Point(zoomInButton.Right + 2, zoomComboBox.Top - 1); 
      panel.Controls.Add(zoomOutButton); 
 
      // Create the image viewer taking the rest of the form 
      _imageViewer = new ImageViewer(); 
      _imageViewer.Dock = DockStyle.Fill; 
      _imageViewer.ViewBorderThickness = 1; 
      this.Controls.Add(_imageViewer); 
      _imageViewer.BringToFront(); 
 
      // Set UseDpi to true to view the image at its original resolution 
      _imageViewer.UseDpi = true; 
 
      // Add Pan/Zoom interactive mode 
      // Click and drag to pan, CTRL-Click and drag to zoom in and out 
      _imageViewer.DefaultInteractiveMode = new ImageViewerPanZoomInteractiveMode(); 
 
      // Initialize the zoom system 
      InitZoom(zoomComboBox, zoomInButton, zoomOutButton); 
 
      // Load an image 
      using (var codecs = new RasterCodecs()) 
         _imageViewer.Image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif")); 
 
      base.OnLoad(e); 
   } 
 
   private void UpdateZoomValueFromView() 
   { 
      // Get the current scale factor from the viewer and set it in the zoom combo box 
      var percentage = _imageViewer.ScaleFactor * 100.0; 
      var zoomComboBox = this.Controls.Find("zoomComboBox", true)[0] as ComboBox; 
      zoomComboBox.Text = percentage.ToString("F1") + "%"; 
   } 
 
   private void InitZoom(ComboBox zoomComboBox, Button zoomInButton, Button zoomOutButton) 
   { 
      // Add support for user typing the zoom value in the combo box directly 
      zoomComboBox.LostFocus += (sender, e) => 
      { 
         // When the user moves away from the combo box, make sure it has a valid value 
         UpdateZoomValueFromView(); 
      }; 
 
      zoomComboBox.KeyPress += (sender, e) => 
      { 
         // Check if the finished editing by pressing Enter 
         if (e.KeyChar == (char)Keys.Return) 
         { 
            // Yes, get the new value 
            var value = zoomComboBox.Text.Trim(); 
            if (!string.IsNullOrEmpty(value)) 
            { 
               // Remove the % sign if present 
               if (value.EndsWith("%")) 
                  value = value.Remove(value.Length - 1, 1).Trim(); 
 
               // Try to parse the new zoom value 
               double percentage; 
               if (double.TryParse(value, out percentage)) 
               { 
                  // Valid value, zoom the viewer 
                  _imageViewer.Zoom(ControlSizeMode.None, percentage / 100.0, _imageViewer.DefaultZoomOrigin); 
               } 
 
               // And update the combo box from this value (in case we set a value not in the min/max range) 
               UpdateZoomValueFromView(); 
            } 
         } 
      }; 
 
      zoomComboBox.SelectedIndexChanged += (sender, e) => 
      { 
         // Get the value from the combo box 
         var value = zoomComboBox.Text.Trim(); 
         switch (value) 
         { 
            case "Actual Size": 
               _imageViewer.Zoom(ControlSizeMode.ActualSize, 1, _imageViewer.DefaultZoomOrigin); 
               break; 
 
            case "Fit Page": 
               _imageViewer.Zoom(ControlSizeMode.FitAlways, 1, _imageViewer.DefaultZoomOrigin); 
               break; 
 
            case "Fit Width": 
               _imageViewer.Zoom(ControlSizeMode.FitWidth, 1, _imageViewer.DefaultZoomOrigin); 
               break; 
 
            case "Fit Height": 
               _imageViewer.Zoom(ControlSizeMode.FitHeight, 1, _imageViewer.DefaultZoomOrigin); 
               break; 
 
            default: 
               if (!string.IsNullOrEmpty(value)) 
               { 
                  // A percentage, use it 
                  var percentage = double.Parse(value.Substring(0, value.Length - 1)); 
                  _imageViewer.Zoom(ControlSizeMode.None, percentage / 100.0, _imageViewer.DefaultZoomOrigin); 
               } 
               break; 
         } 
      }; 
 
      // For zoom in button, use current ScaleFactor multiplied by the ratio 
      zoomInButton.Click += (sender, e) => 
      { 
         _imageViewer.Zoom(ControlSizeMode.None, _imageViewer.ScaleFactor * _zoomRatio, _imageViewer.DefaultZoomOrigin); 
      }; 
 
      // For zoom out button, use current ScaleFactor divided by the ratio 
      zoomOutButton.Click += (sender, e) => 
      { 
         _imageViewer.Zoom(ControlSizeMode.None, _imageViewer.ScaleFactor / _zoomRatio, _imageViewer.DefaultZoomOrigin); 
      }; 
 
      // Also update the value from the viewer when the transform changed, this happens if the user selects a fit mode, 
      // such as fit width or fit page. The viewer will change the scale factor accordingly and we need to update it 
      // in our combo box 
      // This also takes care of Pan/Zoom interactive mode updating the scale fatcor 
      _imageViewer.TransformChanged += (sender, e) => 
      { 
         UpdateZoomValueFromView(); 
      }; 
 
      // Get the value from the viewer into the combo box 
      UpdateZoomValueFromView(); 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
} 
Requirements

Target Platforms

See Also

Reference

Leadtools.Controls Namespace

Help Version 22.0.2023.1.24
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Leadtools.Controls Assembly
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.