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ImageViewerViewLayout Object

Summary

Defines an ImageViewer layout controller.

Syntax

TypeScript

JavaScript

function lt.Controls.ImageViewerViewLayout

class lt.Controls.ImageViewerViewLayout()

Remarks

ImageViewerViewLayout is the main class responsible for setting up the image viewer layout.

Derived classes must implement the following:

Name: Return the friendly name of the layout.
UpdateTransform: Called by ImageViewer.UpdateTransform to move and size the items in the layout.

The layout must perform the following actions when UpdateTransform is called. All the values calculation must use the scale factor passed to the method and the viewer will update for view alignment after the method returns:

Update the itemBounds property: This is an array of rectangles that must be filled with the location and size of each item. Each value must be calculated based on the item size and its transformations. The items must be arranged in any way desired usually creating rows and columns or stacked on top of each other.
Update the values of ImageViewerItem.RowIndex and ImageViewerItem.ColumnIndex for each item: These values must be set to the 0-based index of the item row and column in the view grid (if any). The value will be used by code that requires finding the item to the left, top, right or bottom of another item such as ImageViewerSelectItemsInteractiveMode when using the arrow keys.
Set the value of SizeModeWidth: This is the width of the layout in pixels. The viewer will use this value to control how much to zoom when FitWidth> is used for example. Typically this should be the width of largest column.
Set the value of SizeModeWidthItemCount: The number of items in the largest column.
Set the value of SizeModeHeight: This is the height of the layout in pixels. The viewer will use this value to control how much to zoom when FitHeight is used for example. Typically this should be the height of the largest row.
Set the value of SizeModeHeightItemCount: The number of items in the largest row.

The following methods are available to help with the calculations of these values:

AlignHeights: Align the heights of the items and return the largest value.
AlignWidths: Align the widths of the items and return the largest value.
AlignRow: Align the items to even distances in a row.
AlignColumn: Align the items to even distances in a column.

For more information, refer to Image Viewer Layouts, Image Viewer Items, Image Viewer Transformation and Image Viewer Bounds and Transform.

Example

ViewLayout.ts

ImageViewer.ts

ViewLayout.js

ImageViewer.js

ViewLayout.html

import { ImageViewer_Example } from "../ImageViewer"; 
 
export class ImageViewer_ViewLayoutExample { 
   private viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   private run = (viewer: lt.Controls.ImageViewer) => { 
      let flip: boolean = false; 
      const setLayout = () => { 
         flip = !flip; 
         let layout: lt.Controls.ImageViewerViewLayout; 
         if (flip) { 
            layout = new lt.Controls.ImageViewerVerticalViewLayout(); 
            (layout as lt.Controls.ImageViewerVerticalViewLayout).columns = 2; 
         } 
         else { 
            layout = new lt.Controls.ImageViewerHorizontalViewLayout(); 
            (layout as lt.Controls.ImageViewerHorizontalViewLayout).rows = 2; 
         } 
         viewer.viewLayout = layout; 
      } 
 
      // Set the initial layout 
      setLayout(); 
 
      // Add borders and padding 
      viewer.viewBorderThickness = 2; 
      viewer.itemPadding = lt.Controls.ControlPadding.createAll(20); 
 
      // Clear the items and add 6 new items 
      viewer.beginUpdate(); 
      viewer.items.clear(); 
      for (let i = 0; i < 6; i++) { 
         const item: lt.Controls.ImageViewerItem = new lt.Controls.ImageViewerItem(); 
         item.url = "https://demo.leadtools.com/images/jpeg/cannon.jpg"; 
         item.text = "Item " + i; 
         viewer.items.add(item); 
      } 
      viewer.endUpdate(); 
 
      // Zoom out so we can see all the items 
      viewer.zoom(lt.Controls.ControlSizeMode.fit, .5, viewer.defaultZoomOrigin); 
 
      // Add a button to update the layout 
      const button = document.createElement("button"); 
      button.innerHTML = "Change Layout"; 
      button.onclick = () => { 
         setLayout(); 
      }; 
      const output = document.getElementById("output"); 
      output.appendChild(button); 
   } 
}

export class ImageViewer_Example { 
   // LEADTOOLS ImageViewer to be used with this example 
   protected imageViewer: lt.Controls.ImageViewer = null; 
   // Generic state value used by the examples 
   public timesClicked: number = 0; 
 
   constructor(callback?: (viewer: lt.Controls.ImageViewer) => void) { 
      // Set the LEADTOOLS license. Replace this with your actual license file 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
 
      // Create an image viewer inside the imageViewerDiv element 
      const imageViewerDiv = document.getElementById("imageViewerDiv"); 
      const createOptions: lt.Controls.ImageViewerCreateOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
      this.imageViewer = new lt.Controls.ImageViewer(createOptions); 
      this.imageViewer.viewVerticalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.autoCreateCanvas = true; 
 
      // Add Pan/Zoom interactive mode 
      // Click and drag to pan, CTRL-Click and drag to zoom in and out 
      this.imageViewer.interactiveModes.add(new lt.Controls.ImageViewerPanZoomInteractiveMode()); 
 
      // Load an image 
      this.imageViewer.imageUrl = "https://demo.leadtools.com/images/jpeg/cannon.jpg"; 
 
      this.imageViewer.zoom(lt.Controls.ControlSizeMode.fit, .9, this.imageViewer.defaultZoomOrigin); 
 
      const exampleButton = document.getElementById("exampleButton"); 
      exampleButton.addEventListener("click", () => { 
         this.timesClicked++; 
         // Run the example 
         if (callback) 
            callback(this.imageViewer); 
      }); 
   } 
}

import { ImageViewer_Example } from "../ImageViewer"; 
 
export class ImageViewer_ViewLayoutExample { 
   viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   run = (viewer) => { 
      let flip = false; 
      const setLayout = () => { 
         flip = !flip; 
         let layout; 
         if (flip) { 
            layout = new lt.Controls.ImageViewerVerticalViewLayout(); 
            (layout).columns = 2; 
         } 
         else { 
            layout = new lt.Controls.ImageViewerHorizontalViewLayout(); 
            (layout).rows = 2; 
         } 
         viewer.viewLayout = layout; 
      } 
 
      // Set the initial layout 
      setLayout(); 
 
      // Add borders and padding 
      viewer.viewBorderThickness = 2; 
      viewer.itemPadding = lt.Controls.ControlPadding.createAll(20); 
 
      // Clear the items and add 6 new items 
      viewer.beginUpdate(); 
      viewer.items.clear(); 
      for (let i = 0; i < 6; i++) { 
         const item = new lt.Controls.ImageViewerItem(); 
         item.url = "https://demo.leadtools.com/images/jpeg/cannon.jpg"; 
         item.text = "Item " + i; 
         viewer.items.add(item); 
      } 
      viewer.endUpdate(); 
 
      // Zoom out so we can see all the items 
      viewer.zoom(lt.Controls.ControlSizeMode.fit, .5, viewer.defaultZoomOrigin); 
 
      // Add a button to update the layout 
      const button = document.createElement("button"); 
      button.innerHTML = "Change Layout"; 
      button.onclick = () => { 
         setLayout(); 
      }; 
      const output = document.getElementById("output"); 
      output.appendChild(button); 
   } 
}

export class ImageViewer_Example { 
   // LEADTOOLS ImageViewer to be used with this example 
   imageViewer = null; 
   // Generic state value used by the examples 
   timesClicked = 0; 
 
   constructor(callback) { 
      // Set the LEADTOOLS license. Replace this with your actual license file 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
 
      // Create an image viewer inside the imageViewerDiv element 
      const imageViewerDiv = document.getElementById("imageViewerDiv"); 
      const createOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
      this.imageViewer = new lt.Controls.ImageViewer(createOptions); 
      this.imageViewer.viewVerticalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.autoCreateCanvas = true; 
 
      // Add Pan/Zoom interactive mode 
      // Click and drag to pan, CTRL-Click and drag to zoom in and out 
      this.imageViewer.interactiveModes.add(new lt.Controls.ImageViewerPanZoomInteractiveMode()); 
 
      // Load an image 
      this.imageViewer.imageUrl = "https://demo.leadtools.com/images/jpeg/cannon.jpg"; 
 
      this.imageViewer.zoom(lt.Controls.ControlSizeMode.fit, .9, this.imageViewer.defaultZoomOrigin); 
 
      const exampleButton = document.getElementById("exampleButton"); 
      exampleButton.addEventListener("click", () => { 
         this.timesClicked++; 
         // Run the example 
         if (callback) 
            callback(this.imageViewer); 
      }); 
   } 
}

<!doctype html> 
<html lang="en"> 
<title>Controls Example | ViewLayout</title> 
 
<head> 
   <script src="https://code.jquery.com/jquery-2.2.4.min.js" 
      integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script> 
 
   <script src="../../LT/Leadtools.js"></script> 
   <script src="../../LT/Leadtools.Controls.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Engine.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Designers.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Rendering.Javascript.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Automation.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Main.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Color.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Core.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Effects.js"></script> 
   <script src="../../LT/Leadtools.Document.js"></script> 
   <script src="../../LT/Leadtools.Document.Viewer.js"></script> 
   <style> 
      body { 
         font-family: 'Segoe UI', sans-serif; 
      } 
 
      #imageViewerDiv { 
         border: 1px solid #888; 
         width: 500px; 
         height: 500px; 
         background-color: #eee; 
      } 
   </style> 
 
   <!-- All demo files are bundled and appended to the window --> 
   <script src="../../bundle.js" type="text/javascript"></script> 
</head> 
 
<body> 
   <p>Press and drag on the image to pan.</p> 
   <p>Hold down the control key and press and drag on the image or pinch with two fingers to zoom in and out.</p> 
   <div> 
      <button type="button" id="exampleButton">Run Example</button> 
   </div> 
   <div id="imageViewerDiv"></div> 
   <div id="output"></div> 
</body> 
 
<script> 
   window.onload = () => { 
      const example = new window.examples.ImageViewer.ViewLayout(); 
 
   }; 
</script> 
</html>

Requirements

Target Platforms

Reference

ImageViewerViewLayout Members

Leadtools.Controls Namespace

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