hitTestItem Method

Summary

First item that is under a physical point (in viewer pixel) coordinates.

Syntax
TypeScript
JavaScript
ImageViewer.prototype.hitTestItem = function( 
   point 
) 
hitTestItem( 
   point: LeadPointD 
): ImageViewerItem; 

Parameters

point

The point, in physical (in viewer pixel) coordinates.

Return Value

The first item that is under this point, or null if no such item exists.

Remarks

The HitTestItem method will return the item if any part of it is under the specified point. To further fine-tune the hit-testing operation and obtain the specific item part, call HitTestItemPart, passing the item obtained from HitTestItem and the desired part.

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

Example

This example will perform hit-testing when a "tap" is registered in the viewer.

HitTestItem.ts
ImageViewer.ts
HitTestItem.js
ImageViewer.js
HitTestItem.html
import { ImageViewer_Example } from "../ImageViewer"; 
 
export class ImageViewer_HitTestItemExample { 
   private viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   private run = (viewer: lt.Controls.ImageViewer) => { 
      // Add some padding and margin so we can detect more item parts 
      viewer.itemMargin = lt.Controls.ControlPadding.createAll(10); 
      viewer.itemBorderThickness = 5; 
      viewer.itemPadding = lt.Controls.ControlPadding.createAll(20); 
      viewer.itemBackgroundColor = "white"; 
 
      const item: lt.Controls.ImageViewerItem = viewer.items.item(0); 
      item.text = "This is some text."; 
 
      // Rotate so we can tell "content" from "image" 
      item.rotateAngle = 45; 
 
      const itemPartNames: string[] = ["View", "Item", "Content", "Image", "TextArea", "Text", "Floater"]; 
 
      const output = document.getElementById("output"); 
 
      viewer.interactiveService.tap.add((sender, e) => { 
         // Hit-test the item 
         const item: lt.Controls.ImageViewerItem = viewer.hitTestItem(e.position); 
         let text: string = "Clicked the view."; 
 
         // If we have an item, find out the part 
         if (item) { 
            const part: lt.Controls.ImageViewerItemPart = viewer.hitTestItemPart(item, e.position); 
            text = "Clicked the '" + itemPartNames[part] + "' part!"; 
         } 
 
         output.innerHTML = text; 
      }); 
   } 
} 
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_HitTestItemExample { 
   viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   run = (viewer) => { 
      // Add some padding and margin so we can detect more item parts 
      viewer.itemMargin = lt.Controls.ControlPadding.createAll(10); 
      viewer.itemBorderThickness = 5; 
      viewer.itemPadding = lt.Controls.ControlPadding.createAll(20); 
      viewer.itemBackgroundColor = "white"; 
 
      const item = viewer.items.item(0); 
      item.text = "This is some text."; 
 
      // Rotate so we can tell "content" from "image" 
      item.rotateAngle = 45; 
 
      const itemPartNames = ["View", "Item", "Content", "Image", "TextArea", "Text", "Floater"]; 
 
      const output = document.getElementById("output"); 
 
      viewer.interactiveService.tap.add((sender, e) => { 
         // Hit-test the item 
         const item = viewer.hitTestItem(e.position); 
         let text = "Clicked the view."; 
 
         // If we have an item, find out the part 
         if (item) { 
            const part = viewer.hitTestItemPart(item, e.position); 
            text = "Clicked the '" + itemPartNames[part] + "' part!"; 
         } 
 
         output.innerHTML = text; 
      }); 
   } 
} 
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 | HitTestItem</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.HitTestItem(); 
 
   }; 
</script> 
</html> 
Requirements

Target Platforms

Help Version 22.0.2021.9.24
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© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Controls Assembly
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.