handleDragStarted Method

Summary

Abstract method handling the action of the user clicking (using mouse/touch) on the item where the drawable is located.

Syntax
TypeScript
JavaScript
Drawable.prototype.handleDragStarted = function( 
   item, 
   x, 
   y, 
   args 
) 
handleDragStarted( 
   item: ImageViewerItem, 
   x: number, 
   y: number, 
   args: InteractiveDragStartedEventArgs 
): void;

Parameters

item

The item where the drawable is located in

x

The mouse's x-coordinate

y

The mouse's y-coordinate

args

The native interactive arguments

Remarks

Use the HandleDragStart method to control the mouse/touch down.

Use the HandleDragCompleted method to control the mouse/touch up.

Perform the following steps to make the drawable interactive:

  1. Create a class that derives this class.
  2. Implement the HandleDragStart, HandleDragDelta, and HandleDragStop methods.
  3. Implement the paint method so the drawable Draw can be painted.
  4. Create an instance of the new class and add it to the drawable list Drawables.

Implement the HitTest method to detect whether the created drawable has been clicked on.

Example
Drawable.js
MedicalViewer_2D_Color_Example.js
Drawable.ts
MedicalViewer_2D_Color_Example.ts
Drawable.html 
import { MedicalViewer_2D_Color_Example } from "../MedicalViewer_2D_Color_Example"; 
class customDrawable extends lt.Controls.Medical.Drawable { 
    constructor() { 
        super(); 
        this.hitTestResult = -1; 
        this._item = null; 
        this.points = []; 
        var centerX = 100; 
        var centerY = 100; 
        var size = 100; 
        var halfSize = size / 2; 
        this.points.add(lt.LeadPointD.create(centerX - halfSize, centerY - halfSize)); 
        this.points.add(lt.LeadPointD.create(centerX + halfSize, centerY - halfSize)); 
        this.points.add(lt.LeadPointD.create(centerX + halfSize, centerY + halfSize)); 
        this.points.add(lt.LeadPointD.create(centerX - halfSize, centerY + halfSize)); 
    } 
    draw(item, context, rect) { 
        context.save(); 
        context.beginPath(); 
        context.strokeStyle = "#FFF"; 
        context.fillStyle = "yellow"; 
        context.lineWidth = 2; 
        var index = 0; 
        var length = this.points.length; 
        var point; 
        point = this.points[0]; 
        context.moveTo(point.x, point.y); 
        for (index = 1; index < length; index++) { 
            point = this.points[index]; 
            context.lineTo(point.x, point.y); 
        } 
        context.lineTo(this.points[0].x, this.points[0].y); 
        context.stroke(); 
        context.closePath(); 
        for (index = 0; index < length; index++) { 
            context.beginPath(); 
            point = this.points[index]; 
            context.arc(point.x, point.y, 4, 0, 2 * Math.PI, false); 
            context.fill(); 
            context.stroke(); 
        } 
        context.restore(); 
    } 
    get_visible() { 
        return true; 
    } 
    set_visible(value) { 
    } 
    hitTest(item, x, y) { 
        var index = 0; 
        var length = this.points.length; 
        var point; 
        for (index = 0; index < length; index++) { 
            point = this.points[index]; 
            if (Math.max(Math.abs(point.x - x), Math.abs(point.y - y)) < 10) { 
                this.hitTestResult = index; 
                return true; 
            } 
        } 
        return false; 
    } 
    handleDragStarted(item, x, y, args) { 
        this._item = item; 
        this.hitTest(item, x, y); 
    } 
    handleDragDelta(x, y, args) { 
        if (this.hitTestResult != -1) { 
            this.points[this.hitTestResult] = lt.LeadPointD.create(x, y); 
            this._item.invalidate(); 
        } 
    } 
    handleDragCompleted(x, y, args) { 
    } 
    handleDoubleTap(item, x, y, args) { 
    } 
} 
export class Drawable_Example { 
    constructor() { 
        this.run = (medicalViewer) => { 
            this.medicalViewer = medicalViewer; 
            var cell = this.medicalViewer.layout.items.get_item(0); 
            cell.drawables["CustomDrawable"] = new customDrawable(); 
            cell.invalidate(); 
        }; 
        this.viewerExample = new MedicalViewer_2D_Color_Example(this.run); 
    } 
} 
export class MedicalViewer_2D_Color_Example { 
    constructor(callback) { 
        // LEADTOOLS ImageViewer to be used with this example 
        this.medicalViewer = null; 
        // Generic state value used by the examples 
        this.timesClicked = 0; 
        // Set the LEADTOOLS license. Replace this with your actual license file 
        lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/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.medicalViewer = new lt.Controls.Medical.MedicalViewer(imageViewerDiv, 1, 1); 
        this.medicalViewer.onSizeChanged(); 
        var cell = new lt.Controls.Medical.Cell(this.medicalViewer, this.medicalViewer.get_divId(), 1, 1); 
        // Set the show border to "true", to show a border around the cell.  
        cell.set_showFrameBorder(true); 
        // Add the cell to the viewer.   
        this.medicalViewer.layout.get_items().add(cell); 
        // [optional] Select the cell (it can also be selected by clicking on it.)  
        cell.set_selected(true); 
        // Now create a frame object which will hold the image inside the cell.  
        var cellFrame = new lt.Controls.Medical.Frame(cell); 
        // Add the frame to the cell class.  
        cell.get_frames().add(cellFrame); 
        // we are now going to to download an image from leadtools medical viewer demo web site, you need to change this to download images from your database.  
        var xhttp = new XMLHttpRequest(); 
        xhttp.onreadystatechange = function (data) { 
            if (this.readyState == 4 && this.status == 200) { 
                // here we got the authentication Code that we need to retrieve the images from leadtools database.  
                var authenticationCode = encodeURIComponent(this.responseText); 
                // now, this is the MRTI info that contains the image information, width, height, tiles....etc.  
                var mrtiInfo = new lt.Controls.Medical.MRTIImage(); 
                // The image dpi.  
                mrtiInfo.fullDpi = lt.LeadSizeD.create(150, 150); 
                // the tile size, recommended value is 256  
                mrtiInfo.tileSize = lt.LeadSizeD.create(1944, 1944); 
                mrtiInfo.frameIndex = 0; 
                // does this image support window level.  
                mrtiInfo.supportWindowLevel = true; 
                // different resolution for the image.  
                var resolutions = [{ "width": 1944, "height": 1944 }, { "width": 972, "height": 972 }, { "width": 486, "height": 486 }, { "width": 243, "height": 243 }, { "width": 121, "height": 121 }]; 
                mrtiInfo.resolutions = []; 
                for (var i = 0; i < resolutions.length; i++) { 
                    mrtiInfo.resolutions[i] = lt.LeadSizeD.create(resolutions[i].width, resolutions[i].height); 
                } 
                // the image width and height.  
                cellFrame.set_width(mrtiInfo.resolutions[0].width); 
                cellFrame.set_height(mrtiInfo.resolutions[0].height); 
                // the image full size.  
                mrtiInfo.fullSize = lt.LeadSizeD.create(cellFrame.get_width(), cellFrame.get_height()); 
                // now we need the image URL,  
                var imageUri = "https://medicaldemos.leadtools.com/MedicalViewerServiceAsp/api/retrieve"; 
                imageUri += "/GetImageTile?auth="; 
                imageUri += authenticationCode; 
                // this the image instance UID, change this if you want to retrieve anything else.  
                imageUri += "&instance=1.2.840.114434.12387576.10100457.4075310.6503931"; 
                mrtiInfo.imageUri = imageUri; 
                mrtiInfo.supportWindowLevel = false; 
                // set this info to the cell frame.  
                cellFrame.mrtiInfo = mrtiInfo; 
                // now we need to set the information for the image so we can do window level.  
                var imageInfo = new lt.Controls.Medical.DICOMImageInformation(); 
                // set the image width and height.  
                imageInfo.width = 1944; 
                imageInfo.height = 1944; 
                // bits per pixel for the image  
                imageInfo.bitsPerPixel = 24; 
                // set these information to the frame.  
                cellFrame.set_information(imageInfo); 
            } 
        }; 
        // We are trying here to get an image from the Leadtools database, we need to login and get the authentication code.  
        xhttp.open("POST", "https://medicaldemos.leadtools.com/MedicalViewerServiceAsp/api/auth/AuthenticateUser", true); 
        xhttp.setRequestHeader('Content-Type', 'application/json; charset=UTF-8'); 
        // we log in as a 'guest', after calling the below line, we will receive the authentication code sent via 'onreadystatechange' above.  
        xhttp.send(JSON.stringify({ userName: 'guest', password: 'guest', userData: '' })); 
        // 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.medicalViewer); 
        }); 
    } 
} 
import { MedicalViewer_2D_Color_Example } from "../MedicalViewer_2D_Color_Example"; 
 
 
class customDrawable extends lt.Controls.Medical.Drawable 
{ 
 
   constructor() 
   { 
      super(); 
      this.points = []; 
 
      var centerX = 100; 
      var centerY = 100; 
      var size = 100; 
      var halfSize = size / 2; 
 
      this.points.add(lt.LeadPointD.create(centerX - halfSize, centerY - halfSize)); 
      this.points.add(lt.LeadPointD.create(centerX + halfSize, centerY - halfSize)); 
      this.points.add(lt.LeadPointD.create(centerX + halfSize, centerY + halfSize)); 
      this.points.add(lt.LeadPointD.create(centerX - halfSize, centerY + halfSize)); 
 
   } 
   public draw(item: lt.Controls.ImageViewerItem, context: CanvasRenderingContext2D, rect: lt.LeadRectD): void 
   { 
      context.save(); 
      context.beginPath(); 
      context.strokeStyle = "#FFF"; 
      context.fillStyle = "yellow"; 
      context.lineWidth = 2; 
 
      var index = 0; 
      var length = this.points.length; 
      var point : lt.LeadPointD; 
 
      point = this.points[0]; 
      context.moveTo(point.x, point.y); 
      for (index = 1; index < length; index++) 
      { 
         point = this.points[index]; 
         context.lineTo(point.x, point.y); 
      } 
      context.lineTo(this.points[0].x, this.points[0].y); 
      context.stroke(); 
      context.closePath(); 
        
 
      for (index = 0; index < length; index++) { 
         context.beginPath(); 
         point = this.points[index]; 
         context.arc(point.x, point.y, 4, 0, 2 * Math.PI, false); 
         context.fill(); 
         context.stroke(); 
      } 
 
      context.restore();       
   } 
 
   private points : any; 
 
   public get_visible(): boolean 
   { 
      return true; 
   } 
 
   public set_visible(value: boolean): void 
   { 
   } 
 
   private hitTestResult = -1; 
   private _item = null; 
   public hitTest(item: lt.Controls.ImageViewerItem, x: number, y: number): boolean 
   { 
      var index = 0; 
      var length = this.points.length; 
      var point : lt.LeadPointD; 
 
      for (index = 0; index < length; index++) 
      { 
         point = this.points[index]; 
 
         if (Math.max( Math.abs(point.x - x), Math.abs(point.y - y) ) < 10) 
         { 
            this.hitTestResult = index; 
            return true; 
         } 
      } 
 
      return false; 
   } 
 
   public handleDragStarted(item: lt.Controls.ImageViewerItem, x: number, y: number, args: lt.Controls.InteractiveDragStartedEventArgs): void 
   { 
      this._item = item; 
      this.hitTest(item, x, y); 
   } 
 
   public handleDragDelta(x: number, y: number, args: lt.Controls.InteractiveDragDeltaEventArgs): void 
   { 
      if (this.hitTestResult != -1) 
      { 
         this.points[this.hitTestResult] = lt.LeadPointD.create(x, y); 
         this._item.invalidate(); 
      } 
   } 
 
   public handleDragCompleted(x: number, y: number, args: lt.Controls.InteractiveDragCompletedEventArgs): void 
   { 
 
   } 
 
   public handleDoubleTap(item: lt.Controls.ImageViewerItem, x: number, y: number, args: lt.Controls.InteractiveEventArgs): void 
   { 
 
   } 
 
} 
 
export class Drawable_Example { 
   private viewerExample; 
   private medicalViewer; 
   constructor() { 
      this.viewerExample = new MedicalViewer_2D_Color_Example(this.run); 
   } 
 
   private run = (medicalViewer: lt.Controls.Medical.MedicalViewer) => { 
      this.medicalViewer = medicalViewer; 
 
      var cell: lt.Controls.Medical.Cell = this.medicalViewer.layout.items.get_item(0); 
 
      cell.drawables["CustomDrawable"] = new customDrawable(); 
      cell.invalidate(); 
 
   } 
} 
export class MedicalViewer_2D_Color_Example { 
   // LEADTOOLS ImageViewer to be used with this example 
   protected medicalViewer: lt.Controls.Medical.MedicalViewer = null; 
   // Generic state value used by the examples 
   public timesClicked: number = 0; 
 
   constructor(callback?: (medicalViewer: lt.Controls.Medical.MedicalViewer ) => void) { 
      // Set the LEADTOOLS license. Replace this with your actual license file 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt", "EVAL", null); 
 
      // Create an image viewer inside the imageViewerDiv element 
      const imageViewerDiv : HTMLDivElement = <HTMLDivElement>document.getElementById("imageViewerDiv"); 
      const createOptions: lt.Controls.ImageViewerCreateOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
 
 
 
      this.medicalViewer = new lt.Controls.Medical.MedicalViewer(imageViewerDiv, 1, 1); 
      this.medicalViewer.onSizeChanged(); 
 
      var cell = new lt.Controls.Medical.Cell(this.medicalViewer, this.medicalViewer.get_divId(), 1, 1);  
  
      // Set the show border to "true", to show a border around the cell.  
      cell.set_showFrameBorder(true);  
    
      // Add the cell to the viewer.   
      this.medicalViewer.layout.get_items().add(cell);  
    
      // [optional] Select the cell (it can also be selected by clicking on it.)  
      cell.set_selected(true);  
    
      // Now create a frame object which will hold the image inside the cell.  
      var cellFrame = new lt.Controls.Medical.Frame(cell);  
    
      // Add the frame to the cell class.  
      cell.get_frames().add(cellFrame);  
    
      // we are now going to download an image from LEADTOOLS Medical Viewer demo web site, you need to change this to download images from your database.  
      var xhttp = new XMLHttpRequest();  
      xhttp.onreadystatechange = function(data)  
      {  
        if (this.readyState == 4 && this.status == 200)  
        {  
           // here we got the authentication Code that we need to retrieve the images from the LEADTOOLS database.  
           var authenticationCode = encodeURIComponent(this.responseText);  
          
        
           // now, this is the MRTI info that contains the image information, width, height, tiles....etc.  
           var mrtiInfo = new lt.Controls.Medical.MRTIImage();  
        
           // The image dpi.  
           mrtiInfo.fullDpi = lt.LeadSizeD.create(150, 150);  
             
           // the tile size, recommended value is 256  
           mrtiInfo.tileSize = lt.LeadSizeD.create(1944, 1944);  
           mrtiInfo.frameIndex = 0;  
             
           // does this image support window level?  
           mrtiInfo.supportWindowLevel = true;  
        
           // different resolution for the image.  
           var resolutions = [{ "width": 1944, "height": 1944 }, { "width": 972, "height": 972 }, { "width": 486, "height": 486 }, { "width": 243, "height": 243 }, { "width": 121, "height": 121 }];  
 
           mrtiInfo.resolutions = [];  
           for (var i = 0; i < resolutions.length; i++) {  
                    mrtiInfo.resolutions[i] = lt.LeadSizeD.create(resolutions[i].width, resolutions[i].height);  
           }  
        
           // the image width and height.  
           cellFrame.set_width(mrtiInfo.resolutions[0].width);  
           cellFrame.set_height(mrtiInfo.resolutions[0].height);  
             
           // the image full size.  
           mrtiInfo.fullSize = lt.LeadSizeD.create(cellFrame.get_width(), cellFrame.get_height());  
        
           // now we need the image URL,  
           var imageUri = "https://medicaldemos.leadtools.com/MedicalViewerServiceAsp/api/retrieve";  
           imageUri += "/GetImageTile?auth=";  
           imageUri += authenticationCode;  
           // this is the image instance UID, change this if you want to retrieve anything else.  
           imageUri += "&instance=1.2.840.114434.12387576.10100457.4075310.6503931";  
           mrtiInfo.imageUri = imageUri;  
           mrtiInfo.supportWindowLevel = false; 
        
           // set this info to the cell frame.  
           cellFrame.mrtiInfo = mrtiInfo;            
             
             
           // now we need to set the information for the image so we can do window level.  
           var imageInfo = new lt.Controls.Medical.DICOMImageInformation();  
 
           // set the image width and height.  
           imageInfo.width = 1944;  
           imageInfo.height = 1944;  
             
           // bits per pixel for the image  
           imageInfo.bitsPerPixel = 24;  
             
           // set these information to the frame.  
          
           cellFrame.set_information(imageInfo);  
        }  
      };  
        
      // We are trying to get an image from the LEADTOOLS database. We need to login and get the authentication code.  
      xhttp.open("POST", "https://medicaldemos.leadtools.com/MedicalViewerServiceAsp/api/auth/AuthenticateUser", true);  
        xhttp.setRequestHeader('Content-Type', 'application/json; charset=UTF-8');  
         // we log in as a 'guest', after calling the below line, we will receive the authentication code sent via 'onreadystatechange' above.  
      xhttp.send(JSON.stringify({ userName: 'guest', password: 'guest', userData: '' })); 
 
      // 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.medicalViewer); 
      }); 
   } 
} 
<!doctype html> 
<html lang="en"> 
   <title>Drawable Example</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> 
   <script src="../../LT/Leadtools.Controls.Medical.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  oncontextmenu="return false;"> 
   <p>Check the rectangle with handles on the cell that is been created by overriding the drawable class. Click on one of the points and drag it around.</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.MedicalViewer.Drawable(); 
 
   }; 
</script> 
</html>
Requirements
Target Platforms
Help Version 21.0.2021.6.30
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Controls.Medical Assembly
Introduction
Getting Started
Namespaces
Leadtools.Controls.Medical Namespace
Assemblies
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.