getViewBounds Method

Summary

Current bounds of the view in physical (in control pixel) coordinates.

Syntax
TypeScript
JavaScript
ImageViewer.prototype.getViewBounds = function( 
   withPadding, 
   clipped 
) 
getViewBounds( 
   withPadding: boolean, 
   clipped: boolean 
): LeadRectD; 

Parameters

withPadding

true to include the value of ViewPadding when calculating the value, otherwise; false.

clipped

true to intersect the returned value with the current viewer control rectangle, otherwise; false.

Return Value

The view bounds in pixels or LeadRectD.Empty if the viewer does not have any items or if the view does not intersect with the control rectangle.

Remarks

The view consists of all current the items in the viewer plus any padding (set in ViewPadding). This is the area that the viewer use to determine whether horizontal and vertical scrollbars are needed and to calculate their size and position.

The view area is calculated during UpdateTransform. The current ViewLayout determines where each item is placed and calculates their sizes. The total of these sizes is calculated and multiplied by any scale factor (XScaleFactor and YScaleFactor) set by the Zoom method. The final size is the view area.

During the calculations, the viewer will calculate the transformation matrix used when rendering the view. This matrix contains the current padding, scroll offset and scale factors and stored in ViewTransform. For example, to render the view border, the viewer simply draws the value of GetViewBounds transformed with ViewTransform.

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

Example
RenderRedirect.ts
ImageViewer.ts
RenderRedirect.js
ImageViewer.js
RenderRedirect.html
import { ImageViewer_Example } from "../ImageViewer"; 
 
export class ImageViewer_RenderRedirectExample { 
   private viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   private run = (viewer: lt.Controls.ImageViewer) => { 
      viewer.itemBorderThickness = 5; 
 
      // Create the canvas we will render to 
      const redirectCanvas = document.createElement("canvas"); 
      redirectCanvas.style.border = "2px solid black"; 
      const redirectWidth: number = 300; 
      const redirectHeight: number = 300; 
      redirectCanvas.width = redirectWidth; 
      redirectCanvas.height = redirectHeight; 
 
      // Add it to the page 
      const output = document.getElementById("output"); 
      output.appendChild(redirectCanvas); 
 
      // Add a 20px margin around the redirect render area 
      const delta: number = 20; 
      const destRect: lt.LeadRectD = lt.LeadRectD.create(0, 0, redirectWidth, redirectHeight); 
      destRect.inflate(-delta, -delta); 
 
      const options: lt.Controls.ImageViewerRenderRedirectOptions = new lt.Controls.ImageViewerRenderRedirectOptions(); 
 
      viewer.rotateAngle = 35; 
      // Use "null" to draw the whole imageViewer 
      //let item = null; 
      const item: lt.Controls.ImageViewerItem = viewer.activeItem; 
 
      if (item) { 
         // Don't worry about rendering the below 
         options.renderBackgrounds = false; 
         options.renderBorders = false; 
         options.renderItemStates = false; 
         options.renderShadows = false; 
         options.renderText = false; 
      } 
 
      // On imageViewer render... 
      viewer.redirectRender.add(() => { 
         let sourceRect: lt.LeadRectD; 
         let sourceRectClipped: lt.LeadRectD; 
         if (!item) { 
            // Draw the whole imageViewer 
            sourceRect = viewer.getViewBounds(true, false); 
            sourceRectClipped = viewer.getViewBounds(true, true); 
         } 
         else { 
            // Only draw the rect for the active item 
            sourceRect = viewer.getItemViewBounds(item, lt.Controls.ImageViewerItemPart.image, false); 
            sourceRectClipped = viewer.getItemViewBounds(item, lt.Controls.ImageViewerItemPart.image, true); 
         } 
 
         const ctx: CanvasRenderingContext2D = redirectCanvas.getContext("2d"); 
         ctx.clearRect(0, 0, redirectWidth, redirectHeight); 
 
         // Draw a rect around the maximum render area 
         ctx.strokeStyle = "green"; 
         ctx.strokeRect(destRect.x, destRect.y, destRect.width, destRect.height); 
 
         // Create the transformation for this rect 
         options.createTransform(viewer, destRect, sourceRect, lt.Controls.ControlSizeMode.fit, lt.Controls.ControlAlignment.center, lt.Controls.ControlAlignment.center); 
 
         // Draw a rect around the actual render area 
         const clipRect: lt.LeadRectD = options.transform.transformRect(sourceRect); 
         ctx.strokeStyle = "orange"; 
         ctx.strokeRect(clipRect.x, clipRect.y, clipRect.width, clipRect.height); 
 
         // Do the redirect render 
         viewer.renderRedirect(ctx, options, lt.LeadRectD.empty); 
 
         // Show how to draw the item's border 
         const manuallyComputeRedirectedBorder = () => { 
            const points: lt.LeadPointD[] = [lt.LeadPointD.create(sourceRectClipped.left, sourceRectClipped.top), lt.LeadPointD.create(sourceRectClipped.right, sourceRectClipped.bottom)]; 
            options.transform.transformPoints(points); 
 
            let xmin = points[0].x; 
            let ymin = points[0].y; 
            let xmax = xmin; 
            let ymax = ymin; 
 
            for (let i = 1; i < points.length; i++) { 
               if (points[i].x < xmin) xmin = points[i].x; 
               if (points[i].x > xmax) xmax = points[i].x; 
               if (points[i].y < ymin) ymin = points[i].y; 
               if (points[i].y > ymax) ymax = points[i].y; 
            } 
 
            const bounds: lt.LeadRectD = lt.LeadRectD.fromLTRB(xmin, ymin, xmax, ymax); 
 
            ctx.strokeStyle = "blue"; 
            ctx.strokeRect(bounds.x, bounds.y, bounds.width, bounds.height); 
         }; 
         manuallyComputeRedirectedBorder(); 
      }); 
      viewer.invalidate(lt.LeadRectD.empty); 
   } 
} 
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_RenderRedirectExample { 
   viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   run = (viewer) => { 
      viewer.itemBorderThickness = 5; 
 
      // Create the canvas we will render to 
      const redirectCanvas = document.createElement("canvas"); 
      redirectCanvas.style.border = "2px solid black"; 
      const redirectWidth = 300; 
      const redirectHeight = 300; 
      redirectCanvas.width = redirectWidth; 
      redirectCanvas.height = redirectHeight; 
 
      // Add it to the page 
      const output = document.getElementById("output"); 
      output.appendChild(redirectCanvas); 
 
      // Add a 20px margin around the redirect render area 
      const delta = 20; 
      const destRect = lt.LeadRectD.create(0, 0, redirectWidth, redirectHeight); 
      destRect.inflate(-delta, -delta); 
 
      const options = new lt.Controls.ImageViewerRenderRedirectOptions(); 
 
      viewer.rotateAngle = 35; 
      // Use "null" to draw the whole imageViewer 
      //let item = null; 
      const item = viewer.activeItem; 
 
      if (item) { 
         // Don't worry about rendering the below 
         options.renderBackgrounds = false; 
         options.renderBorders = false; 
         options.renderItemStates = false; 
         options.renderShadows = false; 
         options.renderText = false; 
      } 
 
      // On imageViewer render... 
      viewer.redirectRender.add(() => { 
         let sourceRect; 
         let sourceRectClipped; 
         if (!item) { 
            // Draw the whole imageViewer 
            sourceRect = viewer.getViewBounds(true, false); 
            sourceRectClipped = viewer.getViewBounds(true, true); 
         } 
         else { 
            // Only draw the rect for the active item 
            sourceRect = viewer.getItemViewBounds(item, lt.Controls.ImageViewerItemPart.image, false); 
            sourceRectClipped = viewer.getItemViewBounds(item, lt.Controls.ImageViewerItemPart.image, true); 
         } 
 
         const ctx = redirectCanvas.getContext("2d"); 
         ctx.clearRect(0, 0, redirectWidth, redirectHeight); 
 
         // Draw a rect around the maximum render area 
         ctx.strokeStyle = "green"; 
         ctx.strokeRect(destRect.x, destRect.y, destRect.width, destRect.height); 
 
         // Create the transformation for this rect 
         options.createTransform(viewer, destRect, sourceRect, lt.Controls.ControlSizeMode.fit, lt.Controls.ControlAlignment.center, lt.Controls.ControlAlignment.center); 
 
         // Draw a rect around the actual render area 
         const clipRect = options.transform.transformRect(sourceRect); 
         ctx.strokeStyle = "orange"; 
         ctx.strokeRect(clipRect.x, clipRect.y, clipRect.width, clipRect.height); 
 
         // Do the redirect render 
         viewer.renderRedirect(ctx, options, lt.LeadRectD.empty); 
 
         // Show how to draw the item's border 
         const manuallyComputeRedirectedBorder = () => { 
            const points = [lt.LeadPointD.create(sourceRectClipped.left, sourceRectClipped.top), lt.LeadPointD.create(sourceRectClipped.right, sourceRectClipped.bottom)]; 
            options.transform.transformPoints(points); 
 
            let xmin = points[0].x; 
            let ymin = points[0].y; 
            let xmax = xmin; 
            let ymax = ymin; 
 
            for (let i = 1; i < points.length; i++) { 
               if (points[i].x < xmin) xmin = points[i].x; 
               if (points[i].x > xmax) xmax = points[i].x; 
               if (points[i].y < ymin) ymin = points[i].y; 
               if (points[i].y > ymax) ymax = points[i].y; 
            } 
 
            const bounds = lt.LeadRectD.fromLTRB(xmin, ymin, xmax, ymax); 
 
            ctx.strokeStyle = "blue"; 
            ctx.strokeRect(bounds.x, bounds.y, bounds.width, bounds.height); 
         }; 
         manuallyComputeRedirectedBorder(); 
      }); 
      viewer.invalidate(lt.LeadRectD.empty); 
   } 
} 
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 | RenderRedirect</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.RenderRedirect(); 
 
   }; 
</script> 
</html> 
Requirements

Target Platforms

Help Version 23.0.2024.2.29
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2024 LEAD Technologies, Inc. All Rights Reserved.

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