updateCanvas Method


Update the HTML5 Canvas Element of an item.


JavaScript Syntax
ImageViewerItems.prototype.updateCanvas = function(item, canvas, resolution) 
TypeScript Syntax
updateCanvas(item: ImageViewerItem, canvas: HTMLCanvasElement, resolution: LeadSizeD): void; 



Item to update


New HTML5 Canvas Element. If this is null, then the item will be empty after this method returns.


The resolution to use of the image in dots/inch (or DPI). A value of 0,0 or Empty means use the default image

resolution which is 96 pixels.


This method is a shortcut for updating the Canvas and Resolution properties. It is equivalent to:

item.canvas = canvas; 
item.resolution = resolution; 

UpdateElement is a shortcut for updating not only Canvas, but also Element and Image. Passing a valid HTML Image Element to UpdateElement sets the Image property just as UpdateImage does. Similarly, passing a valid HTML5 Canvas Element to UpdateElement sets the Canvas property just as UpdateCanvas does. The item can have a value in only one of Image, Element or Canvas. Setting one value will automatically delete the values of the others.


JavaScript Example
var canvas = document.getElementById("myCanvas"); 
var context = canvas.getContext("2d"); 
context.fillStyle = "rgba(0, 0, 255, .5)"; 
context.fillRect(25, 25, 125, 125); 
this._imageViewer.items.updateCanvas(this._imageViewer.activeItem, canvas, lt.LeadSizeD.create(96, 96)); 


Target Platforms

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