updateCanvas Method (ImageViewerItems)
Summary
Update the HTML5 Canvas Element of an item.
Syntax
JavaScript Syntax
ImageViewerItems.prototype.updateCanvas = function(item, canvas, resolution)TypeScript Syntax
updateCanvas(item: ImageViewerItem, canvas: HTMLCanvasElement, resolution: LeadSizeD): void;Parameters
item
Item to update
canvas
New HTML5 Canvas Element. If this is null, then the item will be empty after this method returns.
resolution
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.
Remarks
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.
Example
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));
Requirements
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© 1991-2017 LEAD Technologies, Inc. All Rights Reserved.
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