LEADTOOLS JavaScript (Leadtools.Controls)
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UpdateCanvas Method
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| Leadtools.Controls Namespace > ImageViewerItems Object : UpdateCanvas Method |
function Leadtools.Controls.ImageViewerItems.updateCanvas( item , canvas , resolution )
| Parameter | Type | Description |
|---|---|---|
| item | ImageViewerItem | Item to update |
| canvas | CanvasElement | New HTML5 Canvas Element. If this is null, then the item will be empty after this method returns. |
| resolution | LeadSizeD | 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.
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));