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Render and Canvas
Canvas
.createCanvas
Creates a canvas object. The first call creates the primary on-screen canvas; subsequent calls create off-screen canvases for background rendering. Returns a Canvas object.
Return value
Field | Type | Description |
width | number | Width of the canvas |
height | number | Height of the canvas |
getContext | function | Gets the drawing context of the canvas object |
toDataURL | function | Returns the content drawn on the canvas in the format of a string. After enabling the open data domain, all canvases in the main domain cannot call this interface. |
.createImage
Creates an image object, used for loading and drawing images onto a canvas. Returns an Image object with src, width, height, and event listener methods.
Return value
The return value is Image, which is of type object. The detailed parameter descriptions are as follows:
Field | Type | Description |
src | string | URL of the image, base64 content, or ArrayBuffer data |
width | number | True width of the image |
height | number | True height of the image |
addEventListener | function | Add event listener |
removeEventListener | function | Remove event listener |
Canvas
.getContext(enum contextType)
Returns the drawing context (2d or webgl) for the canvas.
Parameter
When the parameter is 2D, the return value CanvasRenderingContext2D implements most of the properties and methods defined by the HTML Canvas 2D Context , and the features not currently supported are as listed:
CanvasRenderingContext2D.clipCanvasRenderingContext2D.lineDashOffsetCanvasRenderingContext2D.isPointInPathCanvasRenderingContext2D.isPointInStroke
When the parameter is webgl, the return value WebGLRenderingContext implements all attributes, methods, and constants defined by WebGL 1.0 .
Field | Default Value | Value | Description | Required |
contextType | None | 2d/webgl | Context type. | Yes |
Return value
Type | Description |
object | Canvas context object |
.toDataURL
Returns canvas content as a data URI string.
Return value
String in data URI format
Font
.loadFont
Loads a custom font and returns its font‑family name or null.
Parameter
Field | Type | Description |
path | string | Font file path. Supports local paths and code package paths |
Return value
Type | Description |
string | If the font is successfully loaded, return the font family value; otherwise, return null |