Properties
canvasElm
canvasElm: HTMLElement
Optional debug
debug: undefined | false | true
Optional devicePixelRatio
devicePixelRatio: undefined | number
Optional isAntialias
isAntialias: undefined | false | true
Optional isPremultipliedAlpha
isPremultipliedAlpha: undefined | false | true
Optional nativeHeight
nativeHeight: undefined | number
Optional nativeWidth
nativeWidth: undefined | number
GFX设备描述信息。