Interface Context

A backend-provided object. Each Context instance can display a node tree on the screen.

In Shadow Mode, Context provides the core rendering context for glass-easel.

interface Context {
    dropBackendAfterRelease?: boolean;
    mode: Shadow;
    addPriorEventListener?(listener): void;
    addStyleSheetProperty?(sheetIndex, ruleIndex, inlineStyle, callback): void;
    addStyleSheetRule?(mediaQueryStr, selector, callback): void;
    appendStyleSheetPath(path, styleScope?): number;
    createContext?(options, cb): void;
    createFragment(): glassEasel.backend.Element;
    createMediaQueryObserver?(status, listener): Observer;
    destroy(): void;
    disableStyleSheet(index): void;
    elementFromPoint?(left, top, cb): void;
    getActiveElement?(cb): void;
    getDevicePixelRatio(): number;
    getFocusedNode?(cb): void;
    getRootNode(): ShadowRootContext;
    getStyleSheetIndexForNewRules?(callback): void;
    getTheme(): string;
    getWindowHeight(): number;
    getWindowWidth(): number;
    modifyStyleSheetRuleSelector?(sheetIndex, ruleIndex, selector, callback): void;
    onEvent(createEvent, listener): void;
    onThemeChange?(cb): void;
    onWindowResize?(cb): void;
    performanceTraceEnd?(id, cb): void;
    performanceTraceStart?(): number;
    registerStyleSheetContent(path, content): void;
    removePriorEventListener?(listener): void;
    removeStyleSheetProperty?(sheetIndex, ruleIndex, propertyIndex, callback): void;
    render(cb): void;
    replaceStyleSheetAllProperties?(sheetIndex, ruleIndex, inlineStyle, callback): void;
    replaceStyleSheetProperty?(sheetIndex, ruleIndex, propertyIndex, inlineStyle, callback): void;
    resetStyleSheetRule?(sheetIndex, ruleIndex, callback): void;
    setFocusedNode?(target): void;
    setStyleSheetPropertyDisabled?(sheetIndex, ruleIndex, propertyIndex, disabled, callback): void;
    startOverlayInspect?(cb): void;
    stopOverlayInspect?(): void;
}

Hierarchy

Implemented by

Properties

dropBackendAfterRelease? mode

Methods

addPriorEventListener? addStyleSheetProperty? addStyleSheetRule? appendStyleSheetPath createContext? createFragment createMediaQueryObserver? destroy disableStyleSheet elementFromPoint? getActiveElement? getDevicePixelRatio getFocusedNode? getRootNode getStyleSheetIndexForNewRules? getTheme getWindowHeight getWindowWidth modifyStyleSheetRuleSelector? onEvent onThemeChange? onWindowResize? performanceTraceEnd? performanceTraceStart? registerStyleSheetContent removePriorEventListener? removeStyleSheetProperty? render replaceStyleSheetAllProperties? replaceStyleSheetProperty? resetStyleSheetRule? setFocusedNode? setStyleSheetPropertyDisabled? startOverlayInspect? stopOverlayInspect?

Properties

Optional dropBackendAfterRelease

dropBackendAfterRelease?: boolean

mode

mode: Shadow

Protocol mode. Always BackendMode.Shadow in this protocol.

Methods

Optional addPriorEventListener

Optional addStyleSheetProperty

  • addStyleSheetProperty(sheetIndex, ruleIndex, inlineStyle, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • inlineStyle: string
    • callback: ((propertyIndex) => void)
        • (propertyIndex): void

        • Parameters

          • propertyIndex: null | number

          Returns void

    Returns void

Optional addStyleSheetRule

  • addStyleSheetRule(mediaQueryStr, selector, callback): void

  • Parameters

    • mediaQueryStr: string
    • selector: string
    • callback: ((ruleIndex) => void)
        • (ruleIndex): void

        • Parameters

          • ruleIndex: null | number

          Returns void

    Returns void

appendStyleSheetPath

  • appendStyleSheetPath(path, styleScope?): number

  • Insert a style sheet item whose content comes from the specified path. styleScope is an optional scope identifier. Returns the new style sheet index. If styleScope is not a positive integer, it is treated as empty (globally effective).

    Parameters

    • path: string
    • Optional styleScope: number

    Returns number

Optional createContext

  • createContext(options, cb): void

  • Parameters

    Returns void

createFragment

Optional createMediaQueryObserver

  • createMediaQueryObserver(status, listener): Observer

  • Parameters

    • status: MediaQueryStatus
    • listener: ((res) => void)
        • (res): void

        • Parameters

          • res: {
                matches: boolean;
            }
            • matches: boolean

          Returns void

    Returns Observer

destroy

  • destroy(): void

  • Destroy this Context instance. glass-easel does not call this directly; other modules should call it.

    Returns void

disableStyleSheet

  • disableStyleSheet(index): void

  • Disable an inserted style sheet.

    Parameters

    • index: number

    Returns void

Optional elementFromPoint

  • elementFromPoint(left, top, cb): void

  • Parameters

    • left: number
    • top: number
    • cb: ((node) => void)

    Returns void

Optional getActiveElement

  • getActiveElement(cb): void

  • Parameters

    • cb: ((node) => void)

    Returns void

getDevicePixelRatio

  • getDevicePixelRatio(): number

  • Get the device pixel ratio of this Context.

    Returns number

Optional getFocusedNode

  • getFocusedNode(cb): void

  • Parameters

    • cb: ((node) => void)
        • (node): void

        • Parameters

          Returns void

    Returns void

getRootNode

  • getRootNode(): ShadowRootContext

  • Get the root node. In Shadow Mode, the root node must be a component root node.

    Returns ShadowRootContext

Optional getStyleSheetIndexForNewRules

  • getStyleSheetIndexForNewRules(callback): void

  • Parameters

    • callback: ((sheetIndex) => void)
        • (sheetIndex): void

        • Parameters

          • sheetIndex: number

          Returns void

    Returns void

getTheme

  • getTheme(): string

  • Get the current theme of this Context, typically "light" or "dark".

    Returns string

getWindowHeight

  • getWindowHeight(): number

  • Get the display area height of this Context.

    Returns number

getWindowWidth

  • getWindowWidth(): number

  • Get the display area width of this Context.

    Returns number

Optional modifyStyleSheetRuleSelector

  • modifyStyleSheetRuleSelector(sheetIndex, ruleIndex, selector, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • selector: string
    • callback: ((ruleIndex) => void)
        • (ruleIndex): void

        • Parameters

          • ruleIndex: null | number

          Returns void

    Returns void

onEvent

  • onEvent(createEvent, listener): void

  • Set the global event callback. This callback is the only one. Shadow Mode only; for Composed Mode see the other onEvent signature.

    Parameters

    • createEvent: ((type, detail, options) => Event<unknown>)

      Creates an event object from the given type, detail, and options.

        • (type, detail, options): Event<unknown>

        • Parameters

          Returns Event<unknown>

    • listener: ((event, currentTarget, mark, target, isCapture) => void | EventBubbleStatus)

      Called when an event occurs.

    Returns void

Optional onThemeChange

  • onThemeChange(cb): void

  • Parameters

    • cb: ((res) => void)
        • (res): void

        • Parameters

          • res: {
                theme: string;
            }
            • theme: string

          Returns void

    Returns void

Optional onWindowResize

  • onWindowResize(cb): void

  • Parameters

    • cb: ((res) => void)
        • (res): void

        • Parameters

          • res: {
                devicePixelRatio: number;
                height: number;
                width: number;
            }
            • devicePixelRatio: number
            • height: number
            • width: number

          Returns void

    Returns void

Optional performanceTraceEnd

  • performanceTraceEnd(id, cb): void

  • Parameters

    • id: number
    • cb: ((stats) => void)
        • (stats): void

        • Parameters

          • stats: {
                endTimestamp: number;
                startTimestamp: number;
            }
            • endTimestamp: number
            • startTimestamp: number

          Returns void

    Returns void

Optional performanceTraceStart

  • performanceTraceStart(): number

  • Returns number

registerStyleSheetContent

  • registerStyleSheetContent(path, content): void

  • Register a style sheet. path is the style sheet path, content is the corresponding CSS style sheet in a format the backend can interpret. If the CSS contains @import or similar references, the referenced content may also be registered via another registerStyleSheetContent call, either before or after this one.

    Parameters

    • path: string
    • content: unknown

    Returns void

Optional removePriorEventListener

  • removePriorEventListener(listener): void

  • Parameters

    Returns void

Optional removeStyleSheetProperty

  • removeStyleSheetProperty(sheetIndex, ruleIndex, propertyIndex, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • propertyIndex: number
    • callback: ((propertyIndex) => void)
        • (propertyIndex): void

        • Parameters

          • propertyIndex: null | number

          Returns void

    Returns void

render

  • render(cb): void

  • Wait for the next render to complete (align with the backend vsync). The backend must ensure the callback is asynchronous. Setting new properties inside the callback should trigger CSS transitions.

    Parameters

    • cb: ((err) => void)
        • (err): void

        • Parameters

          • err: null | Error

          Returns void

    Returns void

Optional replaceStyleSheetAllProperties

  • replaceStyleSheetAllProperties(sheetIndex, ruleIndex, inlineStyle, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • inlineStyle: string
    • callback: ((propertyIndex) => void)
        • (propertyIndex): void

        • Parameters

          • propertyIndex: null | number

          Returns void

    Returns void

Optional replaceStyleSheetProperty

  • replaceStyleSheetProperty(sheetIndex, ruleIndex, propertyIndex, inlineStyle, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • propertyIndex: number
    • inlineStyle: string
    • callback: ((propertyIndex) => void)
        • (propertyIndex): void

        • Parameters

          • propertyIndex: null | number

          Returns void

    Returns void

Optional resetStyleSheetRule

  • resetStyleSheetRule(sheetIndex, ruleIndex, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • callback: ((ruleIndex) => void)
        • (ruleIndex): void

        • Parameters

          • ruleIndex: null | number

          Returns void

    Returns void

Optional setFocusedNode

  • setFocusedNode(target): void

  • Parameters

    Returns void

Optional setStyleSheetPropertyDisabled

  • setStyleSheetPropertyDisabled(sheetIndex, ruleIndex, propertyIndex, disabled, callback): void

  • Parameters

    • sheetIndex: number
    • ruleIndex: number
    • propertyIndex: number
    • disabled: boolean
    • callback: ((propertyIndex) => void)
        • (propertyIndex): void

        • Parameters

          • propertyIndex: null | number

          Returns void

    Returns void

Optional startOverlayInspect

  • startOverlayInspect(cb): void

  • Parameters

    • cb: ((event, node) => void)
        • (event, node): void

        • Parameters

          Returns void

    Returns void

Optional stopOverlayInspect

  • stopOverlayInspect(): void

  • Returns void

Settings

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On This Page

dropBackendAfterReleasemodeaddPriorEventListeneraddStyleSheetPropertyaddStyleSheetRuleappendStyleSheetPathcreateContextcreateFragmentcreateMediaQueryObserverdestroydisableStyleSheetelementFromPointgetActiveElementgetDevicePixelRatiogetFocusedNodegetRootNodegetStyleSheetIndexForNewRulesgetThemegetWindowHeightgetWindowWidthmodifyStyleSheetRuleSelectoronEventonThemeChangeonWindowResizeperformanceTraceEndperformanceTraceStartregisterStyleSheetContentremovePriorEventListenerremoveStyleSheetPropertyrenderreplaceStyleSheetAllPropertiesreplaceStyleSheetPropertyresetStyleSheetRulesetFocusedNodesetStyleSheetPropertyDisabledstartOverlayInspectstopOverlayInspect