Class CanvasBox

A Box that exists on a HTMLCanvasElement

Hierarchy (View Summary)

Box
- CanvasBox

Constructors

constructor

new CanvasBox(
    parent: undefined | CanvasBox,
    id: string,
    bounds?: Geometry.RectPositioned,
): CanvasBox
Parameters
- parent: undefined | CanvasBox
- id: string
- Optionalbounds: Geometry.RectPositioned
Returns CanvasBox
Overrides Box.constructor

Properties

`Protected`_layoutPosition

_layoutPosition: undefined | Geometry.Point

`Protected`_measuredSize

_measuredSize: undefined | Geometry.Rect

`Protected`_needsDrawing

_needsDrawing: boolean = true

`Protected`_needsLayoutX

_needsLayoutX: boolean = true

`Protected`_needsMeasuring

_needsMeasuring: boolean = true

`Protected` `Readonly`_parent

_parent: undefined | Box

`Protected`_ready

_ready: boolean = true

bounds

bounds: undefined | Geometry.RectPositioned

canvasRegion

canvasRegion: Geometry.RectPositioned = RectsPlaceholderPositioned

Rectangle Box occupies in canvas/etc

`Protected`children

children: Box[] = []

debugHue

debugHue: number = ...

debugLayout

debugLayout: boolean = false

`Readonly`id

id: string

takesSpaceWhenInvisible

takesSpaceWhenInvisible: boolean = false

Accessors

desiredRegion

get desiredRegion(): undefined | BoxRect
Gets the box's desired region, or undefined

Returns undefined | BoxRect
Inherited from Box.desiredRegion
set desiredRegion(v: undefined | BoxRect): void
Sets the box's desired region. Calls onLayoutNeeded()
Parameters
- v: undefined | BoxRect
Returns void
Inherited from Box.desiredRegion

root

get root(): Box
Returns the root box

Returns Box
Inherited from Box.root

visible

get visible(): boolean
Gets visible state

Returns boolean
Inherited from Box.visible
set visible(v: boolean): void
Sets visible state
Parameters
- v: boolean
Returns void
Inherited from Box.visible

Methods

addEventHandlers

addEventHandlers(element: HTMLElement): void
Called if this is the parent Box
Parameters
- element: HTMLElement
Returns void

debugLog

debugLog(m: any): void
Debug log from this box context
Parameters
- m: any
Returns void
Inherited from Box.debugLog

draw

draw(ctx: CanvasRenderingContext2D, force?: boolean): void
Parameters
- ctx: CanvasRenderingContext2D
- force: boolean = false
Returns void

drawingInvalidated

drawingInvalidated(_reason: string): void
Parameters
- _reason: string
Returns void
Inherited from Box.drawingInvalidated

`Protected`drawSelf

drawSelf(_ctx: CanvasRenderingContext2D): void
Draw this object
Parameters
- _ctx: CanvasRenderingContext2D
Returns void

getBounds

getBounds(): undefined | Geometry.RectPositioned
Returns undefined | Geometry.RectPositioned

getChildren

getChildren(): Generator<never, ArrayIterator<[number, Box]>, unknown>
Returns Generator<never, ArrayIterator<[number, Box]>, unknown>
Inherited from Box.getChildren

hasChild

hasChild(box: Box): boolean
Returns true if box is a child
Parameters
- box: Box
Returns boolean
Inherited from Box.hasChild

`Protected`layoutApply

layoutApply(l: Layout): boolean
Parameters
- l: Layout
Returns boolean
Overrides Box.layoutApply

layoutInvalidated

layoutInvalidated(reason: string): void
Calls notifyChildLayoutNeeded
Parameters
- reason: string
Returns void
Inherited from Box.layoutInvalidated

`Protected`layoutSelf

layoutSelf(
    measureState: MeasureState,
    layoutState: LayoutState,
    _parent?: Layout,
): undefined | Geometry.Point
Parameters
- measureState: MeasureState
- layoutState: LayoutState
- Optional_parent: Layout
Returns undefined | Geometry.Point
Inherited from Box.layoutSelf

layoutStart

layoutStart(
    measureState: MeasureState,
    layoutState: LayoutState,
    force: boolean,
    parent?: Layout,
): undefined | Layout
Parameters
- measureState: MeasureState
- layoutState: LayoutState
- force: boolean
- Optionalparent: Layout
Returns undefined | Layout
Inherited from Box.layoutStart

`Protected`measureApply

measureApply(m: Measurement): boolean
Applies actual size, returning true if size is different than before
1. Sets _needsLayout to false.
2. Sets visual to m
3. Calls measureApply on each child
4. If there's a change or force, sets needsDrawing to true, and notifies root of measureApplied
Parameters
- m: Measurement
  Measurement for box
Returns boolean
Overrides Box.measureApply

`Protected`measurePreflight

measurePreflight(): void
Prepare for measuring

Returns void
Inherited from Box.measurePreflight

`Protected`measureSelf

measureSelf(opts: MeasureState, parent?: Measurement): string | Geometry.Rect
Measure the box
1. Uses desired rectangle, if possible
2. Otherwise uses parent's size
Parameters
- opts: MeasureState
  Measure state
- Optionalparent: Measurement
  Parent size
Returns string | Geometry.Rect
Inherited from Box.measureSelf

measureStart

measureStart(
    opts: MeasureState,
    force: boolean,
    parent?: Measurement,
): undefined | Measurement
Start of measuring
1. Keeps track of measurements in opts.measurements
2. If this box takes space 2.1. Measure itself if needed 2.2. Use size
3. Calls measureStart on each child
Parameters
- opts: MeasureState
  Options
- force: boolean
  Force measurement
- Optionalparent: Measurement
  Parent's measurement
Returns undefined | Measurement
Measurement

Inherited from Box.measureStart

notify

notify(message: string, source: Box): void
Sends a message to all child boxes.

This first calls onNotify on this instance, before calling notify() on each child.
Parameters
- message: string
- source: Box
Returns void
Inherited from Box.notify

`Protected`onChildAdded

onChildAdded(child: Box): void
Notification a child box has been added

Throws if
- child has parent as its own child
- child is same as this
- child is already child of this
Parameters
- child: Box
Returns void
Inherited from Box.onChildAdded

`Protected`onClick

onClick(_p: Geometry.Point): void
Parameters
- _p: Geometry.Point
Returns void

`Protected`onNotify

onNotify(_message: string, _source: Box): void
Handles a received message
Parameters
- _message: string
- _source: Box
Returns void
Inherited from Box.onNotify

`Protected`onPointerLeave

onPointerLeave(): void
Handler when pointer has left

Returns void

`Protected`onPointerMove

onPointerMove(_p: Geometry.Point): void
Handler when pointer moves within our region
Parameters
- _p: Geometry.Point
Returns void

setReady

setReady(ready: boolean, includeChildren?: boolean): void
Sets _ready to ready. If includeChildren is true, setReady is called on each child
Parameters
- ready: boolean
- includeChildren: boolean = false
Returns void
Inherited from Box.setReady

unsetBounds

unsetBounds(): void
Returns void

update

update(context: CanvasRenderingContext2D, force?: boolean): void
Performs recalculations and drawing as necessary If nothing needs to happen, function returns.
Parameters
- context: CanvasRenderingContext2D
- force: boolean = false
  Force update
Returns void
Overrides Box.update

`Protected`updateBegin

updateBegin(context: CanvasRenderingContext2D): [MeasureState, LayoutState]
Update begins.
Parameters
- context: CanvasRenderingContext2D
Returns [MeasureState, LayoutState]
MeasureState

Overrides Box.updateBegin

`Protected`updateComplete

updateComplete(_measureChanged: boolean, _layoutChanged: boolean): void
Parameters
- _measureChanged: boolean
- _layoutChanged: boolean
Returns void
Overrides Box.updateComplete

`Static`fromCanvas

fromCanvas(canvasElement: HTMLCanvasElement): CanvasBox
Parameters
- canvasElement: HTMLCanvasElement
Returns CanvasBox