Struct CanvasRenderingContext2D 

#[repr(C)]
pub(crate) struct CanvasRenderingContext2D {
    reflector_: Reflector<AssociatedMemory>,
    canvas: HTMLCanvasElementOrOffscreenCanvas,
    canvas_state: CanvasState,
}

Fields

reflector_: Reflector<AssociatedMemory>

canvas: HTMLCanvasElementOrOffscreenCanvas

canvas_state: CanvasState

Implementations

impl CanvasRenderingContext2D

fn __assert_parent_type(&self)

impl CanvasRenderingContext2D

const RGBA8_BYTES_PER_PIXEL: usize = 4

const ASSOCIATED_MEMORY_BUFFER_COUNT: usize = 4

Ideally this would be two bitmap buffers, unfortunately we currently have ~4 copies which are all retained until GC:

1. The draw target’s backing bitmap in the canvas paint thread (CanvasData::draw_target, e.g. pixmap in VelloCPUDrawTarget).
2. Additional backend resources (approximated with 1 bitmap buffer, actually depends on backend): e.g. ctx and resources in VelloCPUDrawTarget for vello_cpu. TODO: #46785 tracks getting accurate statistics from the backend.
3. CachedImageData::Raw in WebRender (cpu memory copy).
4. GPU memory in webrender / driver (also lives in RAM on unified memory systems).

This metric is only used to inform the GC about memory pressure, so it doesn’t need to be completely accurate, but undercounting may delay GCs and hence increase memory usage. On mobile devices this slightly undercounts (usually unified memory), on desktop this slightly overcounts, since GPU memory is separate.

fn associated_memory_size(size: Size2D<u64>) -> usize

pub(crate) fn update_associated_memory_size(&self)

pub(crate) fn new_inherited( global: &GlobalScope, canvas: HTMLCanvasElementOrOffscreenCanvas, size: Size2D<u32>, ) -> Option<CanvasRenderingContext2D>

pub(crate) fn new( cx: &mut JSContext, global: &GlobalScope, canvas: &HTMLCanvasElement, size: Size2D<u32>, ) -> Option<DomRoot<CanvasRenderingContext2D>>

pub(crate) fn send_canvas_command_immediate(&self, msg: CanvasCommand)

pub(crate) fn set_image_key(&self, image_key: ImageKey)

pub(crate) fn update_rendering(&self, canvas_epoch: Epoch) -> bool

Trait Implementations

impl CanvasContext for CanvasRenderingContext2D

type ID = CanvasId

fn context_id(&self) -> Self::ID

fn canvas(&self) -> Option<HTMLCanvasElementOrOffscreenCanvas<DomTypeHolder>>

fn resize(&self)

fn reset_bitmap(&self)

fn get_image_data(&self) -> Option<Snapshot>

Returns none if area of canvas is zero.

fn origin_is_clean(&self) -> bool

fn mark_as_dirty(&self)

fn size(&self) -> Size2D<u32>

fn onscreen(&self) -> bool

impl CanvasRenderingContext2DMethods<DomTypeHolder> for CanvasRenderingContext2D

fn Canvas(&self) -> DomRoot<HTMLCanvasElement>

https://html.spec.whatwg.org/multipage/#dom-context-2d-canvas

fn Save(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-save

fn Restore(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-restore

fn Reset(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-reset

fn Scale(&self, x: f64, y: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-scale

fn Rotate(&self, angle: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-rotate

fn Translate(&self, x: f64, y: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-translate

fn Transform(&self, a: f64, b: f64, c: f64, d: f64, e: f64, f: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-transform

fn GetTransform(&self, cx: &mut JSContext) -> DomRoot<DOMMatrix>

https://html.spec.whatwg.org/multipage/#dom-context-2d-gettransform

fn SetTransform( &self, a: f64, b: f64, c: f64, d: f64, e: f64, f: f64, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-settransform

fn SetTransform_(&self, transform: &DOMMatrix2DInit) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-settransform-matrix

fn ResetTransform(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-resettransform

fn GlobalAlpha(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-globalalpha

fn SetGlobalAlpha(&self, alpha: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-globalalpha

fn GlobalCompositeOperation(&self) -> DOMString

https://html.spec.whatwg.org/multipage/#dom-context-2d-globalcompositeoperation

fn SetGlobalCompositeOperation(&self, op_str: DOMString)

https://html.spec.whatwg.org/multipage/#dom-context-2d-globalcompositeoperation

fn FillRect(&self, x: f64, y: f64, width: f64, height: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-fillrect

fn ClearRect(&self, x: f64, y: f64, width: f64, height: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-clearrect

fn StrokeRect(&self, x: f64, y: f64, width: f64, height: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-strokerect

fn BeginPath(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-beginpath

fn ClosePath(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-closepath

fn Fill(&self, fill_rule: CanvasFillRule)

https://html.spec.whatwg.org/multipage/#dom-context-2d-fill

fn Fill_(&self, path: &Path2D, fill_rule: CanvasFillRule)

https://html.spec.whatwg.org/multipage/#dom-context-2d-fill

fn Stroke(&self)

https://html.spec.whatwg.org/multipage/#dom-context-2d-stroke

fn Stroke_(&self, path: &Path2D)

https://html.spec.whatwg.org/multipage/#dom-context-2d-stroke

fn Clip(&self, fill_rule: CanvasFillRule)

https://html.spec.whatwg.org/multipage/#dom-context-2d-clip

fn Clip_(&self, path: &Path2D, fill_rule: CanvasFillRule)

https://html.spec.whatwg.org/multipage/#dom-context-2d-clip

fn IsPointInPath(&self, x: f64, y: f64, fill_rule: CanvasFillRule) -> bool

https://html.spec.whatwg.org/multipage/#dom-context-2d-ispointinpath

fn IsPointInPath_( &self, path: &Path2D, x: f64, y: f64, fill_rule: CanvasFillRule, ) -> bool

https://html.spec.whatwg.org/multipage/#dom-context-2d-ispointinpath

fn FillText(&self, text: DOMString, x: f64, y: f64, max_width: Option<f64>)

https://html.spec.whatwg.org/multipage/#dom-context-2d-filltext

fn StrokeText(&self, text: DOMString, x: f64, y: f64, max_width: Option<f64>)

https://html.spec.whatwg.org/multipage/#dom-context-2d-stroketext

fn MeasureText( &self, cx: &mut JSContext, text: DOMString, ) -> DomRoot<TextMetrics>

https://html.spec.whatwg.org/multipage/#textmetrics

fn Font(&self) -> DOMString

https://html.spec.whatwg.org/multipage/#dom-context-2d-font

fn SetFont(&self, value: DOMString)

https://html.spec.whatwg.org/multipage/#dom-context-2d-font

fn TextAlign(&self) -> CanvasTextAlign

https://html.spec.whatwg.org/multipage/#dom-context-2d-textalign

fn SetTextAlign(&self, value: CanvasTextAlign)

https://html.spec.whatwg.org/multipage/#dom-context-2d-textalign

fn TextBaseline(&self) -> CanvasTextBaseline

https://html.spec.whatwg.org/multipage/#dom-context-2d-textbaseline

fn SetTextBaseline(&self, value: CanvasTextBaseline)

https://html.spec.whatwg.org/multipage/#dom-context-2d-textbaseline

fn Direction(&self) -> CanvasDirection

https://html.spec.whatwg.org/multipage/#dom-context-2d-direction

fn SetDirection(&self, value: CanvasDirection)

https://html.spec.whatwg.org/multipage/#dom-context-2d-direction

fn DrawImage( &self, image: CanvasImageSource<DomTypeHolder>, dx: f64, dy: f64, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-drawimage

fn DrawImage_( &self, image: CanvasImageSource<DomTypeHolder>, dx: f64, dy: f64, dw: f64, dh: f64, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-drawimage

fn DrawImage__( &self, image: CanvasImageSource<DomTypeHolder>, sx: f64, sy: f64, sw: f64, sh: f64, dx: f64, dy: f64, dw: f64, dh: f64, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-drawimage

fn MoveTo(&self, x: f64, y: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-moveto

fn LineTo(&self, x: f64, y: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-lineto

fn Rect(&self, x: f64, y: f64, width: f64, height: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-rect

fn QuadraticCurveTo(&self, cpx: f64, cpy: f64, x: f64, y: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-quadraticcurveto

fn BezierCurveTo( &self, cp1x: f64, cp1y: f64, cp2x: f64, cp2y: f64, x: f64, y: f64, )

https://html.spec.whatwg.org/multipage/#dom-context-2d-beziercurveto

fn Arc( &self, x: f64, y: f64, r: f64, start: f64, end: f64, ccw: bool, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-arc

fn ArcTo( &self, cp1x: f64, cp1y: f64, cp2x: f64, cp2y: f64, r: f64, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-arcto

fn Ellipse( &self, x: f64, y: f64, rx: f64, ry: f64, rotation: f64, start: f64, end: f64, ccw: bool, ) -> ErrorResult

https://html.spec.whatwg.org/multipage/#dom-context-2d-ellipse

fn ImageSmoothingEnabled(&self) -> bool

https://html.spec.whatwg.org/multipage/#dom-context-2d-imagesmoothingenabled

fn SetImageSmoothingEnabled(&self, value: bool)

https://html.spec.whatwg.org/multipage/#dom-context-2d-imagesmoothingenabled

fn StrokeStyle(&self) -> StringOrCanvasGradientOrCanvasPattern<DomTypeHolder>

https://html.spec.whatwg.org/multipage/#dom-context-2d-strokestyle

fn SetStrokeStyle( &self, value: StringOrCanvasGradientOrCanvasPattern<DomTypeHolder>, )

https://html.spec.whatwg.org/multipage/#dom-context-2d-strokestyle

fn FillStyle(&self) -> StringOrCanvasGradientOrCanvasPattern<DomTypeHolder>

https://html.spec.whatwg.org/multipage/#dom-context-2d-strokestyle

fn SetFillStyle( &self, value: StringOrCanvasGradientOrCanvasPattern<DomTypeHolder>, )

https://html.spec.whatwg.org/multipage/#dom-context-2d-strokestyle

fn CreateImageData( &self, cx: &mut JSContext, sw: i32, sh: i32, ) -> Fallible<DomRoot<ImageData>>

https://html.spec.whatwg.org/multipage/#dom-context-2d-createimagedata

fn CreateImageData_( &self, cx: &mut JSContext, imagedata: &ImageData, ) -> Fallible<DomRoot<ImageData>>

https://html.spec.whatwg.org/multipage/#dom-context-2d-createimagedata

fn GetImageData( &self, cx: &mut JSContext, sx: i32, sy: i32, sw: i32, sh: i32, ) -> Fallible<DomRoot<ImageData>>

https://html.spec.whatwg.org/multipage/#dom-context-2d-getimagedata

fn PutImageData(&self, no_gc: &NoGC, imagedata: &ImageData, dx: i32, dy: i32)

https://html.spec.whatwg.org/multipage/#dom-context-2d-putimagedata

fn CreateLinearGradient( &self, cx: &mut JSContext, x0: Finite<f64>, y0: Finite<f64>, x1: Finite<f64>, y1: Finite<f64>, ) -> DomRoot<CanvasGradient>

https://html.spec.whatwg.org/multipage/#dom-context-2d-createlineargradient

fn CreateRadialGradient( &self, cx: &mut JSContext, x0: Finite<f64>, y0: Finite<f64>, r0: Finite<f64>, x1: Finite<f64>, y1: Finite<f64>, r1: Finite<f64>, ) -> Fallible<DomRoot<CanvasGradient>>

https://html.spec.whatwg.org/multipage/#dom-context-2d-createradialgradient

fn CreatePattern( &self, cx: &mut JSContext, image: CanvasImageSource<DomTypeHolder>, repetition: DOMString, ) -> Fallible<Option<DomRoot<CanvasPattern>>>

https://html.spec.whatwg.org/multipage/#dom-context-2d-createpattern

fn LineWidth(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-linewidth

fn SetLineWidth(&self, width: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-linewidth

fn LineCap(&self) -> CanvasLineCap

https://html.spec.whatwg.org/multipage/#dom-context-2d-linecap

fn SetLineCap(&self, cap: CanvasLineCap)

https://html.spec.whatwg.org/multipage/#dom-context-2d-linecap

fn LineJoin(&self) -> CanvasLineJoin

https://html.spec.whatwg.org/multipage/#dom-context-2d-linejoin

fn SetLineJoin(&self, join: CanvasLineJoin)

https://html.spec.whatwg.org/multipage/#dom-context-2d-linejoin

fn MiterLimit(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-miterlimit

fn SetMiterLimit(&self, limit: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-miterlimit

fn SetLineDash(&self, segments: Vec<f64>)

https://html.spec.whatwg.org/multipage/#dom-context-2d-setlinedash

fn GetLineDash(&self) -> Vec<f64>

https://html.spec.whatwg.org/multipage/#dom-context-2d-getlinedash

fn LineDashOffset(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-linedashoffset

fn SetLineDashOffset(&self, offset: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-linedashoffset

fn ShadowOffsetX(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowoffsetx

fn SetShadowOffsetX(&self, value: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowoffsetx

fn ShadowOffsetY(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowoffsety

fn SetShadowOffsetY(&self, value: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowoffsety

fn ShadowBlur(&self) -> f64

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowblur

fn SetShadowBlur(&self, value: f64)

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowblur

fn ShadowColor(&self) -> DOMString

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowcolor

fn SetShadowColor(&self, value: DOMString)

https://html.spec.whatwg.org/multipage/#dom-context-2d-shadowcolor

fn PutImageData_( &self, no_gc: &NoGC, imagedata: &ImageData, dx: i32, dy: i32, dirty_x: i32, dirty_y: i32, dirty_width: i32, dirty_height: i32, )

impl DomObject for CanvasRenderingContext2D

type ReflectorType = AssociatedMemory

fn reflector(&self) -> &Reflector<Self::ReflectorType>

Returns the receiver’s reflector.

impl DomObjectWrap<DomTypeHolder> for CanvasRenderingContext2D

const WRAP: unsafe fn(&mut JSContext, &GlobalScope, Option<HandleObject<'_>>, Box<Self>) -> Root<Dom<Self>>

Function pointer to the general wrap function type

impl Drop for CanvasRenderingContext2D

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl HasParent for CanvasRenderingContext2D

fn as_parent(&self) -> &Reflector<AssociatedMemory>

This is used in a type assertion to ensure that the source and webidls agree as to what the parent type is

type Parent = Reflector<AssociatedMemory>

impl IDLInterface for CanvasRenderingContext2D

const PROTO_FIRST: u16 = 48

First prototype ID in the DFS-ordered range for this interface and its descendants.

const PROTO_LAST: u16 = 48

Last prototype ID in the DFS-ordered range for this interface and its descendants.

fn derives(class: &'static DOMClass) -> bool

Returns whether the given DOM class derives that interface.

impl MallocSizeOf for CanvasRenderingContext2D

fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize

Measure the heap usage of all descendant heap-allocated structures, but not the space taken up by the value itself.

impl MutDomObject for CanvasRenderingContext2D

unsafe fn init_reflector<Actual>(&self, obj: *mut JSObject)

Initializes the Reflector

unsafe fn init_reflector_without_associated_memory(&self, obj: *mut JSObject)

Initializes the Reflector without recording any associated memory usage.

impl PartialEq for CanvasRenderingContext2D

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ToJSValConvertible for CanvasRenderingContext2D

fn safe_to_jsval(&self, cx: &mut JSContext, rval: MutableHandleValue<'_>)

Convert self to a JSVal. JSAPI failure causes a panic.

impl Traceable for CanvasRenderingContext2D

unsafe fn trace(&self, tracer: *mut JSTracer)

Trace self.

impl Eq for CanvasRenderingContext2D