CanvasBlock¶

Overview¶

Handles a visual Canvas layer of drawables.

@author Jonathan Olson <jonathan.olson@colorado.edu>

Class CanvasBlock¶

import { CanvasBlock } from 'scenerystack/scenery';

Constructor¶

new CanvasBlock( display, renderer, transformRootInstance, filterRootInstance )¶

Instance Methods¶

initialize( display, renderer, transformRootInstance, filterRootInstance )¶

@public

@param {Display} display @param {number} renderer @param {Instance} transformRootInstance - All transforms of this instance and its ancestors will already have been applied. This block will only be responsible for applying transforms of this instance's descendants. @param {Instance} filterRootInstance - All filters (visibility/opacity/filters) of this instance and its ancestors will already have been applied. This block will only be responsible for applying filters of this instance's descendants.

setSizeFullDisplay()¶

@public @override

setSizeFitBounds()¶

@public @override

update()¶

Updates the DOM appearance of this drawable (whether by preparing/calling draw calls, DOM element updates, etc.) @public @override

@returns {boolean} - Whether the update should continue (if false, further updates in supertype steps should not be done).

applyClip( drawable )¶

Reapplies clips to the current context. It's necessary to fully apply every clipping area for every ancestor, due to how Canvas is set up. Should ideally be called when the clip is dirty. @private

This is necessary since you can't apply "nested" clipping areas naively in Canvas, but you specify one entire clip area.

@param {CanvasSelfDrawable} Drawable

pushWrapper()¶

Pushes a wrapper onto our stack (creating if necessary), and initializes. @private

popWrapper()¶

Pops a wrapper off of our stack. @private

walkDown( trail, branchIndex )¶

Walk down towards the root, popping any clip/opacity effects that were needed. @private

@param {Trail} trail @param {number} branchIndex - The first index where our before and after trails have diverged.

walkUp( trail, branchIndex )¶

Walk up towards the next leaf, pushing any clip/opacity effects that are needed. @private

@param {Trail} trail @param {number} branchIndex - The first index where our before and after trails have diverged.

renderDrawable( drawable )¶

Draws the drawable into our main Canvas. @private

For things like opacity/clipping, as part of this we walk up/down part of the instance tree for rendering each drawable.

@param {CanvasSelfDrawable} - TODO: In the future, we'll need to support Canvas caches (this should be updated https://github.com/phetsims/scenery/issues/1581 with a proper generalized type)