Update Canvas 2D API

This repo contains new, current and old proposals for the Canvas 2D API, following a set of rationales.

Explainer video

In active development

• Layers. Support layers in canvas, that will be drawn in one, allowing effects only possible with auxiliary canvases.

• WebGPU Access. Switch contexts between Canvas2D and WebGPU/WebGL.

• Enhanced Text Metrics. Extend measureText to support DOM-provided APIs, like selection rect and more.

• Mesh2D. Draw a large number of texture-mapped triangles efficiently.

Launched

Those proposals have already been incorporated on the WhatWG spec and may be in different stages of implementation on browsers.

• Canvas context loss. Allow canvas to be discarded and re-drawn by demand.

• willReadFrequently. context creation attribute.

• Text modifiers. CSS text/font properties on Canvas.

• Reset function. Draw primitive.

• RoundRect. Draw primitive.

• Conic Gradient. Draw primitive.

Parked / Future ideas

• Perspective transforms. Allow for perspective transforms Canvas 2D rendering. Support 4x4 transform matrices.

• Recorded pictures. Create a record object that receives all the commands from a Canvas2D and can be replayed multiple times.

• Conic curves. Draw primitive.

• Batch text rendering.

• Text blob.

• Path2D Inspection. Allow inspection of Path2D objects, that are currently opaque.

• Element as a source for drawImage.

• Display list object. Format and data structure for retained mode drawings, making Canvas apps faster, more accessible and indexable.

• WebGPU Shaders. Allow for WebGPU shaders to be used as Canvas2D layers filters.

Dropped ideas

• Color input. support for new color input on Canvas.

• Batch drawImage. Support for multiple images being drawn within a single API call.

• Modern filters. Support composited filters, create a filter object that can be updated, and support more SVG-like filters. Superseded by layers.