#  [](https://www.npmjs.com/package/@thi.ng/rdom-canvas)  [](https://mastodon.thi.ng/@toxi) > [!NOTE] > This is one of 209 standalone projects, maintained as part > of the [@thi.ng/umbrella](https://github.com/thi-ng/umbrella/) monorepo > and anti-framework. > > 🚀 Please help me to work full-time on these projects by [sponsoring me on > GitHub](https://github.com/sponsors/postspectacular). Thank you! ❤️ - [About](#about) - [General usage](#general-usage) - [Control attributes](#control-attributes) - [Status](#status) - [Related packages](#related-packages) - [Installation](#installation) - [Dependencies](#dependencies) - [Usage examples](#usage-examples) - [API](#api) - [Authors](#authors) - [License](#license) ## About [@thi.ng/rdom](https://github.com/thi-ng/umbrella/tree/develop/packages/rdom) component wrapper for [@thi.ng/hiccup-canvas](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup-canvas) and declarative canvas drawing. Please consult these packages' READMEs for further background information... ### General usage As with most thi.ng/rdom components, the state (aka geometry/scenegraph) for the canvas component is being sourced from a [thi.ng/rstream](https://github.com/thi-ng/umbrella/tree/develop/packages/rstream) subscription. The canvas redraws every time that subscription delivers a new value. The size of the canvas can be given as a subscription too and if so will also automatically trigger resizing of the canvas. The geometry to rendered to the canvas is expressed as [thi.ng/hiccup](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup), specifically the flavor used by [thi.ng/hiccup-canvas](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup-canvas), which (not just coincidentally) is the same as also used by [thi.ng/geom](https://github.com/thi-ng/umbrella/tree/develop/packages/geom) shapes. ```ts tangle:export/readme1.ts import { circle, group } from "@thi.ng/geom"; import { $canvas } from "@thi.ng/rdom-canvas"; import { fromRAF } from "@thi.ng/rstream"; import { repeatedly } from "@thi.ng/transducers"; // create geometry stream/subscription const geo = fromRAF().map((t) => // shape group w/ attribs (also see section in readme) group({ __background: "#0ff" }, [ // create 10 circles ...repeatedly( (i) => circle( [ Math.sin(t * 0.01 + i * 0.5) * 150 + 300, Math.sin(t * 0.03 + i * 0.5) * 150 + 300 ], 50, // colors can be given as RGBA vectors or CSS { fill: [i * 0.1, 0, i * 0.05] } ), 10 ) ]) ); // create & mount canvas component (w/ fixed size) $canvas(geo, [600, 600]).mount(document.body); ``` ### Control attributes The root shape/group support the following special attributes: - `__background`: background color. If given, fills the canvas will given color before drawing - `__clear`: clear background flag. If true clears the canvas before drawing Also see relevant section in the [thi.ng/hiccup-canvas README](https://github.com/thi-ng/umbrella/blob/develop/packages/hiccup-canvas/README.md#special-attributes)... ## Status **ALPHA** - bleeding edge / work-in-progress [Search or submit any issues for this package](https://github.com/thi-ng/umbrella/issues?q=%5Brdom-canvas%5D+in%3Atitle) ## Related packages - [@thi.ng/hiccup-canvas](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup-canvas) - Hiccup shape tree renderer for vanilla Canvas 2D contexts - [@thi.ng/hiccup-svg](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup-svg) - SVG element functions for [@thi.ng/hiccup](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup) & related tooling - [@thi.ng/geom](https://github.com/thi-ng/umbrella/tree/develop/packages/geom) - Functional, polymorphic API for 2D geometry types & SVG generation - [@thi.ng/scenegraph](https://github.com/thi-ng/umbrella/tree/develop/packages/scenegraph) - Extensible 2D/3D scene graph with [@thi.ng/hiccup-canvas](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup-canvas) support ## Installation ```bash yarn add @thi.ng/rdom-canvas ``` ESM import: ```ts import * as rc from "@thi.ng/rdom-canvas"; ``` Browser ESM import: ```html ``` [JSDelivr documentation](https://www.jsdelivr.com/) Package sizes (brotli'd, pre-treeshake): ESM: 689 bytes ## Dependencies - [@thi.ng/api](https://github.com/thi-ng/umbrella/tree/develop/packages/api) - [@thi.ng/canvas](https://github.com/thi-ng/umbrella/tree/develop/packages/canvas) - [@thi.ng/checks](https://github.com/thi-ng/umbrella/tree/develop/packages/checks) - [@thi.ng/hiccup-canvas](https://github.com/thi-ng/umbrella/tree/develop/packages/hiccup-canvas) - [@thi.ng/object-utils](https://github.com/thi-ng/umbrella/tree/develop/packages/object-utils) - [@thi.ng/rdom](https://github.com/thi-ng/umbrella/tree/develop/packages/rdom) - [@thi.ng/rstream](https://github.com/thi-ng/umbrella/tree/develop/packages/rstream) Note: @thi.ng/api is in _most_ cases a type-only import (not used at runtime) ## Usage examples 10 projects in this repo's [/examples](https://github.com/thi-ng/umbrella/tree/develop/examples) directory are using this package: | Screenshot | Description | Live demo | Source | |:--------------------------------------------------------------------------------------------------------------------------|:-------------------------------------------------------------------------------|:---------------------------------------------------------|:--------------------------------------------------------------------------------------| | | Basic 2D boid simulation and spatial indexing neighbor lookups | [Demo](https://demo.thi.ng/umbrella/boid-basics/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/boid-basics) | | | Interactive visualization of closest points on ellipses | [Demo](https://demo.thi.ng/umbrella/ellipse-proximity/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/ellipse-proximity) | | | 2.5D hidden line visualization of digital elevation files (DEM) | [Demo](https://demo.thi.ng/umbrella/geom-terrain-viz/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/geom-terrain-viz) | | | Live coding playground for 2D geometry generation using @thi.ng/pointfree-lang | [Demo](https://demo.thi.ng/umbrella/pointfree-geom/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/pointfree-geom) | | | Quasi-random lattice generator | [Demo](https://demo.thi.ng/umbrella/quasi-lattice/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/quasi-lattice) | | | Minimal rdom-canvas animation | [Demo](https://demo.thi.ng/umbrella/rdom-canvas-basics/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/rdom-canvas-basics) | | | rdom & hiccup-canvas interop test | [Demo](https://demo.thi.ng/umbrella/rdom-lissajous/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/rdom-lissajous) | | | Fitting, transforming & plotting 10k data points per frame using SIMD | [Demo](https://demo.thi.ng/umbrella/simd-plot/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/simd-plot) | | | Multi-layer vectorization & dithering of bitmap images | [Demo](https://demo.thi.ng/umbrella/trace-bitmap/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/trace-bitmap) | | | Animated t-SNE visualization of 4D data | [Demo](https://demo.thi.ng/umbrella/tsne-colors/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/tsne-colors) | ## API [Generated API docs](https://docs.thi.ng/umbrella/rdom-canvas/) TODO ## Authors - [Karsten Schmidt](https://thi.ng) If this project contributes to an academic publication, please cite it as: ```bibtex @misc{thing-rdom-canvas, title = "@thi.ng/rdom-canvas", author = "Karsten Schmidt", note = "https://thi.ng/rdom-canvas", year = 2020 } ``` ## License © 2020 - 2025 Karsten Schmidt // Apache License 2.0