skills/pixijs-html-source/SKILL.md
HTMLSource and ElementImageSource turn a DOM element into a TextureSource you can use anywhere a normal texture works: on a Sprite, as a Texture frame, or mapped onto a Mesh. HTMLSource mirrors a live element's pixels into the GPU (the element stays editable and clickable in the browser); ElementImageSource wraps an immutable snapshot that never repaints. Both require a side-effect import 'pixi.js/html-source' to register their extensions.
These sources rely on the experimental HTML-in-Canvas browser proposal and are marked EXPERIMENTAL in PixiJS v8. The browser API must be enabled or the texture uploader throws on first render; feature-detect with
canvas.requestPaintbefore relying on it. The API may change between minor releases.
Assumes familiarity with pixijs-scene-sprite and textures. These are texture sources, not display objects: wrap them in a Sprite (or Texture/Mesh) to put them on screen. Not available in Web Workers; a worker has no DOM to capture.
import "pixi.js/html-source";
import { Application, Sprite } from "pixi.js";
import { HTMLSource } from "pixi.js/html-source";
const app = new Application();
await app.init({ resizeTo: window });
document.body.appendChild(app.canvas);
// The element must be a direct child of the Pixi canvas.
const form = document.createElement("form");
form.innerHTML = '<input value="still editable" />';
app.canvas.appendChild(form);
// Render the live form as a sprite. It stays interactive in the browser.
const source = new HTMLSource({ resource: form });
const sprite = Sprite.from(source);
sprite.anchor.set(0.5);
sprite.position.set(app.screen.width / 2, app.screen.height / 2);
app.stage.addChild(sprite);
Related skills: pixijs-scene-sprite (display the texture), pixijs-scene-mesh (map onto geometry, PerspectiveMesh), pixijs-scene-dom-container (the opposite: overlay HTML above the canvas, outside the GPU pipeline), pixijs-assets (texture sources vs the loader/cache), pixijs-environments (no DOM in Web Workers).
Both sources extend TextureSource, so all TextureSourceOptions (resolution, scaleMode, addressMode, label, etc.) are valid. resource is required on each.
HTMLSourceOptions (live element):
| Option | Type | Default | Description |
|---|---|---|---|
resource | Element | — | Required. The live DOM element to render. Must be a direct child of the owning canvas, or the constructor throws. |
canvas | HTMLSourceCanvas | — | The canvas that owns the element's layout subtree. Inferred from resource.parentElement when the element is a direct canvas child; pass it when inference is not possible. |
autoLayout | boolean | true | Set the layoutsubtree attribute on the owning canvas. The browser only lays out and paints canvas children when it is present. Set false if you write <canvas layoutsubtree> yourself. |
autoUpdate | boolean | true | Listen for the canvas paint event and re-upload when the element repaints. Set false for a static, captured-once texture. |
autoRequestPaint | boolean | true | Request one initial paint after construction. Set false and call source.requestPaint() yourself each frame for continuous animation. |
ElementImageSourceOptions (immutable snapshot):
| Option | Type | Default | Description |
|---|---|---|---|
resource | ElementImage | — | Required. A snapshot from canvas.captureElementImage(element). |
autoClose | boolean | false | Call snapshot.close() when the source is destroyed. Leave false when the snapshot is shared with other sources, or you risk a use-after-free. |
import "pixi.js/html-source";
import { HTMLSource, ElementImageSource } from "pixi.js/html-source";
pixi.js/html-source calls extensions.add(...) to register HTMLSource, ElementImageSource, and their WebGL/WebGPU uploaders. Without it, the renderer has no 'html' uploader and these sources never render. The classes are exported from pixi.js/html-source, not pixi.js.
Importing a named export from pixi.js/html-source also triggers the side effect, so a bare import 'pixi.js/html-source' is only needed when you don't import anything else from that path.
The HTML-in-Canvas API is gated behind a browser flag. Feature-detect before relying on it:
import type { HTMLSourceCanvas } from "pixi.js/html-source";
const canvas = app.canvas as HTMLSourceCanvas;
if (canvas.requestPaint) {
// HTML-in-Canvas is available.
}
Cast app.canvas to HTMLSourceCanvas for the typed requestPaint and captureElementImage members. source.requestPaint() returns false when the browser lacks the API; the texture uploader throws on first render when it is disabled.
const form = document.createElement("form");
app.canvas.appendChild(form); // direct child of the canvas
const source = new HTMLSource({ resource: form });
const sprite = Sprite.from(source);
The element must be a direct child of the renderer's <canvas>; the source infers the owning canvas from resource.parentElement (or pass canvas). With the defaults, it sets layoutsubtree on the canvas, listens for the canvas paint event, and requests one initial paint. source.isReady is false until that first paint lands, then true. resourceWidth/resourceHeight report the element's real-pixel size (offsetWidth/offsetHeight).
const source = new HTMLSource({ resource: clock, autoRequestPaint: false });
const sprite = Sprite.from(source);
app.ticker.add(() => {
clock.textContent = new Date().toLocaleTimeString();
source.requestPaint(); // re-snapshot the DOM this frame
});
The browser only repaints canvas children on demand. For an element whose content changes every frame, set autoRequestPaint: false and call source.requestPaint() in your own ticker to drive repaints on your schedule.
import { ElementImageSource } from "pixi.js/html-source";
import type { HTMLSourceCanvas } from "pixi.js/html-source";
const canvas = app.canvas as HTMLSourceCanvas;
const snapshot = canvas.captureElementImage!(element);
const source = new ElementImageSource({ resource: snapshot, autoClose: true });
const sprite = Sprite.from(source);
captureElementImage() freezes an element's current pixels into an immutable ElementImage. There is no owning canvas, no paint listener, and no repaint lifecycle, so the source is ready the moment it is constructed. Reach for it when you need a frozen copy that outlives its element or is transferred around (transitions, "shatter" or trail effects). Release the snapshot with snapshot.close() when done, or pass autoClose: true to let the source close it on destroy().
Both sources are normal TextureSources. Wrap them with Sprite.from(source) / Texture.from(source), frame or slice them into sub-textures, or map them onto a mesh:
import { Rectangle, Texture } from "pixi.js";
// A 64x64 slice of the rendered element.
const chunk = new Texture({
source,
frame: new Rectangle(0, 0, 64, 64),
});
// Mapped onto geometry (e.g. a perspective warp).
const mesh = new PerspectiveMesh({ texture: Texture.from(source) /* ... */ });
// Resolves to an HTMLSource (element) or ElementImageSource (snapshot) only as a last resort.
const sprite = Sprite.from(elementAlreadyInTheCanvas);
A generic HTML element or an ElementImage passed to Texture.from/Sprite.from resolves to these sources at the lowest texture-source priority (-10), so they only claim a resource no other built-in source handles. Image, video, and canvas elements are deliberately rejected; they have dedicated, faster sources. Construct the source explicitly when you need options (autoUpdate, autoClose) or non-HTML elements such as SVG.
Wrong:
import { HTMLSource } from "pixi.js/html-source";
// ...but never importing the side effect, in a build that tree-shakes it away
Correct:
import "pixi.js/html-source";
import { HTMLSource } from "pixi.js/html-source";
The 'html' uploaders are registered by the side-effect import. Without it, the source has no uploader and the texture never renders.
The HTML-in-Canvas proposal is not shipped by default. If the API is disabled, the uploader throws on first render. Feature-detect first:
const canvas = app.canvas as HTMLSourceCanvas;
if (!canvas.requestPaint) {
// Fall back to a static image, DOMContainer overlay, or a message.
}
document.body.appendChild(form); // wrong parent
const source = new HTMLSource({ resource: form }); // throws
HTMLSource requires the element to be a direct child of the owning canvas (app.canvas.appendChild(form)) and throws otherwise. Append the element to the canvas before constructing the source, or pass the canvas option.
A non-animating element updates automatically on browser paint events (autoUpdate: true). Content that changes every frame will not re-upload unless something triggers a paint; drive it with source.requestPaint() each frame (with autoRequestPaint: false).
const source = new ElementImageSource({ resource: snapshot, autoClose: true });
const other = new ElementImageSource({ resource: snapshot }); // shares the snapshot
source.destroy(); // closes the snapshot — `other` is now a use-after-free
Only set autoClose: true when the source owns the snapshot exclusively. For a shared snapshot, leave autoClose off and call snapshot.close() once, after the last source is destroyed.
source.destroy();
HTMLSource.destroy() detaches the canvas paint listener and nulls its canvas reference. ElementImageSource.destroy() closes the snapshot when autoClose was set; otherwise call snapshot.close() yourself to release the memory.