tav-media/lib/libpag/src/core/render-canvas.js

Cross platform media editing framework

import { WEBGL_CONTEXT_ATTRIBUTES } from '../constant';
import { BackendContext } from './backend-context';
const renderCanvasList = [];
export class RenderCanvas {
    constructor(canvas, contextAttributes) {
        this._canvas = null;
        this._glContext = null;
        this.retainCount = 0;
        this._canvas = canvas;
        const gl = canvas.getContext('webgl', Object.assign(Object.assign({}, WEBGL_CONTEXT_ATTRIBUTES), contextAttributes));
        if (!gl)
            throw new Error('Canvas context is not WebGL!');
        this._glContext = BackendContext.from(gl);
    }
    static from(canvas, contextAttributes) {
        let renderCanvas = renderCanvasList.find((targetCanvas) => targetCanvas.canvas === canvas);
        if (renderCanvas)
            return renderCanvas;
        renderCanvas = new RenderCanvas(canvas, contextAttributes);
        renderCanvasList.push(renderCanvas);
        return renderCanvas;
    }
    retain() {
        this.retainCount += 1;
    }
    release() {
        this.retainCount -= 1;
        if (this.retainCount === 0) {
            if (!this._glContext)
                return;
            this._glContext.destroy();
            this._glContext = null;
            this._canvas = null;
        }
    }
    get canvas() {
        return this._canvas;
    }
    get glContext() {
        return this._glContext;
    }
}