vislite/lib/getWebGLContext/index.es.js

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/*!
* getWebGLContext of VISLite JavaScript Library v1.3.0
* git+https://github.com/oi-contrib/VISLite.git
*/
function getWebGLContext (canvas, scale, opts, mode) {
    if (opts === void 0) { opts = {}; }
    if (mode === void 0) { mode = "scaleToFill"; }
    var names = ["experimental-webgl", "webkit-3d", "moz-webgl"];
    var painter = canvas.getContext("webgl", opts);
    for (var i = 0; i < names.length; i++) {
        try {
            painter = canvas.getContext(names[i], opts);
        }
        catch (e) { }
        if (painter)
            break;
    }
    if (!painter)
        throw new Error('Non canvas or browser does not support webgl.');
    var width = painter.canvas.width, height = painter.canvas.height;
    var scaleX = scale, scaleY = scale;
    if (mode == "aspectFit") {
        if (width > height) {
            scaleX *= height / width;
        }
        else if (height > width) {
            scaleY *= width / height;
        }
    }
    else if (mode == "aspectFill") {
        if (width > height) {
            scaleY *= width / height;
        }
        else if (height > width) {
            scaleX *= height / width;
        }
    }
    var viewWidth = width * scaleX;
    var viewHeight = height * scaleY;
    painter.viewport((width - viewWidth) * 0.5, (height - viewHeight) * 0.5, viewWidth, viewHeight);
    painter.depthFunc(painter.LEQUAL);
    painter.enable(painter.DEPTH_TEST);
    return painter;
}

var index = (function (el, scale, mode) {
    if (scale === void 0) { scale = 1; }
    if (!el) {
        throw new Error("VISLite getWebGLContext:The mount point requires an HTMLElement type but encountered null.");
    }
    var width = el.clientWidth, height = el.clientHeight;
    var ViewCanvas;
    var _el = el;
    if (_el._vislite_canvas_) {
        ViewCanvas = _el._vislite_canvas_;
    }
    else {
        ViewCanvas = document.createElement('canvas');
        el.appendChild(ViewCanvas);
        _el._vislite_canvas_ = ViewCanvas;
        el.setAttribute('vislite', 'WebGL');
    }
    ViewCanvas.style.width = width + "px";
    ViewCanvas.setAttribute('width', width + "");
    ViewCanvas.style.height = height + "px";
    ViewCanvas.setAttribute('height', height + "");
    return getWebGLContext(ViewCanvas, scale, {}, mode);
});

export { index as default };