kingraph/lib/to_png_image.js

Plots family trees using JavaScript and Graphviz

/*
 * toPNG for the browser
 */

function toPng (svgXml) {
    var scaleFactor = 1;

    if (typeof window !== 'undefined' && 'devicePixelRatio' in window) {
        if (window.devicePixelRatio > 1) {
            scaleFactor = window.devicePixelRatio;
        }
    }

    var svgImage = new Image();
    svgImage.src = 'data:image/svg+xml;utf8,' + svgXml;

    var pngImage = new Image();

    svgImage.onload = function() {
        var canvas = document.createElement('canvas');
        canvas.width = svgImage.width * scaleFactor;
        canvas.height = svgImage.height * scaleFactor;

        var context = canvas.getContext('2d');
        context.drawImage(svgImage, 0, 0, canvas.width, canvas.height);

        pngImage.src = canvas.toDataURL;
        pngImage.width = svgImage.width;
        pngImage.height = svgImage.height;
    };

    return pngImage;
}

module.exports = toPng;