Local font loading into SVG in Phantom.js

Ensures use of Verdana server-side when rendering images.

phantomjs-svg2png.js

@@ -1,27 +1,53 @@
 var page = require('webpage').create();
 var system = require('system');
 var svg = system.args[1];
-var svgUrl = 'data:image/svg+xml,' + window.encodeURI(svg);
 var tmpFile = system.args[2];
 
-page.viewportSize = getSvgDimensions(svg);
-page.open(svgUrl, function(status) {
-  if (status !== 'success') {
-    console.error('Failed to load the following SVG data:');
-    console.error(svgUrl);
-    phantom.exit(1);
-  } else {
-    page.render(tmpFile);
-    phantom.exit();
-  }
-});
+// Optional local font loading.
+var fs = require('fs');
+var fontPath = './Verdana.ttf';
+if (fs.isFile(fontPath)) {
+  var fontData = fs.read(fontPath, 'b');
+  btoa(fontData, function(fontBase64) {
+    svg = svg.slice(0, svg.indexOf('</svg>')) + '<style><![CDATA['
+      + '@font-face{font-family:"Verdana";src:url(data:font/ttf;base64,'
+      + fontBase64 + ');}]]></style></svg>';
+    renderSvg(svg);
+  });
+} else { renderSvg(svg); }
+
+function renderSvg(svg) {
+  var svgUrl = 'data:image/svg+xml,' + window.encodeURI(svg);
+  page.viewportSize = getSvgDimensions(svg);
+  page.open(svgUrl, function(status) {
+    if (status !== 'success') {
+      console.error('Failed to load the following SVG data:');
+      console.error(svgUrl);
+      phantom.exit(1);
+    } else {
+      page.render(tmpFile);
+      phantom.exit();
+    }
+  });
+}
 
 function getSvgDimensions(svg) {
   var frag = window.document.createElement('div');
   frag.innerHTML = svg;
   var svgRoot = frag.querySelector('svg');
   return {
     width: parseFloat(svgRoot.getAttribute('width') || 80),
-    height: parseFloat(svgRoot.getAttribute('height') || 19)
+    height: parseFloat(svgRoot.getAttribute('height') || 18)
   };
 }
+
+function btoa(data, cb) {
+  page.open('about:blank', function(status) {
+    if (status !== 'success') {
+      console.error('Failed to load blank page.');
+      phantom.exit(1);
+    } else {
+      cb(page.evaluate(function(data) { return window.btoa(data); }, data));
+    }
+  });
+}

svg-to-img.js

@@ -5,6 +5,13 @@ var phantom = require('phantomjs');
 var childProcess = require('child_process');
 var phantomScript = path.join(__dirname, 'phantomjs-svg2png.js');
 
+// If available, use the font here.
+var fontPath = './Verbana.ttf';
+try {
+  // This happens at startup. Needn't be async.
+  var fontBase64 = fs.readFileSync(fontPath, 'base64');
+} catch(e) {}
+
 module.exports = function (svg, format, out, cb) {
   var tmpFile = path.join(os.tmpdir(),
       "svg2img-" + (Math.random()*2147483648|0) + "." + format);