use createObjectURL during svgToImg

- which speeds up things for loooong SVG strings
- must (still) use encodeSVG in Safari and IE9

Author: etpinard

src/lib/index.js

@@ -733,6 +733,14 @@ lib.isIE = function() {
     return typeof window.navigator.msSaveBlob !== 'undefined';
 };
 
+lib.isIE9orBelow = function() {
+    return (
+        lib.isIE() &&
+        typeof window.navigator !== 'undefined' &&
+        /MSIE [1-9]\./.test(window.navigator.userAgent)
+    );
+};
+
 var IS_SAFARI_REGEX = /Version\/[\d\.]+.*Safari/;
 lib.isSafari = function() {
     return IS_SAFARI_REGEX.test(window.navigator.userAgent);

src/snapshot/filesaver.js

@@ -31,7 +31,7 @@ function fileSaver(url, name, format) {
         var blob;
         var objectUrl;
 
-        if(isIE9orBelow()) {
+        if(Lib.isIE9orBelow()) {
             reject(new Error('IE < 10 unsupported'));
         }
 
@@ -73,12 +73,5 @@ function fileSaver(url, name, format) {
     return promise;
 }
 
-function isIE9orBelow() {
-    return (
-        Lib.isIE() &&
-        typeof window.navigator !== 'undefined' &&
-        /MSIE [1-9]\./.test(window.navigator.userAgent)
-    );
-}
 
 module.exports = fileSaver;

src/snapshot/svgtoimg.js

@@ -43,18 +43,24 @@ function svgToImg(opts) {
 
         var ctx = canvas.getContext('2d');
         var img = new Image();
+        var svgBlob, url;
 
-        // for Safari support, eliminate createObjectURL
-        //  this decision could cause problems if content
-        //  is not restricted to svg
-        var url = helpers.encodeSVG(svg);
+        if(format === 'svg' || Lib.isIE9orBelow() || Lib.isSafari()) {
+            url = helpers.encodeSVG(svg);
+        } else {
+            svgBlob = helpers.createBlob(svg, 'svg');
+            url = helpers.createObjectURL(svgBlob);
+        }
 
         canvas.width = w1;
         canvas.height = h1;
 
         img.onload = function() {
             var imgData;
 
+            svgBlob = null;
+            helpers.revokeObjectURL(url);
+
             // don't need to draw to canvas if svg
             //  save some time and also avoid failure on IE
             if(format !== 'svg') {
@@ -92,6 +98,9 @@ function svgToImg(opts) {
         };
 
         img.onerror = function(err) {
+            svgBlob = null;
+            helpers.revokeObjectURL(url);
+
             reject(err);
             // eventually remove the ev
             //  in favor of promises