Support SVG strings with leading line-breaks

Closes #1813

src/svg/SvgImport.js

@@ -662,8 +662,12 @@ new function() {
 
         function onLoad(svg) {
             try {
-                var node = typeof svg === 'object' ? svg : new self.DOMParser()
-                        .parseFromString(svg, 'image/svg+xml');
+                var node = typeof svg === 'object'
+                    ? svg
+                    : new self.DOMParser().parseFromString(
+                        svg,
+                        'image/svg+xml'
+                    );
                 if (!node.nodeName) {
                     node = null;
                     throw new Error('Unsupported SVG source: ' + source);
@@ -693,8 +697,10 @@ new function() {
 
         // Have the group not pass on all transformations to its children,
         // as this is how SVG works too.
-        // See if it's a string but handle markup separately
-        if (typeof source === 'string' && !/^.*</.test(source)) {
+        // See if it's a string but handle markup separately, using `[\s\S]` to
+        // also match the first tag if it only starts on the second line in a
+        // multi-line string.
+        if (typeof source === 'string' && !/^[\s\S]*</.test(source)) {
             // First see if we're meant to import an element with the given
             // id.
             var node = document.getElementById(source);

test/tests/SvgImport.js

@@ -158,6 +158,16 @@ test('Import SVG switch', function(assert) {
     });
 });
 
+test('Import SVG string with leading line-breaks', function() {
+    var svg = '\n<svg xmlns="http://www.w3.org/2000/svg">\n  <rect fill="red" width="100" height="100"/>\n</svg>\n'
+    var imported = paper.project.importSVG(svg);
+    equals(imported.children.length, 1);
+    equals(imported.firstChild, new Shape.Rectangle({
+        size: [100, 100],
+        fillColor: 'red'
+    }));
+});
+
 function importSVG(assert, url, message, options) {
     var done = assert.async();
     project.importSVG(url, {