do not include font styling options in svg when set to normal

Author: archmoj

src/snapshot/tosvg.js

@@ -104,6 +104,20 @@ module.exports = function toSVG(gd, format, scale) {
             if(ff && ff.indexOf('"') !== -1) {
                 txt.style('font-family', ff.replace(DOUBLEQUOTE_REGEX, DUMMY_SUB));
             }
+
+            // Drop normal font-weight, font-style and font-variant to reduce the size
+            var fw = this.style.fontWeight;
+            if(fw && fw === 'normal') {
+                txt.style('font-weight', undefined);
+            }
+            var fs = this.style.fontStyle;
+            if(fs && fs === 'normal') {
+                txt.style('font-style', undefined);
+            }
+            var fv = this.style.fontVariant;
+            if(fv && fv === 'normal') {
+                txt.style('font-variant', undefined);
+            }
         });
 
     svg.selectAll('.gradient_filled,.pattern_filled').each(function() {

test/jasmine/tests/toimage_test.js

@@ -179,7 +179,7 @@ describe('Plotly.toImage', function() {
         .then(function() { return Plotly.toImage(gd, {format: 'svg', imageDataOnly: true}); })
         .then(function(d) {
             expect(d.indexOf('data:image/')).toBe(-1);
-            expect(d.length).toBeWithin(35149, 1e3, 'svg image length');
+            expect(d.length).toBeWithin(32062, 1e3, 'svg image length');
         })
         .then(function() { return Plotly.toImage(gd, {format: 'webp', imageDataOnly: true}); })
         .then(function(d) {