Merge pull request #1043 from mathjax/issue3166

Fix issues with line breaks and spacing in SVG output. (mathjax/MathJax#3166)

Author: dpvc

ts/output/common/LineBBox.ts

@@ -99,7 +99,7 @@ export class LineBBox extends BBox {
    */
   public append(cbox: LineBBox) {
     if (this.isFirst) {
-      cbox.originalL = cbox.L;
+      cbox.originalL += cbox.L;
       cbox.L = 0;  // remove spacing after an operator with a linebreak after it
     }
     if (cbox.indentData) {

ts/output/common/Wrappers/mspace.ts

@@ -201,7 +201,8 @@ export function CommonMspaceMixin<
       const bbox = LineBBox.from(BBox.zero(), leading);
       if (i === 1) {
         bbox.getIndentData(this.node);
-        bbox.isFirst = true;
+        bbox.w = this.getBBox().w;
+        bbox.isFirst = (bbox.w === 0);
       }
       return bbox;
     }

ts/output/svg.ts

@@ -397,12 +397,12 @@ CommonOutputJax<
       if (forced && mo.node.attributes.get('linebreakstyle') === 'after') {
         const k = mml.parent.node.childIndex(mml.node) + 1;
         const next = mml.parent.childNodes[k];
-        const dimen = (next ? next.getLineBBox(0).originalL : 0) * scale;
+        const dimen = (next ? next.getLineBBox(0).originalL * scale : 0);
         if (dimen) {
           this.addInlineBreak(nsvg, dimen, forced);
         }
       } else if (forced || i) {
-        const dimen = (mml && i ? mml.getLineBBox(0).originalL : 0) * scale;
+        const dimen = (mml && i ? mml.getLineBBox(0).originalL * scale : 0);
         if (dimen || !forced) {
           this.addInlineBreak(nsvg, dimen, forced || !!mml.node.getProperty('forcebreak'));
         }