using one space character instead of a blank string to avoid jumps during treemap transition

Author: archmoj

Diff for: src/traces/treemap/draw_ancestors.js

@@ -141,7 +141,7 @@ module.exports = function drawAncestors(gd, cd, entry, slices, opts) {
             s.attr('data-notex', 1);
         });
 
-        sliceText.text(pt._text)
+        sliceText.text(pt._text || ' ') // use one space character instead of a blank string to avoid jumps during transition
             .classed('slicetext', true)
             .attr('text-anchor', 'start')
             .call(Drawing.font, helpers.determineTextFont(trace, pt, fullLayout.font, trace.pathdir))

Diff for: src/traces/treemap/draw_descendants.js

@@ -157,8 +157,8 @@ module.exports = function drawDescendants(gd, cd, entry, slices, opts) {
             hovered: false
         });
 
-        if(pt.x0 === pt.x1 && pt.y0 === pt.y1) {
-            pt._text = ' '; // use one space character instead of a blank string in this case
+        if(pt.x0 === pt.x1 || pt.y0 === pt.y1) {
+            pt._text = '';
         } else {
             if(isHeader) {
                 pt._text = noRoomForHeader ? '' : helpers.getPtLabel(pt) || '';
@@ -174,7 +174,7 @@ module.exports = function drawDescendants(gd, cd, entry, slices, opts) {
             s.attr('data-notex', 1);
         });
 
-        sliceText.text(pt._text)
+        sliceText.text(pt._text || ' ') // use one space character instead of a blank string to avoid jumps during transition
             .classed('slicetext', true)
             .attr('text-anchor', hasRight ? 'end' : (hasLeft || isHeader) ? 'start' : 'middle')
             .call(Drawing.font, helpers.determineTextFont(trace, pt, fullLayout.font))

Diff for: test/jasmine/tests/treemap_test.js

@@ -1066,7 +1066,7 @@ describe('Test treemap restyle:', function() {
         .then(_restyle({textinfo: 'value'}))
         .then(_assert('show input values', ['Root', 'B', '1', '3']))
         .then(_restyle({textinfo: 'none'}))
-        .then(_assert('no textinfo', ['Root', 'B', '', '']))
+        .then(_assert('no textinfo', ['Root', 'B', ' ', ' '])) // use one space character instead of a blank string to avoid jumps during transition
         .then(_restyle({textinfo: 'label+text+value'}))
         .then(_assert('show everything', ['Root', 'B', 'A\n1\nnode1', 'b\n3\nnode3']))
         .then(_restyle({textinfo: null}))