Merge pull request #6625 from lvlte/fix-contour-colorscale-6623

Fix contour plot colorscale domain

Author: archmoj

draftlogs/6625_fix.md

@@ -0,0 +1 @@
+ - Fix contour plot colorscale domain (take account of [zmin, zmax] and [cmin, cmax]) [[#6625](https://github.com/plotly/plotly.js/pull/6625)], with thanks to @lvlte for the contribution!

src/components/colorbar/draw.js

@@ -512,7 +512,7 @@ function drawColorBar(g, opts, gd) {
             .data(fillLevels);
         fills.enter().append('rect')
             .classed(cn.cbfill, true)
-            .style('stroke', 'none');
+            .attr('style', '');
         fills.exit().remove();
 
         var zBounds = zrange

src/traces/contour/make_color_map.js

@@ -29,10 +29,10 @@ module.exports = function makeColorMap(trace) {
 
     var si, i;
 
-    if(contours.coloring === 'heatmap') {
-        var zmin0 = cOpts.min;
-        var zmax0 = cOpts.max;
+    var zmin0 = cOpts.min;
+    var zmax0 = cOpts.max;
 
+    if(contours.coloring === 'heatmap') {
         for(i = 0; i < len; i++) {
             si = scl[i];
             domain[i] = si[0] * (zmax0 - zmin0) + zmin0;
@@ -60,11 +60,37 @@ module.exports = function makeColorMap(trace) {
             range.push(range[range.length - 1]);
         }
     } else {
+        var zRangeInput = trace._input && (
+            typeof trace._input.zmin === 'number' && typeof trace._input.zmax === 'number'
+        );
+
+        // If zmin/zmax are explicitly set, consider case where user specifies a
+        // narrower z range than that of the contours start/end.
+        if(zRangeInput && (start <= zmin0 || end >= zmax0)) {
+            if(start <= zmin0) start = zmin0;
+            if(end >= zmax0) end = zmax0;
+            nc = Math.floor((end - start) / cs) + 1;
+            extra = 0;
+        }
+
         for(i = 0; i < len; i++) {
             si = scl[i];
             domain[i] = (si[0] * (nc + extra - 1) - (extra / 2)) * cs + start;
             range[i] = si[1];
         }
+
+        // Make the colorscale fit the z range except if contours are explicitly
+        // set BUT NOT zmin/zmax.
+        if(zRangeInput || trace.autocontour) {
+            if(domain[0] > zmin0) {
+                domain.unshift(zmin0);
+                range.unshift(range[0]);
+            }
+            if(domain[domain.length - 1] < zmax0) {
+                domain.push(zmax0);
+                range.push(range[range.length - 1]);
+            }
+        }
     }
 
     return Colorscale.makeColorScaleFunc(