Make maxheight apply to horizontal and vertical legends

Author: camdecoster

src/components/legend/attributes.js

@@ -33,15 +33,16 @@ module.exports = {
         editType: 'legend',
         description: 'Sets the color of the border enclosing the legend.'
     },
-    hmaxheight: {
+    maxheight: {
         valType: 'number',
         min: 0,
-        dflt: 0.5,
         editType: 'legend',
         description: [
-            'If greater than one, it sets the max height (in px) of the horizontaly aligned legend.',
-            'Otherwise, it sets the max height ratio (layout * ratio) of the visible legend when horizontaly aligned.',
-            'Default value is 0.5; the legend will take up to 50% of the layout height before displaying a scrollbar.'
+            'Sets the max height (in px) of the legend, or max height ratio (reference height * ratio) if less than one.',
+            'Default value is: 0.5 for horizontal legends; 1 for vertical legends. The minimum allowed height is 30px.',
+            'For a ratio of 0.5, the legend will take up to 50% of the reference height before displaying a scrollbar.',
+            'The reference height is the full layout height except for vertically oriented legends with',
+            'a `yref` of `"paper"`, where the reference height is the plot height.'
         ].join(' ')
     },
     borderwidth: {

src/components/legend/defaults.js

@@ -188,7 +188,7 @@ function groupDefaults(legendId, layoutIn, layoutOut, fullData) {
 
     coerce('xanchor', defaultXAnchor);
     coerce('yanchor', defaultYAnchor);
-    coerce('hmaxheight');
+    coerce('maxheight', isHorizontal ? 0.5 : 1);
     coerce('valign');
     Lib.noneOrAll(containerIn, containerOut, ['x', 'y']);
 

src/components/legend/draw.js

@@ -769,15 +769,9 @@ function computeLegendDimensions(gd, groups, traces, legendObj) {
     var traceGroupGap = legendObj.tracegroupgap;
     var legendGroupWidths = {};
 
-    // - if below/above plot area, give it the user defined maximum potential margin-push value
-    // - otherwise, extend the height of the plot area
-    if (isBelowPlotArea || isAbovePlotArea) {
-        legendObj._maxHeight = legendObj.hmaxheight > 1
-            ? legendObj.hmaxheight
-            : fullLayout.height * legendObj.hmaxheight;
-    } else { 
-        legendObj._maxHeight = Math.max(gs.h, 30);
-    }
+    var { maxheight, orientation, yref } = legendObj;
+    var heightToBeScaled = orientation === "v" && yref === "paper" ? gs.h : fullLayout.height;
+    legendObj._maxHeight = Math.max(maxheight > 1 ? maxheight : maxheight * heightToBeScaled, 30);
 
     var toggleRectWidth = 0;
     legendObj._width = 0;