Switch to single attribute for controlling legend height

Author: camdecoster

src/components/legend/attributes.js

@@ -33,23 +33,17 @@ module.exports = {
         editType: 'legend',
         description: 'Sets the color of the border enclosing the legend.'
     },
-    hmaxheightratio: {
-        valType: 'number',
-        min: 2,
-        dflt: 2,
-        role: 'style',
-        editType: 'legend',
-        description: [
-	    'Sets the max height ratio (layout / ratio) of the visible legend when horizontaly aligned.',
-	    'Default value is 2; the legend will take up to 50% of the layout height before displaying a scrollbar',
-	].join(' ')
-    },
     hmaxheight: {
         valType: 'number',
         min: 0,
+        dflt: 0.5,
         role: 'style',
         editType: 'legend',
-        description: 'Sets the max height (in px) of the horizontaly aligned 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'
+        ].join(' ')
     },
     borderwidth: {
         valType: 'number',

src/components/legend/defaults.js

@@ -188,7 +188,6 @@ function groupDefaults(legendId, layoutIn, layoutOut, fullData) {
 
     coerce('xanchor', defaultXAnchor);
     coerce('yanchor', defaultYAnchor);
-    coerce('hmaxheightratio');
     coerce('hmaxheight');
     coerce('valign');
     Lib.noneOrAll(containerIn, containerOut, ['x', 'y']);

src/components/legend/draw.js

@@ -769,19 +769,25 @@ 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
+    // - 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) {
-        if (legendObj.hmaxheight !== undefined) {
-            legendObj._maxHeight = legendObj.hmaxheight;
-        } else { 
-            legendObj._maxHeight = fullLayout.height / legendObj.hmaxheightratio; 
-        }
-    }
-    else { 
+        legendObj._maxHeight = legendObj.hmaxheight > 1
+            ? legendObj.hmaxheight
+            : fullLayout.height * legendObj.hmaxheight;
+    } else { 
         legendObj._maxHeight = Math.max(gs.h, 30);
     }
 
+    console.log({
+        isBelowPlotArea,
+        isAbovePlotArea,
+        hmaxheight: legendObj.hmaxheight,
+        fullLayout_height: fullLayout.height,
+        gs_h: gs.h,
+        legendObj_maxHeight: legendObj._maxHeight
+    })
+
     var toggleRectWidth = 0;
     legendObj._width = 0;
     legendObj._height = 0;