feat(legend): custom legend width

integration/tests/legend_stories.test.ts

@@ -234,4 +234,27 @@ describe('Legend stories', () => {
       );
     });
   });
+
+  describe('Custom width', () => {
+    // eslint-disable-next-line unicorn/consistent-function-scoping
+    const getUrl = (position: string, size: number) =>
+      `http://localhost:9001/?path=/story/legend--${position}&knob-enable legend size=true&knob-legend size=${size}`;
+
+    describe.each(['top', 'right', 'bottom', 'left'])('position %s', (position) => {
+      const isVertical = position === 'left' || position === 'right';
+      if (isVertical) {
+        it('should limit width to min of 30% of computed width', async () => {
+          await common.expectChartAtUrlToMatchScreenshot(getUrl(position, 1));
+        });
+      }
+
+      it('should limit size to max 70% of chart dimension', async () => {
+        await common.expectChartAtUrlToMatchScreenshot(getUrl(position, 100000));
+      });
+
+      it('should set exact size of legend within constraints', async () => {
+        await common.expectChartAtUrlToMatchScreenshot(getUrl(position, isVertical ? 400 : 300));
+      });
+    });
+  });
 });

packages/charts/api/charts.api.md

@@ -752,7 +752,7 @@ export const DEFAULT_TOOLTIP_SNAP = true;
 export const DEFAULT_TOOLTIP_TYPE: "vertical";
 
 // @public (undocumented)
-export type DefaultSettingsProps = 'id' | 'chartType' | 'specType' | 'rendering' | 'rotation' | 'resizeDebounce' | 'pointerUpdateDebounce' | 'pointerUpdateTrigger' | 'animateData' | 'debug' | 'tooltip' | 'theme' | 'brushAxis' | 'minBrushDelta' | 'externalPointerEvents' | 'showLegend' | 'showLegendExtra' | 'legendPosition' | 'legendMaxDepth' | 'ariaUseDefaultSummary' | 'ariaLabelHeadingLevel' | 'ariaTableCaption' | 'allowBrushingLastHistogramBin';
+export type DefaultSettingsProps = 'id' | 'chartType' | 'specType' | 'rendering' | 'rotation' | 'resizeDebounce' | 'pointerUpdateDebounce' | 'pointerUpdateTrigger' | 'animateData' | 'debug' | 'tooltip' | 'theme' | 'brushAxis' | 'minBrushDelta' | 'externalPointerEvents' | 'showLegend' | 'showLegendExtra' | 'legendPosition' | 'legendMaxDepth' | 'legendSize' | 'ariaUseDefaultSummary' | 'ariaLabelHeadingLevel' | 'ariaTableCaption' | 'allowBrushingLastHistogramBin';
 
 // @public (undocumented)
 export const DEPTH_KEY = "depth";
@@ -1373,6 +1373,7 @@ export interface LegendSpec {
     legendColorPicker?: LegendColorPicker;
     legendMaxDepth: number;
     legendPosition: Position | LegendPositionConfig;
+    legendSize: number;
     legendStrategy?: LegendStrategy;
     // (undocumented)
     onLegendItemClick?: LegendItemListener;

packages/charts/src/components/__snapshots__/chart.test.tsx.snap

@@ -56,7 +56,7 @@ exports[`Chart should render the legend name test 1`] = `
         <Connect(SpecsParserComponent)>
           <SpecsParserComponent specParsed={[Function (anonymous)]} specUnmounted={[Function (anonymous)]}>
             <Connect(SpecInstance) debug={true} rendering=\\"svg\\" showLegend={true}>
-              <SpecInstance debug={true} rendering=\\"svg\\" showLegend={true} upsertSpec={[Function (anonymous)]} removeSpec={[Function (anonymous)]} id=\\"__global__settings___\\" chartType=\\"global\\" specType=\\"settings\\" rotation={0} animateData={true} resizeDebounce={10} tooltip={{...}} pointerUpdateTrigger=\\"x\\" externalPointerEvents={{...}} baseTheme={{...}} brushAxis=\\"x\\" minBrushDelta={2} ariaUseDefaultSummary={true} ariaLabelHeadingLevel=\\"p\\" allowBrushingLastHistogramBin={true} showLegendExtra={false} legendMaxDepth={Infinity} legendPosition=\\"right\\" />
+              <SpecInstance debug={true} rendering=\\"svg\\" showLegend={true} upsertSpec={[Function (anonymous)]} removeSpec={[Function (anonymous)]} id=\\"__global__settings___\\" chartType=\\"global\\" specType=\\"settings\\" rotation={0} animateData={true} resizeDebounce={10} tooltip={{...}} pointerUpdateTrigger=\\"x\\" externalPointerEvents={{...}} baseTheme={{...}} brushAxis=\\"x\\" minBrushDelta={2} ariaUseDefaultSummary={true} ariaLabelHeadingLevel=\\"p\\" allowBrushingLastHistogramBin={true} legendSize={NaN} showLegendExtra={false} legendMaxDepth={Infinity} legendPosition=\\"right\\" />
             </Connect(SpecInstance)>
             <Connect(SpecInstance) id=\\"test\\" data={{...}}>
               <SpecInstance id=\\"test\\" data={{...}} upsertSpec={[Function (anonymous)]} removeSpec={[Function (anonymous)]} chartType=\\"xy_axis\\" specType=\\"series\\" seriesType=\\"bar\\" groupId=\\"__global__\\" xScaleType=\\"ordinal\\" yScaleType=\\"linear\\" xAccessor=\\"x\\" yAccessors={{...}} hideInLegend={false} enableHistogramMode={false} />

packages/charts/src/specs/constants.ts

@@ -144,6 +144,7 @@ export const DEFAULT_TOOLTIP_SNAP = true;
  */
 export const DEFAULT_LEGEND_CONFIG = {
   showLegend: false,
+  legendSize: NaN,
   showLegendExtra: false,
   legendMaxDepth: Infinity,
   legendPosition: Position.Right,

packages/charts/src/specs/settings.tsx

@@ -453,6 +453,13 @@ export interface LegendSpec {
    * Limit the legend to the specified maximal depth when showing a hierarchical legend
    */
   legendMaxDepth: number;
+  /**
+   * Sets the exact legend width (vertical) or height (horizontal)
+   *
+   * Limited to max of 70% of the chart container dimension
+   * Vertical legends limited to min of 30% of computed width
+   */
+  legendSize: number;
   /**
    * Display the legend as a flat list. If true, legendStrategy is always `LegendStrategy.Key`.
    */
@@ -692,6 +699,7 @@ export type DefaultSettingsProps =
   | 'showLegendExtra'
   | 'legendPosition'
   | 'legendMaxDepth'
+  | 'legendSize'
   | 'ariaUseDefaultSummary'
   | 'ariaLabelHeadingLevel'
   | 'ariaTableCaption'

packages/charts/src/state/selectors/get_legend_config_selector.ts

@@ -18,6 +18,7 @@ export const getLegendConfigSelector = createCustomCachedSelector(
     legendAction,
     legendColorPicker,
     legendMaxDepth,
+    legendSize,
     legendPosition,
     legendStrategy,
     onLegendItemClick,
@@ -33,6 +34,7 @@ export const getLegendConfigSelector = createCustomCachedSelector(
       legendAction,
       legendColorPicker,
       legendMaxDepth,
+      legendSize,
       legendPosition: getLegendPositionConfig(legendPosition),
       legendStrategy,
       onLegendItemClick,

packages/charts/src/state/selectors/get_legend_size.ts

@@ -66,19 +66,28 @@ export const getLegendSizeSelector = createCustomCachedSelector(
       const legendItemHeight = bbox.height + VERTICAL_PADDING * 2;
       const legendHeight = legendItemHeight * labels.length + TOP_MARGIN;
       const scrollBarDimension = legendHeight > parentDimensions.height ? SCROLL_BAR_WIDTH : 0;
+      const staticWidth = spacingBuffer + actionDimension + scrollBarDimension;
+
+      const width = Number.isFinite(legendConfig.legendSize)
+        ? Math.min(Math.max(legendConfig.legendSize, legendItemWidth * 0.3 + staticWidth), parentDimensions.width * 0.7)
+        : Math.floor(Math.min(legendItemWidth + staticWidth, verticalWidth));
 
       return {
-        width: Math.floor(
-          Math.min(legendItemWidth + spacingBuffer + actionDimension + scrollBarDimension, verticalWidth),
-        ),
+        width,
         height: legendHeight,
         margin,
         position: legendPosition,
       };
     }
     const isSingleLine = (parentDimensions.width - 20) / 200 > labels.length;
+    const height = Number.isFinite(legendConfig.legendSize)
+      ? Math.min(legendConfig.legendSize, parentDimensions.height * 0.7)
+      : isSingleLine
+      ? bbox.height + 16
+      : bbox.height * 2 + 24;
+
     return {
-      height: isSingleLine ? bbox.height + 16 : bbox.height * 2 + 24,
+      height,
       width: Math.floor(Math.min(legendItemWidth + spacingBuffer + actionDimension, verticalWidth)),
       margin,
       position: legendPosition,

storybook/stories/legend/1_legend_right.story.tsx

@@ -12,14 +12,21 @@ import { Axis, BarSeries, Chart, Position, ScaleType, Settings } from '@elastic/
 import * as TestDatasets from '@elastic/charts/src/utils/data_samples/test_dataset';
 
 import { useBaseTheme } from '../../use_base_theme';
+import { getLegendSizeKnob } from './legend_size_knob';
 
 export const Example = () => {
   const yAccessors = ['y1', 'y2'];
   const splitSeriesAccessors = ['g1', 'g2'];
 
   return (
     <Chart>
-      <Settings showLegend showLegendExtra legendPosition={Position.Right} baseTheme={useBaseTheme()} />
+      <Settings
+        showLegend
+        showLegendExtra
+        legendPosition={Position.Right}
+        legendSize={getLegendSizeKnob()}
+        baseTheme={useBaseTheme()}
+      />
       <Axis id="bottom" position={Position.Bottom} title="Bottom axis" showOverlappingTicks />
       <Axis id="left2" title="Left axis" position={Position.Left} tickFormat={(d) => Number(d).toFixed(2)} />
 

storybook/stories/legend/2_legend_bottom.story.tsx

@@ -12,10 +12,17 @@ import { Axis, BarSeries, Chart, Position, ScaleType, Settings } from '@elastic/
 import * as TestDatasets from '@elastic/charts/src/utils/data_samples/test_dataset';
 
 import { useBaseTheme } from '../../use_base_theme';
+import { getLegendSizeKnob } from './legend_size_knob';
 
 export const Example = () => (
   <Chart>
-    <Settings showLegend showLegendExtra legendPosition={Position.Bottom} baseTheme={useBaseTheme()} />
+    <Settings
+      showLegend
+      showLegendExtra
+      legendPosition={Position.Bottom}
+      legendSize={getLegendSizeKnob()}
+      baseTheme={useBaseTheme()}
+    />
     <Axis id="bottom" position={Position.Bottom} title="Bottom axis" showOverlappingTicks />
     <Axis id="left2" title="Left axis" position={Position.Left} tickFormat={(d) => Number(d).toFixed(2)} />
 

storybook/stories/legend/3_legend_left.story.tsx

@@ -12,10 +12,17 @@ import { Axis, BarSeries, Chart, Position, ScaleType, Settings } from '@elastic/
 import * as TestDatasets from '@elastic/charts/src/utils/data_samples/test_dataset';
 
 import { useBaseTheme } from '../../use_base_theme';
+import { getLegendSizeKnob } from './legend_size_knob';
 
 export const Example = () => (
   <Chart>
-    <Settings showLegend showLegendExtra legendPosition={Position.Left} baseTheme={useBaseTheme()} />
+    <Settings
+      showLegend
+      showLegendExtra
+      legendPosition={Position.Left}
+      legendSize={getLegendSizeKnob()}
+      baseTheme={useBaseTheme()}
+    />
     <Axis id="bottom" position={Position.Bottom} title="Bottom axis" showOverlappingTicks />
     <Axis id="left2" title="Left axis" position={Position.Left} tickFormat={(d) => Number(d).toFixed(2)} />
 

storybook/stories/legend/4_legend_top.story.tsx

@@ -12,10 +12,17 @@ import { Axis, BarSeries, Chart, Position, ScaleType, Settings } from '@elastic/
 import * as TestDatasets from '@elastic/charts/src/utils/data_samples/test_dataset';
 
 import { useBaseTheme } from '../../use_base_theme';
+import { getLegendSizeKnob } from './legend_size_knob';
 
 export const Example = () => (
   <Chart>
-    <Settings showLegend showLegendExtra legendPosition={Position.Top} baseTheme={useBaseTheme()} />
+    <Settings
+      showLegend
+      showLegendExtra
+      legendPosition={Position.Top}
+      legendSize={getLegendSizeKnob()}
+      baseTheme={useBaseTheme()}
+    />
     <Axis id="bottom" position={Position.Bottom} title="Bottom axis" showOverlappingTicks />
     <Axis id="left2" title="Left axis" position={Position.Left} tickFormat={(d) => Number(d).toFixed(2)} />
 

storybook/stories/legend/legend_size_knob.ts

@@ -0,0 +1,15 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { boolean, number } from '@storybook/addon-knobs';
+
+export const getLegendSizeKnob = (group?: string) => {
+  const enabled = boolean('enable legend size', false, group);
+  const size = enabled ? number('legend size', 200, { min: 0, step: 1 }, group) : NaN;
+  return size;
+};