From ca004a66f3f5a0847d2f39314a1526298ca03b8a Mon Sep 17 00:00:00 2001
From: Nick Partridge <nick.ryan.partridge@gmail.com>
Date: Tue, 2 Nov 2021 09:47:59 -0500
Subject: [PATCH] fix(interactions): line cursor above the chart, band cursor
 below (#1453) (#1457)

---
 .../xy_chart/renderer/dom/cursor_band.tsx     | 86 +++++++++++++++++
 .../{crosshair.tsx => cursor_crossline.tsx}   | 69 ++------------
 .../xy_chart/renderer/dom/cursor_line.tsx     | 92 +++++++++++++++++++
 .../xy_chart/state/chart_state.tsx            |  8 +-
 .../__snapshots__/chart.test.tsx.snap         | 12 ++-
 5 files changed, 201 insertions(+), 66 deletions(-)
 create mode 100644 packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_band.tsx
 rename packages/charts/src/chart_types/xy_chart/renderer/dom/{crosshair.tsx => cursor_crossline.tsx} (60%)
 create mode 100644 packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_line.tsx

diff --git a/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_band.tsx b/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_band.tsx
new file mode 100644
index 0000000000..a4992d3fd0
--- /dev/null
+++ b/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_band.tsx
@@ -0,0 +1,86 @@
+/*
+ * 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 React from 'react';
+import { connect } from 'react-redux';
+
+import { Rect } from '../../../../geoms/types';
+import { getTooltipType } from '../../../../specs';
+import { TooltipType } from '../../../../specs/constants';
+import { GlobalChartState } from '../../../../state/chart_state';
+import { getChartRotationSelector } from '../../../../state/selectors/get_chart_rotation';
+import { getChartThemeSelector } from '../../../../state/selectors/get_chart_theme';
+import { getInternalIsInitializedSelector, InitStatus } from '../../../../state/selectors/get_internal_is_intialized';
+import { getSettingsSpecSelector } from '../../../../state/selectors/get_settings_specs';
+import { Rotation } from '../../../../utils/common';
+import { LIGHT_THEME } from '../../../../utils/themes/light_theme';
+import { Theme } from '../../../../utils/themes/theme';
+import { getCursorBandPositionSelector } from '../../state/selectors/get_cursor_band';
+
+interface CursorBandProps {
+  theme: Theme;
+  chartRotation: Rotation;
+  cursorPosition?: Rect;
+  tooltipType: TooltipType;
+  fromExternalEvent?: boolean;
+}
+
+function canRenderBand(type: TooltipType, visible: boolean, fromExternalEvent?: boolean) {
+  return visible && (type === TooltipType.Crosshairs || type === TooltipType.VerticalCursor || fromExternalEvent);
+}
+
+class CursorBandComponent extends React.Component<CursorBandProps> {
+  static displayName = 'CursorBand';
+
+  render() {
+    const {
+      theme: {
+        crosshair: { band },
+      },
+      cursorPosition,
+      tooltipType,
+      fromExternalEvent,
+    } = this.props;
+    const isBand = (cursorPosition?.width ?? 0) > 0 && (cursorPosition?.height ?? 0) > 0;
+    if (!isBand || !cursorPosition || !canRenderBand(tooltipType, band.visible, fromExternalEvent)) {
+      return null;
+    }
+    const { x, y, width, height } = cursorPosition;
+    const { fill } = band;
+    return (
+      <svg className="echCrosshair__cursor" width="100%" height="100%">
+        <rect {...{ x, y, width, height, fill }} />
+      </svg>
+    );
+  }
+}
+
+const mapStateToProps = (state: GlobalChartState): CursorBandProps => {
+  if (getInternalIsInitializedSelector(state) !== InitStatus.Initialized) {
+    return {
+      theme: LIGHT_THEME,
+      chartRotation: 0,
+      tooltipType: TooltipType.None,
+    };
+  }
+  const settings = getSettingsSpecSelector(state);
+  const cursorBandPosition = getCursorBandPositionSelector(state);
+  const fromExternalEvent = cursorBandPosition?.fromExternalEvent;
+  const tooltipType = getTooltipType(settings, fromExternalEvent);
+
+  return {
+    theme: getChartThemeSelector(state),
+    chartRotation: getChartRotationSelector(state),
+    cursorPosition: cursorBandPosition,
+    tooltipType,
+    fromExternalEvent,
+  };
+};
+
+/** @internal */
+export const CursorBand = connect(mapStateToProps)(CursorBandComponent);
diff --git a/packages/charts/src/chart_types/xy_chart/renderer/dom/crosshair.tsx b/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_crossline.tsx
similarity index 60%
rename from packages/charts/src/chart_types/xy_chart/renderer/dom/crosshair.tsx
rename to packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_crossline.tsx
index 8d4019bd9b..1eedfe3daf 100644
--- a/packages/charts/src/chart_types/xy_chart/renderer/dom/crosshair.tsx
+++ b/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_crossline.tsx
@@ -9,7 +9,7 @@
 import React from 'react';
 import { connect } from 'react-redux';
 
-import { Line, Rect } from '../../../../geoms/types';
+import { Line } from '../../../../geoms/types';
 import { getTooltipType } from '../../../../specs';
 import { TooltipType } from '../../../../specs/constants';
 import { GlobalChartState } from '../../../../state/chart_state';
@@ -23,62 +23,22 @@ import { Theme } from '../../../../utils/themes/theme';
 import { getCursorBandPositionSelector } from '../../state/selectors/get_cursor_band';
 import { getCursorLinePositionSelector } from '../../state/selectors/get_cursor_line';
 
-interface CrosshairProps {
+interface CursorCrossLineProps {
   theme: Theme;
   chartRotation: Rotation;
-  cursorPosition?: Rect;
   cursorCrossLinePosition?: Line;
   tooltipType: TooltipType;
-  fromExternalEvent?: boolean;
-  zIndex: number;
-}
-
-function canRenderBand(type: TooltipType, visible: boolean, fromExternalEvent?: boolean) {
-  return visible && (type === TooltipType.Crosshairs || type === TooltipType.VerticalCursor || fromExternalEvent);
 }
 
 function canRenderHelpLine(type: TooltipType, visible: boolean) {
   return visible && type === TooltipType.Crosshairs;
 }
 
-class CrosshairComponent extends React.Component<CrosshairProps> {
-  static displayName = 'Crosshair';
+class CursorCrossLineComponent extends React.Component<CursorCrossLineProps> {
+  static displayName = 'CursorCrossLine';
 
-  renderCursor() {
-    const {
-      zIndex,
-      theme: {
-        crosshair: { band, line },
-      },
-      cursorPosition,
-      tooltipType,
-      fromExternalEvent,
-    } = this.props;
-
-    if (!cursorPosition || !canRenderBand(tooltipType, band.visible, fromExternalEvent)) {
-      return null;
-    }
-    const { x, y, width, height } = cursorPosition;
-    const isLine = width === 0 || height === 0;
-    const { strokeWidth, stroke, dash } = line;
-    const { fill } = band;
-    const strokeDasharray = (dash ?? []).join(' ');
-    return (
-      <svg
-        className="echCrosshair__cursor"
-        width="100%"
-        height="100%"
-        style={{ zIndex: cursorPosition && isLine ? zIndex : undefined }}
-      >
-        {isLine && <line {...{ x1: x, x2: x + width, y1: y, y2: y + height, strokeWidth, stroke, strokeDasharray }} />}
-        {!isLine && <rect {...{ x, y, width, height, fill }} />}
-      </svg>
-    );
-  }
-
-  renderCrossLine() {
+  render() {
     const {
-      zIndex,
       theme: {
         crosshair: { crossLine },
       },
@@ -98,29 +58,19 @@ class CrosshairComponent extends React.Component<CrosshairProps> {
     };
 
     return (
-      <svg className="echCrosshair__crossLine" width="100%" height="100%" style={{ zIndex }}>
+      <svg className="echCrosshair__crossLine" width="100%" height="100%">
         <line {...cursorCrossLinePosition} {...style} />
       </svg>
     );
   }
-
-  render() {
-    return (
-      <>
-        {this.renderCursor()}
-        {this.renderCrossLine()}
-      </>
-    );
-  }
 }
 
-const mapStateToProps = (state: GlobalChartState): CrosshairProps => {
+const mapStateToProps = (state: GlobalChartState): CursorCrossLineProps => {
   if (getInternalIsInitializedSelector(state) !== InitStatus.Initialized) {
     return {
       theme: LIGHT_THEME,
       chartRotation: 0,
       tooltipType: TooltipType.None,
-      zIndex: 0,
     };
   }
   const settings = getSettingsSpecSelector(state);
@@ -131,13 +81,10 @@ const mapStateToProps = (state: GlobalChartState): CrosshairProps => {
   return {
     theme: getChartThemeSelector(state),
     chartRotation: getChartRotationSelector(state),
-    cursorPosition: cursorBandPosition,
     cursorCrossLinePosition: getCursorLinePositionSelector(state),
     tooltipType,
-    fromExternalEvent,
-    zIndex: state.zIndex,
   };
 };
 
 /** @internal */
-export const Crosshair = connect(mapStateToProps)(CrosshairComponent);
+export const CursorCrossLine = connect(mapStateToProps)(CursorCrossLineComponent);
diff --git a/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_line.tsx b/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_line.tsx
new file mode 100644
index 0000000000..dd7de0d96a
--- /dev/null
+++ b/packages/charts/src/chart_types/xy_chart/renderer/dom/cursor_line.tsx
@@ -0,0 +1,92 @@
+/*
+ * 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 React from 'react';
+import { connect } from 'react-redux';
+
+import { Rect } from '../../../../geoms/types';
+import { getTooltipType } from '../../../../specs';
+import { TooltipType } from '../../../../specs/constants';
+import { GlobalChartState } from '../../../../state/chart_state';
+import { getChartRotationSelector } from '../../../../state/selectors/get_chart_rotation';
+import { getChartThemeSelector } from '../../../../state/selectors/get_chart_theme';
+import { getInternalIsInitializedSelector, InitStatus } from '../../../../state/selectors/get_internal_is_intialized';
+import { getSettingsSpecSelector } from '../../../../state/selectors/get_settings_specs';
+import { Rotation } from '../../../../utils/common';
+import { LIGHT_THEME } from '../../../../utils/themes/light_theme';
+import { Theme } from '../../../../utils/themes/theme';
+import { getCursorBandPositionSelector } from '../../state/selectors/get_cursor_band';
+
+interface CursorLineProps {
+  theme: Theme;
+  chartRotation: Rotation;
+  cursorPosition?: Rect;
+  tooltipType: TooltipType;
+  fromExternalEvent?: boolean;
+  isLine: boolean;
+}
+
+function canRenderBand(type: TooltipType, visible: boolean, fromExternalEvent?: boolean) {
+  return visible && (type === TooltipType.Crosshairs || type === TooltipType.VerticalCursor || fromExternalEvent);
+}
+
+class CursorLineComponent extends React.Component<CursorLineProps> {
+  static displayName = 'CursorLine';
+
+  render() {
+    const {
+      theme: {
+        crosshair: { band, line },
+      },
+      cursorPosition,
+      tooltipType,
+      fromExternalEvent,
+      isLine,
+    } = this.props;
+
+    if (!cursorPosition || !canRenderBand(tooltipType, band.visible, fromExternalEvent) || !isLine) {
+      return null;
+    }
+    const { x, y, width, height } = cursorPosition;
+    const { strokeWidth, stroke, dash } = line;
+    const strokeDasharray = (dash ?? []).join(' ');
+    return (
+      <svg className="echCrosshair__cursor" width="100%" height="100%">
+        <line {...{ x1: x, x2: x + width, y1: y, y2: y + height, strokeWidth, stroke, strokeDasharray }} />
+      </svg>
+    );
+  }
+}
+
+const mapStateToProps = (state: GlobalChartState): CursorLineProps => {
+  if (getInternalIsInitializedSelector(state) !== InitStatus.Initialized) {
+    return {
+      theme: LIGHT_THEME,
+      chartRotation: 0,
+      tooltipType: TooltipType.None,
+      isLine: false,
+    };
+  }
+  const settings = getSettingsSpecSelector(state);
+  const cursorBandPosition = getCursorBandPositionSelector(state);
+  const fromExternalEvent = cursorBandPosition?.fromExternalEvent;
+  const tooltipType = getTooltipType(settings, fromExternalEvent);
+  const isLine = cursorBandPosition?.width === 0 || cursorBandPosition?.height === 0;
+
+  return {
+    theme: getChartThemeSelector(state),
+    chartRotation: getChartRotationSelector(state),
+    cursorPosition: cursorBandPosition,
+    tooltipType,
+    fromExternalEvent,
+    isLine,
+  };
+};
+
+/** @internal */
+export const CursorLine = connect(mapStateToProps)(CursorLineComponent);
diff --git a/packages/charts/src/chart_types/xy_chart/state/chart_state.tsx b/packages/charts/src/chart_types/xy_chart/state/chart_state.tsx
index 050c833f2e..1af9fb9502 100644
--- a/packages/charts/src/chart_types/xy_chart/state/chart_state.tsx
+++ b/packages/charts/src/chart_types/xy_chart/state/chart_state.tsx
@@ -19,7 +19,9 @@ import { InitStatus } from '../../../state/selectors/get_internal_is_intialized'
 import { htmlIdGenerator } from '../../../utils/common';
 import { XYChart } from '../renderer/canvas/xy_chart';
 import { Annotations } from '../renderer/dom/annotations';
-import { Crosshair } from '../renderer/dom/crosshair';
+import { CursorBand } from '../renderer/dom/cursor_band';
+import { CursorCrossLine } from '../renderer/dom/cursor_crossline';
+import { CursorLine } from '../renderer/dom/cursor_line';
 import { Highlighter } from '../renderer/dom/highlighter';
 import { computeChartDimensionsSelector } from './selectors/compute_chart_dimensions';
 import { computeLegendSelector } from './selectors/compute_legend';
@@ -112,8 +114,10 @@ export class XYAxisChartState implements InternalChartState {
   chartRenderer(containerRef: BackwardRef, forwardCanvasRef: RefObject<HTMLCanvasElement>) {
     return (
       <>
-        <Crosshair />
+        <CursorBand />
         <XYChart forwardCanvasRef={forwardCanvasRef} />
+        <CursorLine />
+        <CursorCrossLine />
         <Tooltip getChartContainerRef={containerRef} />
         <Annotations getChartContainerRef={containerRef} chartAreaRef={forwardCanvasRef} />
         <Highlighter />
diff --git a/packages/charts/src/components/__snapshots__/chart.test.tsx.snap b/packages/charts/src/components/__snapshots__/chart.test.tsx.snap
index d0682a2ccf..df63303f9f 100644
--- a/packages/charts/src/components/__snapshots__/chart.test.tsx.snap
+++ b/packages/charts/src/components/__snapshots__/chart.test.tsx.snap
@@ -67,9 +67,9 @@ exports[`Chart should render the legend name test 1`] = `
           <Connect(ChartContainer) getChartContainerRef={[Function (anonymous)]} forwardStageRef={{...}}>
             <ChartContainer getChartContainerRef={[Function (anonymous)]} forwardStageRef={{...}} status=\\"Initialized\\" initialized={true} isChartEmpty={false} pointerCursor=\\"default\\" isBrushingAvailable={false} isBrushing={false} internalChartRenderer={[Function (anonymous)]} settings={{...}} onPointerMove={[Function (anonymous)]} onMouseUp={[Function (anonymous)]} onMouseDown={[Function (anonymous)]} onKeyPress={[Function (anonymous)]}>
               <div className=\\"echChartPointerContainer\\" style={{...}} onMouseMove={[Function (anonymous)]} onMouseLeave={[Function (anonymous)]} onMouseDown={[Function (anonymous)]} onMouseUp={[Function (anonymous)]}>
-                <Connect(Crosshair)>
-                  <Crosshair theme={{...}} chartRotation={0} cursorPosition={[undefined]} cursorCrossLinePosition={[undefined]} tooltipType=\\"vertical\\" fromExternalEvent={[undefined]} zIndex={0} dispatch={[Function: dispatch]} />
-                </Connect(Crosshair)>
+                <Connect(CursorBand)>
+                  <CursorBand theme={{...}} chartRotation={0} cursorPosition={[undefined]} tooltipType=\\"vertical\\" fromExternalEvent={[undefined]} dispatch={[Function: dispatch]} />
+                </Connect(CursorBand)>
                 <Connect(XYChart) forwardCanvasRef={{...}}>
                   <XYChart forwardCanvasRef={{...}} initialized={true} isChartEmpty={false} debug={true} geometries={{...}} geometriesIndex={{...}} theme={{...}} chartContainerDimensions={{...}} highlightedLegendItem={[undefined]} rotation={0} renderingArea={{...}} chartTransform={{...}} axesSpecs={{...}} perPanelAxisGeoms={{...}} perPanelGridLines={{...}} axesStyles={{...}} annotationDimensions={{...}} annotationSpecs={{...}} panelGeoms={{...}} a11ySettings={{...}} onChartRendered={[Function (anonymous)]}>
                     <figure aria-labelledby={[undefined]} aria-describedby=\\"chart1--defaultSummary\\">
@@ -95,6 +95,12 @@ exports[`Chart should render the legend name test 1`] = `
                     </Connect(ScreenReaderSummaryComponent)>
                   </XYChart>
                 </Connect(XYChart)>
+                <Connect(CursorLine)>
+                  <CursorLine theme={{...}} chartRotation={0} cursorPosition={[undefined]} tooltipType=\\"vertical\\" fromExternalEvent={[undefined]} isLine={false} dispatch={[Function: dispatch]} />
+                </Connect(CursorLine)>
+                <Connect(CursorCrossLine)>
+                  <CursorCrossLine theme={{...}} chartRotation={0} cursorCrossLinePosition={[undefined]} tooltipType=\\"vertical\\" dispatch={[Function: dispatch]} />
+                </Connect(CursorCrossLine)>
                 <Connect(Tooltip) getChartContainerRef={[Function (anonymous)]}>
                   <Tooltip getChartContainerRef={[Function (anonymous)]} visible={false} zIndex={0} info={{...}} position={{...}} headerFormatter={[undefined]} settings={{...}} rotation={0} chartId=\\"chart1\\" backgroundColor=\\"transparent\\" onPointerMove={[Function (anonymous)]} />
                 </Connect(Tooltip)>