fix: align line and rect annotation on continuous scales

packages/charts/src/chart_types/xy_chart/annotations/line/dimensions.ts

@@ -11,14 +11,13 @@ import { Colors } from '../../../../common/colors';
 import { SmallMultipleScales, getPanelSize } from '../../../../common/panel_utils';
 import { Line } from '../../../../geoms/types';
 import { ScaleBand, ScaleContinuous } from '../../../../scales';
-import { isBandScale, isContinuousScale } from '../../../../scales/types';
 import { Position, Rotation } from '../../../../utils/common';
 import { Dimensions, Size } from '../../../../utils/dimensions';
 import { GroupId } from '../../../../utils/ids';
 import { mergeWithDefaultAnnotationLine } from '../../../../utils/themes/merge_utils';
 import { isHorizontalRotation, isVerticalRotation } from '../../state/utils/common';
-import { computeXScaleOffset } from '../../state/utils/utils';
 import { AnnotationDomainType, LineAnnotationDatum, LineAnnotationSpec } from '../../utils/specs';
+import { getAnnotationXScaledValue } from '../scale_utils';
 
 function computeYDomainLineAnnotationDimensions(
   annotationSpec: LineAnnotationSpec,
@@ -137,36 +136,7 @@ function computeXDomainLineAnnotationDimensions(
 
   dataValues.forEach((datum: LineAnnotationDatum, i) => {
     const { dataValue } = datum;
-    let annotationValueXPosition = xScale.scale(dataValue);
-    if (Number.isNaN(annotationValueXPosition)) {
-      return;
-    }
-    if (isContinuousScale(xScale) && typeof dataValue === 'number') {
-      const [minDomain, scaleMaxDomain] = xScale.domain;
-      const maxDomain = isHistogramMode ? scaleMaxDomain + xScale.minInterval : scaleMaxDomain;
-      if (dataValue < minDomain || dataValue > maxDomain) {
-        return;
-      }
-      if (isHistogramMode) {
-        const offset = computeXScaleOffset(xScale, true);
-        const pureScaledValue = xScale.pureScale(dataValue);
-        if (!Number.isNaN(pureScaledValue)) {
-          // Number.isFinite is regrettably not a type guard yet https://github.com/microsoft/TypeScript/issues/10038#issuecomment-924115831
-          annotationValueXPosition = pureScaledValue - offset;
-        }
-      } else {
-        annotationValueXPosition += (xScale.bandwidth * xScale.totalBarsInCluster) / 2;
-      }
-    } else if (isBandScale(xScale)) {
-      annotationValueXPosition += isHistogramMode
-        ? -(xScale.step - xScale.originalBandwidth) / 2
-        : xScale.originalBandwidth / 2;
-    } else {
-      return;
-    }
-    if (!isFinite(annotationValueXPosition)) {
-      return;
-    }
+    const annotationValueXPosition = getAnnotationXScaledValue(xScale, dataValue, isHistogramMode);
 
     vertical.domain.forEach((verticalValue) => {
       horizontal.domain.forEach((horizontalValue) => {

packages/charts/src/chart_types/xy_chart/annotations/rect/dimensions.ts

@@ -18,6 +18,7 @@ import { PrimitiveValue } from '../../../partition_chart/layout/utils/group_by_r
 import { isHorizontalRotation, isVerticalRotation } from '../../state/utils/common';
 import { getAxesSpecForSpecId } from '../../state/utils/spec';
 import { AxisSpec, RectAnnotationDatum, RectAnnotationSpec } from '../../utils/specs';
+import { getAnnotationXScaledValue } from '../scale_utils';
 import { Bounds } from '../types';
 
 /** @internal */
@@ -199,14 +200,10 @@ function scaleXonContinuousScale(
   if (typeof x1 !== 'number' || typeof x0 !== 'number') {
     return null;
   }
-  const scaledX0 = xScale.scale(x0);
-  const scaledX1 =
-    xScale.totalBarsInCluster > 0 && !isHistogramModeEnabled ? xScale.scale(x1 + xScale.minInterval) : xScale.scale(x1);
-  // the width needs to be computed before adjusting the x anchor
+  const scaledX0 = getAnnotationXScaledValue(xScale, x0, isHistogramModeEnabled) ?? NaN;
+  const scaledX1 = getAnnotationXScaledValue(xScale, x1, isHistogramModeEnabled) ?? NaN;
   const width = Math.abs(scaledX1 - scaledX0);
-  return Number.isNaN(width)
-    ? null
-    : { width, x: scaledX0 - (xScale.bandwidthPadding / 2) * xScale.totalBarsInCluster };
+  return Number.isNaN(width) ? null : { width, x: scaledX0 };
 }
 
 /**

packages/charts/src/chart_types/xy_chart/annotations/scale_utils.ts

@@ -0,0 +1,50 @@
+/*
+ * 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 { ScaleBand, ScaleContinuous } from '../../../scales';
+import { isBandScale, isContinuousScale } from '../../../scales/types';
+import { computeXScaleOffset } from '../state/utils/utils';
+
+/** @internal */
+export function getAnnotationXScaledValue(
+  xScale: ScaleBand | ScaleContinuous,
+  dataValue: string | number,
+  isHistogramMode: boolean,
+): number {
+  let annotationValueXPosition = xScale.scale(dataValue);
+  if (Number.isNaN(annotationValueXPosition)) {
+    return NaN;
+  }
+  if (isContinuousScale(xScale) && typeof dataValue === 'number') {
+    const [minDomain, scaleMaxDomain] = xScale.domain;
+    const maxDomain = isHistogramMode ? scaleMaxDomain + xScale.minInterval : scaleMaxDomain;
+    if (dataValue < minDomain || dataValue > maxDomain) {
+      return NaN;
+    }
+    if (isHistogramMode) {
+      const offset = computeXScaleOffset(xScale, true);
+      const pureScaledValue = xScale.pureScale(dataValue);
+      if (!Number.isNaN(pureScaledValue)) {
+        // Number.isFinite is regrettably not a type guard yet https://github.com/microsoft/TypeScript/issues/10038#issuecomment-924115831
+        annotationValueXPosition = pureScaledValue - offset;
+      }
+    } else {
+      annotationValueXPosition += (xScale.bandwidth * xScale.totalBarsInCluster) / 2;
+    }
+  } else if (isBandScale(xScale)) {
+    annotationValueXPosition += isHistogramMode
+      ? -(xScale.step - xScale.originalBandwidth) / 2
+      : xScale.originalBandwidth / 2;
+  } else {
+    return NaN;
+  }
+  if (!isFinite(annotationValueXPosition)) {
+    return NaN;
+  }
+  return annotationValueXPosition;
+}

storybook/stories/bar/1_basic.story.tsx

@@ -7,20 +7,22 @@
  */
 
 import { boolean } from '@storybook/addon-knobs';
+import moment from 'moment-timezone';
 import React from 'react';
 
-import { BarSeries, Chart, ScaleType, Settings } from '@elastic/charts';
+import { Axis, BarSeries, Chart, LineAnnotation, Position, RectAnnotation, ScaleType, Settings } from '@elastic/charts';
 
 import { ChartsStory } from '../../types';
 import { useBaseTheme } from '../../use_base_theme';
 
 export const Example: ChartsStory = (_, { title, description }) => {
   const toggleSpec = boolean('toggle bar spec', true);
+  const now = Date.now();
   const data1 = [
-    { x: 0, y: 2 },
-    { x: 1, y: 7 },
-    { x: 2, y: 3 },
-    { x: 3, y: 6 },
+    { x: now, y: 2 },
+    { x: now + 1000 * 60 * 60 * 1, y: 1 },
+    { x: now + 1000 * 60 * 60 * 2, y: 3 },
+    { x: now + 1000 * 60 * 60 * 3, y: 6 },
   ];
   const data2 = data1.map((datum) => ({ ...datum, y: datum.y - 1 }));
   const data = toggleSpec ? data1 : data2;
@@ -31,12 +33,69 @@ export const Example: ChartsStory = (_, { title, description }) => {
       <BarSeries
         id={specId}
         name="Simple bar series"
-        xScaleType={ScaleType.Linear}
+        xScaleType={ScaleType.Time}
         yScaleType={ScaleType.Linear}
+        enableHistogramMode
         xAccessor="x"
         yAccessors={['y']}
+        stackAccessors={['x']}
         data={data}
       />
+      <BarSeries
+        id="bars 2"
+        name="Simple bar series"
+        xScaleType={ScaleType.Time}
+        yScaleType={ScaleType.Linear}
+        enableHistogramMode
+        stackAccessors={['x']}
+        xAccessor="x"
+        yAccessors={['y']}
+        data={data}
+      />
+      <Axis id="y" position={Position.Left} domain={{ min: 0, max: 10 }} />
+      <Axis
+        id="bottom"
+        position={Position.Bottom}
+        timeAxisLayerCount={2}
+        style={{
+          tickLabel: {
+            alignment: { horizontal: 'left' },
+          },
+        }}
+      />
+      <LineAnnotation
+        id="line1"
+        domainType="xDomain"
+        style={{
+          line: {
+            opacity: 1,
+            stroke: 'red',
+            strokeWidth: 2,
+          },
+        }}
+        marker={<div style={{ width: 50, height: 50, background: 'rgba(122,40,112,0.5)' }}></div>}
+        dataValues={[
+          {
+            dataValue: now + 1000 * 60 * 60 * 1,
+            details: `1.5`,
+          },
+        ]}
+      />
+      <RectAnnotation
+        id="rect1"
+        style={{
+          fill: 'red',
+        }}
+        dataValues={[
+          {
+            coordinates: {
+              x0: now + 1000 * 60 * 60 * 1,
+              x1: now + 1000 * 60 * 60 * 3,
+            },
+            details: `1.5 - 2.5`,
+          },
+        ]}
+      />
     </Chart>
   );
 };