fix(axis): misaligned axis with rotated histogram

integration/tests/bar_stories.test.ts

@@ -20,6 +20,16 @@
 import { common } from '../page_objects';
 
 describe('Bar series stories', () => {
+  describe('[test] axis positions with histogram bar series', () => {
+    [0, 90, -90, 180].forEach((rotation) => {
+      it(`Should render correct axis - rotation ${rotation === -90 ? 'negative 90' : rotation}`, async () => {
+        await common.expectChartAtUrlToMatchScreenshot(
+          `http://localhost:9001/?path=/story/interactions--brush-selection-tool-on-histogram-time-charts&knob-debug=&knob-chartRotation=${rotation}`,
+        );
+      });
+    });
+  });
+
   describe('[test] switch ordinal/linear x axis', () => {
     it('using ordinal x axis', async () => {
       await common.expectChartAtUrlToMatchScreenshot(

src/chart_types/xy_chart/utils/axis_utils.test.ts

@@ -355,9 +355,8 @@ describe('Axis computational utils', () => {
 
   describe('getAvailableTicks', () => {
     test('should compute to end of domain when histogram mode not enabled', () => {
-      const enableHistogramMode = false;
       const scale = getScaleForAxisSpec(verticalAxisSpec, xDomain, [yDomain], 0, 0, 100, 0);
-      const axisPositions = getAvailableTicks(verticalAxisSpec, scale!, 0, enableHistogramMode, (v) => `${v}`);
+      const axisPositions = getAvailableTicks(verticalAxisSpec, scale!, 0, false, (v) => `${v}`, 0);
       const expectedAxisPositions = [
         { label: '0', position: 100, value: 0 },
         { label: '0.1', position: 90, value: 0.1 },
@@ -374,6 +373,26 @@ describe('Axis computational utils', () => {
       expect(axisPositions).toEqual(expectedAxisPositions);
     });
 
+    test('should compute positions with rotational offset', () => {
+      const rotationalOffset = 2;
+      const scale = getScaleForAxisSpec(verticalAxisSpec, xDomain, [yDomain], 0, 0, 100, 0);
+      const axisPositions = getAvailableTicks(verticalAxisSpec, scale!, 0, false, (v) => `${v}`, rotationalOffset);
+      const expectedAxisPositions = [
+        { label: '0', position: 100 + rotationalOffset, value: 0 },
+        { label: '0.1', position: 90 + rotationalOffset, value: 0.1 },
+        { label: '0.2', position: 80 + rotationalOffset, value: 0.2 },
+        { label: '0.3', position: 70 + rotationalOffset, value: 0.3 },
+        { label: '0.4', position: 60 + rotationalOffset, value: 0.4 },
+        { label: '0.5', position: 50 + rotationalOffset, value: 0.5 },
+        { label: '0.6', position: 40 + rotationalOffset, value: 0.6 },
+        { label: '0.7', position: 30 + rotationalOffset, value: 0.7 },
+        { label: '0.8', position: 20 + rotationalOffset, value: 0.8 },
+        { label: '0.9', position: 10 + rotationalOffset, value: 0.9 },
+        { label: '1', position: 0 + rotationalOffset, value: 1 },
+      ];
+      expect(axisPositions).toEqual(expectedAxisPositions);
+    });
+
     test('should extend ticks to domain + minInterval in histogram mode for linear scale', () => {
       const enableHistogramMode = true;
       const xBandDomain: XDomain = {
@@ -390,6 +409,7 @@ describe('Axis computational utils', () => {
         1,
         enableHistogramMode,
         (v) => `${v}`,
+        0,
       );
       const histogramTickLabels = histogramAxisPositions.map(({ label }: AxisTick) => label);
       expect(histogramTickLabels).toEqual(['0', '10', '20', '30', '40', '50', '60', '70', '80', '90', '100', '110']);
@@ -411,6 +431,7 @@ describe('Axis computational utils', () => {
         1,
         enableHistogramMode,
         (v) => `${v}`,
+        0,
       );
       const histogramTickValues = histogramAxisPositions.map(({ value }: AxisTick) => value);
 
@@ -449,6 +470,7 @@ describe('Axis computational utils', () => {
         1,
         enableHistogramMode,
         (v) => `${v}`,
+        0,
       );
       const histogramTickValues = histogramAxisPositions.map(({ value }: AxisTick) => value);
       const expectedTickValues = [1560438420000, 1560438510000];

src/chart_types/xy_chart/utils/axis_utils.ts

@@ -511,6 +511,7 @@ export function getAvailableTicks(
   totalBarsInCluster: number,
   enableHistogramMode: boolean,
   fallBackTickFormatter: TickFormatter,
+  rotationOffset: number,
   tickFormatOptions?: TickFormatterOptions,
 ): AxisTick[] {
   const ticks = scale.ticks();
@@ -534,7 +535,8 @@ export function getAvailableTicks(
 
   const band = scale.bandwidth / (1 - scale.barsPadding);
   const halfPadding = (band - scale.bandwidth) / 2;
-  const offset = enableHistogramMode ? -halfPadding : (scale.bandwidth * shift) / 2;
+  const offset =
+    (enableHistogramMode ? -halfPadding : (scale.bandwidth * shift) / 2) + (scale.isSingleValue() ? 0 : rotationOffset);
   const tickFormatter = axisSpec.tickFormat ?? fallBackTickFormatter;
 
   if (isSingleValueScale && hasAdditionalTicks) {
@@ -739,12 +741,20 @@ export function getAxisTicksPositions(
     };
     const { axisTitle, tickLine, tickLabel, gridLine } = axesStyles.get(id) ?? sharedAxesStyle;
     const isVertical = isVerticalAxis(axisSpec.position);
+    // TODO: Find the true cause of the this offset error
+    const rotationOffset =
+      enableHistogramMode &&
+      ((isVertical && [-90].includes(chartRotation)) || (!isVertical && [180].includes(chartRotation)))
+        ? scale.step
+        : 0;
+
     const allTicks = getAvailableTicks(
       axisSpec,
       scale,
       totalGroupsCount,
       enableHistogramMode,
       isVertical ? fallBackTickFormatter : defaultTickFormatter,
+      rotationOffset,
       tickFormatOptions,
     );
 
@@ -791,6 +801,7 @@ export function getAxisTicksPositions(
     axisVisibleTicks.set(id, visibleTicks);
     axisTicks.set(id, allTicks);
   });
+
   return {
     axisPositions,
     axisTicks,

src/mocks/scale/scale.ts

@@ -27,6 +27,7 @@ export class MockScale {
     scaleOrThrow: jest.fn().mockImplementation((x) => x),
     scale: jest.fn().mockImplementation((x) => x),
     type: ScaleType.Linear,
+    step: 0,
     bandwidth: 0,
     bandwidthPadding: 0,
     minInterval: 0,

src/scales/index.ts

@@ -29,6 +29,10 @@ import { ScaleType } from './constants';
 export interface Scale {
   domain: any[];
   range: number[];
+  /**
+   * Returns the distance between the starts of adjacent bands.
+   */
+  step: number;
   ticks: () => any[];
   scaleOrThrow(value?: PrimitiveValue): number;
   scale: (value?: PrimitiveValue) => number | null;

src/scales/scale_continuous.ts

@@ -196,7 +196,7 @@ export class ScaleContinuous implements Scale {
     this.bandwidth = bandwidth * (1 - safeBarPadding);
     this.bandwidthPadding = bandwidth * safeBarPadding;
     this.d3Scale.range(range);
-    this.step = 0;
+    this.step = this.bandwidth + this.barsPadding + this.bandwidthPadding;
     this.type = type;
     this.range = range;
     this.minInterval = minInterval;