feat(chart): support fixed y-axis domains

src/components/core/fixedYDomainLayout.test.ts

@@ -0,0 +1,116 @@
+import { zoomIdentity } from 'd3'
+import { describe, expect, it } from 'vitest'
+
+import { DEFAULT_WAVEFORM_RENDERING_OPTIONS } from '../../core'
+import type { DisplaySeries, DisplayTrack } from './types'
+import { buildTrackLayouts, resolveYAxisSeriesGroups } from './layout'
+
+function series(id: string, minimum: number, maximum: number): DisplaySeries {
+  return {
+    id,
+    name: id,
+    color: '#1677ff',
+    lineType: 'linear',
+    lineStyle: 'solid',
+    pointType: 'none',
+    errorBar: { visible: false, width: 1.5, capWidth: 8 },
+    points: [
+      { x: 0, y: minimum },
+      { x: 1, y: maximum },
+    ],
+    xDomain: [0, 1],
+    yDomain: [minimum, maximum],
+    hasErrorPoints: false,
+  }
+}
+
+function track(seriesList: DisplaySeries[]): DisplayTrack {
+  return {
+    id: 'track',
+    series: seriesList,
+    visibleSeries: seriesList,
+    xDomain: [0, 1],
+    yDomain: [0, 100],
+  }
+}
+
+describe('fixed Y-domain layout', () => {
+  it('uses an exact global fixed domain without applying nice bounds', () => {
+    const sourceTrack = track([series('a', 0, 100)])
+    const result = buildTrackLayouts({
+      cells: [
+        {
+          slotIndex: 0,
+          row: 0,
+          column: 0,
+          left: 0,
+          top: 0,
+          width: 120,
+          height: 100,
+          plotHeight: 100,
+          cellHeight: 130,
+          xAxisBand: 30,
+          series: sourceTrack,
+        },
+      ],
+      grid: { rowCount: 1, columnCount: 1, showPagination: false, trackLines: {} },
+      displayMode: 'independent',
+      overlayMode: 'single-axis',
+      independentTransforms: [zoomIdentity],
+      sharedZoomDomain: [0, 1],
+      fixedYDomain: [3, 97],
+      timeUnit: 'ms',
+      rendering: DEFAULT_WAVEFORM_RENDERING_OPTIONS,
+      hideSecondaryLabels: false,
+      yAxisLabelX: -50,
+      showCompactEmptyTracks: false,
+    })[0]
+
+    expect(result?.yScale.domain()).toEqual([3, 97])
+    expect(result?.yAxes[0]?.tickValues).toContain(3)
+    expect(result?.yAxes[0]?.tickValues).toContain(97)
+    expect(result?.seriesPaths[0]?.yScale.domain()).toEqual([3, 97])
+  })
+
+  it('resolves track, series, and global fixed-domain precedence', () => {
+    const sourceTrack = track([series('a', 0, 10), series('b', 20, 30)])
+
+    expect(
+      resolveYAxisSeriesGroups(sourceTrack, 'single-axis', [-5, 5], {
+        a: [-10, 10],
+        track: [300, 100],
+      })[0]?.domain,
+    ).toEqual([100, 300])
+
+    expect(
+      resolveYAxisSeriesGroups(sourceTrack, 'single-axis', [-5, 5], {
+        a: [-10, 10],
+      })[0]?.domain,
+    ).toEqual([-10, 10])
+  })
+
+  it('keeps per-series fixed domains on separate axes and merges axis overflow', () => {
+    const sourceTrack = track([
+      series('a', 0, 1),
+      series('b', 10, 11),
+      series('c', 20, 21),
+      series('d', 30, 31),
+      series('e', 40, 41),
+    ])
+    const groups = resolveYAxisSeriesGroups(sourceTrack, 'multi-axis', undefined, {
+      a: [-1, 1],
+      b: [-2, 2],
+      c: [-3, 3],
+      d: [-4, 4],
+      e: [-5, 5],
+    })
+
+    expect(groups.map((group) => group.domain)).toEqual([
+      [-1, 1],
+      [-2, 2],
+      [-3, 3],
+      [-5, 5],
+    ])
+    expect(groups.every((group) => group.fixed)).toBe(true)
+  })
+})