feat(网格): 支持不完整末行铺满布局

README.md

@@ -114,8 +114,8 @@ const data = ref<WaveformData>({
 | `xDomainStrategy`                 | `WaveformXDomainStrategy`                   | `{ type: 'data' }`                                      | 自动 X 轴视口范围策略                         |
 | `yDomain`                         | `[number, number]`                          | 未设置                                                  | 所有波形的固定 Y 轴范围                       |
 | `yDomains`                        | `Record<string, [number, number]>`          | 未设置                                                  | 按 track/series ID 配置固定范围               |
-| `grid`                            | `WaveformGridOptions`                       | `{ rowCount: 2, columnCount: 1, showPagination: true }` | 网格和分页                                    |
+| `grid`                            | `WaveformGridOptions`                       | `{ rowCount: 2, columnCount: 1, showPagination: true, fillIncompleteLastRow: false }` | 网格和分页                                    |
-| `axes`                            | `WaveformAxesOptions`                       | 轴线均显示                                              | X/Y 轴基线显隐与 X 轴 label 格式化            |
+| `axes`                            | `WaveformAxesOptions`                       | 轴线均显示                                              | X/Y 轴基线、Y 轴分割数与 X 轴 label 格式化    |
 | `rendering`                       | `WaveformRenderingOptions`                  | `{}`                                                    | 降采样与点/误差棒间距                         |
 | `title` / `legend` / `frameStyle` | 对应公开类型                                | 未设置                                                  | 标题、图例和图框样式                          |
 | `frameNumber`                     | `string \| number`                          | 未设置                                                  | 图框水印内容                                  |
@@ -208,7 +208,8 @@ import 'waveform-analysis/style.css'
 
 范围优先级为 `trackId` 配置、`seriesId` 配置、全局 `yDomain`、数据自动范围。上下限必须
 是两个有限且不相等的数字；倒序范围会自动调整为升序，无效配置会回退到下一优先级。
-固定范围会精确作为坐标域使用，不会经过 D3 的 `nice()` 扩展。
+固定范围作为 Y 轴刻度算法的初始范围；轴会按漂亮步长经过 D3 的 `nice()` 扩展，确保主刻度
+等间距。原始数据和传入的范围值不会被修改。
 
 单值轴叠加模式会合并同一根轴上所有可见系列的有效范围；多值轴模式按系列分别使用配置，
 超过四根轴后复用第 4 根轴的系列会取范围并集。隐藏系列不参与公共范围合并。
@@ -216,6 +217,16 @@ import 'waveform-analysis/style.css'
 固定范围存在时，对应图框的 Y 轴不会被平移或视口重置覆盖；X 轴缩放、平移和重置保持原有
 行为。运行时更新或移除 `yDomain` / `yDomains` 会立即重新布局，移除后恢复自动范围。
 
+### Y 轴自动等分
+
+Y 轴默认显示 5 个主刻度（包含上下端点），并使用类似 ECharts 的 `1 / 2 / 5 × 10ⁿ` 漂亮
+步长，保证主刻度之间数值等间距。可以通过 `axes.y.splitNumber` 指定主刻度总数；每条
+Y 轴会独立计算：
+
+```vue
+<WaveformChart :data="chartData" :axes="{ y: { splitNumber: 5 } }" />
+```
+
 ### 缩放后按可视区间加载数据
 
 组件支持 Plotly 风格的矩形框选缩放：在 zoom 模式下按住鼠标左键拖拽，松开后同时缩放
@@ -533,6 +544,10 @@ scale 定位零线：
 `grid` 控制独立图框的行列数（范围 `1–10`）以及是否显示分页器。默认值为 `2` 行、
 `1` 列并开启分页；当图框数量超过网格容量时，分页器会显示在图表右下角。
 
+`fillIncompleteLastRow` 默认关闭。开启后，分页容量仍由 `rowCount * columnCount` 决定；
+最后一页或未满页会移除没有数据的整行，并将最后一行的实际图框等宽铺满可用宽度。例如 2 列
+网格的最后一行只有一个图框时，该图框会占满整行。完整页和关闭该选项时的布局保持不变。
+
 还可以通过 `trackLines` 按轨道 ID 分别控制水平/垂直网格线的显隐和颜色。颜色未配置时，
 继续使用组件默认的主/次网格颜色：
 
@@ -543,6 +558,7 @@ scale 定位零线：
     rowCount: 2,
     columnCount: 2,
     showPagination: true,
+    fillIncompleteLastRow: true,
     trackLines: {
       voltage: {
         horizontal: false,

package.json

@@ -1,6 +1,6 @@
 {
   "name": "waveform-analysis",
-  "version": "0.1.40",
+  "version": "0.1.42",
   "main": "./dist/index.cjs",
   "module": "./dist/index.js",
   "types": "./dist/types/index.d.ts",

src/components/annotation/WaveformAnnotationEditor.css

@@ -1,3 +1,33 @@
+/* The modal is teleported to body. Keep its entire subtree namespaced so host
+   application resets (for example `button { ... }`) cannot change the editor. */
+:global(.waveform-annotation-editor-root),
+:global(.waveform-annotation-editor-root *) {
+  box-sizing: border-box;
+}
+
+:global(.waveform-annotation-editor-root) {
+  color: #344054;
+  font-family:
+    -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial,
+    'Noto Sans', sans-serif;
+  line-height: 1.5715;
+  text-align: left;
+  text-transform: none;
+}
+
+:global(.waveform-annotation-editor-root button),
+:global(.waveform-annotation-editor-root input),
+:global(.waveform-annotation-editor-root select),
+:global(.waveform-annotation-editor-root textarea) {
+  font-family: inherit;
+  letter-spacing: normal;
+  text-transform: none;
+}
+
+:global(.waveform-annotation-editor-root button) {
+  appearance: auto;
+}
+
 .waveform-annotation-editor__content {
   display: grid;
   gap: 20px;

src/components/annotation/WaveformAnnotationEditor.vue

@@ -126,6 +126,7 @@ function handleSeriesChange(event: Event) {
     cancel-text="取消"
     ok-text="保存标注"
     :ok-button-props="{ disabled: !canConfirm }"
+    root-class-name="waveform-annotation-editor-root"
     wrap-class-name="waveform-annotation-editor"
     @cancel="emit('cancel')"
     @ok="confirm"

src/components/annotation/components.test.ts

@@ -18,13 +18,14 @@ const modalStub = defineComponent({
     'cancelText',
     'okText',
     'okButtonProps',
+    'rootClassName',
   ],
   emits: ['cancel', 'ok'],
   setup(props, { emit, slots }) {
     return () => {
       const title = slots.title?.() ?? []
       const titleId = (title[0]?.props as { id?: string } | undefined)?.id
-      return h('div', { class: 'ant-modal-root' }, [
+      return h('div', { class: ['ant-modal-root', props.rootClassName] }, [
         h(
           'div',
           {
@@ -96,6 +97,18 @@ describe('waveform annotation controls', () => {
     expect(second.get('[role="dialog"]').attributes('aria-labelledby')).toBe(secondTitleId)
   })
 
+  it('uses a dedicated root class to isolate teleported modal styles', () => {
+    const wrapper = mountEditor({
+      props: {
+        annotation: { id: 'isolated', seriesId: 'a', x: 1, y: 2, text: '说明' },
+        mode: 'add',
+      },
+    })
+
+    expect(wrapper.get('.ant-modal-root').classes()).toContain('waveform-annotation-editor-root')
+    expect(wrapper.get('.ant-modal-wrap').classes()).toContain('waveform-annotation-editor')
+  })
+
   it.each(['add', 'edit'] as const)('shows the X-axis snapping hint in %s mode', (mode) => {
     const wrapper = mountEditor({
       props: {

src/components/core/fixedYDomainLayout.test.ts

@@ -35,7 +35,7 @@ function track(seriesList: DisplaySeries[]): DisplayTrack {
 }
 
 describe('fixed Y-domain layout', () => {
-  it('uses an exact global fixed domain without applying nice bounds', () => {
+  it('expands a global fixed domain to nice equal intervals', () => {
     const sourceTrack = track([series('a', 0, 100)])
     const result = buildTrackLayouts({
       cells: [
@@ -53,7 +53,13 @@ describe('fixed Y-domain layout', () => {
           series: sourceTrack,
         },
       ],
-      grid: { rowCount: 1, columnCount: 1, showPagination: false, trackLines: {} },
+      grid: {
+        rowCount: 1,
+        columnCount: 1,
+        showPagination: false,
+        fillIncompleteLastRow: false,
+        trackLines: {},
+      },
       displayMode: 'independent',
       overlayMode: 'single-axis',
       independentTransforms: [zoomIdentity],
@@ -66,10 +72,92 @@ describe('fixed Y-domain layout', () => {
       showCompactEmptyTracks: false,
     })[0]
 
-    expect(result?.yScale.domain()).toEqual([3, 97])
+    expect(result?.yScale.domain()).toEqual([0, 100])
-    expect(result?.yAxes[0]?.tickValues).toContain(3)
+    expect(result?.yAxes[0]?.tickValues).toContain(0)
-    expect(result?.yAxes[0]?.tickValues).toContain(97)
+    expect(result?.yAxes[0]?.tickValues).toContain(100)
-    expect(result?.seriesPaths[0]?.yScale.domain()).toEqual([3, 97])
+    expect(result?.seriesPaths[0]?.yScale.domain()).toEqual([0, 100])
+  })
+
+  it('uses the configured split number for fixed domains', () => {
+    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: track([series('a', 0, 100)]),
+        },
+      ],
+      grid: {
+        rowCount: 1,
+        columnCount: 1,
+        showPagination: false,
+        fillIncompleteLastRow: false,
+        trackLines: {},
+      },
+      displayMode: 'independent',
+      overlayMode: 'single-axis',
+      independentTransforms: [zoomIdentity],
+      sharedZoomDomain: [0, 1],
+      fixedYDomain: [3, 97],
+      yAxisSplitNumber: 5,
+      timeUnit: 'ms',
+      rendering: DEFAULT_WAVEFORM_RENDERING_OPTIONS,
+      hideSecondaryLabels: false,
+      yAxisLabelX: -50,
+      showCompactEmptyTracks: false,
+    })[0]
+
+    expect(result?.yAxes[0]?.majorTicks).toEqual([0, 25, 50, 75, 100])
+  })
+
+  it('defaults to five ticks and supports a two-tick axis', () => {
+    const build = (splitNumber?: number) =>
+      buildTrackLayouts({
+        cells: [
+          {
+            slotIndex: 0,
+            row: 0,
+            column: 0,
+            left: 0,
+            top: 0,
+            width: 120,
+            height: 100,
+            plotHeight: 100,
+            cellHeight: 130,
+            xAxisBand: 30,
+            series: track([series('a', 3, 97)]),
+          },
+        ],
+        grid: {
+          rowCount: 1,
+          columnCount: 1,
+          showPagination: false,
+          fillIncompleteLastRow: false,
+          trackLines: {},
+        },
+        displayMode: 'independent',
+        overlayMode: 'single-axis',
+        independentTransforms: [zoomIdentity],
+        sharedZoomDomain: [0, 1],
+        fixedYDomain: [3, 97],
+        yAxisSplitNumber: splitNumber,
+        timeUnit: 'ms',
+        rendering: DEFAULT_WAVEFORM_RENDERING_OPTIONS,
+        hideSecondaryLabels: false,
+        yAxisLabelX: -50,
+        showCompactEmptyTracks: false,
+      })[0]?.yAxes[0]?.majorTicks
+
+    expect(build()).toHaveLength(5)
+    expect(build(2)).toEqual([0, 100])
   })
 
   it('resolves track, series, and global fixed-domain precedence', () => {

src/components/core/grid.test.ts

@@ -15,12 +15,14 @@ describe('waveform grid helpers', () => {
       rowCount: 2,
       columnCount: 1,
       showPagination: true,
+      fillIncompleteLastRow: false,
       trackLines: {},
     })
     expect(normalizeGridOptions({ rowCount: 0, columnCount: 99 })).toEqual({
       rowCount: 1,
       columnCount: 10,
       showPagination: true,
+      fillIncompleteLastRow: false,
       trackLines: {},
     })
   })
@@ -131,4 +133,50 @@ describe('waveform grid helpers', () => {
     expect(cells[1].left).toBe(232)
     expect(cells[2].top).toBe(cells[0].plotHeight + X_AXIS_BAND + 14)
   })
+
+  it('fills incomplete final rows without changing page capacity', () => {
+    const oneColumn = resolveGridCellGeometry(
+      400,
+      400,
+      normalizeGridOptions({ rowCount: 4, columnCount: 1, fillIncompleteLastRow: true }),
+      'separated',
+      [true, true, true],
+    )
+    expect(oneColumn).toHaveLength(3)
+    expect(oneColumn.map((cell) => cell.width)).toEqual([400, 400, 400])
+    expect(oneColumn.at(-1)?.isLastRow).toBe(true)
+
+    const twoColumns = resolveGridCellGeometry(
+      400,
+      300,
+      normalizeGridOptions({ rowCount: 2, columnCount: 2, fillIncompleteLastRow: true }),
+      'separated',
+      [true, true, true],
+    )
+    expect(twoColumns).toHaveLength(3)
+    expect(twoColumns[2]).toMatchObject({ row: 1, column: 0, left: 0, width: 400 })
+
+    const threeColumns = resolveGridCellGeometry(
+      400,
+      300,
+      normalizeGridOptions({ rowCount: 2, columnCount: 3, fillIncompleteLastRow: true }),
+      'separated',
+      [true, true, true, true, true],
+    )
+    expect(threeColumns).toHaveLength(5)
+    expect(threeColumns.slice(3).map((cell) => cell.width)).toEqual([192, 192])
+    expect(threeColumns.slice(3).map((cell) => cell.left)).toEqual([0, 208])
+  })
+
+  it('keeps full pages and the disabled option byte-for-byte compatible', () => {
+    const base = normalizeGridOptions({ rowCount: 2, columnCount: 2 })
+    const filled = normalizeGridOptions({ rowCount: 2, columnCount: 2, fillIncompleteLastRow: true })
+    const fullSlots = [true, true, true, true]
+    expect(resolveGridCellGeometry(400, 300, filled, 'independent', fullSlots)).toEqual(
+      resolveGridCellGeometry(400, 300, base, 'independent', fullSlots),
+    )
+    expect(resolveGridCellGeometry(400, 300, base, 'independent', [true, true, true])).toHaveLength(
+      4,
+    )
+  })
 })

src/components/core/grid.ts

@@ -8,6 +8,7 @@ export interface WaveformGridOptions {
   rowCount?: number
   columnCount?: number
   showPagination?: boolean
+  fillIncompleteLastRow?: boolean
   trackLines?: WaveformGridTrackLines
 }
 
@@ -33,6 +34,7 @@ export interface NormalizedWaveformGridOptions {
   rowCount: number
   columnCount: number
   showPagination: boolean
+  fillIncompleteLastRow: boolean
   trackLines: Record<string, NormalizedWaveformGridLineOptions>
 }
 
@@ -48,6 +50,7 @@ export interface GridCellGeometry {
   plotHeight: number
   cellHeight: number
   xAxisBand: number
+  isLastRow?: boolean
 }
 
 const normalizeCount = (value: unknown, fallback: number) => {
@@ -78,6 +81,7 @@ export function normalizeGridOptions(options?: WaveformGridOptions): NormalizedW
     rowCount: normalizeCount(options?.rowCount, 2),
     columnCount: normalizeCount(options?.columnCount, 1),
     showPagination: options?.showPagination ?? true,
+    fillIncompleteLastRow: options?.fillIncompleteLastRow ?? false,
     trackLines,
   }
 }
@@ -114,20 +118,23 @@ export function resolveGridCellGeometry(
   horizontalGap?: number,
   showXAxis = true,
 ): GridCellGeometry[] {
+  const pageSize = getPageSize(options)
+  const seriesCount = slotHasSeries.filter(Boolean).length
+  const filledLastRow = options.fillIncompleteLastRow && seriesCount > 0 && seriesCount < pageSize
+  const rowCount = filledLastRow ? Math.ceil(seriesCount / options.columnCount) : options.rowCount
   const defaultGap = getGridGap(displayMode)
   const columnGap = Number.isFinite(horizontalGap)
     ? Math.max(0, horizontalGap as number)
     : defaultGap
-  const totalHorizontalGap = Math.max(0, options.columnCount - 1) * columnGap
   const axisRows = new Set<number>()
   if (!showXAxis) {
     // Net view uses the full drawing area for waveform pixels.
   } else if (displayMode === 'independent') {
-    for (let row = 0; row < options.rowCount; row += 1) axisRows.add(row)
+    for (let row = 0; row < rowCount; row += 1) axisRows.add(row)
   } else if (displayMode === 'compact') {
     // Compact tracks share one continuous plot stack. Reserve the X-axis band
     // only beneath the final grid row, including when that row is empty.
-    axisRows.add(options.rowCount - 1)
+    axisRows.add(rowCount - 1)
   } else {
     for (let column = 0; column < options.columnCount; column += 1) {
       for (let slotIndex = getPageSize(options) - 1; slotIndex >= 0; slotIndex -= 1) {
@@ -139,17 +146,22 @@ export function resolveGridCellGeometry(
       }
     }
   }
-  const totalVerticalGap = Math.max(0, options.rowCount - 1) * defaultGap
+  const totalVerticalGap = Math.max(0, rowCount - 1) * defaultGap
   const totalAxisBand = axisRows.size * X_AXIS_BAND
-  const width = Math.max(1, (innerWidth - totalHorizontalGap) / options.columnCount)
   const plotHeight = Math.max(
     1,
-    (innerHeight - totalVerticalGap - totalAxisBand) / options.rowCount,
+    (innerHeight - totalVerticalGap - totalAxisBand) / rowCount,
   )
 
-  return Array.from({ length: getPageSize(options) }, (_, slotIndex) => {
+  return Array.from({ length: filledLastRow ? seriesCount : pageSize }, (_, slotIndex) => {
     const row = Math.floor(slotIndex / options.columnCount)
     const column = slotIndex % options.columnCount
+    const rowSeriesCount =
+      filledLastRow && row === rowCount - 1
+        ? seriesCount - row * options.columnCount
+        : options.columnCount
+    const rowGap = Math.max(0, rowSeriesCount - 1) * columnGap
+    const width = Math.max(1, (innerWidth - rowGap) / rowSeriesCount)
     const xAxisBand = axisRows.has(row) ? X_AXIS_BAND : 0
     const cellHeight = plotHeight + xAxisBand
     const top = Array.from({ length: row }, (_, previousRow) => {
@@ -167,6 +179,7 @@ export function resolveGridCellGeometry(
       plotHeight,
       cellHeight,
       xAxisBand,
+      isLastRow: row === rowCount - 1,
     }
   })
 }

src/components/core/layout.test.ts

@@ -9,6 +9,7 @@ import {
   findClosestTrackAtPointer,
   MAX_MULTI_Y_AXIS_COUNT,
   measureYAxisGroupClearance,
+  resolveYAxisTickCount,
 } from './layout'
 
 function series(id: string, minimum: number, maximum: number): DisplaySeries {
@@ -64,7 +65,13 @@ function layoutForSeries(
         series: sourceTrack,
       },
     ],
-    grid: { rowCount: 1, columnCount: 1, showPagination: false, trackLines: {} },
+    grid: {
+      rowCount: 1,
+      columnCount: 1,
+      showPagination: false,
+      fillIncompleteLastRow: false,
+      trackLines: {},
+    },
     displayMode: 'independent',
     overlayMode: 'single-axis',
     independentTransforms: [transform],
@@ -106,7 +113,13 @@ describe('multi-value Y-axis grouping', () => {
           series: sourceTrack,
         },
       ],
-      grid: { rowCount: 1, columnCount: 1, showPagination: false, trackLines: {} },
+      grid: {
+        rowCount: 1,
+        columnCount: 1,
+        showPagination: false,
+        fillIncompleteLastRow: false,
+        trackLines: {},
+      },
       displayMode: 'independent',
       overlayMode: 'single-axis',
       independentTransforms: [zoomIdentity],
@@ -119,8 +132,15 @@ describe('multi-value Y-axis grouping', () => {
       showCompactEmptyTracks: false,
     })[0]
 
-    expect(result?.yScale.domain()).toEqual([25, 75])
+    expect(result?.yScale.domain()).toEqual([20, 80])
-    expect(result?.seriesPaths[0]?.yScale.domain()).toEqual([25, 75])
+    expect(result?.seriesPaths[0]?.yScale.domain()).toEqual([20, 80])
+  })
+
+  it('normalizes configured Y-axis split counts', () => {
+    expect(resolveYAxisTickCount(100, 0)).toBe(2)
+    expect(resolveYAxisTickCount(100, 4.8)).toBe(4)
+    expect(resolveYAxisTickCount(100, Number.NaN)).toBe(5)
+    expect(resolveYAxisTickCount(220)).toBe(5)
   })
 
   it('keeps every overlaid series on one axis in single-axis mode', () => {
@@ -209,7 +229,13 @@ describe('multi-value Y-axis grouping', () => {
           series: track([series('left', 1000, 3000), series('right', 1000, 3000)]),
         },
       ],
-      grid: { rowCount: 1, columnCount: 1, showPagination: false, trackLines: {} },
+      grid: {
+        rowCount: 1,
+        columnCount: 1,
+        showPagination: false,
+        fillIncompleteLastRow: false,
+        trackLines: {},
+      },
       displayMode: 'independent',
       overlayMode: 'multi-axis',
       independentTransforms: [zoomIdentity],

src/components/core/layout.ts

@@ -20,6 +20,13 @@ const Y_AXIS_OUTER_PADDING = 4
 const Y_AXIS_LABEL_GAP = 6
 const Y_AXIS_LABEL_BAND_WIDTH = 24
 
+export function resolveYAxisTickCount(_plotHeight: number, splitNumber?: number): number {
+  if (typeof splitNumber === 'number' && Number.isFinite(splitNumber)) {
+    return Math.max(2, Math.floor(splitNumber))
+  }
+  return 5
+}
+
 export interface YAxisSeriesGroup {
   index: number
   side: 'left' | 'right'
@@ -104,11 +111,16 @@ export function axisTextMetrics(
   nice = true,
   tickValues?: number[],
   unit?: string,
+  tickCount = 10,
 ): { tickTextWidth: number } {
+  const effectiveTickCount =
+    typeof tickCount === 'number' && Number.isFinite(tickCount)
+      ? Math.max(2, Math.floor(tickCount))
+      : 10
   const scale = scaleLinear(domain, [1, 0])
-  if (nice) scale.nice()
+  if (nice) scale.nice(effectiveTickCount)
   const [axisMin, axisMax] = scale.domain()
-  const values = tickValues ?? Array.from(new Set([axisMin, ...scale.ticks(10), axisMax]))
+  const values = tickValues ?? scale.ticks(effectiveTickCount)
   const topTickValue = Math.max(...values)
   const maximumTickCharacters = Math.max(
     1,
@@ -121,9 +133,9 @@ export function axisTextMetrics(
   }
 }
 
-export function measureYAxisGroupClearance(group: YAxisSeriesGroup): number {
+export function measureYAxisGroupClearance(group: YAxisSeriesGroup, tickCount?: number): number {
   return (
-    axisTextMetrics(group.domain, !group.fixed, undefined, group.seriesList[0]?.unit)
+    axisTextMetrics(group.domain, true, undefined, group.seriesList[0]?.unit, tickCount)
       .tickTextWidth +
     Y_AXIS_TICK_PADDING +
     Y_AXIS_LABEL_GAP +
@@ -132,9 +144,9 @@ export function measureYAxisGroupClearance(group: YAxisSeriesGroup): number {
   )
 }
 
-function measureYAxisGroupTickClearance(group: YAxisSeriesGroup): number {
+function measureYAxisGroupTickClearance(group: YAxisSeriesGroup, tickCount?: number): number {
   return (
-    axisTextMetrics(group.domain, !group.fixed, undefined, group.seriesList[0]?.unit)
+    axisTextMetrics(group.domain, true, undefined, group.seriesList[0]?.unit, tickCount)
       .tickTextWidth +
     Y_AXIS_TICK_PADDING +
     Y_AXIS_OUTER_PADDING
@@ -146,13 +158,14 @@ export function measureTrackYAxisClearance(
   overlayMode: WaveformOverlayMode,
   yDomain?: WaveformYDomain,
   yDomains?: Record<string, WaveformYDomain>,
+  tickCount?: number,
 ): { left: number; right: number } {
   return resolveYAxisSeriesGroups(track, overlayMode, yDomain, yDomains).reduce(
     (clearance, group) => {
       clearance[group.side] +=
         overlayMode === 'multi-axis' || track.visibleSeries.length === 1
-          ? measureYAxisGroupClearance(group)
+          ? measureYAxisGroupClearance(group, tickCount)
-          : measureYAxisGroupTickClearance(group)
+          : measureYAxisGroupTickClearance(group, tickCount)
       return clearance
     },
     { left: 0, right: 0 },

src/components/core/trackLayoutBuilder.ts

@@ -25,7 +25,7 @@ import {
   type GridCellGeometry,
   type NormalizedWaveformGridOptions,
 } from './grid'
-import { axisTextMetrics, resolveYAxisSeriesGroups } from './layout'
+import { axisTextMetrics, resolveYAxisSeriesGroups, resolveYAxisTickCount } from './layout'
 import type { DisplaySeries, DisplayTrack, TrackLayout, WaveformYAxisLayout } from './types'
 import { applyXDomainStrategy } from './xDomain'
 import {
@@ -54,6 +54,7 @@ export interface BuildTrackLayoutsOptions {
   yDomains?: Record<string, [number, number]>
   timeUnit: 's' | 'ms'
   xAxisLabelFormatter?: WaveformXAxisLabelFormatter
+  yAxisSplitNumber?: number
   rendering: ResolvedWaveformRenderingOptions
   hideSecondaryLabels: boolean
   yAxisLabelX: number
@@ -124,22 +125,26 @@ export function buildTrackLayouts(options: BuildTrackLayoutsOptions): TrackLayou
     )
     const sideOffsets = { left: 0, right: 0 }
     const yAxes: WaveformYAxisLayout[] = yAxisGroups.map((group) => {
+      const tickCount = resolveYAxisTickCount(cell.plotHeight, options.yAxisSplitNumber)
+      const niceCount = Math.max(1, tickCount - 1)
       const scale = scaleLinear(group.domain, [cell.plotHeight, 0])
-      if (!group.fixed) scale.nice()
+      scale.nice(niceCount)
-      const majorTicks = scale.ticks(Math.max(2, Math.floor(cell.plotHeight / 55)))
       const [axisStart, axisEnd] = scale.domain()
+      const majorTicks = Array.from(
+        { length: tickCount },
+        (_, index) => axisStart + ((axisEnd - axisStart) * index) / (tickCount - 1),
+      )
       const showAxisEnd = options.displayMode !== 'compact' || cell.row === 0
       const visibleMajorTicks = showAxisEnd
         ? majorTicks
         : majorTicks.filter((tick) => tick !== axisEnd)
-      const tickValues = Array.from(
+      const tickValues = visibleMajorTicks
-        new Set([axisStart, ...visibleMajorTicks, ...(showAxisEnd ? [axisEnd] : [])]),
-      )
       const { tickTextWidth } = axisTextMetrics(
-        group.domain,
+        scale.domain() as [number, number],
-        !group.fixed,
+        false,
         tickValues,
         group.seriesList[0]?.unit,
+        tickCount,
       )
       const clearance =
         tickTextWidth +
@@ -261,7 +266,7 @@ export function buildTrackLayouts(options: BuildTrackLayoutsOptions): TrackLayou
         (isEmpty || hasVisibleSeries) &&
         (options.displayMode === 'independent' ||
           (options.displayMode === 'compact'
-            ? cell.row === options.grid.rowCount - 1
+            ? (cell.isLastRow ?? cell.row === options.grid.rowCount - 1)
             : bottomCells.has(cell.slotIndex))),
     }
   })

src/components/core/useWaveformChartLifecycle.ts

@@ -11,6 +11,7 @@ import {
 
 import type { AnnotationSeriesCandidate } from '../annotation'
 import type { useWaveformAnnotationInteraction } from '../annotation'
+import type { NormalizedWaveformGridOptions } from './grid'
 import type { DisplaySeries, DisplayTrack, TrackLayout } from './types'
 import type { ResolvedWaveformChartProps, WaveformChartEmit } from './waveformChartTypes'
 import { constrainZoomDomain, transformForDomain } from '../interaction/zoomConstraints'
@@ -33,7 +34,7 @@ interface LifecycleContext {
   currentPage: Ref<number>
   pageCount: ComputedRef<number>
   pagedTracks: ComputedRef<Array<DisplayTrack | undefined>>
-  gridOptions: ComputedRef<{ rowCount: number; columnCount: number }>
+  gridOptions: ComputedRef<NormalizedWaveformGridOptions>
   chartSeries: ComputedRef<DisplaySeries[]>
   chartTracks: ComputedRef<DisplayTrack[]>
   trackLayouts: ComputedRef<TrackLayout[]>
@@ -220,6 +221,7 @@ export function useWaveformChartLifecycle(context: LifecycleContext) {
       currentPage,
       () => gridOptions.value.rowCount,
       () => gridOptions.value.columnCount,
+      () => gridOptions.value.fillIncompleteLastRow,
       activeInteractionMode,
     ],
     async () => {
@@ -239,7 +241,14 @@ export function useWaveformChartLifecycle(context: LifecycleContext) {
     },
   )
 
-  watch([pageCount, () => props.grid?.rowCount, () => props.grid?.columnCount], () => {
+  watch(
+    [
+      pageCount,
+      () => props.grid?.rowCount,
+      () => props.grid?.columnCount,
+      () => props.grid?.fillIncompleteLastRow,
+    ],
+    () => {
       const previousPage = currentPage.value
       currentPage.value =
         currentPage.value > pageCount.value
@@ -252,7 +261,8 @@ export function useWaveformChartLifecycle(context: LifecycleContext) {
       }
       clearHover()
       void nextTick(configureZoom)
-  })
+    },
+  )
 
   watch(activeInteractionMode, () => {
     editorSeriesOptions.value = []

src/components/core/useWaveformLayout.ts

@@ -114,8 +114,13 @@ export function useWaveformLayout(context: LayoutContext) {
       )
       .map(
         (group) =>
-          axisTextMetrics(group.domain, !group.fixed, undefined, group.seriesList[0]?.unit)
+          axisTextMetrics(
-            .tickTextWidth,
+            group.domain,
+            true,
+            undefined,
+            group.seriesList[0]?.unit,
+            props.axes?.y?.splitNumber,
+          ).tickTextWidth,
       )
     const tickTextWidth = Math.max(Y_AXIS_CHARACTER_WIDTH, ...axisText)
     const tickClearance = tickTextWidth + Y_AXIS_TICK_PADDING + Y_AXIS_OUTER_PADDING
@@ -161,6 +166,7 @@ export function useWaveformLayout(context: LayoutContext) {
           props.overlayMode,
           props.yDomain,
           props.yDomains,
+          props.axes?.y?.splitNumber,
         )
         return {
           left: Math.max(maximum.left, clearance.left),
@@ -302,6 +308,7 @@ export function useWaveformLayout(context: LayoutContext) {
           : sharedYDomains.value,
       timeUnit: props.timeUnit,
       xAxisLabelFormatter: props.axes?.x?.labelFormatter,
+      yAxisSplitNumber: props.axes?.y?.splitNumber,
       rendering: renderingOptions.value,
       hideSecondaryLabels: isCleanView.value || yAxisLayout.value.hideSecondaryLabels,
       yAxisLabelX: yAxisMetrics.value.labelCenterX,

src/components/waveformChartCases/compactAndSharedHover.test.ts

@@ -65,9 +65,9 @@ describe('WaveformChart', () => {
     )
 
     expect(endTicks[0]).toHaveLength(1)
-    expect(Number(endTicks[0][0].text())).toBe(0.9)
+    expect(Number(endTicks[0][0].text())).toBe(1)
     expect(endTicks[1]).toHaveLength(1)
-    expect(Number(endTicks[1][0].text())).toBe(1.9)
+    expect(Number(endTicks[1][0].text())).toBe(2)
     expect(endTicks[2]).toHaveLength(0)
     expect(endTicks[3]).toHaveLength(0)
   })

src/components/waveformChartCases/dataLifecycle.test.ts

@@ -261,7 +261,7 @@ describe('WaveformChart', () => {
       })
 
       expect(startTicks).toHaveLength(1)
-      expect(Number(startTicks[0].text())).toBe(0.1)
+      expect(Number(startTicks[0].text())).toBe(0)
     },
   )
 
@@ -297,7 +297,7 @@ describe('WaveformChart', () => {
         { displayMode },
       )
 
-      const expectedEndValues = [0.9, 4.9]
+      const expectedEndValues = [1, 5]
       wrapper.findAll('.waveform-chart__track').forEach((track, index) => {
         const endTicks = track.findAll('.waveform-chart__axis--y .tick').filter((tick) => {
           const match = tick.attributes('transform')?.match(/translate\(0,\s*([\d.]+)\)/)

src/components/waveformChartCases/gridFill.test.ts

@@ -0,0 +1,95 @@
+import { flushPromises } from '@vue/test-utils'
+import { describe, expect, it } from 'vitest'
+
+import { gridSeries, mountSizedChart } from '../../test/waveformChart'
+
+function geometry(track: { attributes: (name: string) => string | undefined }) {
+  return {
+    left: Number(track.attributes('data-track-left')),
+    top: Number(track.attributes('data-track-top')),
+    width: Number(track.attributes('data-track-width')),
+    height: Number(track.attributes('data-track-height')),
+  }
+}
+
+describe('WaveformChart incomplete grid rows', () => {
+  it.each(['independent', 'separated', 'compact'] as const)(
+    'fills an incomplete two by two row in %s mode',
+    async (displayMode) => {
+      const wrapper = await mountSizedChart(gridSeries(3), {
+        displayMode,
+        grid: { rowCount: 2, columnCount: 2, fillIncompleteLastRow: true },
+      })
+      const tracks = wrapper.findAll('.waveform-chart__track')
+      const first = geometry(tracks[0]!)
+      const last = geometry(tracks[2]!)
+
+      expect(tracks).toHaveLength(3)
+      expect(wrapper.findAll('.waveform-chart__track--empty')).toHaveLength(0)
+      expect(wrapper.findAll('.waveform-chart__grid-slot-placeholder')).toHaveLength(0)
+      expect(last.left).toBe(0)
+      expect(last.width).toBeGreaterThan(first.width * 1.8)
+      expect(last.top).toBeGreaterThan(first.top)
+      if (displayMode === 'independent') {
+        const overlays = wrapper.findAll('.waveform-chart__overlay--independent')
+        expect(overlays).toHaveLength(3)
+        expect(Number(overlays[2]?.attributes('width'))).toBe(last.width)
+      } else {
+        expect(wrapper.findAll('.waveform-chart__overlay--shared')).toHaveLength(1)
+      }
+    },
+  )
+
+  it('removes unused one-column rows and redistributes chart height', async () => {
+    const base = await mountSizedChart(gridSeries(3), {
+      displayMode: 'independent',
+      grid: { rowCount: 4, columnCount: 1 },
+    })
+    const filled = await mountSizedChart(gridSeries(3), {
+      displayMode: 'independent',
+      grid: { rowCount: 4, columnCount: 1, fillIncompleteLastRow: true },
+    })
+    const baseFirst = geometry(base.findAll('.waveform-chart__track')[0]!)
+    const filledTracks = filled.findAll('.waveform-chart__track')
+    const filledFirst = geometry(filledTracks[0]!)
+    const filledLast = geometry(filledTracks[2]!)
+
+    expect(filledTracks).toHaveLength(3)
+    expect(filledFirst.height).toBeGreaterThan(baseFirst.height)
+    expect(filledLast.top + filledLast.height).toBeGreaterThan(baseFirst.height * 3)
+  })
+
+  it('keeps the final two tracks evenly distributed in a two by three grid', async () => {
+    const wrapper = await mountSizedChart(gridSeries(5), {
+      displayMode: 'separated',
+      grid: { rowCount: 2, columnCount: 3, fillIncompleteLastRow: true },
+    })
+    const tracks = wrapper.findAll('.waveform-chart__track').map(geometry)
+
+    expect(tracks).toHaveLength(5)
+    expect(tracks[3]?.left).toBe(0)
+    expect(tracks[3]?.width).toBeCloseTo(tracks[4]?.width ?? 0)
+    expect(tracks[4]?.left).toBeGreaterThan((tracks[3]?.width ?? 0) + 1)
+  })
+
+  it('keeps full pages unchanged and fills a partial second page', async () => {
+    const data = gridSeries(5)
+    const standard = await mountSizedChart(data, {
+      displayMode: 'separated',
+      grid: { rowCount: 2, columnCount: 2 },
+    })
+    const filled = await mountSizedChart(data, {
+      displayMode: 'separated',
+      grid: { rowCount: 2, columnCount: 2, fillIncompleteLastRow: true },
+    })
+    const standardFirstPage = standard.findAll('.waveform-chart__track').map(geometry)
+    expect(filled.findAll('.waveform-chart__track').map(geometry)).toEqual(standardFirstPage)
+
+    await filled.get('.ant-pagination-next button').trigger('click')
+    await flushPromises()
+    const secondPage = filled.findAll('.waveform-chart__track').map(geometry)
+    expect(secondPage).toHaveLength(1)
+    expect(secondPage[0]?.left).toBe(0)
+    expect(secondPage[0]?.width).toBeGreaterThan(standardFirstPage[0]?.width ?? 0)
+  })
+})

src/components/waveformChartCases/layoutAndDomains.test.ts

@@ -6,6 +6,26 @@ import { resizeObservers } from '../../test/setup'
 import { gridSeries, mountSizedChart } from '../../test/waveformChart'
 
 describe('WaveformChart', () => {
+  it('applies the configured Y-axis split number', async () => {
+    const wrapper = await mountSizedChart(
+      {
+        kind: 'points',
+        points: [
+          { x: 0, y: 3 },
+          { x: 1, y: 97 },
+        ],
+      },
+      { axes: { y: { splitNumber: 5 } } },
+    )
+
+    expect(
+      wrapper
+        .get('.waveform-chart__axis--y')
+        .findAll('.tick text')
+        .map((tick) => tick.text()),
+    ).toEqual(['0', '25', '50', '75', '100'])
+  })
+
   it('expands the Y-axis label gutter for signed values and long exponents', async () => {
     const wrapper = await mountSizedChart(
       {
@@ -296,7 +316,7 @@ describe('WaveformChart', () => {
     expect(wrapper.get('.waveform-chart__axis-endpoint--end').text()).toBe('1000')
   })
 
-  it('reacts to exact fixed Y-domain props and returns to automatic bounds', async () => {
+  it('reacts to nice fixed Y-domain props and returns to automatic bounds', async () => {
     const wrapper = await mountSizedChart({
       kind: 'points',
       points: [
@@ -312,8 +332,8 @@ describe('WaveformChart', () => {
 
     await wrapper.setProps({ yDomain: [3, 97] })
     await flushPromises()
-    expect(yTickLabels()).toContain('3')
+    expect(yTickLabels()).toContain('0')
-    expect(yTickLabels()).toContain('97')
+    expect(yTickLabels()).toContain('100')
 
     await wrapper.setProps({ yDomain: undefined })
     await flushPromises()

src/types/chart.ts

@@ -174,6 +174,8 @@ export interface WaveformAxesOptions {
   }
   y?: {
     lineVisible?: boolean
+    /** Target total number of equal Y-axis ticks, including endpoints. Defaults to 5. */
+    splitNumber?: number
   }
 }