bokeh · bryevdv · Jul 31, 2024 · Jul 20, 2024 · Jul 21, 2024
diff --git a/bokehjs/src/lib/models/tickers/customjs_ticker.ts b/bokehjs/src/lib/models/tickers/customjs_ticker.ts
@@ -0,0 +1,93 @@
+import type {FactorTickSpec} from "./categorical_ticker"
+import type {TickSpec} from "./ticker"
+import {Ticker} from "./ticker"
+import {FactorRange} from "../ranges/factor_range"
+import type {Range} from "../ranges/range"
+import type * as p from "core/properties"
+import type {Dict} from "core/types"
+import {keys, values} from "core/util/object"
+import {use_strict} from "core/util/string"
+
+type MajorCBData = {
+  start: number
+  end: number
+  range: Range
+  cross_loc: number
+}
+
+type MinorCBData = MajorCBData & {
+  major_ticks: any[]
+}
+
+export namespace CustomJSTicker {
+  export type Attrs = p.AttrsOf<Props>
+
+  export type Props = Ticker.Props & {
+    args: p.Property<Dict<unknown>>
+    major_code: p.Property<string>
+    minor_code: p.Property<string>
+  }
+}
+
+export interface CustomJSTicker extends CustomJSTicker.Attrs {}
+
+export class CustomJSTicker extends Ticker {
+  declare properties: CustomJSTicker.Props
+
+  constructor(attrs?: Partial<CustomJSTicker.Attrs>) {
+    super(attrs)
+  }
+
+  static {
+    this.define<CustomJSTicker.Props>(({Unknown, Str, Dict}) => ({
+      args: [ Dict(Unknown), {} ],
+      major_code: [ Str, "" ],
+      minor_code: [ Str, "" ],
+    }))
+  }
+
+  get names(): string[] {
+    return keys(this.args)
+  }
+
+  get values(): unknown[] {
+    return values(this.args)
+  }
+
+  get_ticks(start: number, end: number, range: Range, cross_loc: number): TickSpec<number> | FactorTickSpec {
+    const major_cb_data = {start, end, range, cross_loc}
+    const major_ticks = this.major_ticks(major_cb_data)
+
+    // CustomJSTicker for categorical axes only support a single level of major ticks
+    if (range instanceof FactorRange) {
+      return {major: major_ticks, minor: [], tops: [], mids: []}
+    }
+
+    const minor_cb_data = {major_ticks, ...major_cb_data}
+    const minor_ticks = this.minor_ticks(minor_cb_data)
+
+    return {
+      major: major_ticks,
+      minor: minor_ticks,
+    }
+  }
+
+  protected major_ticks(cb_data: MajorCBData): any[] {
+    if (this.major_code == "") {
+      return []
+    }
+    const code = use_strict(this.major_code)
+    const func = new Function("cb_data", ...this.names, code)
+    return func(cb_data, ...this.values)
+  }
+
+  protected minor_ticks(cb_data: MinorCBData): any[] {
+    if (this.minor_code == "") {
+      return []
+    }
+    const code = use_strict(this.minor_code)
+    const func = new Function("cb_data", ...this.names, code)
+    return func(cb_data, ...this.values)
+  }
+
+}
diff --git a/bokehjs/src/lib/models/tickers/index.ts b/bokehjs/src/lib/models/tickers/index.ts
@@ -3,6 +3,7 @@ export {BasicTicker}          from "./basic_ticker"
 export {CategoricalTicker}    from "./categorical_ticker"
 export {CompositeTicker}      from "./composite_ticker"
 export {ContinuousTicker}     from "./continuous_ticker"
+export {CustomJSTicker}       from "./customjs_ticker"
 export {DatetimeTicker}       from "./datetime_ticker"
 export {DaysTicker}           from "./days_ticker"
 export {FixedTicker}          from "./fixed_ticker"

diff --git a/bokehjs/test/unit/base.ts b/bokehjs/test/unit/base.ts
@@ -105,6 +105,7 @@ describe("default model resolver", () => {
       "CustomJSFilter",
       "CustomJSHover",
       "CustomJSTickFormatter",
+      "CustomJSTicker",
       "CustomJSTransform",
       "CustomLabelingPolicy",
       "DataCube",

diff --git a/bokehjs/test/unit/models/tickers/customjs_ticker.ts b/bokehjs/test/unit/models/tickers/customjs_ticker.ts
@@ -0,0 +1,106 @@
+import {expect} from "assertions"
+
+import {CustomJSTicker} from "@bokehjs/models/tickers/customjs_ticker"
+import type {FactorTickSpec} from "@bokehjs/models/tickers/categorical_ticker"
+import {FactorRange} from "@bokehjs/models/ranges/factor_range"
+import {Range1d} from "@bokehjs/models/ranges/range1d"
+
+describe("CustomJSTicker Model", () => {
+
+  describe("Continuous get_ticks method", () => {
+    it("should handle case with no major_code", () => {
+      const ticker = new CustomJSTicker()
+      const range = new Range1d({start: -1, end: 11})
+      const ticks = ticker.get_ticks(0, 10, range, NaN)
+      expect(ticks.major).to.be.equal([])
+      expect(ticks.minor).to.be.equal([])
+    })
+
+    it("should return major_code result", () => {
+      const ticker = new CustomJSTicker({major_code: "return [2,4,6,8]"})
+      const range = new Range1d({start: -1, end: 11})
+      const ticks = ticker.get_ticks(0, 10, range, NaN)
+      expect(ticks.major).to.be.equal([2, 4, 6, 8])
+      expect(ticks.minor).to.be.equal([])
+    })
+
+    it("should pass start and end to major_code", () => {
+      const ticker = new CustomJSTicker({major_code: "return [cb_data.start, cb_data.end]"})
+      const range = new Range1d({start: -1, end: 11})
+      const ticks = ticker.get_ticks(0, 10, range, NaN)
+      expect(ticks.major).to.be.equal([0, 10])
+      expect(ticks.minor).to.be.equal([])
+    })
+
+    it("should pass range to major_code", () => {
+      const ticker = new CustomJSTicker({major_code: "return [cb_data.range.start, cb_data.range.end]"})
+      const range = new Range1d({start: -1, end: 11})
+      const ticks = ticker.get_ticks(0, 10, range, NaN)
+      expect(ticks.major).to.be.equal([-1, 11])
+      expect(ticks.minor).to.be.equal([])
+    })
+
+    it("should pass cross_loc to major_code", () => {
+      const ticker = new CustomJSTicker({major_code: "return [cb_data.cross_loc]"})
+      const range = new Range1d({start: -1, end: 11})
+      const ticks = ticker.get_ticks(0, 10, range, 20)
+      expect(ticks.major).to.be.equal([20])
+      expect(ticks.minor).to.be.equal([])
+    })
+
+  })
+
+  describe("Categorical get_ticks method", () => {
+
+    it("should handle case with no major_code", () => {
+      const ticker = new CustomJSTicker()
+      const range = new FactorRange({factors: ["foo", "bar", "baz"]})
+      const ticks = ticker.get_ticks(0, 10, range, NaN) as FactorTickSpec
+      expect(ticks.major).to.be.equal([])
+      expect(ticks.minor).to.be.equal([])
+      expect(ticks.mids).to.be.equal([])
+      expect(ticks.tops).to.be.equal([])
+    })
+
+    it("should handle case where range has factors", () => {
+      const ticker = new CustomJSTicker({major_code: "return['foo', 'baz']"})
+      const range = new FactorRange({factors: ["foo", "bar", "baz"]})
+      const ticks = ticker.get_ticks(0, 3, range, NaN) as FactorTickSpec
+      expect(ticks.major).to.be.equal(["foo", "baz"])
+      expect(ticks.minor).to.be.equal([])
+      expect(ticks.mids).to.be.equal([])
+      expect(ticks.tops).to.be.equal([])
+    })
+
+    it("should pass start and end to major_code", () => {
+      const ticker = new CustomJSTicker({major_code: "return [cb_data.start.toString(), cb_data.end.toString()]"})
+      const range = new FactorRange({factors: ["foo", "bar", "baz"]})
+      const ticks = ticker.get_ticks(0, 10, range, NaN) as FactorTickSpec
+      expect(ticks.major).to.be.equal(["0", "10"])
+      expect(ticks.minor).to.be.equal([])
+      expect(ticks.mids).to.be.equal([])
+      expect(ticks.tops).to.be.equal([])
+    })
+
+    it("should pass range to major_code", () => {
+      const ticker = new CustomJSTicker({major_code: "return cb_data.range.factors"})
+      const range = new FactorRange({factors: ["foo", "bar", "baz"]})
+      const ticks = ticker.get_ticks(0, 10, range, NaN) as FactorTickSpec
+      expect(ticks.major).to.be.equal(["foo", "bar", "baz"])
+      expect(ticks.minor).to.be.equal([])
+      expect(ticks.mids).to.be.equal([])
+      expect(ticks.tops).to.be.equal([])
+    })
+
+    it("should pass cross_loc to major_code", () => {
+      const ticker = new CustomJSTicker({major_code: "return [cb_data.cross_loc.toString()]"})
+      const range = new FactorRange({factors: ["foo", "bar", "baz"]})
+      const ticks = ticker.get_ticks(0, 10, range, 20) as FactorTickSpec
+      expect(ticks.major).to.be.equal(["20"])
+      expect(ticks.minor).to.be.equal([])
+      expect(ticks.mids).to.be.equal([])
+      expect(ticks.tops).to.be.equal([])
+    })
+
+  })
+})
diff --git a/docs/bokeh/source/docs/user_guide/styling/plots.rst b/docs/bokeh/source/docs/user_guide/styling/plots.rst
@@ -364,6 +364,18 @@ As a shortcut, you can also supply the list of ticks directly to an axis'
 .. bokeh-plot:: __REPO__/examples/styling/plots/fixed_ticker.py
     :source-position: above
 
+``CustomJSTicker``
+''''''''''''''''''
+
+To fully customize the location of axis ticks, use the |CustomJSTicker| in
+combination with a JavaScript snippet as its ``major_code`` and ``minor_code``
+properties.
+
+These code snippets should return lists of tick locations:
+
+.. bokeh-plot:: __REPO__/examples/styling/plots/custom_js_ticker.py
+    :source-position: above
+
 Tick lines
 ~~~~~~~~~~
 
@@ -843,6 +855,7 @@ You can see a complete example with output in the section
 .. |BasicTickFormatter| replace:: :class:`~bokeh.models.formatters.BasicTickFormatter`
 .. |CategoricalTickFormatter| replace:: :class:`~bokeh.models.formatters.CategoricalTickFormatter`
 .. |DatetimeTickFormatter| replace:: :class:`~bokeh.models.formatters.DatetimeTickFormatter`
+.. |CustomJSTicker| replace:: :class:`~bokeh.models.tickers.CustomJSTicker`
 .. |CustomJSTickFormatter| replace:: :class:`~bokeh.models.formatters.CustomJSTickFormatter`
 .. |LogTickFormatter| replace:: :class:`~bokeh.models.formatters.LogTickFormatter`
 .. |NumeralTickFormatter| replace:: :class:`~bokeh.models.formatters.NumeralTickFormatter`

diff --git a/examples/styling/plots/custom_js_ticker.py b/examples/styling/plots/custom_js_ticker.py
@@ -0,0 +1,34 @@
+from bokeh.models import CustomJSTicker
+from bokeh.plotting import figure, show
+
+xticker = CustomJSTicker(
+    # always three equally spaced ticks
+    major_code="""
+        const {start, end} = cb_data.range
+        const interval = (end-start) / 4
+        return [start + interval, start + 2*interval, start + 3*interval]
+    """,
+    # minor ticks in between the major ticks
+    minor_code="""
+        const {start, end, major_ticks} = cb_data
+        return [
+            (start+major_ticks[0])/2,
+            (major_ticks[0]+major_ticks[1])/2,
+            (major_ticks[1]+major_ticks[2])/2,
+            (major_ticks[2]+end)/2,
+        ]
+    """,
+)
+
+yticker = CustomJSTicker(major_code="return ['a', 'c', 'e', 'g']")
+
+p = figure(y_range=list("abcdefg"))
+p.scatter([1,2,3,4,5], ["a","d","b","f","c"], size=30)
+
+p.xaxis.ticker = xticker
+
+# keep the grid lines at all original tick locations
+p.ygrid.ticker = p.yaxis.ticker
+p.yaxis.ticker = yticker
+
+show(p)