5 changed files with 105 additions and 3 deletions
--- a/examples/markers.html
+++ b/examples/markers.html
@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta content="text/html;charset=utf-8" http-equiv="Content-Type">
+    <meta content="utf-8" http-equiv="encoding">
+
+    <script src="../dist/index.dev.js" type="text/javascript"></script>
+  </head>
+  <body>
+    <div id="chart" style="width: 100%; height: 500px;"></div>
+
+    <script type="text/javascript">
+      const startTime = 1701790172908;
+      const timeSerieData = [5, 6, 3, 7, 5, 6, 8, 4, 5, 6, 4, 3, 5, 7, 8]
+        .map((el, idx) => [startTime + idx * 1000, el]);
+      const markersData1 = [3, 6, 9].map(el => startTime + el * 1000);
+      const markersData2 = [4, 11].map(el => startTime + el * 1000);
+      let options = {
+        renderLegend: false,
+        axis: {
+          y: { range: [0, 10] },
+          x: { format: 'time' }
+        },
+      }
+      var pod = new LinePod(
+        document.getElementById('chart'),
+        [
+          { datapoints: timeSerieData, color: 'black' },
+        ],
+        options,
+        [
+          { data: markersData1, color: 'red' },
+          { data: markersData2, color: 'blue' },
+        ]
+      );
+      pod.render();
+    </script>
+  </body>
+</html>
--- a/src/components/markers.ts
+++ b/src/components/markers.ts
@ -0,0 +1,51 @@
+import { MarkerSerie } from "../models/marker";
+import { PodState } from "@chartwerk/core";
+import { LineTimeSerie, LineOptions } from "../types";
+
+import d3 from "d3";
+
+export class Markers {
+  // TODO: more sentic name
+  private _d3Holder = null;
+
+  constructor(private _markers: MarkerSerie[], private _state: PodState<LineTimeSerie, LineOptions>) {
+  }
+
+  render(metricContainer: d3.Selection<SVGGElement, unknown, null, undefined>) {
+    if(this._d3Holder !== null) {
+      this._d3Holder.remove();
+    }
+    this._d3Holder = metricContainer.append('g').attr('class', 'markers-layer');
+    for (const ms of this._markers) {
+      this.renderMarkerSerie(ms);
+    }
+  }
+
+  protected renderMarkerSerie(serie: MarkerSerie) {
+    serie.data.forEach((d) => {
+      let linePosition = this._state.xScale(d) as number;
+      this._d3Holder.append('line')
+        .attr('class', 'gap-line')
+        .attr('stroke', serie.color)
+        .attr('stroke-width', '1px')
+        .attr('stroke-opacity', '0.3')
+        .attr('stroke-dasharray', '4')
+        .attr('x1', linePosition)
+        .attr('x2', linePosition)
+        .attr('y1', 0)
+        // @ts-ignore // TODO: remove ignore but boxParams are protected
+        .attr('y2', this._state.boxParams.height)
+        .attr('pointer-events', 'none');
+      this._d3Holder.append('circle')
+        .attr('class', 'gap-circle')
+        .attr('stroke', serie.color)
+        .attr('stroke-width', '2px')
+        .attr('r', 4)
+        .attr('cx', linePosition)
+        .attr('cy', 5)
+        .attr('pointer-events', 'none') // TODO: make all on implementation of Events
+        .style('cursor', 'pointer')
+    });
+
+  }
+}
--- a/src/index.ts
+++ b/src/index.ts
@ -1,5 +1,6 @@
 import { ChartwerkPod, VueChartwerkPodMixin, TimeFormat, CrosshairOrientation, BrushOrientation, yAxisOrientation } from '@chartwerk/core';
 import { LineTimeSerie, LineOptions } from './types';
+import { Markers } from './components/markers';

 import { LineSeries } from './models/line_series';

@ -17,12 +18,17 @@ export class LinePod extends ChartwerkPod<LineTimeSerie, LineOptions> {
  lineGeneratorY1 = null;
  areaGeneratorY1 = null;

-  constructor(_el: HTMLElement, _series: LineTimeSerie[] = [], _options: LineOptions = {}) {
+  private _markersLayer: Markers = null;
+
+  constructor(
+    _el: HTMLElement, _series: LineTimeSerie[] = [], _options: LineOptions = {},
+    private _markerSeries = []
+  ) {
    super(_el, _series, _options);
    this.series = new LineSeries(_series);
  }

-  renderMetrics(): void {
+  override renderMetrics(): void {
    this.clearAllMetrics();

    this.updateCrosshair();
@ -36,6 +42,8 @@ export class LinePod extends ChartwerkPod<LineTimeSerie, LineOptions> {
    for(const serie of this.series.visibleSeries) {
      this._renderMetric(serie);
    }
+    this._markersLayer = new Markers(this._markerSeries, this.state);
+    this._markersLayer.render(this.metricContainer);
  }

  clearAllMetrics(): void {
@ -386,6 +394,7 @@ export class LinePod extends ChartwerkPod<LineTimeSerie, LineOptions> {
  }
 }

+// TODO: it should be moved to VUE folder
 // it is used with Vue.component, e.g.: Vue.component('chartwerk-line-pod', VueChartwerkLinePod)
 export const VueChartwerkLinePod = {
  // alternative to `template: '<div class="chartwerk-line-pod" :id="id" />'`
--- a/src/models/line_series.ts
+++ b/src/models/line_series.ts
@ -15,7 +15,6 @@ const LINE_SERIE_DEFAULTS = {
 };

 export class LineSeries extends CoreSeries<LineTimeSerie> {
-
  constructor(series: LineTimeSerie[]) {
    super(series, _.clone(LINE_SERIE_DEFAULTS));
  }
--- a/src/models/marker.ts
+++ b/src/models/marker.ts
@ -0,0 +1,4 @@
+export type MarkerSerie = {
+  color: string;
+  data: [number, number, any][] // [x, y, payload] payload is any data for tooltip
+}