Adding markers

Add markers

Add some markers to the candlestick graph.

final chart = GChart(
    panels: [
      GPanel(
        valueViewPorts: ...
        valueAxes: ...
        pointAxes: ...
        graphs: [
          // ...
          GGraphOhlc(
            ohlcValueKeys: const ["open", "high", "low", "close"],
            // overlay markers on the OHLC graph
            overlayMarkers: [
              // A label marker pinned at the left top corner of the graph area
              GLabelMarker(
                text: "Stock chart for AAPL",
                anchorCoord: GPositionCoord.absolute(x: 10, y: 10),
                alignment: Alignment.bottomRight,
                hitTestMode: GHitTestMode.none,
                theme: theme.overlayMarkerTheme.copyWith(
                  labelStyle: theme.overlayMarkerTheme.labelStyle!.copyWith(
                    textStyle: theme.overlayMarkerTheme.labelStyle!.textStyle!
                        .copyWith(fontSize: 16),
                  ),
                ),
              ),
              // A star marker pinned at the last close data point of the graph
              GShapeMarker(
                anchorCoord: GViewPortCoord(
                  point: dataSource.lastPoint.toDouble(),
                  value: dataSource.getSeriesValue(
                    point: dataSource.lastPoint,
                    key: "close",
                  )!,
                ),
                radiusSize: GSize.pointSize(5),
                pathGenerator: (r) => GShapes.star(r, vertexCount: 5),
                rotation: pi / 10, // Rotate the star marker
              ),
            ],
          ),
        ]
        tooltip: ...
      ),
    ],
);

The result

chart view

On the chart when dragging the graph, the label marker stays at the top left corner of the graph area,
while the star marker moving along with the graph.
Also the size of the star marker is difined by 5 bars count, its size changes when zooming the graph point viewport on X axis.