Questions

Hello Arun,
looks like it is possible to make only a stroke transparent, but not a background fill, in this case.
At this point, I can suggest using this fact as a workaround and temporary solution.

I was able to hide the point markers by setting ‘strokeThickness’ to the size of a marker and conditionally setting ‘stroke’ to “#FFFFFF00”.

class MyCustomPaletteProvider implements IPointMarkerPaletteProvider {
    readonly strokePaletteMode: EStrokePaletteMode;
    private readonly stroke: number;
    private readonly fill: number;
    private readonly rule: (yValue: number) => boolean;

    constructor(stroke: string, fill: string, rule: (yValue: number) => boolean) {
        this.rule = rule;
        this.stroke = parseColorToUIntArgb(stroke);
        this.fill = parseColorToUIntArgb(fill);
    }

    onAttached(parentSeries: FastLineRenderableSeries): void { }

    onDetached(): void { }

    overridePointMarkerArgb(xValue: number, yValue: number, index: number): TPointMarkerArgb {
        if (this.rule(yValue)) {
            return {
                fill: this.fill,
                stroke: this.stroke,
            };
        }
        return undefined;
    }
}

 sciChartSurface.renderableSeries.add(
            new FastLineRenderableSeries(wasmContext, {
                stroke: "LightSteelBlue",
                pointMarker: new EllipsePointMarker(wasmContext, {
                    width: 10,
                    height: 10,
                    strokeThickness: 10,
                    fill: "blue",
                    stroke: "green",
                }),
                paletteProvider: new MyCustomPaletteProvider("#FFFFFF00", "#FFFFFF00", yValue => yValue < 0.5),
                dataSeries: dataSeriesArr[0],
            })
        );