Chart combinations and axes

Combine series when they share a coordinate system. Each series keeps its own stable ID, observations and configuration; one chart owns the axes, frame and theme. The tables below describe the supported layouts. The family ledger records individual options, and API conventions covers observations, stacks and missing values.

Cartesian layouts

For example, bars and a line can share categories while retaining separate value scales:

using ChartForgeX;
using ChartForgeX.Core;
using ChartForgeX.Themes;

var orders = ChartSeries.CreateBar(new ChartSeriesId("orders"), "Orders",
    ChartPoints.FromValues(28, 34, 41));
var latency = ChartSeries.CreateLine(new ChartSeriesId("latency"), "Latency",
    ChartPoints.FromValues(120, 95, 110));
latency.UseSecondaryYAxis();

var chart = Chart.Create()
    .WithTheme(VisualTheme.Graphite())
    .WithTitle("Orders and response time")
    .WithXLabels("Monday", "Tuesday", "Wednesday")
    .WithYAxis("Orders")
    .WithSecondaryYAxis("Latency (ms)")
    .AddSeries(orders)
    .AddSeries(latency);
chart.ConfigureYAxis(axis => axis.Minimum = 0);
chart.ConfigureSecondaryYAxis(axis => axis.Minimum = 0);
chart.SaveSvg("orders-and-latency.svg");
chart.SavePng("orders-and-latency.png");

Category alignment follows source X coordinates rather than series positions. The shared category owner groups corresponding bar and radial coordinates within four floating-point ULPs while retaining the original observations. Missing observations stay absent unless the selected family explicitly defines derived values. A line gap requires an authored segment break; an omitted point alone does not promise a gap in a connected line. An authored zero remains an observation.

Radial layouts

RadialBar and RadialColumn support signed linear, positive logarithmic and symmetric logarithmic value scales. Time value axes, explicit category bounds and logarithmic category spacing reject. RadialBar cannot mix with RadialColumn; Radar cannot mix with Polar. The implemented cross-kind radial layout is RadialColumn with Radar.

Category-axis reversal is supported for numeric radial charts, Radar and Polar, including mixed columns/radar. Numeric radius reversal uses the selected value axis. Polar-area radius reversal and schedule reversal reject. Equivalent coordinates within one radar or mixed-radial series are ambiguous and reject before preparation or export; cross-series equivalents align through the shared category owner.

The compiled mixed radial recipe demonstrates retained series handles, curved radar forms and category reversal. The comparison recipe demonstrates ordinary line/area/bar mixtures. Their gallery downloads include the selected factory and ordinary package imports.

Constructing and updating supported combinations

The compiled supported combination recipe uses the same series and chart vocabulary for three layouts:

• vertical-secondary combines grouped bars with typed Bubble observations on a secondary percentage axis. Bubble size remains independent of its percentage value.
• horizontal combines grouped horizontal bars with a Line on the primary physical X value axis. The category captions and parent groups belong to physical Y.
• mixed-radial combines RadialColumn with a Radar line on a shared numeric scale. Complete location names identify each radial category.

Each layout retains explicit series and observation IDs. Repeated leaf captions retain their parent context, omitted observations stay absent, and an authored zero keeps its identity. Prefix a variant with updated- to exercise changed values and paint order. The vertical variant replaces the complete typed Bubble collection, then assigns observation IDs in its new order; full typed replacement clears earlier observation metadata. The numeric variants update an item through Points[index], preserving its ID. MoveSeries changes paint order without changing identity or configuration.

Prepare a new scene after source changes and reuse the immutable paired theme with the intended mode. A previously prepared scene remains detached from later source, axis and theme edits. ToSvg() and ToPng() on that preparation export the same committed facts. In a browser host, pass a newly generated section to the existing controller's update; surviving explicit identities retain selection, legend state and keyboard focus. These recipes exercise supported mixtures without widening horizontal or radial compatibility rules.

Independent layouts and qualification

Matrix, schedule, map, relationship, part-to-whole and scalar families use their own layouts. They cannot share a chart with unrelated Cartesian or radial series. Heatmap/HexbinHeatmap rows, Bullet, Timeline, StateTimeline, GanttLane and Gantt support their documented homogeneous multi-series layouts. Numeric and categorical heatmap rows cannot mix. Other exclusive layouts require one series. Use a chart grid when independent coordinate systems belong together in a report.

Preparation, SVG and native PNG use the same compatibility checks. Existing regression tests cover representative shared domains, missing values, secondary scales, horizontal constraints, stacks, radial mixtures and rejection paths. This is a supported-layout contract rather than a claim that every pair of family options has been exhaustively tested. The roadmap retains deeper visual, lifecycle and platform qualification work.