class mrpt::imgui::CImGuiPlotPanel

Overview

A 2D plot (ImPlot) with named data series, for live or static data.

Series can be appended to point by point (addPoint(), e.g. a live signal, optionally shown over a rolling time window), or replaced as a whole (setSeries()). Series may carry a shaded band (e.g. a confidence interval). Long series are decimated for drawing, preserving their extremes. A toolbar offers pause (to inspect), autoscale, and exporting the data to CSV.

mrpt::imgui::CImGuiPlotPanel plot;
plot.rollingSpan = 10.0;  // show the last 10 s
plot.addPoint("speed", t, v);
// In a window:
plot.render("Speed");

#include <mrpt/imgui/CImGuiPlotPanel.h>

class CImGuiPlotPanel
{
public:
    // enums

    enum Style;

    // structs

    struct Series;

    // fields

    size_t maxPoints = 200000;
    double rollingSpan = 0;
    std::string xLabel;
    std::string yLabel;
    bool showLegend = true;
    bool autoscale = true;
    bool paused = false;
    bool equalAxes = false;
    bool showToolbar = true;
    std::function<void()> onPlotOverlay;

    // construction

    CImGuiPlotPanel();

    // methods

    void addPoint(const std::string& series, double x, double y);
    void setSeries(const std::string& series, std::vector<double> x, std::vector<double> y);

    void setBand(
        const std::string& series,
        std::vector<double> x,
        std::vector<double> low,
        std::vector<double> high
        );

    Series* series(const std::string& name);
    const Series* series(const std::string& name) const;
    Series& seriesOrCreate(const std::string& name);
    const std::vector<Series>& allSeries() const;
    void clear();
    void clearData();
    void removeSeries(const std::string& name);
    void render(const char* title, float height = 0);
    std::string toCSV() const;

    static std::vector<size_t> decimateMinMax(
        const std::vector<double>& x,
        const std::vector<double>& y,
        double xMin,
        double xMax,
        size_t buckets
        );
};

Fields

size_t maxPoints = 200000

Maximum points kept per series appended with addPoint().

double rollingSpan = 0

If > 0, the x axis follows the last rollingSpan units of data.

bool paused = false

Freezes the view (data keeps being appended).

bool equalAxes = false

Same scale in both axes (e.g.

for 2D maps).

std::function<void()> onPlotOverlay

Called inside the plot (between ImPlot::BeginPlot()/EndPlot()) to draw extra items, e.g.

ellipses or annotations.

Methods

void addPoint(const std::string& series, double x, double y)

Appends a point to a series (created if needed).

Old points are dropped beyond maxPoints, and beyond twice rollingSpan, if set.

void setSeries(
    const std::string& series,
    std::vector<double> x,
    std::vector<double> y
    )

Replaces the data of a series (created if needed).

void setBand(
    const std::string& series,
    std::vector<double> x,
    std::vector<double> low,
    std::vector<double> high
    )

Sets a shaded band [low, high] along a series (created if needed).

If x is given, it also replaces the series x values.

Series* series(const std::string& name)

The series with that name, or nullptr.

Series& seriesOrCreate(const std::string& name)

The series with that name, created (empty) if it does not exist.

void render(const char* title, float height = 0)

Draws the toolbar and the plot in the current window.

A height <= 0 uses the available height.

std::string toCSV() const

Data as CSV: one x,y column pair per series, with a header row.

static std::vector<size_t> decimateMinMax(
    const std::vector<double>& x,
    const std::vector<double>& y,
    double xMin,
    double xMax,
    size_t buckets
    )

Indices of the points of (x,y) (x sorted ascending) to draw, at most about 2*buckets: for each of buckets equal x intervals within [xMin, xMax], its minimum and maximum y; plus the points just outside the interval, so lines reach the plot edges.

All indices, if few enough.