Programmatically autofit data

[Poooel]

As the title suggests, is there a way to programmatically autofit data? Adding data to the plot after the fact doesn't fit automatically and the user has to autofit to see the new data. If there was a way to autofit the data, I could just call it, when adding new data. I tried using SetupAxis with ImPlot3DCond_Once to set the correct limits when data is added but it doesn't seem to have any effect.

[Poooel]

How I've done it for now:

if (triggerAutofit) {
    triggerAutofit        = false;
    ImPlot3DContext& gp   = *ImPlot3D::GImPlot3D;
    ImPlot3DPlot&    plot = *gp.CurrentPlot;
    plot.FitThisFrame     = true;
    for (int i = 0; i < 3; ++i) {
        plot.Axes[i].FitThisFrame = true;
    }
}

triggerAutofit is turned to true when new data is added.

[brenocq]

Hi @Poooel, the flag ImPlot3DCond_Once currently only works with the SetupAxisLimits method. When used, it will set the limits only the first time the plot is created (first call to SetupAxisLimits for that plot). If you have new data coming in and you want it to be fitted, you could call SetupAxis/SetupAxes with the flag ImPlot3DAxisFlags_AutoFit to fit the data in that frame.

if (triggerAutofit) {
   ImPlot3D::SetupAxes(nullptr, nullptr, nullptr, ImPlot3DAxisFlags_AutoFit, ImPlot3DAxisFlags_AutoFit, ImPlot3DAxisFlags_AutoFit);
}

I modified the Line Plots demo to test this and it appears to work fine

    static float xs1[1001], ys1[1001], zs1[1001];
    for (int i = 0; i < 1001; i++) {
        xs1[i] = i * 0.001f;
        ys1[i] = 0.5f + 0.5f * cosf(50 * (xs1[i] + (float)ImGui::GetTime() / 10));
        zs1[i] = 0.5f + 0.5f * sinf(50 * (xs1[i] + (float)ImGui::GetTime() / 10));
    }
    static double xs2[20], ys2[20], zs2[20];
    for (int i = 0; i < 20; i++) {
        xs2[i] = i * 1 / 19.0f;
        ys2[i] = xs2[i] * xs2[i];
        zs2[i] = xs2[i] * ys2[i];
    }

    // Button to trigger auto-fit
    bool trigger_auto_fit = false;
    if (ImGui::Button("Trigger auto-fit"))
        trigger_auto_fit = true;

    if (ImPlot3D::BeginPlot("Line Plots")) {
        // Use AutoFit flag when needed
        ImPlot3DAxisFlags flags = trigger_auto_fit ? ImPlot3DAxisFlags_AutoFit : ImPlot3DAxisFlags_None;
        ImPlot3D::SetupAxes("x", "y", "z", flags, flags, flags);

        ImPlot3D::PlotLine("f(x)", xs1, ys1, zs1, 1001);
        ImPlot3D::SetNextMarkerStyle(ImPlot3DMarker_Circle);
        ImPlot3D::PlotLine("g(x)", xs2, ys2, zs2, 20, ImPlot3DLineFlags_Segments);
        ImPlot3D::EndPlot();
    }

Peek.2024-12-27.16-26.mp4

Do let me know if this works for you!

[Poooel]

Thank you!