Function Demo_TimeScale

Source/3rdParty/implot/implot_demo.cpp:1506–1552

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void Demo_TimeScale() {
    IMGUI_DEMO_MARKER("Axes/Time Scale");

    static double t_min = 1609459200; // 01/01/2021 @ 12:00:00am (UTC)
    static double t_max = 1640995200; // 01/01/2022 @ 12:00:00am (UTC)

    ImGui::BulletText("When ImPlotAxisFlags_Time is enabled on the X-Axis, values are interpreted as\n"
                        "UNIX timestamps in seconds and axis labels are formated as date/time.");
    ImGui::BulletText("By default, labels are in UTC time but can be set to use local time instead.");

    ImGui::Checkbox("Local Time",&ImPlot::GetStyle().UseLocalTime);
    ImGui::SameLine();
    ImGui::Checkbox("ISO 8601",&ImPlot::GetStyle().UseISO8601);
    ImGui::SameLine();
    ImGui::Checkbox("24 Hour Clock",&ImPlot::GetStyle().Use24HourClock);

    static HugeTimeData* data = nullptr;
    if (data == nullptr) {
        ImGui::SameLine();
        if (ImGui::Button("Generate Huge Data (~500MB!)")) {
            static HugeTimeData sdata(t_min);
            data = &sdata;
        }
    }

    if (ImPlot::BeginPlot("##Time", ImVec2(-1,0))) {
        ImPlot::SetupAxisScale(ImAxis_X1, ImPlotScale_Time);
        ImPlot::SetupAxesLimits(t_min,t_max,0,1);
        if (data != nullptr) {
            // downsample our data
            int downsample = (int)ImPlot::GetPlotLimits().X.Size() / 1000 + 1;
            int start = (int)(ImPlot::GetPlotLimits().X.Min - t_min);
            start = start < 0 ? 0 : start > HugeTimeData::Size - 1 ? HugeTimeData::Size - 1 : start;
            int end = (int)(ImPlot::GetPlotLimits().X.Max - t_min) + 1000;
            end = end < 0 ? 0 : end > HugeTimeData::Size - 1 ? HugeTimeData::Size - 1 : end;
            int size = (end - start)/downsample;
            // plot it
            ImPlot::PlotLine("Time Series", &data->Ts[start], &data->Ys[start], size, {ImPlotProp_Stride, sizeof(double)*downsample});
        }
        // plot time now
        double t_now = (double)time(nullptr);
        double y_now = HugeTimeData::GetY(t_now);
        ImPlot::PlotScatter("Now",&t_now,&y_now,1);
        ImPlot::Annotation(t_now,y_now,ImPlot::GetLastItemColor(),ImVec2(10,10),false,"Now");
        ImPlot::EndPlot();
    }
}

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