satdump/src-core/common/widgets/spinner.cpp

#include "spinner.h"
#include "imgui/imgui_internal.h"

namespace widgets
{
    bool Spinner(const char *label, float radius, int thickness, const ImU32 &color)
    {
        ImGuiWindow *window = ImGui::GetCurrentWindow();
        if (window->SkipItems)
            return false;

        ImGuiContext &g = *GImGui;
        const ImGuiStyle &style = g.Style;
        const ImGuiID id = window->GetID(label);

        ImVec2 pos = window->DC.CursorPos;
        ImVec2 size((radius) * 2, (radius + style.FramePadding.y) * 2);

        const ImRect bb(pos, ImVec2(pos.x + size.x, pos.y + size.y));
        ImGui::ItemSize(bb, style.FramePadding.y);
        if (!ImGui::ItemAdd(bb, id))
            return false;

        // Render
        window->DrawList->PathClear();

        int num_segments = 30;
        int start = abs(int(ImSin(g.Time * 1.8f) * (num_segments - 5)));

        const float a_min = IM_PI * 2.0f * ((float)start) / (float)num_segments;
        const float a_max = IM_PI * 2.0f * ((float)num_segments - 3) / (float)num_segments;

        const ImVec2 centre = ImVec2(pos.x + radius, pos.y + radius + style.FramePadding.y);

        for (int i = 0; i < num_segments; i++)
        {
            const float a = a_min + ((float)i / (float)num_segments) * (a_max - a_min);
            window->DrawList->PathLineTo(ImVec2(centre.x + ImCos(a + g.Time * 8) * radius,
                                                centre.y + ImSin(a + g.Time * 8) * radius));
        }

        window->DrawList->PathStroke(color, false, thickness);

        return true;
    }
}