图示

我的测试

原理

绘制数个大小不一的圆形排列的圆形图案

代码

#include "imgui.h"
#include "imgui_internal.h"
#include <algorithm>
#include <cmath>
//... 不同于原代码 
void LoadingIndicatorCircle(const char* label, const float indicator_radius,
    const ImVec4& main_color, const ImVec4& backdrop_color,
    const int circle_count, const float speed) {

    using namespace ImGui;

    ImGuiWindow* window = GetCurrentWindow();
    if (window->SkipItems) {
        return;
    }

    ImGuiContext& g = *GImGui;

    const ImGuiID id = window->GetID(label);

    const ImVec2 pos = window->DC.CursorPos;

    const float circle_radius = indicator_radius / 10.0f;

    const ImRect bb(pos, ImVec2(pos.x + indicator_radius * 2.0f,
        pos.y + indicator_radius * 2.0f));
   
    ItemSize(bb, ImGui::GetStyle().FramePadding.y);
    if (!ItemAdd(bb, id)) {
        return;
    }
    const float t = g.Time;
    const auto degree_offset = 2.0f * IM_PI / circle_count;
    for (int i = 0; i < circle_count; ++i) {
        const auto x = indicator_radius * std::sin(degree_offset * i);
        const auto y = indicator_radius * std::cos(degree_offset * i);

        auto growth =  std::sin(t * speed - i * degree_offset) <0;
        if (growth < 0)
        {
            growth = 0.0f;
        }

        ImVec4 color;
        color.x = main_color.x * growth + backdrop_color.x * (1.0f - growth);
        color.y = main_color.y * growth + backdrop_color.y * (1.0f - growth);
        color.z = main_color.z * growth + backdrop_color.z * (1.0f - growth);
        color.w = 1.0f;
        window->DrawList->AddCircleFilled(ImVec2(pos.x + indicator_radius + x,
            pos.y + indicator_radius - y),
            circle_radius + growth * circle_radius,
            GetColorU32(color));
    }
    
}

调用示例，效果见本文第二张图

            LoadingIndicatorCircle("cce",
                20.f,
                ImVec4(144, 0, 0, 1.0),// 颜色 此表达类似于  RGBA(255,255,255,1.0)
                ImVec4(0, 255, 0, 1.0),//一处不合理的地方 这两个参数对应构造参数之和
					//不能大于255 ，具体原因去看上面的代码
                12,
                7);

相关

• 原issue
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