ImCoolBar

macOS Dock-style magnification bar for Dear ImGui.

Features

• Bubble magnification effect -- Items smoothly scale up when the mouse approaches, mimicking the macOS Dock behavior (cos^8 curve).
• Cursor pinning -- The exact pixel under the cursor stays fixed as items grow, even for edge items.
• Horizontal and Vertical -- Supports both orientations via ImCoolBarFlags_Horizontal / ImCoolBarFlags_Vertical.
• Configurable anchor -- Position the bar anywhere on screen with anchor (viewport-relative, 0..1).
• Per-bar settings -- Normal/hovered size, animation speed, effect strength.
• Built-in demo window -- ShowCoolBarDemoWindow() lets you tweak all settings at runtime, with save/reset defaults.
• Built-in metrics window -- ShowCoolBarMetrics() to inspect internal state.
• C API -- All functions available as plain C wrappers for binding generators (cimgui, etc.).
• DLL-ready -- IMCOOLBAR_API macro for __declspec(dllexport) support.

Demo App

A full demo is available in the ImEffects repository or with this Emscripten demo

Integration

1. Add files

Copy ImCoolBar.h and ImCoolBar.cpp into your project. Include ImCoolBar.h after imgui.h.

2. Usage

#include "ImCoolBar.h"

// Optional: check version at startup
IMCOOLBAR_CHECKVERSION();

// In your render loop
ImGui::ImCoolBarSettings settings;
settings.normalSize = 40.0f;
settings.hoveredSize = 150.0f;
settings.anchor = ImVec2(0.5f, 1.0f);  // bottom-center

if (ImGui::BeginCoolBar("MyDock", ImCoolBarFlags_Horizontal, settings)) {
    for (int i = 0; i < itemCount; ++i) {
        if (ImGui::CoolBarItem()) {
            float w = ImGui::GetCoolBarItemWidth();
            float s = ImGui::GetCoolBarItemScale();
            ImGui::ImageButton("##icon", icons[i], ImVec2(w, w));
        }
    }
    ImGui::EndCoolBar();
}

3. Demo window

static bool showDemo = true;
static ImGui::ImCoolBarSettings settings;
static ImGui::ImCoolBarSettings defaults = settings;
ImGui::ShowCoolBarDemoWindow(&showDemo, &settings, &defaults);

API

namespace ImGui {
    bool BeginCoolBar(const char* aLabel, ImCoolBarFlags aCBFlags = ImCoolBarFlags_Vertical,
                      const ImCoolBarSettings& arSettings = {}, ImGuiWindowFlags aWinFlags = ImGuiWindowFlags_None);
    void EndCoolBar();
    bool CoolBarItem();
    float GetCoolBarItemWidth();
    float GetCoolBarItemScale();
    void ShowCoolBarMetrics(bool* apoOpen);
    void ShowCoolBarDemoWindow(bool* apoOpen = nullptr, ImCoolBarSettings* apoSettings = nullptr,
                               ImCoolBarSettings* apoDefaultSettings = nullptr);
    bool CoolBarDebugCheckVersion(const char* aVersion, size_t aSettingsSize);
}

Settings

ImCoolBarSettings parameters:

Parameter	Default	Description
anchor	(0.5, 0.5)	Viewport-relative position (0..1), clamped
normalSize	40	Item size when not hovered (pixels)
hoveredSize	150	Item size at maximum hover (pixels)
animStep	0.05	Animation speed factor (framerate-independent)
effectStrength	0.5	Bubble curve spread (0..1)

C API

All functions are available as C wrappers prefixed with ImCoolBar_:

bool ImCoolBar_BeginCoolBar(const char* aLabel, int aCBFlags, float aNormalSize, float aHoveredSize,
                             float aAnimStep, float aEffectStrength, float aAnchorX, float aAnchorY, int aWinFlags);
void ImCoolBar_EndCoolBar(void);
bool ImCoolBar_CoolBarItem(void);
float ImCoolBar_GetCoolBarItemWidth(void);
float ImCoolBar_GetCoolBarItemScale(void);
void ImCoolBar_ShowCoolBarMetrics(bool* apoOpen);
void ImCoolBar_ShowCoolBarDemoWindow(bool* apoOpen,
    float* apoNormalSize, float* apoHoveredSize, float* apoAnimStep, float* apoEffectStrength, float* apoAnchorX, float* apoAnchorY,
    float* apoDefNormalSize, float* apoDefHoveredSize, float* apoDefAnimStep, float* apoDefEffectStrength, float* apoDefAnchorX, float* apoDefAnchorY);
const char* ImCoolBar_GetVersion(void);
int ImCoolBar_GetVersionNum(void);

License

MIT License -- Copyright (c) 2024-2026 Stephane Cuillerdier (aka Aiekick)