Client | ImGui Trader Terminal

The client_ui module provides the interactive interface for BetaTrader. Built with Dear ImGui (docking branch) and GLFW/OpenGL 3.3, it manages window lifecycle, theming, and houses the GUI panels that visualize session and market state.

Architecture

classDiagram
    classDef ui fill:#2b303a,stroke:#4caf50,stroke-width:2px,color:white;
    classDef net fill:#1f2833,stroke:#66fcf1,stroke-width:2px,color:white;
    classDef logic fill:#0b0c10,stroke:#c5c6c7,stroke-width:2px,color:white;
 
    class UIManager:::ui {
        +start(title, width, height) : bool
        +stop()
        +shouldClose() : bool
        +beginFrame()
        +endFrame()
        +renderDockspace()
        -mWindow: GLFWwindow*
        -mImGuiContext: ImGuiContext*
    }
    class Theme:::ui {
        +applyBloombergTheme()$
    }
    class ConnectionPanel:::ui {
        +render(session, ioContext)
        -mHost: char[128]
        -mPort: int
        -mSenderCompId: char[64]
        -mLogs: vector~LogEntry~
        -addLog(direction, msg)
    }
    UIManager --> Theme : Applies on start
    ConnectionPanel ..> FixClientSession : Manages

Core Components

1. <tt>UIManager</tt>

RAII wrapper managing the full GLFW + ImGui + ImPlot lifecycle.

• Window Creation: Creates a GLFW window with an OpenGL 3.3 Core Profile context.
• ImGui Bootstrap: Initializes Dear ImGui context with Docking and Multi-Viewport support.
• Frame Lifecycle: beginFrame() / endFrame() encapsulate polling, rendering, and buffer swaps.
• Dockspace: renderDockspace() sets up a full-window docking area with a top menu bar.

2. <tt>Theme</tt>

Provides applyBloombergTheme(), a Bloomberg-terminal-inspired dark palette with orange accents for active/hovered elements. Sets consistent rounding, padding, and spacing across all ImGui widgets.

3. <tt>ConnectionPanel</tt>

ImGui panel for controlling the FIX client session lifecycle (previously in client_fix, moved here to keep the protocol library free of GUI dependencies).

• Session Config: Host, port, SenderCompID, TargetCompID, heartbeat interval, and force-reset toggle.
• Lifecycle Buttons: Connect, Logon (35=A), Logout (35=5), and Force Disconnect — buttons are state-aware (disabled when inappropriate).
• Status Indicator: Color-coded session state display (Disconnected, Connecting, Connected, Logon Sent, Active, Logging Out).
• Message Log: Scrollable, color-coded log of FIX messages with timestamps and auto-scroll support (capped at 500 entries).

Planned Components

<tt>OrderbookModel</tt>

The most critical data structure in the UI.

• Update Logic: Snapshot (35=W) clears and bulk-loads; Incremental (35=X) applies granular updates.
• Performance: Optimized for O(log N) updates and O(N) rendering by maintaining sorted bins.

<tt>MDSubscriptionManager</tt>

Manages market data requirements with auto-resubscribe on reconnect.

<tt>UIEventQueue</tt>

Thread-safe SPSC bridge between the async client_fix thread and the synchronous rendering loop.

Setup & Dependencies

• Dear ImGui (docking branch): Core GUI framework.
• ImPlot: Extension for technical charting.
• GLFW/OpenGL 3.3: Rendering backend (ImGui's built-in GL loader is used; no external GLAD/GL3W needed).