Lumacs/documentation/GUI_ROADMAP.md

GUI Frontend Roadmap: Lumacs with GTK4 (gtkmm)

This document outlines the phased approach to integrate a graphical frontend into Lumacs, utilizing GTK4 with its C++ bindings (gtkmm). The goal is to provide a rich, native user experience while leveraging the existing C++ core and Lua extensibility.

Phase 0: Preparation (Current State)

• Status: Complete
• Description: Core editor logic (EditorCore, Buffer) is decoupled from the UI. An abstract Face system is implemented, allowing for UI-agnostic styling definitions.
• Key Achievements:
  • Abstract Face system in include/lumacs/face.hpp
  • Theme system refactored to manage Face definitions
  • Buffer stores face_name for styling ranges
  • NcursesEditor renders Faces to best of its ability (colors, bold, italic)

Phase 1: Abstract UI Interface Extraction

• Status: Complete
• Goal: Define a clean separation between EditorCore and any UI frontend.
• Achievements:
  • IEditorView interface defined in include/lumacs/ui_interface.hpp.
  • NcursesEditor refactored to TuiEditor implementing IEditorView.
  • EditorCore decoupled from specific UI implementation.

Phase 2: GTK4 Environment Setup & Basic Window

• Status: Complete
• Goal: Integrate GTK4 into the build system and display a minimal window.
• Achievements:
  • Updated CMakeLists.txt with gtkmm-4.0 dependency.
  • Created src/gtk_editor.cpp implementing IEditorView.
  • Single binary architecture with -nw fallback.

Phase 3: Displaying Buffer Content

• Status: Complete
• Goal: Render the active buffer's text content within the GTK window.
• Achievements:
  • Implemented GtkEditor::on_draw using Cairo and Pango.
  • Text rendering works with font metrics.

Phase 4: Styling with Faces

• Status: Complete
• Goal: Implement the Face system within GtkEditor to render styled text.
• Achievements:
  • Mapped FaceAttributes (foreground color) to Cairo source.
  • Cursor rendering implemented.

Phase 5: Input Handling & Minibuffer

• Status: Complete (Prototype)
• Goal: Capture keyboard input and integrate with the minibuffer and other interactive UI elements.
• Achievements:
  • Implemented GtkEditor::on_key_pressed.
  • Mapped GDK key events to Lumacs key strings (with modifiers).
  • Minibuffer command input works.

Phase 6: Full UI Feature Parity

• Status: In Progress
• Goal: Implement all existing features of TuiEditor (window splits, status lines, messages, marks, regions) in GtkEditor.
• Completed Tasks:
  1. Stability: Fix crash on exit. ✅ (2025-11-27)
     • Fixed double-free by clearing event callbacks before view destruction
     • Added null safety checks in draw and event handlers
     • Proper GTK Application/Window lifetime management
  2. Character Input: Self-insert for printable characters. ✅ (2025-11-27)
     • Added fallback handler for unbound printable keys
     • Characters now render correctly when typed
  3. Cursor Rendering: Visible inverted block cursor. ✅ (2025-11-27)
     • Cursor draws with theme color and inverted character
• Remaining Tasks:
  1. Status Line/Modelines: Render status bars for each window. (Basic implementation done)
  2. Window Splits: Implement window splitting logic using GTK containers (e.g., Gtk::Paned or Gtk::Grid).
  3. Scrolling: Implement visual scrolling (viewport offset).

Future Considerations

• High-DPI Support: Ensure crisp rendering on high-resolution displays.
• Accessibility: Integrate with GTK's accessibility features.
• Native File Dialogs: Use Gtk::FileChooserDialog for find-file and save-as.