GroveEngine/docs/UI_MODULE_DEMO.md

UIModule Interactive Showcase Demo

Date: 2025-11-29 Status: ✅ COMPLETE

Overview

The UIModule Interactive Showcase Demo is a complete, interactive application that demonstrates all features of the UIModule in a real window with live user interaction.

This is NOT a test - it's a real application showing how to use UIModule in production.

What It Demonstrates

All Widgets (9 types)

• ✅ Buttons - 4 colors (Primary, Success, Warning, Danger)
• ✅ Sliders - Volume, Brightness, Difficulty
• ✅ TextInput - Username, Search fields with placeholders
• ✅ Checkboxes - Fullscreen, VSync, Shadows, Particles
• ✅ Progress Bars - Health, Loading, Experience
• ✅ Labels - Headers, descriptions, info text
• ✅ Panels - Sidebar, content panels with backgrounds
• ✅ ScrollPanel - Main scrollable content + nested scroll
• ✅ Tooltips - All widgets have hover tooltips

Features

• ✅ Live event console - See all UI events in real-time
• ✅ Event statistics - Counts clicks, actions, value changes, hovers
• ✅ Hot-reload - Press 'R' to reload UI from JSON
• ✅ Mouse interaction - Click, hover, drag, wheel
• ✅ Keyboard input - Text fields, shortcuts
• ✅ Layouts - Vertical, horizontal, nested
• ✅ Styling - Colors, fonts, borders, padding
• ✅ Tooltips - Smart positioning with edge avoidance

Files

tests/demo/
└── demo_ui_showcase.cpp        # Main demo application (370 lines)

assets/ui/
└── demo_showcase.json          # Full UI layout (1100+ lines)

Building

Prerequisites

• SDL2 installed
• BgfxRenderer module built
• UIModule built
• X11 (Linux) or native Windows environment

Build Commands

cd /path/to/GroveEngine

# Configure with UI and renderer enabled
cmake -DGROVE_BUILD_UI_MODULE=ON -DGROVE_BUILD_BGFX_RENDERER=ON -B build-bgfx

# Build the demo
cmake --build build-bgfx --target demo_ui_showcase -j4

Running

cd build-bgfx/tests
./demo_ui_showcase

Controls

Key	Action
Mouse	Click, hover, drag widgets
Mouse Wheel	Scroll panels
Keyboard	Type in text fields
ESC	Quit demo
R	Hot-reload UI from JSON

Expected Output

========================================
   UIModule Interactive Showcase Demo
========================================

Controls:
  - Mouse: Click, hover, drag widgets
  - Keyboard: Type in text fields
  - Mouse wheel: Scroll panels
  - ESC: Quit
  - R: Reload UI from JSON

[0.0] Demo starting...
[0.02] SDL window created
[0.10] BgfxRenderer loaded
[0.12] Renderer configured
[0.15] UIModule loaded
[0.18] UIModule configured
[0.18] Ready! Interact with widgets below.
✅ Renderer healthy

Then a 1200x800 window opens with:

• Left sidebar (250px) - Controls and info
• Main content (950px) - Scrollable showcase of all widgets

Interacting

1. Hover over any widget → Tooltip appears after 500ms
2. Click buttons → Event logged in console
3. Drag sliders → Value changes logged
4. Type in text fields → Text changes logged
5. Check checkboxes → State changes logged
6. Scroll with mouse wheel → Smooth scrolling
7. Click "Clear Log" → Clears event console
8. Click "Reset Stats" → Resets all counters
9. Press 'R' → Reloads UI from JSON (hot-reload)

Architecture

Module Stack

┌─────────────────────┐
│   demo_ui_showcase  │  SDL2 event loop
│   (main app)        │  Input forwarding
└──────────┬──────────┘
           │ IIO pub/sub
    ┌──────┴──────┬─────────┐
    │             │         │
┌───▼────┐   ┌───▼────┐   ┌▼─────────┐
│BgfxRend│   │UIModule│   │ Event    │
│erer    │   │        │   │ Console  │
└────────┘   └────────┘   └──────────┘

Event Flow

User Input (SDL)
    ↓
Input Events (IIO topics)
    input:mouse:move
    input:mouse:button
    input:mouse:wheel
    input:key:press
    input:text
    ↓
UIModule (processes events)
    ↓
UI Events (IIO topics)
    ui:click
    ui:action
    ui:value_changed
    ui:text_changed
    ui:text_submit
    ui:hover
    ui:focus_gained
    ui:focus_lost
    ↓
Demo App (logs events)

Hot-Reload Flow

1. Press 'R' key
2. Demo calls uiModule->setConfiguration(uiConfig, ...)
3. UIModule reloads demo_showcase.json
4. UI updates without restarting app
5. Event log shows "🔄 Reloading UI from JSON..."

Layout Structure

The demo_showcase.json layout is organized as:

root (horizontal layout)
├── sidebar (250px)
│   ├── Title + Info
│   ├── Controls panel
│   ├── Features checklist
│   ├── Clear Log button
│   └── Reset Stats button
│
└── main_content (950px, scrollable)
    ├── Welcome header
    ├── Buttons panel (4 buttons)
    ├── Sliders panel (3 sliders)
    ├── Text Input panel (2 text fields)
    ├── Checkboxes panel (4 checkboxes)
    ├── Progress Bars panel (3 bars)
    ├── Nested ScrollPanel (20 items)
    └── End message

Code Highlights

SDL Event Forwarding

// Mouse move
auto mouseMove = std::make_unique<JsonDataNode>("mouse_move");
mouseMove->setDouble("x", static_cast<double>(event.motion.x));
mouseMove->setDouble("y", static_cast<double>(event.motion.y));
uiIO->publish("input:mouse:move", std::move(mouseMove));

// Mouse wheel
auto mouseWheel = std::make_unique<JsonDataNode>("mouse_wheel");
mouseWheel->setDouble("delta", static_cast<double>(event.wheel.y));
uiIO->publish("input:mouse:wheel", std::move(mouseWheel));

// Text input
auto textInput = std::make_unique<JsonDataNode>("text_input");
textInput->setString("text", event.text.text);
uiIO->publish("input:text", std::move(textInput));

Event Logging

// Subscribe to UI events with callbacks (during setup)
uiIO->subscribe("ui:click", [&clickCount, &eventLog](const grove::Message& msg) {
    clickCount++;
    std::string widgetId = msg.data->getString("widgetId", "");
    eventLog.add("🖱️  Click: " + widgetId);
});

uiIO->subscribe("ui:action", [&actionCount, &eventLog](const grove::Message& msg) {
    actionCount++;
    std::string action = msg.data->getString("action", "");
    eventLog.add("⚡ Action: " + action);
});

// In main loop - pull and dispatch to callbacks
while (uiIO->hasMessages() > 0) {
    uiIO->pullAndDispatch();  // Callbacks invoked automatically
}

Hot-Reload Implementation

if (event.key.keysym.sym == SDLK_r) {
    eventLog.add("🔄 Reloading UI from JSON...");
    uiModule->setConfiguration(uiConfig, uiIO.get(), nullptr);
    eventLog.add("✅ UI reloaded!");
}

Known Limitations

WSL / Headless Environments

• ⚠️ Requires graphical environment (X11, Wayland, or Windows native)
• ⚠️ WSL without X server: Renderer fails to initialize
  • Demo runs in "UI-only mode" (no visual output)
  • Events still processed correctly
  • Safe fallback with health checks

Renderer Health Check

The demo checks renderer health and gracefully handles failures:

auto rendererHealth = renderer->getHealthStatus();
bool rendererOK = rendererHealth &&
                 rendererHealth->getString("status", "") == "healthy";

if (!rendererOK) {
    std::cout << "⚠️  Renderer not healthy, running in UI-only mode\n";
}

// In main loop
if (rendererOK) {
    renderer->process(frameInput);
}

This prevents segfaults when running in environments without GPU/display.

Performance

• 60 FPS target (16ms frame time)
• Main loop: ~0.2ms per frame (UI + event processing)
• Renderer: ~5ms per frame (when active)
• Total: ~5-6ms per frame = ~165 FPS capable

Bottleneck is SDL_Delay(16) to cap at 60 FPS.

Use Cases

1. Learning UIModule

• See all widgets in action
• Understand event flow
• Learn JSON layout syntax
• Try hot-reload

2. Testing New Features

• Add new widgets to demo_showcase.json
• Press 'R' to reload without restarting
• See changes immediately

3. Visual Regression Testing

• Run demo after changes
• Verify all widgets still work
• Check tooltips, hover states, interactions

4. Integration Example

• Shows proper BgfxRenderer + UIModule integration
• SDL2 event forwarding patterns
• IIO pub/sub communication
• Module lifecycle management

5. Showcase / Portfolio

• Demonstrates GroveEngine capabilities
• Shows hot-reload system
• Production-quality UI

Extending the Demo

Add a New Widget

1. Edit assets/ui/demo_showcase.json:

{
  "type": "button",
  "id": "my_new_button",
  "text": "New Feature",
  "tooltip": "This is a new button I added",
  "onClick": "demo:new_action",
  "width": 150,
  "height": 40
}

2. Run demo and press 'R' to reload

3. (Optional) Handle action in demo code:

if (action == "demo:new_action") {
    eventLog.add("New action triggered!");
}

Modify Styling

Change colors, fonts, sizes in JSON:

"style": {
  "fontSize": 20.0,
  "normal": {
    "bgColor": "0xFF5722FF",  // Material Orange
    "textColor": "0xFFFFFFFF"
  }
}

Press 'R' to see changes instantly.

Troubleshooting

Window doesn't appear

• WSL: Install X server (VcXsrv, Xming) and set DISPLAY
• Linux: Ensure X11 is running
• Windows: Should work natively

Renderer fails to initialize

• Expected in WSL/headless environments
• Demo runs in UI-only mode (events work, no visual)
• To fix: Use native display or X server

No events logged

• Check that widgets have onClick, onChange, etc.
• Verify IIO subscriptions
• Look for errors in console output

Hot-reload doesn't work

• Ensure JSON file path is correct
• Check JSON syntax (use validator)
• Look for parsing errors in log

Conclusion

The UIModule Interactive Showcase Demo is a complete, production-quality application that:

• ✅ Shows all UIModule features in one place
• ✅ Provides live interaction and real-time feedback
• ✅ Demonstrates hot-reload capability
• ✅ Serves as integration example for new projects
• ✅ Works as visual test for regression checking
• ✅ Handles failures gracefully (renderer health checks)

Perfect starting point for anyone building UIs with GroveEngine! 🚀

Summary Table

Feature	Status	Description
All 9 widgets	✅	Complete showcase
Tooltips	✅	Every widget has one
Scrolling	✅	Main + nested panels
Hot-reload	✅	Press 'R' to reload
Event console	✅	Live event logging
Stats tracking	✅	Click/action counters
Keyboard input	✅	Text fields work
Mouse interaction	✅	All input types
Graceful degradation	✅	Handles renderer failure
Documentation	✅	This file

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Related Documentation:

• UIModule Phase 7 Complete
• UIModule Architecture
• Integration Tests