vgi 1.0.0
Professional Modern GUI Library for Python - Create stunning applications with ease
License: MIT
Requires Python: >=3.8
Keywords: gui, ui, interface, modern, professional, desktop, application, framework

# VGI - Professional Modern GUI Library for Python

VGI (Visual GUI Interface) is a comprehensive, modern GUI framework for Python designed to create stunning, professional desktop applications with ease. Built on top of Tkinter but providing a much more powerful and intuitive API, VGI offers advanced styling, theming, animations, and a rich set of components that rival the best GUI frameworks available.

## Key Features

### Modern Design Philosophy
- **Clean, Modern Interface**: Professional-grade UI components with contemporary design patterns
- **Responsive Layouts**: Flexible layout system that adapts to different screen sizes and resolutions
- **Professional Themes**: Built-in themes including light, dark, and professional styles
- **Customizable Styling**: Comprehensive styling system with CSS-like properties

### Advanced Component Library
- **Rich Widget Set**: Over 30 professionally designed components
- **Input Validation**: Built-in validation system with real-time feedback
- **Data Visualization**: Integrated charting and graphing capabilities
- **Advanced Layouts**: Sophisticated layout managers (VBox, HBox, Grid, Stack)

### Developer Experience
- **Intuitive API**: Simple, consistent interface that's easy to learn and use
- **Event-Driven Architecture**: Robust event handling system
- **Type Safety**: Full type hints for excellent IDE support
- **Comprehensive Documentation**: Extensive examples and tutorials

### Performance & Reliability
- **High Performance**: Optimized rendering and efficient memory usage
- **Cross-Platform**: Works seamlessly on Windows, macOS, and Linux
- **Stable Foundation**: Built on proven Tkinter technology with modern enhancements
- **Production Ready**: Suitable for commercial applications

## Installation

### From PyPI (Recommended)

```bash
pip install vgi
```

### From Source

```bash
git clone https://github.com/vgi-team/vgi.git
cd vgi
pip install -e .
```

### Requirements

- Python 3.8 or higher
- Tkinter (usually included with Python)
- Pillow (automatically installed)
- NumPy (automatically installed)

## Quick Start

### Basic Application

```python
import vgi

# Create application
app = vgi.Application(theme="modern_light")

# Create main window
window = app.create_window(title="My VGI App", size=(800, 600))

# Create layout container
container = vgi.VBox(padding=20, spacing=15)

# Add components
title = vgi.Heading1("Welcome to VGI!")
container.add(title)

button = vgi.PrimaryButton(
    text="Click Me!",
    on_click=lambda: print("Button clicked!")
)
container.add(button)

# Add container to window
window.add_widget(container, fill="both", expand=True)

# Run application
app.run()
```

### Form Example with Validation

```python
import vgi

app = vgi.Application()
window = app.create_window(title="Contact Form", size=(500, 400))

# Create form layout
form = vgi.Grid(columns=2, spacing=10, padding=20)

# Name field
form.add(vgi.Label("Name:"), row=0, column=0, sticky="e")
name_input = vgi.Input(
    placeholder="Enter your name",
    validator=vgi.Validator().required().min_length(2)
)
form.add(name_input, row=0, column=1, sticky="ew")

# Email field
form.add(vgi.Label("Email:"), row=1, column=0, sticky="e")
email_input = vgi.EmailInput(placeholder="Enter your email")
form.add(email_input, row=1, column=1, sticky="ew")

# Message field
form.add(vgi.Label("Message:"), row=2, column=0, sticky="ne")
message_input = vgi.TextArea(
    placeholder="Enter your message...",
    validator=vgi.Validator().required().min_length(10)
)
form.add(message_input, row=2, column=1, sticky="ew")

# Buttons
button_container = vgi.HBox(spacing=10)
button_container.add(vgi.SecondaryButton("Cancel"))
button_container.add(vgi.PrimaryButton("Submit"))

form.add(button_container, row=3, column=0, columnspan=2, sticky="e")

# Configure grid
form.set_column_weight(1, 1)

window.add_widget(form, fill="both", expand=True)
app.run()
```

## Core Components

### Layout Containers

#### VBox - Vertical Layout
```python
vbox = vgi.VBox(spacing=10, align="stretch")
vbox.add(vgi.Label("First item"))
vbox.add(vgi.Label("Second item"))
vbox.add(vgi.Button("Third item"), expand=True)
```

#### HBox - Horizontal Layout
```python
hbox = vgi.HBox(spacing=10, align="center")
hbox.add(vgi.Button("Left"))
hbox.add(vgi.Button("Center"), expand=True)
hbox.add(vgi.Button("Right"))
```

#### Grid - Flexible Grid Layout
```python
grid = vgi.Grid(rows=3, columns=3, spacing=5)
grid.add(vgi.Button("1,1"), row=0, column=0)
grid.add(vgi.Button("Span"), row=0, column=1, columnspan=2)
grid.add(vgi.Button("2,1"), row=1, column=0, rowspan=2)
```

#### Stack - Layered Layout
```python
stack = vgi.Stack()
stack.add(vgi.Label("Page 1"), name="page1")
stack.add(vgi.Label("Page 2"), name="page2")
stack.show("page1")  # Show specific page
```

### Input Components

#### Basic Input Fields
```python
# Text input with placeholder
text_input = vgi.Input(placeholder="Enter text...")

# Email input with validation
email_input = vgi.EmailInput(placeholder="your@email.com")

# Password input
password_input = vgi.PasswordInput(placeholder="Password")

# Number input with range
number_input = vgi.NumberInput(min_value=0, max_value=100)

# Multi-line text area
text_area = vgi.TextArea(placeholder="Enter message...")
```

#### Input Validation
```python
# Create validator
validator = (vgi.Validator()
    .required()
    .min_length(8)
    .regex(r'.*[A-Z].*', "Must contain uppercase")
    .regex(r'.*\d.*', "Must contain number"))

# Apply to input
password_input = vgi.PasswordInput(
    placeholder="Secure password",
    validator=validator,
    on_change=lambda text: print(f"Valid: {password_input.is_valid}")
)
```

### Button Components

#### Button Styles
```python
# Primary button (main action)
primary_btn = vgi.PrimaryButton("Save", on_click=save_data)

# Secondary button (secondary action)
secondary_btn = vgi.SecondaryButton("Cancel", on_click=cancel)

# Outline button (tertiary action)
outline_btn = vgi.OutlineButton("Options", on_click=show_options)

# Danger button (destructive action)
danger_btn = vgi.DangerButton("Delete", on_click=delete_item)
```

#### Button Sizes
```python
small_btn = vgi.Button("Small", size="small")
medium_btn = vgi.Button("Medium", size="medium")
large_btn = vgi.Button("Large", size="large")
```

#### Button States
```python
# Loading state
loading_btn = vgi.Button("Processing...", loading=True)

# Disabled state
disabled_btn = vgi.Button("Disabled", disabled=True)

# With icon (requires icon implementation)
icon_btn = vgi.Button("Save", icon="save", icon_position="left")
```

### Display Components

#### Labels and Text
```python
# Heading levels
h1 = vgi.Heading1("Main Title")
h2 = vgi.Heading2("Section Title")
h3 = vgi.Heading3("Subsection")

# Regular label
label = vgi.Label("Regular text", text_color="#333333")

# Caption text
caption = vgi.Caption("Small descriptive text")

# Clickable link
link = vgi.Link("Click here", on_click=handle_click)

# Wrapped text
wrapped = vgi.Label(
    "This is a long text that will wrap automatically",
    wrap=True
)
```

#### Containers and Panels
```python
# Basic container
container = vgi.Container(padding=16)

# Styled panel with border
panel = vgi.Panel(title="Settings", border=True, padding=20)

# Simple frame (no styling)
frame = vgi.Frame()

# Scrollable container
scrollable = vgi.Container(scrollable=True, padding=10)
```

## Theming and Styling

### Built-in Themes

```python
# Available themes
app = vgi.Application(theme="modern_light")    # Default light theme
app = vgi.Application(theme="modern_dark")     # Dark theme
app = vgi.Application(theme="professional")    # Professional/corporate theme

# Switch themes at runtime
app.set_theme("modern_dark")
```

### Custom Styling

```python
# Style individual components
button = vgi.Button("Styled Button")
button.set_style(
    background_color="#FF6B6B",
    text_color="#FFFFFF",
    border_radius=8,
    padding=(12, 24),
    font_weight="bold"
)

# Create custom theme
custom_theme = app.theme_manager.create_custom_theme(
    "my_theme", 
    base_theme="modern_light"
)
custom_theme.set_widget_style("button", "background_color", "#4ECDC4")
app.set_theme("my_theme")
```

### Color System

```python
# Using Color class
primary_color = vgi.Color.from_hex("#007ACC")
darker_primary = primary_color.darken(0.2)
lighter_primary = primary_color.lighten(0.2)

# Color palettes
palette = vgi.ColorPalette.create_material_palette()
dark_palette = vgi.ColorPalette.create_dark_palette()

# Apply palette to theme
theme = vgi.Theme("Custom Theme")
theme.set_palette(palette)
```

## Advanced Features

### Event Handling

```python
class MyHandler:
    def __init__(self):
        self.button = vgi.Button("Click me")
        
        # Multiple event handlers
        self.button.on("clicked", self.on_click)
        self.button.on("mouse_enter", self.on_hover)
        self.button.on("mouse_leave", self.on_leave)
    
    def on_click(self, event):
        print(f"Button {event.source.id} was clicked!")
    
    def on_hover(self, event):
        event.source.set_style(background_color="#E3F2FD")
    
    def on_leave(self, event):
        event.source.set_style(background_color="#2196F3")
```

### Animation System

```python
# Simple fade in animation
button = vgi.Button("Animated")
fade_in = vgi.Transition.fade_in(button, duration=0.5)
fade_in.start()

# Custom animation
animation = vgi.Animation(
    button,
    duration=1.0,
    x=100,
    y=50,
    scale_x=1.2,
    scale_y=1.2,
    easing="ease_out_bounce"
)
animation.start()

# Animation with callbacks
def on_complete(anim):
    print("Animation finished!")

pulse = vgi.Transition.pulse(button, duration=0.3)
pulse.on_complete = on_complete
pulse.start()
```

### Data Binding and Validation

```python
# Form with comprehensive validation
class RegistrationForm:
    def __init__(self):
        self.form = vgi.Grid(columns=2, spacing=10)
        
        # Username with custom validation
        self.username = vgi.Input(
            placeholder="Username",
            validator=vgi.Validator()
                .required()
                .min_length(3)
                .max_length(20)
                .regex(r'^[a-zA-Z0-9_]+$', "Only letters, numbers, underscore")
        )
        
        # Email validation
        self.email = vgi.EmailInput(placeholder="Email address")
        
        # Password with strength requirements
        self.password = vgi.PasswordInput(
            placeholder="Password",
            validator=vgi.Validator.create_password_validator(min_length=8)
        )
        
        # Confirm password
        self.confirm_password = vgi.PasswordInput(
            placeholder="Confirm password",
            validator=vgi.Validator().custom(
                lambda x: x == self.password.value,
                "Passwords must match"
            )
        )
        
        self.build_form()
    
    def build_form(self):
        fields = [
            ("Username:", self.username),
            ("Email:", self.email),
            ("Password:", self.password),
            ("Confirm:", self.confirm_password)
        ]
        
        for i, (label, field) in enumerate(fields):
            self.form.add(vgi.Label(label), row=i, column=0, sticky="e")
            self.form.add(field, row=i, column=1, sticky="ew")
        
        # Submit button - only enabled when all fields valid
        submit_btn = vgi.PrimaryButton("Register", on_click=self.submit)
        self.form.add(submit_btn, row=len(fields), column=1, sticky="e")
    
    def submit(self):
        if all(field.is_valid for field in [self.username, self.email, 
                                           self.password, self.confirm_password]):
            print("Registration successful!")
        else:
            print("Please fix validation errors")
```

## Advanced Components

### Data Display Components

```python
# Table with data
table = vgi.Table(
    columns=["Name", "Age", "Email"],
    data=[
        ["John Doe", 30, "john@example.com"],
        ["Jane Smith", 25, "jane@example.com"]
    ]
)

# Data grid with sorting/filtering
grid = vgi.DataGrid()
grid.set_columns([
    {"key": "name", "title": "Name", "sortable": True},
    {"key": "age", "title": "Age", "sortable": True, "type": "number"},
    {"key": "email", "title": "Email", "sortable": True}
])
grid.set_data(data_list)

# Tree view
tree = vgi.TreeView()
root_node = tree.add_node("Root")
child_node = root_node.add_child("Child 1")
child_node.add_child("Grandchild")
```

### Charts and Visualization

```python
# Line chart
line_chart = vgi.LineChart(
    data={
        "x": [1, 2, 3, 4, 5],
        "y": [10, 25, 30, 45, 60]
    },
    title="Sales Over Time"
)

# Bar chart
bar_chart = vgi.BarChart(
    data={
        "categories": ["Q1", "Q2", "Q3", "Q4"],
        "values": [100, 150, 200, 175]
    },
    title="Quarterly Results"
)

# Pie chart
pie_chart = vgi.PieChart(
    data={
        "Desktop": 45,
        "Mobile": 35,
        "Tablet": 20
    },
    title="Platform Usage"
)
```

### Dialog and Modal Components

```python
# Message boxes
vgi.MessageBox.show("Operation completed successfully!", "Success", "info")
vgi.MessageBox.show("Are you sure?", "Confirmation", "warning")
vgi.MessageBox.show("Error occurred!", "Error", "error")

# File dialogs
filename = vgi.FileDialog.open_file(
    title="Open Document",
    filetypes=[("Text files", "*.txt"), ("All files", "*.*")]
)

save_path = vgi.FileDialog.save_file(
    title="Save Document",
    defaultextension=".txt"
)

# Custom dialog
class SettingsDialog(vgi.Dialog):
    def __init__(self, parent):
        super().__init__(parent, title="Settings", size=(400, 300))
        self.build_ui()
    
    def build_ui(self):
        content = vgi.VBox(padding=20, spacing=15)
        
        # Settings options
        content.add(vgi.Label("Application Settings"))
        content.add(vgi.Checkbox("Enable notifications"))
        content.add(vgi.Checkbox("Auto-save documents"))
        
        # Buttons
        buttons = vgi.HBox(spacing=10)
        buttons.add(vgi.SecondaryButton("Cancel", on_click=self.close))
        buttons.add(vgi.PrimaryButton("OK", on_click=self.apply))
        
        content.add(buttons)
        self.add_widget(content)
```

## Application Architecture

### Model-View-Controller Pattern

```python
class Model:
    def __init__(self):
        self.data = []
        self.observers = []
    
    def add_observer(self, observer):
        self.observers.append(observer)
    
    def notify_observers(self):
        for observer in self.observers:
            observer.update()
    
    def add_item(self, item):
        self.data.append(item)
        self.notify_observers()

class View:
    def __init__(self, model, controller):
        self.model = model
        self.controller = controller
        self.model.add_observer(self)
        self.build_ui()
    
    def build_ui(self):
        self.window = vgi.Window(title="MVC Example")
        self.container = vgi.VBox(padding=20)
        
        # Input area
        self.input = vgi.Input(placeholder="Enter item")
        self.add_btn = vgi.PrimaryButton(
            "Add", 
            on_click=lambda: self.controller.add_item(self.input.value)
        )
        
        # List display
        self.list_container = vgi.VBox(spacing=5)
        
        # Layout
        input_row = vgi.HBox(spacing=10)
        input_row.add(self.input, expand=True)
        input_row.add(self.add_btn)
        
        self.container.add(input_row)
        self.container.add(self.list_container)
        
        self.window.add_widget(self.container, fill="both", expand=True)
    
    def update(self):
        # Refresh list display
        self.list_container.clear()
        for item in self.model.data:
            self.list_container.add(vgi.Label(item))

class Controller:
    def __init__(self, model):
        self.model = model
    
    def add_item(self, item):
        if item.strip():
            self.model.add_item(item)

# Usage
model = Model()
controller = Controller(model)
view = View(model, controller)
```

### Plugin Architecture

```python
class PluginManager:
    def __init__(self, app):
        self.app = app
        self.plugins = {}
    
    def register_plugin(self, name, plugin_class):
        plugin = plugin_class(self.app)
        self.plugins[name] = plugin
        plugin.initialize()
    
    def get_plugin(self, name):
        return self.plugins.get(name)

class BasePlugin:
    def __init__(self, app):
        self.app = app
    
    def initialize(self):
        pass
    
    def create_menu_items(self):
        return []

class ThemePlugin(BasePlugin):
    def initialize(self):
        # Add theme menu items
        pass
    
    def create_menu_items(self):
        return [
            vgi.MenuItem("Light Theme", on_click=self.set_light_theme),
            vgi.MenuItem("Dark Theme", on_click=self.set_dark_theme)
        ]

# Usage
app = vgi.Application()
plugin_manager = PluginManager(app)
plugin_manager.register_plugin("themes", ThemePlugin)
```

## Performance Optimization

### Efficient Rendering

```python
# Use containers efficiently
container = vgi.VBox()

# Batch updates
container.begin_update()  # Suspend layout updates
for i in range(100):
    container.add(vgi.Label(f"Item {i}"))
container.end_update()  # Resume and apply all updates

# Virtual scrolling for large lists
large_list = vgi.VirtualListView(
    item_count=10000,
    item_height=30,
    render_item=lambda index: vgi.Label(f"Item {index}")
)

# Lazy loading
def load_data_chunk(start, end):
    # Load data only when needed
    return data[start:end]

lazy_container = vgi.LazyContainer(
    total_items=1000,
    chunk_size=50,
    load_chunk=load_data_chunk
)
```

### Memory Management

```python
# Clean up resources
class DataView:
    def __init__(self):
        self.observers = []
        self.timers = []
    
    def cleanup(self):
        # Remove event handlers
        for observer in self.observers:
            observer.disconnect()
        
        # Stop timers
        for timer in self.timers:
            timer.stop()
        
        # Clear references
        self.observers.clear()
        self.timers.clear()

# Use weak references for callbacks
import weakref

class WeakCallback:
    def __init__(self, obj, method_name):
        self.obj_ref = weakref.ref(obj)
        self.method_name = method_name
    
    def __call__(self, *args, **kwargs):
        obj = self.obj_ref()
        if obj is not None:
            method = getattr(obj, self.method_name)
            return method(*args, **kwargs)
```

## Testing

### Unit Testing Components

```python
import unittest
import vgi

class TestButton(unittest.TestCase):
    def setUp(self):
        self.app = vgi.Application()
        self.button = vgi.Button("Test Button")
    
    def test_button_text(self):
        self.assertEqual(self.button.text, "Test Button")
    
    def test_button_click(self):
        clicked = False
        
        def on_click():
            nonlocal clicked
            clicked = True
        
        self.button.on_click(on_click)
        self.button.click()
        self.assertTrue(clicked)
    
    def test_button_styling(self):
        self.button.set_style(background_color="#FF0000")
        self.assertEqual(self.button.get_style("background_color"), "#FF0000")
    
    def tearDown(self):
        self.app.quit()

class TestLayout(unittest.TestCase):
    def setUp(self):
        self.app = vgi.Application()
        self.container = vgi.VBox(spacing=10)
    
    def test_add_widgets(self):
        widget1 = vgi.Label("Widget 1")
        widget2 = vgi.Label("Widget 2")
        
        self.container.add(widget1)
        self.container.add(widget2)
        
        self.assertEqual(len(self.container.children), 2)
        self.assertIn(widget1, self.container.children)
        self.assertIn(widget2, self.container.children)
    
    def test_remove_widget(self):
        widget = vgi.Label("Test Widget")
        self.container.add(widget)
        self.container.remove(widget)
        
        self.assertEqual(len(self.container.children), 0)
        self.assertNotIn(widget, self.container.children)

if __name__ == '__main__':
    unittest.main()
```

### Integration Testing

```python
import vgi

def test_full_application():
    """Test complete application workflow."""
    app = vgi.Application()
    window = app.create_window(title="Test App")
    
    # Create form
    form = vgi.VBox(spacing=10)
    name_input = vgi.Input(placeholder="Name")
    email_input = vgi.EmailInput(placeholder="Email")
    submit_btn = vgi.PrimaryButton("Submit")
    
    form.add(name_input)
    form.add(email_input)
    form.add(submit_btn)
    
    window.add_widget(form)
    
    # Simulate user input
    name_input.value = "John Doe"
    email_input.value = "john@example.com"
    
    # Verify values
    assert name_input.value == "John Doe"
    assert email_input.value == "john@example.com"
    assert email_input.is_valid
    
    # Simulate button click
    submitted = False
    def on_submit():
        global submitted
        submitted = True
    
    submit_btn.on_click(on_submit)
    submit_btn.click()
    
    assert submitted
    print("Integration test passed!")
    
    app.quit()

if __name__ == '__main__':
    test_full_application()
```

## Deployment

### Creating Executable Applications

```python
# setup.py for PyInstaller
from setuptools import setup

setup(
    name="MyVGIApp",
    version="1.0.0",
    py_modules=["main"],
    install_requires=["vgi>=1.0.0"],
    entry_points={
        "console_scripts": [
            "myapp=main:main",
        ],
    },
)
```

```bash
# Using PyInstaller
pip install pyinstaller
pyinstaller --onefile --windowed main.py

# Using cx_Freeze
pip install cx_freeze
python setup.py build

# Using auto-py-to-exe (GUI for PyInstaller)
pip install auto-py-to-exe
auto-py-to-exe
```

### Distribution

```python
# setup.py for distribution
from setuptools import setup, find_packages

setup(
    name="my-vgi-application",
    version="1.0.0",
    packages=find_packages(),
    install_requires=[
        "vgi>=1.0.0",
    ],
    entry_points={
        "gui_scripts": [
            "myapp=myapp.main:main",
        ],
    },
    classifiers=[
        "Development Status :: 5 - Production/Stable",
        "Intended Audience :: End Users/Desktop",
        "License :: OSI Approved :: MIT License",
        "Operating System :: OS Independent",
        "Programming Language :: Python :: 3",
        "Programming Language :: Python :: 3.8",
        "Programming Language :: Python :: 3.9",
        "Programming Language :: Python :: 3.10",
        "Programming Language :: Python :: 3.11",
        "Topic :: Desktop Environment",
    ],
)
```

## Examples and Tutorials

### Complete Application Examples

The VGI repository includes comprehensive examples:

- **Basic Example**: Simple application demonstrating core features
- **Layout Showcase**: All layout types with interactive examples
- **Theme Demo**: Theme switching and customization
- **Component Gallery**: All components with live examples
- **Professional App**: Full-featured business application
- **Animation Demo**: Showcase of animation capabilities
- **Form Builder**: Dynamic form creation tool
- **Data Visualization**: Charts and graphs examples
- **Plugin System**: Extensible application architecture

### Running Examples

```bash
# Install VGI with examples
pip install vgi[examples]

# Run the main demo launcher
python -m vgi.examples.demo

# Run specific examples
python -m vgi.examples.basic_example
python -m vgi.examples.layout_showcase
python -m vgi.examples.theme_demo
```

## API Reference

### Core Classes

#### Application
Main application class managing windows, themes, and global resources.

**Methods:**
- `create_window(title, size, **kwargs)`: Create new window
- `set_theme(theme_name)`: Change application theme
- `run()`: Start application main loop
- `quit()`: Close application

#### Window
Top-level window container.

**Methods:**
- `add_widget(widget, **layout_options)`: Add widget to window
- `show()`: Show window
- `hide()`: Hide window
- `center()`: Center window on screen
- `set_icon(icon_path)`: Set window icon

#### Widget
Base class for all UI components.

**Properties:**
- `visible`: Widget visibility
- `enabled`: Widget enabled state
- `position`: Widget position
- `size`: Widget size
- `style`: Widget style dictionary

**Methods:**
- `set_style(**kwargs)`: Set style properties
- `on(event_name, handler)`: Add event handler
- `emit(event_name, **kwargs)`: Emit event
- `focus()`: Set focus to widget

### Component Classes

#### Button
Interactive button component.

**Properties:**
- `text`: Button text
- `style`: Button style ("primary", "secondary", etc.)
- `size`: Button size ("small", "medium", "large")
- `loading`: Loading state
- `disabled`: Disabled state

**Methods:**
- `click()`: Programmatically trigger click
- `on_click(handler)`: Set click handler

#### Input
Text input component with validation.

**Properties:**
- `value`: Input value
- `placeholder`: Placeholder text
- `validator`: Validation rules
- `is_valid`: Validation state
- `readonly`: Read-only state

**Methods:**
- `clear()`: Clear input value
- `select_all()`: Select all text
- `focus()`: Set focus to input

#### Layout Containers

**VBox**: Vertical layout
**HBox**: Horizontal layout
**Grid**: Grid layout
**Stack**: Layered layout

Common properties:
- `spacing`: Space between children
- `padding`: Internal padding
- `align`: Child alignment

### Styling Classes

#### Theme
Complete application theme.

**Methods:**
- `set_widget_style(widget_type, property, value)`
- `get_widget_styles(widget_type)`
- `set_global_style(property, value)`

#### Color
Color representation and manipulation.

**Methods:**
- `from_hex(hex_string)`: Create from hex
- `from_name(color_name)`: Create from name
- `lighten(amount)`: Lighten color
- `darken(amount)`: Darken color
- `mix(other_color, ratio)`: Mix colors

### Animation Classes

#### Animation
Property animation over time.

**Parameters:**
- `target`: Widget to animate
- `duration`: Animation duration
- `easing`: Easing function
- `**properties`: Properties to animate

**Methods:**
- `start()`: Start animation
- `pause()`: Pause animation
- `stop()`: Stop animation

#### Transition
Pre-built transition effects.

**Static Methods:**
- `fade_in(widget, duration)`
- `slide_in_left(widget, duration)`
- `scale_in(widget, duration)`
- `pulse(widget, duration)`

## Best Practices

### Application Structure

```python
# Recommended project structure
myapp/
├── __init__.py
├── main.py              # Application entry point
├── models/              # Data models
│   ├── __init__.py
│   └── user.py
├── views/               # UI components
│   ├── __init__.py
│   ├── main_window.py
│   └── dialogs/
├── controllers/         # Business logic
│   ├── __init__.py
│   └── user_controller.py
├── resources/           # Assets
│   ├── images/
│   ├── icons/
│   └── themes/
└── tests/              # Test files
    ├── __init__.py
    └── test_views.py
```

### Code Organization

```python
# main.py - Clean application entry point
import vgi
from views.main_window import MainWindow
from controllers.app_controller import AppController

def main():
    app = vgi.Application(theme="modern_light")
    controller = AppController(app)
    main_window = MainWindow(controller)
    
    app.add_window(main_window)
    app.run()

if __name__ == "__main__":
    main()

# views/main_window.py - Separate UI definition
import vgi

class MainWindow(vgi.Window):
    def __init__(self, controller):
        super().__init__(title="My Application", size=(800, 600))
        self.controller = controller
        self.build_ui()
    
    def build_ui(self):
        # UI construction logic
        pass
```

### Performance Guidelines

1. **Use appropriate containers**: Choose the right layout for your needs
2. **Batch updates**: Group multiple changes together
3. **Lazy loading**: Load data only when needed
4. **Efficient event handling**: Avoid excessive event handlers
5. **Resource cleanup**: Properly dispose of resources

### Accessibility

```python
# Keyboard navigation
button.set_style(focusable=True)
button.on("key_press", handle_key_press)

# Screen reader support
label.set_style(
    accessible_name="User Name Input",
    accessible_description="Enter your full name"
)

# High contrast support
if app.is_high_contrast_mode():
    app.set_theme("high_contrast")
```

## Contributing

We welcome contributions to VGI! Please see our [Contributing Guidelines](CONTRIBUTING.md) for details.

### Development Setup

```bash
# Clone repository
git clone https://github.com/vgi-team/vgi.git
cd vgi

# Create virtual environment
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install development dependencies
pip install -e .[dev]

# Run tests
python -m pytest

# Run examples
python -m vgi.examples.demo
```

### Code Style

We use Black for code formatting and follow PEP 8 guidelines.

```bash
# Format code
black .

# Check style
flake8 .

# Type checking
mypy vgi/
```

## License

VGI is released under the MIT License. See [LICENSE](LICENSE) file for details.

## Support

- **Documentation**: [https://vgi.readthedocs.io/](https://vgi.readthedocs.io/)
- **GitHub Issues**: [https://github.com/vgi-team/vgi/issues](https://github.com/vgi-team/vgi/issues)
- **Discussions**: [https://github.com/vgi-team/vgi/discussions](https://github.com/vgi-team/vgi/discussions)
- **Email**: support@vgi.dev

## Changelog

### Version 1.0.0 (Initial Release)

- Complete widget library with 30+ components
- Advanced layout system (VBox, HBox, Grid, Stack)
- Professional theming system with built-in themes
- Comprehensive styling with CSS-like properties
- Animation and transition system
- Form validation framework
- Event-driven architecture
- Type safety with full type hints
- Comprehensive documentation and examples
- Cross-platform compatibility
- Performance optimizations

## Acknowledgments

VGI builds upon the solid foundation of Tkinter while providing a modern, professional interface. We thank the Python community and all contributors who have made this project possible.

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**VGI - Elevating Python GUI Development to Professional Standards**