PyWry

Native Window Mode

CRITICAL: This is a native desktop application using PyWry/WRY (Rust WebView).

This is NOT a browser. This is NOT Jupyter. This is NOT an iframe.

What Native Mode IS

You're creating widgets for a native desktop window powered by:

• PyWry (Python bindings)
• WRY (Rust WebView library)
• Tauri ecosystem (system-level access)

The widget runs in a standalone system window with:

• Native title bar, minimize, maximize, close buttons
• Direct OS integration (file dialogs, notifications, clipboard)
• No browser chrome, no URL bar, no tabs
• Full screen real estate for your content

What Native Mode is NOT

❌ NOT a web browser - No DevTools (unless explicitly enabled), no extensions, no URL bar ❌ NOT Jupyter - No cell output area, no kernel, no notebook context ❌ NOT an iframe - No parent page, no sandboxing, no cross-origin restrictions

Architecture

┌───────────────────────────────────────────────────────────┐
│                      Native Window                        │
│  ┌─────────────────────────────────────────────────────┐  │
│  │               Title Bar (OS-native)                 │  │
│  ├─────────────────────────────────────────────────────┤  │
│  │                                                     │  │
│  │                 WebView (WRY/Tauri)                 │  │
│  │                                                     │  │
│  │    ┌─────────────────────────────────────────┐      │  │
│  │    │          Your Widget Content            │      │  │
│  │    │      (HTML/CSS/JS via PyWry API)        │      │  │
│  │    └─────────────────────────────────────────┘      │  │
│  │                                                     │  │
│  └─────────────────────────────────────────────────────┘  │
└───────────────────────────────────────────────────────────┘
              ↕ Python ↔ Rust ↔ OS integration

Key Capabilities

Window Control

• Resize, minimize, maximize, close via native controls
• Set window title dynamically
• Window always stays on top (optional)
• Multiple windows possible

System Integration

• Downloads: download tool triggers native OS save dialog
• Navigation: navigate can open external URLs in system browser
• Clipboard: Full clipboard access
• File System: Can reference local files

Persistent State

• Widget state persists until window is closed
• Events accumulate until get_events(clear=True)
• Long-running applications are the norm

Best Practices

1. Layout - Use Full Viewport

# You have the entire window - use it
content = Div(
    content="<h1>Dashboard</h1>",
    component_id="main",
    style="height: 100vh; width: 100vw; padding: 20px;",
)

2. Toolbars - Position Top/Bottom

# Top toolbar for primary navigation
create_widget(
    html=content.build_html(),
    toolbars=[{
        "position": "top",
        "items": [
            {"type": "button", "label": "File", "event": "menu:file"},
            {"type": "button", "label": "Edit", "event": "menu:edit"},
            {"type": "button", "label": "View", "event": "menu:view"},
        ]
    }]
)

3. Theme - Respect System Preference

# Let OS dark/light mode control the theme
update_theme(widget_id, theme="system")

4. Interactive Buttons - The Pattern

CRITICAL: Buttons work automatically when events follow elementId:action pattern.

# Counter widget - buttons update content automatically
create_widget(
    html='<div id="counter" style="font-size:48px;text-align:center">0</div>',
    toolbars=[{
        "position": "top",
        "items": [
            {"type": "button", "label": "+1", "event": "counter:increment"},
            {"type": "button", "label": "-1", "event": "counter:decrement"},
            {"type": "button", "label": "Reset", "event": "counter:reset"}
        ]
    }]
)

The magic: event="counter:increment" automatically:

1. Finds element with id="counter"
2. Increments its text content by 1
3. Updates the display

Supported actions:

• increment - add 1
• decrement - subtract 1
• reset - set to 0
• toggle - switch true/false

5. Window Events

# Detect window close
events = get_events(widget_id, clear=True)
for e in events:
    if e["event_type"] == "pywry:disconnect":
        # User closed the window - cleanup
        cleanup_resources()

Recommended Components

| Component | Why | |-----------|-----| | TabGroup | Multi-view navigation (like app tabs) | | SecretInput | Secure API key storage | | Marquee | Live data tickers (full width available) | | Plotly | Full interactive charts (zoom, pan, export) |

Code Example

from pywry import PyWry
from pywry.toolbar import Button, Div, TabGroup, Toolbar

app = PyWry()

# Create main content area
content = Div(
    content="""
        <h1 style="margin: 0;">Financial Dashboard</h1>
        <p>Real-time market data</p>
    """,
    component_id="dashboard",
    style="padding: 24px; height: calc(100vh - 100px);",
)

# Create window with toolbars
widget = app.show(
    html=content.build_html(),
    title="Market Dashboard",
    height=800,
    toolbars=[
        Toolbar(
            position="top",
            items=[
                Button(label="Refresh", event="action:refresh", variant="primary"),
                Button(label="Settings", event="action:settings", variant="ghost"),
            ]
        )
    ]
)

# Event loop
while True:
    events = widget.get_events(clear=True)
    for e in events:
        if e["event_type"] == "pywry:disconnect":
            exit()
        elif e["event_type"] == "action:refresh":
            # Refresh data...
            pass

Native-Specific Features

File Downloads

# Triggers native OS save dialog
download(widget_id,
         url="data:text/csv;base64,...",
         filename="export.csv")

Open in System Browser

# Opens URL in user's default browser (not the widget)
navigate(widget_id, url="https://example.com", external=True)

Toast Notifications

# Native-style toast (position matters less in native)
show_toast(widget_id, message="Saved!", type="success")