Screen Information

Wails provides a unified screen API that works across all platforms. Get screen information, detect multiple monitors, query screen properties (size, position, DPI), identify the primary display, and handle DPI scaling with consistent code.

Quick Start

// Get all screens
screens := app.Screen.GetAll()

for _, screen := range screens {
    fmt.Printf("Screen: %s (%dx%d)\n", 
        screen.Name, screen.Size.Width, screen.Size.Height)
}

// Get primary screen
primary := app.Screen.GetPrimary()
fmt.Printf("Primary: %s\n", primary.Name)

That’s it! Cross-platform screen information.

Getting Screen Information

All Screens

screens := app.Screen.GetAll()

for _, screen := range screens {
    fmt.Printf("ID: %s\n", screen.ID)
    fmt.Printf("Name: %s\n", screen.Name)
    fmt.Printf("Size: %dx%d\n", screen.Size.Width, screen.Size.Height)
    fmt.Printf("Position: %d,%d\n", screen.X, screen.Y)
    fmt.Printf("Scale: %.2f\n", screen.ScaleFactor)
    fmt.Printf("Primary: %v\n", screen.IsPrimary)
    fmt.Println("---")
}

Primary Screen

primary := app.Screen.GetPrimary()

fmt.Printf("Primary screen: %s\n", primary.Name)
fmt.Printf("Resolution: %dx%d\n", primary.Size.Width, primary.Size.Height)
fmt.Printf("Scale factor: %.2f\n", primary.ScaleFactor)

Current Screen

Get the screen containing a window:

screen, err := window.GetScreen()
if err != nil {
    // handle error
}
fmt.Printf("Window is on: %s\n", screen.Name)

Screen by ID

screen := app.Screen.GetByID("screen-id")
if screen != nil {
    fmt.Printf("Found screen: %s\n", screen.Name)
}

Screen Properties

Screen Structure

type Screen struct {
    ID               string  // Unique identifier
    Name             string  // Display name
    ScaleFactor      float32 // DPI scale (1.0, 1.5, 2.0, etc.)
    X, Y             int     // Position (top-left, logical pixels)
    Size             Size    // Logical size (Width, Height)
    Bounds           Rect    // Logical bounds (X, Y, Width, Height)
    PhysicalBounds   Rect    // Physical bounds (scaled)
    WorkArea         Rect    // Logical work area excluding taskbars/menubars
    PhysicalWorkArea Rect    // Physical work area
    IsPrimary        bool    // Is this the primary screen?
    Rotation         float32 // Screen rotation in degrees (e.g. 0, 90, 180, 270)
}

// Size and Rect are simple value types:
type Size struct{ Width, Height int }
type Rect struct{ X, Y, Width, Height int }

Read pixel sizes via screen.Size.Width / screen.Size.Height — there are no top-level Width/Height fields.

Physical vs Logical Pixels

screen := app.Screen.GetPrimary()

// Logical pixels (what you use)
logicalWidth := screen.Size.Width
logicalHeight := screen.Size.Height

// Physical pixels (actual display)
physicalWidth := int(float32(screen.Size.Width) * screen.ScaleFactor)
physicalHeight := int(float32(screen.Size.Height) * screen.ScaleFactor)

fmt.Printf("Logical: %dx%d\n", logicalWidth, logicalHeight)
fmt.Printf("Physical: %dx%d\n", physicalWidth, physicalHeight)
fmt.Printf("Scale: %.2f\n", screen.ScaleFactor)

Common scale factors:

1.0 - Standard DPI (96 DPI)
1.25 - 125% scaling (120 DPI)
1.5 - 150% scaling (144 DPI)
2.0 - 200% scaling (192 DPI) - Retina
3.0 - 300% scaling (288 DPI) - 4K/5K

Window Positioning

Centre on Screen

func centreOnScreen(window *application.WebviewWindow, screen *Screen) {
    windowWidth, windowHeight := window.Size()
    
    x := screen.X + (screen.Size.Width-windowWidth)/2
    y := screen.Y + (screen.Size.Height-windowHeight)/2
    
    window.SetPosition(x, y)
}

Position on Specific Screen

func moveToScreen(window *application.WebviewWindow, screenIndex int) {
    screens := app.Screen.GetAll()
    
    if screenIndex < 0 || screenIndex >= len(screens) {
        return
    }
    
    screen := screens[screenIndex]
    
    // Centre on target screen
    centreOnScreen(window, screen)
}

Position Relative to Screen

// Top-left corner
func positionTopLeft(window *application.WebviewWindow, screen *Screen) {
    window.SetPosition(screen.X+10, screen.Y+10)
}

// Top-right corner
func positionTopRight(window *application.WebviewWindow, screen *Screen) {
    windowWidth, _ := window.Size()
    window.SetPosition(screen.X+screen.Size.Width-windowWidth-10, screen.Y+10)
}

// Bottom-right corner
func positionBottomRight(window *application.WebviewWindow, screen *Screen) {
    windowWidth, windowHeight := window.Size()
    window.SetPosition(
        screen.X+screen.Size.Width-windowWidth-10,
        screen.Y+screen.Size.Height-windowHeight-10,
    )
}

Multi-Monitor Support

Detect Multiple Monitors

func hasMultipleMonitors() bool {
    return len(app.Screen.GetAll()) > 1
}

func getMonitorCount() int {
    return len(app.Screen.GetAll())
}

List All Monitors

func listMonitors() {
    screens := app.Screen.GetAll()
    
    fmt.Printf("Found %d monitor(s):\n", len(screens))
    
    for i, screen := range screens {
        primary := ""
        if screen.IsPrimary {
            primary = " (Primary)"
        }
        
        fmt.Printf("%d. %s%s\n", i+1, screen.Name, primary)
        fmt.Printf("   Resolution: %dx%d\n", screen.Size.Width, screen.Size.Height)
        fmt.Printf("   Position: %d,%d\n", screen.X, screen.Y)
        fmt.Printf("   Scale: %.2fx\n", screen.ScaleFactor)
    }
}

Choose Monitor

func chooseMonitor() (*Screen, error) {
    screens := app.Screen.GetAll()
    
    if len(screens) == 1 {
        return screens[0], nil
    }
    
    // Show dialog to choose
    var options []string
    for i, screen := range screens {
        primary := ""
        if screen.IsPrimary {
            primary = " (Primary)"
        }
        options = append(options, 
            fmt.Sprintf("%d. %s%s - %dx%d", 
                i+1, screen.Name, primary, screen.Size.Width, screen.Size.Height))
    }
    
    // Use dialog to select
    // (Implementation depends on your dialog system)
    
    return screens[0], nil
}

Complete Examples

Multi-Monitor Window Manager

type MultiMonitorManager struct {
    app     *application.App
    windows map[int]*application.WebviewWindow
}

func NewMultiMonitorManager(app *application.App) *MultiMonitorManager {
    return &MultiMonitorManager{
        app:     app,
        windows: make(map[int]*application.WebviewWindow),
    }
}

func (m *MultiMonitorManager) CreateWindowOnScreen(screenIndex int) error {
    screens := m.app.Screen.GetAll()
    
    if screenIndex < 0 || screenIndex >= len(screens) {
        return errors.New("invalid screen index")
    }
    
    screen := screens[screenIndex]
    
    // Create window
    window := m.app.Window.NewWithOptions(application.WebviewWindowOptions{
        Title:  fmt.Sprintf("Window on %s", screen.Name),
        Width:  800,
        Height: 600,
    })
    
    // Centre on screen
    x := screen.X + (screen.Size.Width-800)/2
    y := screen.Y + (screen.Size.Height-600)/2
    window.SetPosition(x, y)
    
    window.Show()
    
    m.windows[screenIndex] = window
    return nil
}

func (m *MultiMonitorManager) CreateWindowOnEachScreen() {
    screens := m.app.Screen.GetAll()
    
    for i := range screens {
        m.CreateWindowOnScreen(i)
    }
}

Screen Change Detection

type ScreenMonitor struct {
    app           *application.App
    lastScreens   []*Screen
    changeHandler func([]*Screen)
}

func NewScreenMonitor(app *application.App) *ScreenMonitor {
    return &ScreenMonitor{
        app:         app,
        lastScreens: app.Screen.GetAll(),
    }
}

func (sm *ScreenMonitor) OnScreenChange(handler func([]*Screen)) {
    sm.changeHandler = handler
}

func (sm *ScreenMonitor) Start() {
    ticker := time.NewTicker(2 * time.Second)
    
    go func() {
        for range ticker.C {
            sm.checkScreens()
        }
    }()
}

func (sm *ScreenMonitor) checkScreens() {
    current := sm.app.Screen.GetAll()
    
    if len(current) != len(sm.lastScreens) {
        sm.lastScreens = current
        if sm.changeHandler != nil {
            sm.changeHandler(current)
        }
    }
}

DPI-Aware Window Sizing

func createDPIAwareWindow(screen *Screen) *application.WebviewWindow {
    // Base size at 1.0 scale
    baseWidth := 800
    baseHeight := 600
    
    // Adjust for DPI
    width := int(float32(baseWidth) * screen.ScaleFactor)
    height := int(float32(baseHeight) * screen.ScaleFactor)
    
    window := app.Window.NewWithOptions(application.WebviewWindowOptions{
        Title:  "DPI-Aware Window",
        Width:  width,
        Height: height,
    })
    
    // Centre on screen
    x := screen.X + (screen.Size.Width-width)/2
    y := screen.Y + (screen.Size.Height-height)/2
    window.SetPosition(x, y)
    
    return window
}

Screen Layout Visualiser

func visualiseScreenLayout() string {
    screens := app.Screen.GetAll()
    
    var layout strings.Builder
    layout.WriteString("Screen Layout:\n\n")
    
    for i, screen := range screens {
        primary := ""
        if screen.IsPrimary {
            primary = " [PRIMARY]"
        }
        
        layout.WriteString(fmt.Sprintf("Screen %d: %s%s\n", i+1, screen.Name, primary))
        layout.WriteString(fmt.Sprintf("  Position: (%d, %d)\n", screen.X, screen.Y))
        layout.WriteString(fmt.Sprintf("  Size: %dx%d\n", screen.Size.Width, screen.Size.Height))
        layout.WriteString(fmt.Sprintf("  Scale: %.2fx\n", screen.ScaleFactor))
        layout.WriteString(fmt.Sprintf("  Physical: %dx%d\n", 
            int(float32(screen.Size.Width)*screen.ScaleFactor),
            int(float32(screen.Size.Height)*screen.ScaleFactor)))
        layout.WriteString("\n")
    }
    
    return layout.String()
}

Best Practices

✅ Do

Check screen count - Handle single and multiple monitors
Use logical pixels - Wails handles DPI automatically
Centre windows - Better UX than fixed positions
Validate positions - Ensure windows are visible
Handle screen changes - Monitors can be added/removed
Test on different DPI - 100%, 125%, 150%, 200%

❌ Don’t

Don’t hardcode positions - Use screen dimensions
Don’t assume primary screen - User might have multiple
Don’t ignore scale factor - Important for DPI awareness
Don’t position off-screen - Validate coordinates
Don’t forget screen changes - Laptops dock/undock
Don’t use physical pixels - Use logical pixels

Platform Differences

macOS

Retina displays (2x scale factor)
Multiple displays common
Coordinate system: (0,0) at bottom-left
Spaces (virtual desktops) affect positioning

Windows

Various DPI scaling (100%, 125%, 150%, 200%)
Multiple displays common
Coordinate system: (0,0) at top-left
Per-monitor DPI awareness

Linux

Varies by desktop environment
X11 vs Wayland differences
DPI scaling support varies
Multiple displays supported

Next Steps

Windows

Learn about window management.

Learn More →

Window Options

Configure window appearance.

Learn More →

Multiple Windows

Multi-window patterns.

Learn More →

Bindings

Call Go functions from JavaScript.

Learn More →

Questions? Ask in Discord or check the screen examples.