preview-lab/me.tbsten.compose.preview.lab.previewlab/PreviewLab/PreviewLab

PreviewLab

constructor(defaultState: @Composable () -> PreviewLabState = { rememberPreviewLabStateFromUrl() }, defaultScreenSizes: List<ScreenSize> = ScreenSize.SmartphoneAndDesktops, contentRoot: @Composable (content: @Composable () -> Unit) -> Unit = { it() }, defaultIsHeaderShow: @Composable () -> Boolean = { LocalDefaultIsHeaderShow.current }, defaultInspectorTabs: @Composable () -> List<InspectorTab> = { InspectorTab.defaults }, disableTrailingLambda: Nothing? = null)

Parameters

defaultState

Factory for creating the default PreviewLabState. Controls state persistence and initialization. By default, uses rememberSaveable for automatic state persistence across recompositions.

Usage examples:

// Default behavior - state persists across recompositions
PreviewLab() // Uses rememberSaveable internally

// Non-persistent state - resets on every recomposition
PreviewLab(
  defaultState = { remember { PreviewLabState() } }
)

// Custom retained state (requires Rin library)
PreviewLab(
  defaultState = { remember { PreviewLabState() } }
)

defaultScreenSizes

List of screen sizes to display in the preview. Controls which device form factors are available for testing. Defaults to ScreenSize.SmartphoneAndDesktops.

Usage examples:

// Default - smartphone and desktop sizes
PreviewLab() // Uses ScreenSize.SmartphoneAndDesktops

// All available presets including tablets
PreviewLab(
  defaultScreenSizes = ScreenSize.AllPresets
)

// Only mobile devices for focused testing
PreviewLab(
  defaultScreenSizes = listOf(ScreenSize.Phone, ScreenSize.Tablet)
)

// Custom screen sizes for specific requirements
PreviewLab(
  defaultScreenSizes = listOf(
    ScreenSize(360.dp, 640.dp, "Small Phone"),
    ScreenSize(1920.dp, 1080.dp, "Full HD Desktop")
  )
)

contentRoot

Wrapper composable that surrounds the entire PreviewLab UI. Useful for providing custom themes, composition locals, or other global configuration.

Usage examples:

// Default - no wrapper, uses PreviewLabTheme only
PreviewLab() // Uses { it() }

// Apply custom Material3 theme like customizedPreviewLab
PreviewLab(
  contentRoot = { content ->
    MaterialTheme(
      colorScheme = lightColorScheme(
        primary = Color.Red,
        onPrimary = Color.Yellow
      )
    ) {
      content()
    }
  }
)

// Provide composition locals for your design system
PreviewLab(
  contentRoot = { content ->
    MyDesignSystem {
      CompositionLocalProvider(
        LocalCustomTypography provides customTypography,
        LocalBranding provides myBranding
      ) {
        content()
      }
    }
  }
)

// Add global error boundary and logging
PreviewLab(
  contentRoot = { content ->
    ErrorBoundary(onError = { error -> logError(error) }) {
      content()
    }
  }
)

defaultIsHeaderShow

Controls whether the PreviewLab header is visible. When set to false, hides the header controls (scale, inspector panel toggle, etc.) to provide a cleaner preview view. Defaults to true.

Usage examples:

// Default - header is visible
PreviewLab() // Header shown

// Hide header for embedded preview
PreviewLab(
  isHeaderShow = false
) {
  MyComponent()
}

defaultInspectorTabs

List of tabs to display in the inspector panel. Defaults to InspectorTab.defaults which shows the built-in Fields and Events tabs.

Usage examples:

// Default - Fields and Events tabs only
PreviewLab() // Uses InspectorTab.defaults

// Add custom tabs alongside default tabs
val myPreviewLab = PreviewLab(
  defaultInspectorTabs = { InspectorTab.defaults + listOf(DebugTab) }
)

// Only custom tabs (no default Fields/Events)
val customOnlyPreviewLab = PreviewLab(
  defaultInspectorTabs = { listOf(CustomTab1, CustomTab2) }
)

// No tabs at all
val noTabsPreviewLab = PreviewLab(
  defaultInspectorTabs = { emptyList() }
)

disableTrailingLambda

Technical parameter to prevent the invoke method from being treated as a trailing lambda. Always null and has no functional purpose.

Usage example:

// This parameter is always null - you don't need to specify it
PreviewLab(
  defaultScreenSizes = ScreenSize.AllPresets
  // disableTrailingLambda is automatically null
) {
  // Preview content
}