Renderer.CanvasRenderer

@WorkerThread
CanvasRenderer(
    surfaceHolder: SurfaceHolder,
    currentUserStyleRepository: CurrentUserStyleRepository,
    watchState: WatchState,
    canvasType: Int,
    interactiveDrawModeUpdateDelayMillis: @IntRange(from = 0, to = 60000) Long,
    clearWithBackgroundTintBeforeRenderingHighlightLayer: Boolean = false
)

@UiThread
open suspend fun init(): Unit

Perform UiThread specific initialization. Will be called once during initialization before any subsequent calls to render. If you need to override this method in java, consider using androidx.wear.watchface.ListenableCanvasRenderer instead.

open fun onDump(writer: PrintWriter): Unit

Called when adb shell dumpsys is invoked for the WatchFaceService, allowing the renderer to optionally record state for debugging purposes.

@UiThread
abstract fun render(canvas: Canvas, bounds: Rect, zonedDateTime: ZonedDateTime): Unit

Sub-classes should override this to implement their watch face rendering logic which should respect the current renderParameters. Please note WatchState.isAmbient may not match the RenderParameters.drawMode and should not be used to decide what to render. E.g. when editing from the companion phone while the watch is ambient, renders may be requested with DrawMode.INTERACTIVE.

Any highlights due to RenderParameters.highlightLayer should be rendered by renderHighlightLayer instead where possible. For correct behavior this function must use the supplied ZonedDateTime in favor of any other ways of getting the time.

Before any calls to render, init will be called once.

@UiThread
abstract fun renderHighlightLayer(
    canvas: Canvas,
    bounds: Rect,
    zonedDateTime: ZonedDateTime
): Unit

Sub-classes should override this to implement their watch face highlight layer rendering logic for the RenderParameters.highlightLayer aspect of renderParameters. Typically the implementation will clear canvas to RenderParameters.HighlightLayer.backgroundTint before rendering a transparent highlight or a solid outline around the RenderParameters.HighlightLayer.highlightedElement. This will be composited as needed on top of the results of render. For correct behavior this function must use the supplied ZonedDateTime in favor of any other ways of getting the time.

Note if clearWithBackgroundTintBeforeRenderingHighlightLayer is true then canvas will cleared with RenderParameters.HighlightLayer.backgroundTint before renderHighlightLayer is called. Otherwise it is up to the overridden function to clear the Canvas if necessary.

val clearWithBackgroundTintBeforeRenderingHighlightLayer: Boolean

Whether the Canvas is cleared with RenderParameters.HighlightLayer.backgroundTint before renderHighlightLayer is called. Defaults to false.