Method doUpdate

core/render.go:169–225

doUpdate checks scene Needs flags to do whatever updating is required. returns false if already updating. This is the main update call made by the RenderWindow at FPS frequency.

()

// returns false if already updating.
// This is the main update call made by the RenderWindow at FPS frequency.
func (sc *Scene) doUpdate() bool {
	if sc.updating {
		return false
	}
	sc.updating = true // prevent rendering
	defer func() { sc.updating = false }()

	rc := sc.renderContext()

	if sc.showIter < sceneShowIters {
		sc.needsLayout = true
		sc.showIter++
	}

	switch {
	case rc.rebuild:
		pr := profile.Start("rebuild")
		sc.doRebuild()
		sc.needsLayout = false
		sc.sceneNeedsRender = false
		sc.imageUpdated = true
		pr.End()
	case sc.lastRender.needsRestyle(rc):
		pr := profile.Start("restyle")
		sc.applyStyleScene()
		sc.layoutRenderScene()
		sc.needsLayout = false
		sc.sceneNeedsRender = false
		sc.imageUpdated = true
		sc.lastRender.saveRender(rc)
		pr.End()
	case sc.needsLayout:
		pr := profile.Start("layout")
		sc.layoutRenderScene()
		sc.needsLayout = false
		sc.sceneNeedsRender = false
		sc.imageUpdated = true
		pr.End()
	case sc.sceneNeedsRender:
		pr := profile.Start("render")
		sc.doNeedsRender()
		sc.sceneNeedsRender = false
		sc.imageUpdated = true
		pr.End()
	default:
		return false
	}

	if sc.showIter == sceneShowIters { // end of first pass
		sc.showIter++
		if !sc.prefSizing {
			sc.Events.activateStartFocus()
		}
	}

	return true
}