Method Draw

widgets/treeview/treeview.go:618–691

Draw renders the treeview widget.

(cvs *canvas.Canvas, meta *widgetapi.Meta)

// Draw renders the treeview widget.
func (tv *TreeView) Draw(cvs *canvas.Canvas, meta *widgetapi.Meta) error {
	tv.mu.Lock()
	defer tv.mu.Unlock()
	tv.updateVisibleNodes()
	tv.advanceSpinners(time.Now())
	visibleNodes := tv.visibleNodes
	totalHeight := len(visibleNodes)
	width := cvs.Area().Dx()
	tv.canvasWidth = width // Set canvasWidth here
	tv.canvasHeight = cvs.Area().Dy()

	// Log canvas dimensions
	tv.logger.Printf("Canvas Area: Dx=%d, Dy=%d", tv.canvasWidth, tv.canvasHeight)

	if tv.canvasWidth <= 0 || tv.canvasHeight <= 0 {
		return fmt.Errorf("canvas too small")
	}

	// Calculate the maximum valid scroll offset
	maxScrollOffset := tv.totalContentHeight - tv.canvasHeight
	if maxScrollOffset < 0 {
		maxScrollOffset = 0
	}

	// Clamp scrollOffset to ensure it stays within valid bounds
	if tv.scrollOffset > maxScrollOffset {
		tv.scrollOffset = maxScrollOffset
		tv.logger.Printf("Clamped scrollOffset to maxScrollOffset: %d", tv.scrollOffset)
	}
	if tv.scrollOffset < 0 {
		tv.scrollOffset = 0
		tv.logger.Printf("Clamped scrollOffset to 0")
	}

	tv.logger.Printf("Starting Draw with scrollOffset: %d, totalHeight: %d, canvasHeight: %d", tv.scrollOffset, totalHeight, tv.canvasHeight)

	// Clear the canvas
	if err := cvs.Clear(); err != nil {
		return err
	}

	// Determine the range of nodes to draw
	start := tv.scrollOffset
	end := tv.scrollOffset + tv.canvasHeight
	if end > len(visibleNodes) {
		end = len(visibleNodes)
	}

	// Slice the visibleNodes to only the range to draw
	nodesToDraw := visibleNodes[start:end]

	// Draw nodes
	if err := tv.drawNode(cvs, nodesToDraw); err != nil {
		tv.logger.Printf("Error drawing nodes: %v", err)
		return err
	}

	// Draw scroll indicators if needed