Canvas

Canvas

Canvas hands you a drawing context and a size, and you draw straight away — paths, text, images — without creating a view for each thing drawn. Use it when you have hundreds or thousands of items to draw, such as a chart, particles, or a waveform, where a view for each one would be too slow. Pair it with TimelineView, which redraws on a schedule, to animate.

The trade-off is that things drawn in a Canvas are not views. They have no accessibility elements, gestures, or state of their own, so you provide those for the canvas as a whole. For standard charts, use the Swift Charts framework instead.

Plot 200 data points as a line chart in a Canvas, with axis lines. Add an accessibility label that describes the chart.

1. When should you choose Canvas over many small views?
2. What do you give up by drawing in a Canvas?
3. What is TimelineView for?

• Canvas
• TimelineView