Hey,
There is no documentation or guidance on it because we only recently saw a case were an app widget is using the Canvas API extensively, which causes a performance decrease on Android devices. This seems to be a thing on Android devices in combination the hardware acceleration, which is beneficial for most widgets but doesn’t handle Canvas as well. We are still debating what would be the best way to handle this or if we can do something about this from our side.
We have seen that using the Canvas API (heavily) can impact the entire dashboard, even a dashboard that was performing well without the widget. Ideally we would like to run widgets within a sandbox within the app. So they wouldn’t impact the rest of the dashboard or make the app stop responding. This has nothing to do with the number of widgets or memory management of the app, even having a single app widget that heavily uses the Canvas API can achieve this. We have tested this on pretty new flagship devices and this seems to be the case always with Android devices and the Canvas API. This only counts for app widget, all the Homey widgets are native.
In the mean time I would suggest to limit the amount of time you draw using the Canvas API or switch things to CSS/JS side if you don’t necessarily need the Canvas API.
