Don't paint every frame
Set max FPS

Blocked by:
#5

User should be able to draw a border but its width and colour should depend on style used

It's not necessary and unnecessary complicates the code

WidgetPtr should be non copyable. Remove Ownerless, Owned and NewWidget.

Canvas layout should display allows user for arranging child widgets in any way he wants. Widgets can overlap and have empty spaces between them. User needs to specify their position and size in pixels and they will remain in this position and size all the time.

Blocked by:
#5

Something like this one looks good for the start: https://thomaspoignant.medium.com/ci-build-performance-testing-with-github-action-e6b227097c83

It should probably be based on css(?) It would be great if we would be able to use css to style the application.

Other idea is to use RON to store style properties and deserialise it using serde (no need to write custom parser)

Widget that should add border to its content

Editable text label

Linear layout organizes child widgets in single column or row. The orientation and direction should be controlled by an enum. Maybe it could be a generic struct taking this enum as a type parameter so we could create aliases for it (HorizontalLayout, VerticalLayout, HorizontalReversedLayout, VerticalReversedLayout).

Blocked by:
#5

Calculating heigth and width of an item in the layout is not a trivial task but once done it will work the same in every other layout so we should have items size generation in one place.

It shouldn't be possible to add child widget to a widget whichg type we don't know. We allow adding children to layouts and only one child for button for example.

Something like this one looks good for the start: https://thomaspoignant.medium.com/ci-build-performance-testing-with-github-action-e6b227097c83

We need to have some way to notify owner when some button was pressed or text modified. It would be probably more convenient to do this with signals on which we can register rather than bare observer pattern.

User should be able to click the button.
Button should invoke some function on click.
Button should have different appearance while hovered, pressed or idle.