In web design at least, a responsive GUI is one that can adapt to different types and sizes of screens where it is displayed to facilitate usability and navigation, that’s what I’m looking for.
For example if I have 3 subwidgets that I want to display horizontally, filling each one 1/3 of the width of the available space, they should be rendered that way regardless the screen resolution.
There is where having fixed sizes in pixels is a problem.
About canvas, all my widget have a canvas as parent element, but still, the next ‘container’ that you add as child will ask you for an height and a width.