If this flag is enabled for a widget, it will be automatically sized
based on its children. This only works for widgets using a layout.
This allows you to put widgets inside each other without having to
manually calculate how large the container should be. It's not the
perfect API but it's a decent progression in ergonomics. :^)
This patch removes size policies and preferred sizes, and replaces them
with min-size and max-size for each widget.
Box layout now works in 3 passes:
1) Set all items (widgets/spacers) to their min-size
2) Distribute remaining space evenly, respecting max-size
3) Place widgets one after the other, adding spacing in between
I've also added convenience helpers for setting a fixed size (which is
the same as setting min-size and max-size to the same value.)
This significantly reduces the verbosity of widget layout and makes GML
a bit more pleasant to write, too. :^)
This patch adds min_size and max_size properties to GUI::Widget. These
can also be accessed as min_width/min_height and max_width/max_height.
Layouts will respect these constraints and size widgets accordingly.
Instead of everyone overriding save_to() and set_property() and doing
a pretty asymmetric job of implementing the various properties, let's
add a bit of structure here.
Object properties are now represented by a Core::Property. Properties
are registered with a getter and setter (optional) in constructors.
I've added some convenience macros for creating and registering
properties, but this does still feel a bit bulky. We'll have to
iterate on this and see where it goes.
Since space is divided evenly between widgets with SizePolicy::Fill,
we were sometimes ending up with a couple of unused pixels after the
last widget (due to rounding.)
Fix this by always giving the slack pixels at the end to the very last
auto-sized widget in the layout.
This fixes an issue where it was sometimes possible to click on an
"unreachable" part of a Splitter widget. :^)
