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. :^)
Bring the names of various boxes closer to spec language. This should
hopefully make things easier to understand and hack on. :^)
Some notable changes:
- LayoutNode -> Layout::Node
- LayoutBox -> Layout::Box
- LayoutBlock -> Layout::BlockBox
- LayoutReplaced -> Layout::ReplacedBox
- LayoutDocument -> Layout::InitialContainingBlockBox
- LayoutText -> Layout::TextNode
- LayoutInline -> Layout::InlineNode
Note that this is not strictly a "box tree" as we also hang inline/text
nodes in the same tree, and they don't generate boxes. (Instead, they
contribute line box fragments to their containing block!)
Now the functions can actually be demonstrated by small examples,
embedded right inside the documentation via:
spreadsheet://example/<page>#<example_name>
Also allows pages to link to each other via the same scheme:
spreadsheet://doc/<page>
In a few places I also simplified a few format strings:
-outln("{} item{}", items, items.size() == 1 ? ' ' : 's');
+outln("{} item(s)", items);
In my opinion this is more readable and in some places it incorrectly
wrote '0 item' which is "fixed" now. In other places the placeholder
space looked weird.
