Almost every layout and widget need the ui.Config for its environment,
an ui.Ops to store operations. Stateful widgets need an input.Queue
for events.
Add all these common objects to Context, greatly simplifying the
function signatures for Gio programs.
Fixes gio#33
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Context keeps the current Constraints and Dimensions so the layout
function scopes don't have to.
With
ctx := new(layout.Context)
a label with margins and alignment goes from
return al.Layout(ops, cs, func(cs layout.Constraints) layout.Dimensions {
in := layout.Inset{...}
return in.Layout(c, ops, cs, func(cs layout.Constraints) layout.Dimensions {
return text.Label{...}.Layout(ops, cs)
})
})
to
al.Layout(ops, ctx, func() {
in := layout.Inset{...}
in.Layout(c, ops, ctx, func() {
text.Label{...}.Layout(ops, ctx)
})
})
It was a difficult trade-off between the verbose functional approach
and the shorter but more complex Context.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur