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>
Before this change, layout objects followed a pattern where a
begin method would set up the layout and return a tweaked set
of constraints, and a end method would take the widget dimensions
and return the tweaked dimensions.
As has been pointed out, this process is error prone, because the
scope of the layout objects are not clear and because it is easy
to swap two begins or two ends.
It turns out that it is possible to implement layout with function
scopes in garbage free way. A typical layout changes from
al := layout.Align{Alignment: layout.NE}
cs = al.Begin(ops, cs)
in := layout.Inset{Top: ui.Dp(16)}
cs = in.Begin(c, ops, cs)
txt := fmt.Sprintf("m: %d %s", mallocs, u.profile.Timings)
dims := text.Label{Material: theme.text, Face: u.face(fonts.mono, 10), Text: txt}.Layout(ops, cs)
dims = in.End(dims)
return al.End(dims)
to
al := layout.Align{Alignment: layout.NE}
return al.Layout(ops, cs, func(cs layout.Constraints) layout.Dimensions {
in := layout.Inset{Top: ui.Dp(16)}
return in.Layout(c, ops, cs, func(cs layout.Constraints) layout.Dimensions {
txt := fmt.Sprintf("m: %d %s", mallocs, u.profile.Timings)
return text.Label{Material: theme.text, Face: u.face(fonts.mono, 10), Text: txt}.Layout(ops, cs)
})
})
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Rename MainAxisAlignment to Spacing and CrossAxisAlignment to just
Alignment.
Drop the untyped Start, End, Center values and add them as Spacing
and Direction values. Center is both a Direction and Alignment, so
use the synonym "Middle" for the alignment.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Before this change, there was no guarantee that a PopOp matched
the intended PushOp. With a single stack operation, the client is
forced to match pop with the right push.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Move the Record and Stop methods from Ops to MacroOp itself.
Before this change, Ops.Stop stopped the recording of the most
recent macro, which could be a different macro than intended.
After this change, there is no such confusion.
As a bonus, the Ops API becomes less cluttered.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Get rid of the confused LayerOp and the transparent property from
AreaOp. Add an explicit PassOp to specify whether pointer events
pass-through the current area.
Let AreaOp swallow events even when no handlers are active for the
area. That behaviour is less surprising and allow clients to disable
a widget by keeping its areas but leave out its handlers.
Simplify the pointer.HitResult enum to just a bool: hit or no hit.
Finally, simplify the pointer queue by tracking parent areas and
node with indices.
Layouts and path builders are transient and need an ops list for
operation. However, instead of passing the ops list to every method,
pass the list in an init method and store it for subsequent methods.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
We're about to allow OpBlock for invoking ops from multiple (cached)
Ops containers. To allow for drawing state changes to stick after
invoking such a cached block, we can't let OpBlock perform an implicit
save and restore of drawing state.
Instead, introduce OpPush and OpPop for explicit drawing state stack
management.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The layout package switched from interfaces to functions for
composing layouts. The switch made sure that no garbage is
generated for transient layouts such as Align, Inset, Stack, Flex.
Unfortunately, that left the stateful widgets and layouts: as soon
as their layout methods are embedded in a transient layout, a
closure is generated that escapes to the heap.
To avoid garbage for both transient as well as stateful widgets,
replace the functional approach with explicit begin/end methods.
A begin method generally starts an op block and returns the adjusted
constraints. An end method takes computed dimensions, ends its op
block and returns adjusted dimensions.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
With layout.Widget a function instead of an interface, the amount
of per-frame garbage can be drastically reduced.
The layout code ends up slightly more explicit.
As a side benefit, the awkward ordering indexing for Flex and Stack
fit nicely into their new explicit Layout methods.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Pros:
- Much less per-frame garbage
- Allow future preprocessing of ops while building it
- Much fewer interface calls and pointer chasing
- Allow future serialization of ops for remote rendering
Cons:
- Slightly clumsier API
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur