A slice of FontFace pairs are simpler, and thread safe in case a client
wants to append or modify the font collection.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Before this change, package font implemented a global font registry,
with the usual problems of package global state.
This change deletes the global registry and introduces the text.Collection
type for representing a list of fonts and their faces. Collection exports
Lookup that finds the closest match and its face.
The existing FontRegistry is renamed to Cache to reflect its new limited
functionality: a cache of shapes and measurements on top of a Collection.
Then, material.NewTheme is changed to take a Collection and initialize
a Cache.
Updates gio#19 because multiple windows require a separate (writable) Cache per
window, while (read-only) Collections may be shared.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Change the definition of Widget from the implicit
type Widget func()
to the explicit functional
type Widget func(gtx layout.Context) layout.Dimensions
The advantages are numerous:
- Clearer connection between the incoming context and the output dimensions.
- Returning the Dimensions are impossible to omit.
- Contexts passed by value, so its fields can be exported
and freely mutated by the program.
The only disadvantage is the longer function literals and the many "returns".
What tipped the scales in favour of the explicit Widget variant is that type
aliases can dramatically shorten the literals:
type (
C = layout.Context
D = layout.Dimensions
)
widget := func(gtx C) D {
...
}
Note that the aliases are not part of the Gio API and it is up to each user
whether they want to use them.
Finally the Go proposal for lightweight function literals,
https://github.com/golang/go/issues/21498, may remove the disadvantage
completely in future.
Context becomes a plain struct with only public fields, and its Reset is
replaced by a NewContext convenience constructor.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Instead of
type Contraints struct {
Width, Height Constraint
}
use
type Constraints struct {
Min, Max image.Point
}
which leads to simpler use. For example, the Min method is trivally replaced by
the field, and the RigidConstraints constructor is no longer a net win.
API Change. Rewrites:
gofmt -r 'gtx.Constraints.Min() -> gtx.Constraints.Min'
gofmt -r 'gtx.Constraints.Width.Min -> gtx.Constraints.Min.X'
gofmt -r 'gtx.Constraints.Height.Min -> gtx.Constraints.Min.Y'
gofmt -r 'gtx.Constraints.Height.Max -> gtx.Constraints.Max.Y'
gofmt -r 'gtx.Constraints.Width.Max -> gtx.Constraints.Max.X'
Signed-off-by: Elias Naur <mail@eliasnaur.com>
There is nothing theme-specific about displaying images and icons,
so move the types from the material package to the generic widget
package.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur