This commit configures all remaining widgets to draw themselves in a disabled state
when their layout.Context is disabled. A description of the
strategy employed by each follows:
- Checkbox and RadioButton: Draws the icon component in a lighter color. Currently the label text is left
in its default color.
- ProgressBar: The "progress" color is lightened, but not as much as the background color. This makes the current progress value still readable.
- Editor: The cursor is no longer drawn and the text is lightened.
- Switch: The track is unchanged, but the circular "thumb" component is lightened.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
Instead of, say,
var th *material.Theme
var btn *widget.Clickable
material.Button(th, "Click me").Layout(gtx, btn)
move the widget state objects to the constructor:
material.Button(th, btn, "Click me").Layout(gtx)
The advatage is that several widgets can now be used without
wrapping them in function literals. For example,
layout.Inset{}.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
material.Button(th, "Click me").Layout(gtx, btn)
})
collapses to just
layout.Inset{}.Layout(gtx, material.Button(th, btn, "Click me").Layout)
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>
The multitude of widget methods on Theme is unnecessary coupling in that all
possible widgets either have to be included in package material, or be
different than 3rd party widgets:
var th *Theme
// Core widget, calling a method on Theme.
th.Button(...).Layout(...)
// 3rd party widget, calling a function taking a Theme.
datepicker.New(th, ...).Layout(...)
Another reason for the Theme methods was to enable a poor man's
theme replacement, so that you could use the same code for
compatible themes. For example,
mat.Button(...).Layout(...)
would not need to change if the type of mat changed, as long as
the new type had a compatible method Button.
However, that point misses the fact that the mat variable had to
be declared somewhere, naming the theme package:
var mat *material.Theme (or, say, *cocoa.Theme)
A better and complete way to replace a theme is to use import renaming.
For example, to replace the material theme with a hypothetical Windows
theme, replace
import theme "gioui.org/widget/material"
with
import theme "github.com/somebody/windows
This change moves all Theme widget methods to be standalone functions,
and renames the widget style types accordingly.
For example, instead of the method
func (t *Theme) Button(...) Button
there is now a function
func Button(t *Theme, ...) ButtonStyle
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur