giowrap/README.md
2019-08-15 09:34:47 -04:00

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# GIOWrap
An experimental wrapper package for the Gio immediate mode GUI, designed to reduce
boilerplate.
```
go run ~/go/src/git.wow.st/gmp/giowrap/cmd/hello/main.go
```
The basic concept is to define a `Context` type that contains the Gio variables
required for layout and drawing. `Context` contains a pointer to `app.Window` and
`ui.Ops` so that, once layout is complete, you can call `Context.Draw()` to draw
your objects in your window.
The following types and functions are defined in order to transform a `Context`
variable during layout:
```go
type Layout func(Context) Context
type Widget interface {
Layout(Context) Context
}
func LayoutWithContext(ctx Context, ws ...Widget) Context {
for _, w := range ws {
ctx = w.Layout(ctx)
}
return ctx
}
type WidgetCombinator func(...Widget) Widget
type Enclosure interface {
Begin(Context) Context
End(Context) Context
}
func Enclose(e Enclosure, w ...Widget) Widget { ... }
```
The `Context` struct also contains a `map[string]interface{}` allowing arbitrary
data to be maintained. This can be used, for example, to define themes, and control
the operation of a `WidgetCombinator` during operation. For example>
```go
type fWidget struct { l Layout }
func NewfWidget(l layout) fWidget { return fWidget{ l: l } }
func (f Flex) Flexible(v float32) Widget {
return NewfWidget(func(ctx Context) Context {
ctx.extra["Flexible"] = v
return ctx
})
}
...
ctx = giowrap.LayoutWithContext(ctx,
myFlex(
w1,
giowrap.Flexible(0.5),
w2,
giowrap.Flexible(1),
w3,
))
ctx.Draw()
...
```