64 lines
1.6 KiB
Markdown
64 lines
1.6 KiB
Markdown
# GIOWrap
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An experimental wrapper package for the Gio immediate mode GUI, designed to reduce
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boilerplate.
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```
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go run ~/go/src/git.wow.st/gmp/giowrap/cmd/hello/main.go
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```
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The basic concept is to define a `Context` type that contains the Gio variables
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required for layout and drawing. `Context` contains a pointer to `app.Window` and
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`ui.Ops` so that, once layout is complete, you can call `Context.Draw()` to draw
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your objects in your window.
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The following types and functions are defined in order to transform a `Context`
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variable during layout:
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```go
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type Layout func(Context) Context
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type Widget interface {
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Layout(Context) Context
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}
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type WidgetCombinator func(...Widget) Widget
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type Enclosure interface {
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Begin(Context) Context
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End(Context) Context
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}
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func Enclose(e Enclosure, w ...Widget) Widget { ... }
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```
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The giowrap package also includes a private package-global variable called
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extra that is a []interface{}, allowing arbitrary data to be maintained by
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UI elements. Elements can request access to the structure when they are
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allocated and they are returned a unique integer index into the slice. This
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can be used, for example, to define themes, and control
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the operation of a `WidgetCombinator` during operation. For example:
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```go
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type fWidget struct { l Layout }
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func NewfWidget(l layout) fWidget { return fWidget{ l: l } }
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func Flexible(v float32) Widget {
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return NewfWidget(func(ctx Context) Context {
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extra.data[extra.cur].(*FlexOpts).flexible = v
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return ctx
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})
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}
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...
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ctx = myFlex(
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w1,
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giowrap.Flexible(0.5),
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w2,
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giowrap.Flexible(1),
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w3,
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).Layout(ctx)
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ctx.Draw()
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...
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```
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