mirror of
https://git.sr.ht/~eliasnaur/gio
synced 2026-07-01 23:55:39 +00:00
Elias Naur
52 lines
1.5 KiB
Go
52 lines
1.5 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
|
|
|
|
/*
|
|
Package layout implements layouts common to GUI programs.
|
|
|
|
Constraints and dimensions
|
|
|
|
Constraints and dimensions form the interface between layouts and
|
|
interface child elements. This package operates on Widgets, functions
|
|
that compute Dimensions from a a set of constraints for acceptable
|
|
widths and heights. Both the constraints and dimensions are maintained
|
|
in an implicit Context to keep the Widget declaration short.
|
|
|
|
For example, to add space above a widget:
|
|
|
|
gtx := layout.NewContext(...)
|
|
gtx.Reset(...)
|
|
|
|
// Configure a top inset.
|
|
inset := layout.Inset{Top: unit.Dp(8), ...}
|
|
// Use the inset to lay out a widget.
|
|
inset.Layout(gtx, func() {
|
|
// Lay out widget and determine its size given the constraints.
|
|
...
|
|
dims := layout.Dimensions{...}
|
|
gtx.Dimensions = dims
|
|
})
|
|
|
|
Note that the example does not generate any garbage even though the
|
|
Inset is transient. Layouts that don't accept user input are designed
|
|
to not escape to the heap during their use.
|
|
|
|
Layout operations are recursive: a child in a layout operation can
|
|
itself be another layout. That way, complex user interfaces can
|
|
be created from a few generic layouts.
|
|
|
|
This example both aligns and insets a child:
|
|
|
|
inset := layout.Inset{...}
|
|
inset.Layout(gtx, func() {
|
|
align := layout.Align(...)
|
|
align.Layout(gtx, func() {
|
|
widget.Layout(gtx, ...)
|
|
})
|
|
})
|
|
|
|
More complex layouts such as Stack and Flex lay out multiple children,
|
|
and stateful layouts such as List accept user input.
|
|
|
|
*/
|
|
package layout
|