forked from joejulian/gio
Elias Naur
cb1e605203
In the early days of Gio, FrameEvent was part of package app. It was moved to package system to enable layout.NewContext be a convenient short-hand for constructing a layout. However, it seems the better design to leave FrameEvent (and Insets) in package app, and move layout.NewContext there as well. More importantly, the move allows us to replace the event.Queue interface with a concrete type. Signed-off-by: Elias Naur <mail@eliasnaur.com>
72 lines
1.8 KiB
Go
72 lines
1.8 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
|
|
|
|
/*
|
|
Package app provides a platform-independent interface to operating system
|
|
functionality for running graphical user interfaces.
|
|
|
|
See https://gioui.org for instructions to set up and run Gio programs.
|
|
|
|
# Windows
|
|
|
|
Create a new Window by calling NewWindow. On mobile platforms or when Gio
|
|
is embedded in another project, NewWindow merely connects with a previously
|
|
created window.
|
|
|
|
A Window is run by calling NextEvent in a loop. The most important event is
|
|
FrameEvent that prompts an update of the window contents.
|
|
|
|
For example:
|
|
|
|
w := app.NewWindow()
|
|
for {
|
|
e := w.NextEvent()
|
|
if e, ok := e.(app.FrameEvent); ok {
|
|
ops.Reset()
|
|
// Add operations to ops.
|
|
...
|
|
// Completely replace the window contents and state.
|
|
e.Frame(ops)
|
|
}
|
|
}
|
|
|
|
A program must keep receiving events from the event channel until
|
|
DestroyEvent is received.
|
|
|
|
# Main
|
|
|
|
The Main function must be called from a program's main function, to hand over
|
|
control of the main thread to operating systems that need it.
|
|
|
|
Because Main is also blocking on some platforms, the event loop of a Window must run in a goroutine.
|
|
|
|
For example, to display a blank but otherwise functional window:
|
|
|
|
package main
|
|
|
|
import "gioui.org/app"
|
|
|
|
func main() {
|
|
go func() {
|
|
w := app.NewWindow()
|
|
for {
|
|
w.NextEvent()
|
|
}
|
|
}()
|
|
app.Main()
|
|
}
|
|
|
|
# Event queue
|
|
|
|
A FrameEvent's Queue method returns an event.Queue implementation that distributes
|
|
incoming events to the event handlers declared in the last frame.
|
|
See the gioui.org/io/event package for more information about event handlers.
|
|
|
|
# Permissions
|
|
|
|
The packages under gioui.org/app/permission should be imported
|
|
by a Gio program or by one of its dependencies to indicate that specific
|
|
operating-system permissions are required. Please see documentation for
|
|
package gioui.org/app/permission for more information.
|
|
*/
|
|
package app
|