mirror of
https://git.sr.ht/~eliasnaur/gio
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Elias Naur
102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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/*
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Package app provides a platform-independent interface to operating system
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functionality for running graphical user interfaces.
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See https://gioui.org for instructions to set up and run Gio programs.
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Windows
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Create a new Window by calling NewWindow. On mobile platforms or when Gio
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is embedded in another project, NewWindow merely connects with a previously
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created window.
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A Window is run by receiving events from its Events channel. The most
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important event is FrameEvent that prompts an update of the window
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contents and state.
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For example:
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import "gioui.org/unit"
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w := app.NewWindow()
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for e := range w.Events() {
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if e, ok := e.(app.FrameEvent); ok {
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ops.Reset()
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// Add operations to ops.
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...
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// Completely replace the window contents and state.
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w.Update(ops)
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}
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}
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A program must keep receiving events from the event channel until
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DestroyEvent is received.
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Main
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The Main function must be called from a program's main function, to hand over
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control of the main thread to operating systems that need it.
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Because Main is also blocking, the event loop of a Window must run in a goroutine.
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For example, to display a blank but otherwise functional window:
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package main
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import "gioui.org/app"
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func main() {
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go func() {
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w := app.NewWindow()
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for range w.Events() {
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}
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}()
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app.Main()
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}
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Event queue
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A Window's Queue method returns an event.Queue implementation that distributes
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incoming events to the event handlers declared in the latest frame.
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See the gioui.org/io/event package for more information about event handlers.
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Permissions
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The packages under gioui.org/app/permission should be imported
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by a Gio program or by one of its dependencies to indicate that specific
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operating-system permissions are required. For example, if a Gio
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program requires access to a device's Bluetooth interface, it
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should import "gioui.org/app/permission/bluetooth" as follows:
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package main
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import (
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"gioui.org/app"
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_ "gioui.org/app/permission/bluetooth"
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)
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func main() {
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...
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}
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Since there are no exported identifiers in the app/permission/bluetooth
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package, the import uses the anonymous identifier (_) as the imported
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package name.
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As a special case, the gogio tool detects when a program directly or
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indirectly depends on the "net" package from the Go standard library as an
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indication that the program requires network access permissions. If a program
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requires network permissions but does not directly or indirectly import
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"net", it will be necessary to add the following code somewhere in the
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program's source code:
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import (
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...
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_ "net"
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)
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*/
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package app
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