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|
package gui
import (
"fmt"
"image"
"image/draw"
"git.samanthony.xyz/share"
)
// Mux can be used to multiplex an Env, let's call it the parent Env. Mux implements a way to
// create multiple virtual Envs that all interact with the parent Env. They receive the same
// events and their draw functions get redirected to the parent Env.
type Mux struct {
size share.Val[image.Rectangle]
draw chan<- func(draw.Image) image.Rectangle
addChild chan<- muxEnv
removeChild chan<- muxEnv
kill chan<- bool
dead <-chan bool
detachChan <-chan bool
}
func NewMux(parent Env) Mux {
size := share.NewVal[image.Rectangle]()
drawChan := make(chan func(draw.Image) image.Rectangle)
addChild := make(chan muxEnv)
removeChild := make(chan muxEnv)
kill := make(chan bool)
dead := make(chan bool)
detachFromParent := make(chan bool)
go func() {
defer func() {
dead <- true
close(dead)
}()
defer func() {
detachFromParent <- true
close(detachFromParent)
}()
defer close(kill)
defer close(removeChild)
defer close(addChild)
defer close(drawChan)
defer size.Close()
var children []muxEnv
defer func() {
go drain(drawChan) // children may still be sending
for _, child := range children {
child.kill <- true
}
for range children {
<-removeChild
}
}()
for {
select {
case d := <-drawChan:
parent.Draw() <- d
case e := <-parent.Events():
if resize, ok := e.(Resize); ok {
size.Set <- resize.Rectangle
}
for _, child := range children {
child.events.Enqueue <- e
}
case child := <-addChild:
children = append(children, child)
case child := <-removeChild:
var err error
// TODO: faster search
if children, err = remove(child, children); err != nil {
panic(fmt.Sprintf("Mux: failed to remove child Env: %v", err))
}
case <-kill:
return
}
}
}()
mux := Mux{
size: size,
draw: drawChan,
addChild: addChild,
removeChild: removeChild,
kill: kill,
dead: dead,
detachChan: detachFromParent,
}
parent.attach() <- mux
return mux
}
func (mux Mux) Kill() chan<- bool {
return mux.kill
}
func (mux Mux) Dead() <-chan bool {
return mux.dead
}
func (mux Mux) detach() <-chan bool {
return mux.detachChan
}
type muxEnv struct {
events share.Queue[Event]
draw chan<- func(draw.Image) image.Rectangle
attachChan chan<- victim
kill chan<- bool
dead <-chan bool
detachFromMux <-chan bool
}
func (mux Mux) MakeEnv() Env {
events := share.NewQueue[Event]()
drawChan := make(chan func(draw.Image) image.Rectangle)
child := newKiller()
kill := make(chan bool)
dead := make(chan bool)
detachFromMux := make(chan bool)
env := muxEnv{
events: events,
draw: drawChan,
attachChan: child.attach(),
kill: kill,
dead: dead,
detachFromMux: detachFromMux,
}
mux.addChild <- env
// make sure to always send a resize event to a new Env
events.Enqueue <- Resize{mux.size.Get()}
go func() {
defer func() {
dead <- true
close(dead)
}()
defer close(kill)
defer close(drawChan)
defer close(events.Enqueue)
defer func() {
mux.removeChild <- env
}()
defer func() {
child.Kill() <- true
<-child.Dead()
}()
defer func() {
go drain(drawChan)
}()
for {
select {
case d := <-drawChan:
mux.draw <- d
case <-kill:
return
}
}
}()
return env
}
func (env muxEnv) Events() <-chan Event {
return env.events.Dequeue
}
func (env muxEnv) Draw() chan<- func(draw.Image) image.Rectangle {
return env.draw
}
func (env muxEnv) Kill() chan<- bool {
return env.kill
}
func (env muxEnv) Dead() <-chan bool {
return env.dead
}
func (env muxEnv) attach() chan<- victim {
return env.attachChan
}
// remove removes element e from slice s, returning the modified slice, or error if e is not in s.
func remove[S ~[]E, E comparable](e E, s S) ([]E, error) {
for i := range s {
if s[i] == e {
return append(s[:i], s[i+1:]...), nil
}
}
return s, fmt.Errorf("%v not found in %v", e, s)
}
func drain[T any](c <-chan T) {
for range c {
}
}
|