aerc/lib/ui/ui.go
Ben Burwell bcd03c4c4a Add popovers
A popover is a special UI element which can be layered over the rest of
the UI (i.e. it is painted last) and can fall anywhere on the screen,
not just with the bounds of its parent's viewport/context. With these
special abilities comes the restriction that only one popover may be
visible on screen at once.

Popovers are requested from the UI context passed to Draw calls and
specify the anchor point and the desired dimensions. The popover is then
fit to the available space and placed relative to the anchor point.
2019-12-21 09:23:20 -05:00

121 lines
2.3 KiB
Go

package ui
import (
"sync/atomic"
"github.com/gdamore/tcell"
)
type UI struct {
Content DrawableInteractive
exit atomic.Value // bool
ctx *Context
screen tcell.Screen
popover *Popover
tcEvents chan tcell.Event
invalid int32 // access via atomic
}
func Initialize(content DrawableInteractiveBeeper) (*UI, error) {
screen, err := tcell.NewScreen()
if err != nil {
return nil, err
}
if err = screen.Init(); err != nil {
return nil, err
}
screen.Clear()
screen.HideCursor()
width, height := screen.Size()
state := UI{
Content: content,
screen: screen,
tcEvents: make(chan tcell.Event, 10),
}
state.ctx = NewContext(width, height, screen, state.onPopover)
state.exit.Store(false)
go func() {
for !state.ShouldExit() {
state.tcEvents <- screen.PollEvent()
}
}()
state.invalid = 1
content.OnInvalidate(func(_ Drawable) {
atomic.StoreInt32(&state.invalid, 1)
})
content.OnBeep(screen.Beep)
content.Focus(true)
return &state, nil
}
func (state *UI) onPopover(p *Popover) {
state.popover = p
}
func (state *UI) ShouldExit() bool {
return state.exit.Load().(bool)
}
func (state *UI) Exit() {
state.exit.Store(true)
}
func (state *UI) Close() {
state.screen.Fini()
}
func (state *UI) Tick() bool {
more := false
select {
case event := <-state.tcEvents:
switch event := event.(type) {
case *tcell.EventResize:
state.screen.Clear()
width, height := event.Size()
state.ctx = NewContext(width, height, state.screen, state.onPopover)
state.Content.Invalidate()
}
// if we have a popover, and it can handle the event, it does so
if state.popover == nil || !state.popover.Event(event) {
// otherwise, we send the event to the main content
state.Content.Event(event)
}
more = true
default:
}
wasInvalid := atomic.SwapInt32(&state.invalid, 0)
if wasInvalid != 0 {
if state.popover != nil {
// if the previous frame had a popover, rerender the entire display
state.Content.Invalidate()
atomic.StoreInt32(&state.invalid, 0)
}
// reset popover for the next Draw
state.popover = nil
state.Content.Draw(state.ctx)
if state.popover != nil {
// if the Draw resulted in a popover, draw it
state.popover.Draw(state.ctx)
}
state.screen.Show()
more = true
}
return more
}
func (state *UI) EnableMouse() {
state.screen.EnableMouse()
}