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package tui
import (
"github.com/rivo/uniseg"
"golang.org/x/term"
"zgo.at/termfo"
"zgo.at/termfo/caps"
"unicode"
"unicode/utf8"
"bufio"
"os"
)
type pos struct {
x int
y int
}
type char struct {
c string
style Style
}
type surface map[pos]char
type screen struct {
front surface
back surface
prevSize ScreenSize
writer *bufio.Writer
cursor pos
showCursor bool
}
var (
terminfo *termfo.Terminfo
scr screen
)
func init() {
scr.writer = bufio.NewWriterSize(os.Stdout, 50000)
Clear()
}
type ScreenSize struct {
Width int
Height int
}
func Size() ScreenSize {
w, h, _ := term.GetSize(0)
return ScreenSize {w, h}
}
func WriteAt(x int, y int, text string, style Style) int {
width := 0
g := uniseg.NewGraphemes(text)
for g.Next() {
c := g.Str()
r, _ := utf8.DecodeRuneInString(c)
if !unicode.IsGraphic(r) {
continue
}
scr.front[pos {x, y}] = char {c, style}
w := g.Width()
for i := 1; i < w; i++ {
scr.front[pos {x + i, y}] = char {"", style}
}
x += w
width += w
}
return width
}
func Clear() {
scr.front = make(surface)
ClearCursor()
}
func ShowCursor(x int, y int) {
scr.cursor = pos {x, y}
scr.showCursor = true
}
func ClearCursor() {
scr.showCursor = false
}
var saved *term.State
func Start() error {
if saved != nil {
return nil
}
var err error
saved, err = term.MakeRaw(0)
if err != nil {
return err
}
terminfo, err = termfo.New("")
if err != nil {
if terminfo, err = termfo.New("xterm"); err != nil {
return err
}
}
scr.back = make(surface)
_, err = os.Stdout.WriteString(
terminfo.Get(caps.EnterCaMode) +
terminfo.Get(caps.XM, 1) +
terminfo.Get(caps.ClearScreen),
)
return err
}
func End() {
if saved == nil {
return
}
os.Stdout.WriteString(
terminfo.Get(caps.ClearScreen) +
terminfo.Get(caps.XM, 0) +
terminfo.Get(caps.ExitCaMode),
)
if term.Restore(0, saved) != nil {
return
}
saved = nil
}
func writeClearCursor() {
scr.writer.WriteString(terminfo.Get(caps.CursorInvisible))
}
func writeCursor(x int, y int) {
scr.writer.WriteString(terminfo.Get(caps.CursorNormal))
scr.writer.WriteString(terminfo.Get(caps.CursorAddress, y, x))
}
func writeStyle(style Style) {
scr.writer.WriteString(terminfo.Get(caps.ExitAttributeMode))
scr.writer.WriteString(terminfo.Get(caps.SetAForeground, int(style.Fg)))
scr.writer.WriteString(terminfo.Get(caps.SetABackground, int(style.Bg)))
if style.Bold {
scr.writer.WriteString(terminfo.Get(caps.EnterBoldMode))
}
if style.Italic {
scr.writer.WriteString(terminfo.Get(caps.EnterItalicsMode))
}
if style.Underline {
scr.writer.WriteString(terminfo.Get(caps.EnterUnderlineMode))
}
if style.Strikethrough {
scr.writer.WriteString(terminfo.Get(caps.Smxx))
}
}
func Present() error {
writeClearCursor()
s := Size()
reset := true
style := DefaultStyle
var p pos
for p.y = 0; p.y < s.Height; p.y++ {
for p.x = 0; p.x < s.Width; {
c := scr.front[p]
if c.c == "" {
c.c = " "
}
cw := uniseg.StringWidth(c.c)
if p.x + cw > s.Width {
c.c = " "
}
if c != scr.back[p] || scr.prevSize != s {
if reset {
writeCursor(p.x, p.y)
}
if style != c.style {
style = c.style
writeStyle(style)
}
scr.writer.WriteString(c.c)
// make sure that the cursor position remains synced even if
// the terminal mangles a wide char or grapheme
if cw == 1 && len([]rune(c.c)) == 1 {
reset = false
} else {
reset = true
}
} else {
reset = true
}
p.x += cw
}
}
if scr.showCursor {
writeCursor(scr.cursor.x, scr.cursor.y)
}
scr.prevSize = s
f := scr.front
scr.front = scr.back
scr.back = f
return scr.writer.Flush()
}
|
