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|
package tui
import (
"github.com/rivo/uniseg"
"golang.org/x/term"
"unicode"
"unicode/utf8"
"fmt"
"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 Dims
writer *bufio.Writer
cursor pos
}
var scr screen
func init() {
scr.writer = bufio.NewWriterSize(os.Stdout, 50000)
Clear()
}
type Dims struct {
Width int
Height int
}
func Size() Dims {
w, h, _ := term.GetSize(0)
return Dims {w, h}
}
func Write(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)
}
func MoveCursor(x int, y int) {
scr.cursor = pos {x, y}
}
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
}
scr.back = make(surface)
_, err = os.Stdout.WriteString("\033[?47h\033[2J\033[?2004h")
return err
}
func End() {
if saved == nil {
return
}
if term.Restore(0, saved) != nil {
return
}
os.Stdout.WriteString("\033[?2004l\033[2J\033[0;0H\033[?47l")
}
func writeCursor(x int, y int) error {
_, err := scr.writer.WriteString(fmt.Sprintf("\033[%d;%dH", y + 1, x + 1))
return err
}
func writeStyle(style Style) error {
_, err := scr.writer.WriteString("\033[0m")
if err != nil {
return err
}
_, err = scr.writer.WriteString(fmt.Sprintf("\033[38;5;%dm", style.Fg))
if err != nil {
return err
}
_, err = scr.writer.WriteString(fmt.Sprintf("\033[48;5;%dm", style.Bg))
if err != nil {
return err
}
if style.Bold {
_, err = scr.writer.WriteString("\033[1m")
if err != nil {
return err
}
}
if style.Italic {
_, err = scr.writer.WriteString("\033[3m")
if err != nil {
return err
}
}
if style.Underline {
_, err = scr.writer.WriteString("\033[4m")
if err != nil {
return err
}
}
if style.Strikethrough {
_, err = scr.writer.WriteString("\033[9m")
if err != nil {
return err
}
}
return nil
}
func Present() error {
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; {
if reset {
err := writeCursor(p.x, p.y)
if err != nil {
return err
}
}
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 style != c.style {
style = c.style
err := writeStyle(style)
if err != nil {
return err
}
}
_, err := scr.writer.WriteString(c.c)
if err != nil {
return err
}
// 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
}
}
err := writeCursor(scr.cursor.x, scr.cursor.y)
if err != nil {
return err
}
scr.prevSize = s
f := scr.front
scr.front = scr.back
scr.back = f
return scr.writer.Flush()
}
|
