/usr/share/gocode/src/github.com/nsf/termbox-go/_demos/editbox.go is in golang-termbox-dev 0.0~git20140119-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 | package main
import (
"github.com/nsf/termbox-go"
"unicode/utf8"
)
func tbprint(x, y int, fg, bg termbox.Attribute, msg string) {
for _, c := range msg {
termbox.SetCell(x, y, c, fg, bg)
x++
}
}
func fill(x, y, w, h int, cell termbox.Cell) {
for ly := 0; ly < h; ly++ {
for lx := 0; lx < w; lx++ {
termbox.SetCell(x+lx, y+ly, cell.Ch, cell.Fg, cell.Bg)
}
}
}
func rune_advance_len(r rune, pos int) int {
if r == '\t' {
return tabstop_length - pos%tabstop_length
}
return 1
}
func voffset_coffset(text []byte, boffset int) (voffset, coffset int) {
text = text[:boffset]
for len(text) > 0 {
r, size := utf8.DecodeRune(text)
text = text[size:]
coffset += 1
voffset += rune_advance_len(r, voffset)
}
return
}
func byte_slice_grow(s []byte, desired_cap int) []byte {
if cap(s) < desired_cap {
ns := make([]byte, len(s), desired_cap)
copy(ns, s)
return ns
}
return s
}
func byte_slice_remove(text []byte, from, to int) []byte {
size := to - from
copy(text[from:], text[to:])
text = text[:len(text)-size]
return text
}
func byte_slice_insert(text []byte, offset int, what []byte) []byte {
n := len(text) + len(what)
text = byte_slice_grow(text, n)
text = text[:n]
copy(text[offset+len(what):], text[offset:])
copy(text[offset:], what)
return text
}
const preferred_horizontal_threshold = 5
const tabstop_length = 8
type EditBox struct {
text []byte
line_voffset int
cursor_boffset int // cursor offset in bytes
cursor_voffset int // visual cursor offset in termbox cells
cursor_coffset int // cursor offset in unicode code points
}
// Draws the EditBox in the given location, 'h' is not used at the moment
func (eb *EditBox) Draw(x, y, w, h int) {
eb.AdjustVOffset(w)
const coldef = termbox.ColorDefault
fill(x, y, w, h, termbox.Cell{Ch: ' '})
t := eb.text
lx := 0
tabstop := 0
for {
rx := lx - eb.line_voffset
if len(t) == 0 {
break
}
if lx == tabstop {
tabstop += tabstop_length
}
if rx >= w {
termbox.SetCell(x+w-1, y, '→',
coldef, coldef)
break
}
r, size := utf8.DecodeRune(t)
if r == '\t' {
for ; lx < tabstop; lx++ {
rx = lx - eb.line_voffset
if rx >= w {
goto next
}
if rx >= 0 {
termbox.SetCell(x+rx, y, ' ', coldef, coldef)
}
}
} else {
if rx >= 0 {
termbox.SetCell(x+rx, y, r, coldef, coldef)
}
lx += 1
}
next:
t = t[size:]
}
if eb.line_voffset != 0 {
termbox.SetCell(x, y, '←', coldef, coldef)
}
}
// Adjusts line visual offset to a proper value depending on width
func (eb *EditBox) AdjustVOffset(width int) {
ht := preferred_horizontal_threshold
max_h_threshold := (width - 1) / 2
if ht > max_h_threshold {
ht = max_h_threshold
}
threshold := width - 1
if eb.line_voffset != 0 {
threshold = width - ht
}
if eb.cursor_voffset-eb.line_voffset >= threshold {
eb.line_voffset = eb.cursor_voffset + (ht - width + 1)
}
if eb.line_voffset != 0 && eb.cursor_voffset-eb.line_voffset < ht {
eb.line_voffset = eb.cursor_voffset - ht
if eb.line_voffset < 0 {
eb.line_voffset = 0
}
}
}
func (eb *EditBox) MoveCursorTo(boffset int) {
eb.cursor_boffset = boffset
eb.cursor_voffset, eb.cursor_coffset = voffset_coffset(eb.text, boffset)
}
func (eb *EditBox) RuneUnderCursor() (rune, int) {
return utf8.DecodeRune(eb.text[eb.cursor_boffset:])
}
func (eb *EditBox) RuneBeforeCursor() (rune, int) {
return utf8.DecodeLastRune(eb.text[:eb.cursor_boffset])
}
func (eb *EditBox) MoveCursorOneRuneBackward() {
if eb.cursor_boffset == 0 {
return
}
_, size := eb.RuneBeforeCursor()
eb.MoveCursorTo(eb.cursor_boffset - size)
}
func (eb *EditBox) MoveCursorOneRuneForward() {
if eb.cursor_boffset == len(eb.text) {
return
}
_, size := eb.RuneUnderCursor()
eb.MoveCursorTo(eb.cursor_boffset + size)
}
func (eb *EditBox) MoveCursorToBeginningOfTheLine() {
eb.MoveCursorTo(0)
}
func (eb *EditBox) MoveCursorToEndOfTheLine() {
eb.MoveCursorTo(len(eb.text))
}
func (eb *EditBox) DeleteRuneBackward() {
if eb.cursor_boffset == 0 {
return
}
eb.MoveCursorOneRuneBackward()
_, size := eb.RuneUnderCursor()
eb.text = byte_slice_remove(eb.text, eb.cursor_boffset, eb.cursor_boffset+size)
}
func (eb *EditBox) DeleteRuneForward() {
if eb.cursor_boffset == len(eb.text) {
return
}
_, size := eb.RuneUnderCursor()
eb.text = byte_slice_remove(eb.text, eb.cursor_boffset, eb.cursor_boffset+size)
}
func (eb *EditBox) DeleteTheRestOfTheLine() {
eb.text = eb.text[:eb.cursor_boffset]
}
func (eb *EditBox) InsertRune(r rune) {
var buf [utf8.UTFMax]byte
n := utf8.EncodeRune(buf[:], r)
eb.text = byte_slice_insert(eb.text, eb.cursor_boffset, buf[:n])
eb.MoveCursorOneRuneForward()
}
// Please, keep in mind that cursor depends on the value of line_voffset, which
// is being set on Draw() call, so.. call this method after Draw() one.
func (eb *EditBox) CursorX() int {
return eb.cursor_voffset - eb.line_voffset
}
var edit_box EditBox
const edit_box_width = 30
func redraw_all() {
const coldef = termbox.ColorDefault
termbox.Clear(coldef, coldef)
w, h := termbox.Size()
midy := h / 2
midx := (w - edit_box_width) / 2
// unicode box drawing chars around the edit box
termbox.SetCell(midx-1, midy, '│', coldef, coldef)
termbox.SetCell(midx+edit_box_width, midy, '│', coldef, coldef)
termbox.SetCell(midx-1, midy-1, '┌', coldef, coldef)
termbox.SetCell(midx-1, midy+1, '└', coldef, coldef)
termbox.SetCell(midx+edit_box_width, midy-1, '┐', coldef, coldef)
termbox.SetCell(midx+edit_box_width, midy+1, '┘', coldef, coldef)
fill(midx, midy-1, edit_box_width, 1, termbox.Cell{Ch: '─'})
fill(midx, midy+1, edit_box_width, 1, termbox.Cell{Ch: '─'})
edit_box.Draw(midx, midy, edit_box_width, 1)
termbox.SetCursor(midx+edit_box.CursorX(), midy)
tbprint(midx+6, midy+3, coldef, coldef, "Press ESC to quit")
termbox.Flush()
}
func main() {
err := termbox.Init()
if err != nil {
panic(err)
}
defer termbox.Close()
termbox.SetInputMode(termbox.InputEsc)
redraw_all()
mainloop:
for {
switch ev := termbox.PollEvent(); ev.Type {
case termbox.EventKey:
switch ev.Key {
case termbox.KeyEsc:
break mainloop
case termbox.KeyArrowLeft, termbox.KeyCtrlB:
edit_box.MoveCursorOneRuneBackward()
case termbox.KeyArrowRight, termbox.KeyCtrlF:
edit_box.MoveCursorOneRuneForward()
case termbox.KeyBackspace, termbox.KeyBackspace2:
edit_box.DeleteRuneBackward()
case termbox.KeyDelete, termbox.KeyCtrlD:
edit_box.DeleteRuneForward()
case termbox.KeyTab:
edit_box.InsertRune('\t')
case termbox.KeySpace:
edit_box.InsertRune(' ')
case termbox.KeyCtrlK:
edit_box.DeleteTheRestOfTheLine()
case termbox.KeyHome, termbox.KeyCtrlA:
edit_box.MoveCursorToBeginningOfTheLine()
case termbox.KeyEnd, termbox.KeyCtrlE:
edit_box.MoveCursorToEndOfTheLine()
default:
if ev.Ch != 0 {
edit_box.InsertRune(ev.Ch)
}
}
case termbox.EventError:
panic(ev.Err)
}
redraw_all()
}
}
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