| 🛟 Updated. 28d5985 k33g 4h ago | 1 | package ui |
| 2 | |
| 3 | import ( |
| 4 | "strconv" |
| 5 | |
| 6 | "github.com/gdamore/tcell/v2" |
| 7 | |
| 8 | "codeberg.org/turbo-editors/turbo-core/theme" |
| 9 | ) |
| 10 | |
| 11 | // MinWindowWidth and MinWindowHeight are the smallest a window may be dragged |
| 12 | // down to: enough for a frame and one cell of content. |
| 13 | const ( |
| 14 | MinWindowWidth = 12 |
| 15 | MinWindowHeight = 4 |
| 16 | ) |
| 17 | |
| 18 | // Grow says which edges of the desktop a window follows when the desktop is |
| 19 | // resized — Turbo Vision called this a window's grow mode. |
| 20 | // |
| 21 | // A document window follows the right and bottom edges, so its top-left corner |
| 22 | // stays put while its far corner keeps pace with the terminal. That is what |
| 23 | // makes the editor fill a window you have just made larger. |
| 24 | type Grow uint8 |
| 25 | |
| 26 | // The edges a window can follow. |
| 27 | const ( |
| 28 | GrowNone Grow = 0 |
| 29 | GrowRight Grow = 1 << iota // the right edge keeps its distance from the desktop's |
| 30 | GrowBottom // the bottom edge keeps its distance from the desktop's |
| 31 | |
| 32 | // GrowBoth is what a document window uses. |
| 33 | GrowBoth = GrowRight | GrowBottom |
| 34 | ) |
| 35 | |
| 36 | // Window is a framed, movable, resizable box holding one widget. |
| 37 | // |
| 38 | // The frame carries the Turbo Vision furniture: a close box at the top left, a |
| 39 | // title, the window's number so that Alt-1 … Alt-9 can reach it, and a |
| 40 | // maximise box at the top right. The frame is drawn double when the window is |
| 41 | // active and single when it is not, which is how the eye finds the focused |
| 42 | // window even in a monochrome terminal. |
| 43 | type Window struct { |
| 44 | Box |
| 45 | title string |
| 46 | number int |
| 47 | active bool |
| 48 | closable bool |
| 49 | grow Grow |
| 50 | content Widget |
| 51 | |
| 52 | // OnClose is called when the close box is used. It returns whether the |
| 53 | // window may actually go, so an editor can put a "save first?" dialog in |
| 54 | // the way. |
| 55 | OnClose func() bool |
| 56 | |
| 57 | // OnMaximize is called when the maximise box is used. |
| 58 | // |
| 59 | // A window with nobody listening draws no maximise box, because the window |
| 60 | // itself cannot know what to fill: only whatever holds it does. Desktop.Add |
| 61 | // sets this, so a window on a desktop always has a working one. |
| 62 | OnMaximize func() |
| 63 | |
| 64 | // maximized says whether the window is currently filling its desktop, and |
| 65 | // restore is where it was before it did. |
| 66 | maximized bool |
| 67 | restore Rect |
| 68 | |
| 69 | drag dragState |
| 70 | } |
| 71 | |
| 72 | // dragState remembers what a mouse drag on the frame is doing. |
| 73 | type dragState struct { |
| 74 | mode dragMode |
| 75 | startX int |
| 76 | startY int |
| 77 | origin Rect |
| 78 | } |
| 79 | |
| 80 | // dragMode is what the current mouse drag is changing. |
| 81 | type dragMode int |
| 82 | |
| 83 | const ( |
| 84 | dragNone dragMode = iota |
| 85 | dragMove |
| 86 | dragResize |
| 87 | ) |
| 88 | |
| 89 | // NewWindow returns a window titled title, holding content. |
| 90 | // |
| 91 | // w := ui.NewWindow("main.go", editorView) |
| 92 | // w.SetBounds(ui.Rect{X: 0, Y: 1, W: 60, H: 20}) |
| 93 | func NewWindow(title string, content Widget) *Window { |
| 94 | return &Window{title: title, content: content, closable: true, grow: GrowBoth} |
| 95 | } |
| 96 | |
| 97 | // Grow returns which desktop edges this window follows. |
| 98 | func (w *Window) Grow() Grow { return w.grow } |
| 99 | |
| 100 | // SetGrow chooses which desktop edges this window follows. A window set to |
| 101 | // GrowNone keeps its size and is only moved back into view. |
| 102 | func (w *Window) SetGrow(grow Grow) { w.grow = grow } |
| 103 | |
| 104 | // fitInto returns where the window belongs after the desktop has changed from |
| 105 | // one rectangle to another. |
| 106 | // |
| 107 | // The edges the window follows move by the same amount the desktop's did, so |
| 108 | // the gap between them is preserved. Whatever the result, the window is then |
| 109 | // held to the desktop's own size: one larger than the desktop that holds it |
| 110 | // has parts nobody can reach. |
| 111 | func (w *Window) fitInto(from, to Rect) Rect { return w.fitRect(w.Bounds(), from, to) } |
| 112 | |
| 113 | // fitRect is fitInto for any rectangle belonging to this window, which is what |
| 114 | // lets the bounds a maximised window would be restored to travel with it. |
| 115 | func (w *Window) fitRect(bounds, from, to Rect) Rect { |
| 116 | if !from.IsEmpty() { |
| 117 | if w.grow&GrowRight != 0 { |
| 118 | bounds.W += to.Right() - from.Right() |
| 119 | } |
| 120 | if w.grow&GrowBottom != 0 { |
| 121 | bounds.H += to.Bottom() - from.Bottom() |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | bounds.W = min(max(bounds.W, MinWindowWidth), to.W) |
| 126 | bounds.H = min(max(bounds.H, MinWindowHeight), to.H) |
| 127 | return bounds.ClampInto(to) |
| 128 | } |
| 129 | |
| 130 | // followDesktop moves the window as the desktop changes size, taking the |
| 131 | // bounds it would be restored to along with it. |
| 132 | // |
| 133 | // Without the second part, maximising and then making the terminal smaller |
| 134 | // would leave a restore rectangle larger than the desktop — and pressing the |
| 135 | // box would put the window somewhere nobody could reach. |
| 136 | func (w *Window) followDesktop(from, to Rect) { |
| 137 | if w.maximized { |
| 138 | w.restore = w.fitRect(w.restore, from, to) |
| 139 | } |
| 140 | w.SetBounds(w.fitInto(from, to)) |
| 141 | } |
| 142 | |
| 143 | // place puts a window at a rectangle and forgets that it was maximised. |
| 144 | // |
| 145 | // A window the desktop has just laid out is no longer filling anything, so its |
| 146 | // box must go back to offering to maximise rather than to restore a rectangle |
| 147 | // that no longer means anything. |
| 148 | func (w *Window) place(r Rect) { |
| 149 | w.maximized = false |
| 150 | w.SetBounds(r) |
| 151 | } |
| 152 | |
| 153 | // Title returns the window's title. |
| 154 | func (w *Window) Title() string { return w.title } |
| 155 | |
| 156 | // SetTitle changes the window's title, as saving under a new name does. |
| 157 | func (w *Window) SetTitle(title string) { w.title = title } |
| 158 | |
| 159 | // Number returns the window's position in the desktop, from one, or zero when |
| 160 | // it has none. It is what Alt-1 … Alt-9 select. |
| 161 | func (w *Window) Number() int { return w.number } |
| 162 | |
| 163 | // SetNumber records the window's position in the desktop. |
| 164 | func (w *Window) SetNumber(n int) { w.number = n } |
| 165 | |
| 166 | // Active reports whether this is the window the keyboard talks to. |
| 167 | func (w *Window) Active() bool { return w.active } |
| 168 | |
| 169 | // SetActive marks the window as the focused one, which changes how its frame |
| 170 | // is drawn. |
| 171 | // |
| 172 | // A content widget that can hold the focus is told as well, so that only the |
| 173 | // active window draws a cursor. Without that, every open window would show one |
| 174 | // and none of them would mean anything. |
| 175 | func (w *Window) SetActive(active bool) { |
| 176 | w.active = active |
| 177 | if focusable, ok := w.content.(Focusable); ok { |
| 178 | focusable.SetFocused(active) |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | // Closable reports whether the window shows a close box. |
| 183 | func (w *Window) Closable() bool { return w.closable } |
| 184 | |
| 185 | // SetClosable shows or hides the close box. |
| 186 | func (w *Window) SetClosable(closable bool) { w.closable = closable } |
| 187 | |
| 188 | // Content returns the widget filling the window's interior. |
| 189 | func (w *Window) Content() Widget { return w.content } |
| 190 | |
| 191 | // SetBounds places the window and lays its content out inside the frame. |
| 192 | func (w *Window) SetBounds(r Rect) { |
| 193 | w.Box.SetBounds(r) |
| 194 | if w.content != nil { |
| 195 | w.content.SetBounds(r.Inset(1, 1)) |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | // InteriorBounds returns the rectangle inside the frame. |
| 200 | func (w *Window) InteriorBounds() Rect { return w.Bounds().Inset(1, 1) } |
| 201 | |
| 202 | // Draw paints the frame, the title bar and the content. |
| 203 | func (w *Window) Draw(p *Painter, th *theme.Theme) { |
| 204 | bounds := w.Bounds() |
| 205 | if bounds.W < 2 || bounds.H < 2 { |
| 206 | return |
| 207 | } |
| 208 | |
| 209 | DrawShadow(p, bounds, th.Style(theme.KeyShadow)) |
| 210 | |
| 211 | frame := p.Sub(bounds) |
| 212 | frame.Clear(th.Style(theme.KeyWindowBody)) |
| 213 | DrawFrame(frame, frame.Size(), w.frameKind(), th.Style(w.frameStyleKey())) |
| 214 | w.drawTitleBar(frame, th) |
| 215 | w.drawNumber(frame, th) |
| 216 | |
| 217 | if w.content != nil { |
| 218 | w.content.Draw(p.Sub(w.InteriorBounds()), th) |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | // frameKind returns the box-drawing style for the window's current state. |
| 223 | func (w *Window) frameKind() FrameKind { |
| 224 | if w.active { |
| 225 | return FrameDouble |
| 226 | } |
| 227 | return FrameSingle |
| 228 | } |
| 229 | |
| 230 | // frameStyleKey returns the theme key colouring the frame. |
| 231 | func (w *Window) frameStyleKey() string { |
| 232 | if w.active { |
| 233 | return theme.KeyWindowFrameActive |
| 234 | } |
| 235 | return theme.KeyWindowFrameInactive |
| 236 | } |
| 237 | |
| 238 | // titleStyleKey returns the theme key colouring the title. |
| 239 | func (w *Window) titleStyleKey() string { |
| 240 | if w.active { |
| 241 | return theme.KeyWindowTitleActive |
| 242 | } |
| 243 | return theme.KeyWindowTitleInactive |
| 244 | } |
| 245 | |
| 246 | // The two boxes on the top frame. Their widths are counted in **cells**, not |
| 247 | // bytes: the block characters are three bytes each and occupy one column, and |
| 248 | // measuring them with len() was once a real off-by-two. |
| 249 | const ( |
| 250 | // closeBoxLabel closes the window. It sits at the top left, where Turbo |
| 251 | // Vision put it. |
| 252 | closeBoxLabel = "[x]" |
| 253 | // maximizeBoxLabel fills the desktop; restoreBoxLabel puts the window back |
| 254 | // where it was. Only one is ever drawn, so the box says what pressing it |
| 255 | // will do rather than what the window currently is. |
| 256 | maximizeBoxLabel = "[■]" |
| 257 | restoreBoxLabel = "[▬]" |
| 258 | |
| 259 | // boxWidth is how many columns any of them takes on screen. |
| 260 | boxWidth = 3 |
| 261 | ) |
| 262 | |
| 263 | // numberOffset and maximizeOffset are how far from the right edge the window |
| 264 | // number and the maximise box are drawn. |
| 265 | // |
| 266 | // The maximise box occupies the three columns before the corner, and the |
| 267 | // number sits two further left, so the two never touch. |
| 268 | const ( |
| 269 | maximizeOffset = 4 |
| 270 | numberOffset = 6 |
| 271 | ) |
| 272 | |
| 273 | // Maximized reports whether the window is filling the area it was maximised |
| 274 | // into. |
| 275 | func (w *Window) Maximized() bool { return w.maximized } |
| 276 | |
| 277 | // Maximize makes the window fill area, remembering where it was so Restore can |
| 278 | // put it back. |
| 279 | // |
| 280 | // Maximising an already maximised window only moves it to the new area, which |
| 281 | // is what keeps it filling a terminal that has been resized. |
| 282 | // |
| 283 | // desktop := ui.NewDesktop() |
| 284 | // w.Maximize(desktop.Bounds()) |
| 285 | func (w *Window) Maximize(area Rect) { |
| 286 | if !w.maximized { |
| 287 | w.restore = w.Bounds() |
| 288 | w.maximized = true |
| 289 | } |
| 290 | w.SetBounds(area) |
| 291 | } |
| 292 | |
| 293 | // Restore puts the window back where it was before Maximize, and does nothing |
| 294 | // to a window that was never maximised. |
| 295 | func (w *Window) Restore() { |
| 296 | if !w.maximized { |
| 297 | return |
| 298 | } |
| 299 | w.maximized = false |
| 300 | w.SetBounds(w.restore) |
| 301 | } |
| 302 | |
| 303 | // maximizeBoxLabelFor returns the box to draw: the one that says what pressing |
| 304 | // it will do. |
| 305 | func (w *Window) maximizeBoxLabelFor() string { |
| 306 | if w.maximized { |
| 307 | return restoreBoxLabel |
| 308 | } |
| 309 | return maximizeBoxLabel |
| 310 | } |
| 311 | |
| 312 | // drawTitleBar puts the two boxes and the centred title into the top frame. |
| 313 | func (w *Window) drawTitleBar(p *Painter, th *theme.Theme) { |
| 314 | frameStyle := th.Style(w.frameStyleKey()) |
| 315 | |
| 316 | if w.closable && p.Size().W > boxWidth+4 { |
| 317 | p.Text(2, 0, closeBoxLabel, frameStyle) |
| 318 | } |
| 319 | if w.OnMaximize != nil && p.Size().W > numberOffset+boxWidth { |
| 320 | p.Text(p.Size().W-maximizeOffset, 0, w.maximizeBoxLabelFor(), frameStyle) |
| 321 | } |
| 322 | |
| 323 | if w.title == "" { |
| 324 | return |
| 325 | } |
| 326 | |
| 327 | // The title sits in the middle of the top frame, with a space either side |
| 328 | // so the box-drawing characters do not touch the letters. Five cells are |
| 329 | // kept clear on the left — corner, frame, close box — and six on the right |
| 330 | // for the number, the maximise box and the corner, so the title never runs |
| 331 | // into any of them. TestTheTitleNeverRunsIntoTheFurniture checks the sum |
| 332 | // against the offsets rather than trusting this arithmetic. |
| 333 | const reservedForFurniture = 5 + numberOffset |
| 334 | available := p.Size().W - reservedForFurniture |
| 335 | if available < 4 { |
| 336 | return |
| 337 | } |
| 338 | text := " " + w.title + " " |
| 339 | if len([]rune(text)) > available { |
| 340 | text = " " + string([]rune(w.title)[:available-3]) + "… " |
| 341 | } |
| 342 | |
| 343 | x := (p.Size().W - len([]rune(text))) / 2 |
| 344 | p.Text(x, 0, text, th.Style(w.titleStyleKey())) |
| 345 | } |
| 346 | |
| 347 | // drawNumber puts the window's number in the top right of the frame, where |
| 348 | // Turbo Vision showed it. |
| 349 | func (w *Window) drawNumber(p *Painter, th *theme.Theme) { |
| 350 | if w.number < 1 || w.number > 9 || p.Size().W < numberOffset+boxWidth+1 { |
| 351 | return |
| 352 | } |
| 353 | p.Text(p.Size().W-numberOffset, 0, strconv.Itoa(w.number), th.Style(w.frameStyleKey())) |
| 354 | } |
| 355 | |
| 356 | // HandleKey passes the key to the content; the window itself has no shortcuts |
| 357 | // of its own, since those belong to the menu bar. |
| 358 | func (w *Window) HandleKey(ev *tcell.EventKey) bool { |
| 359 | return w.content != nil && w.content.HandleKey(ev) |
| 360 | } |
| 361 | |
| 362 | // HandleMouse deals with the frame — closing, moving, resizing — and passes |
| 363 | // anything landing on the interior to the content. |
| 364 | func (w *Window) HandleMouse(ev *tcell.EventMouse) bool { |
| 365 | if w.drag.mode != dragNone { |
| 366 | return w.continueDrag(ev) |
| 367 | } |
| 368 | if !w.hit(ev) { |
| 369 | return false |
| 370 | } |
| 371 | |
| 372 | x, y := ev.Position() |
| 373 | if w.InteriorBounds().Contains(x, y) { |
| 374 | return w.content != nil && w.content.HandleMouse(ev) |
| 375 | } |
| 376 | if ev.Buttons() != tcell.Button1 { |
| 377 | return true // a click on the frame, but not one that starts anything |
| 378 | } |
| 379 | return w.startFrameAction(x, y) |
| 380 | } |
| 381 | |
| 382 | // startFrameAction reacts to a press on the frame: close, resize or move. |
| 383 | func (w *Window) startFrameAction(x, y int) bool { |
| 384 | bounds := w.Bounds() |
| 385 | |
| 386 | switch { |
| 387 | case w.closable && y == bounds.Y && w.onCloseBox(x): |
| 388 | w.requestClose() |
| 389 | case w.OnMaximize != nil && y == bounds.Y && w.onMaximizeBox(x): |
| 390 | w.OnMaximize() |
| 391 | case x == bounds.Right()-1 && y == bounds.Bottom()-1: |
| 392 | w.beginDrag(dragResize, x, y) |
| 393 | case y == bounds.Y: |
| 394 | w.beginDrag(dragMove, x, y) |
| 395 | } |
| 396 | return true |
| 397 | } |
| 398 | |
| 399 | // onCloseBox reports whether a column falls on the close box. |
| 400 | func (w *Window) onCloseBox(x int) bool { |
| 401 | start := w.Bounds().X + 2 |
| 402 | return x >= start && x < start+boxWidth |
| 403 | } |
| 404 | |
| 405 | // onMaximizeBox reports whether a column falls on the maximise box. |
| 406 | func (w *Window) onMaximizeBox(x int) bool { |
| 407 | start := w.Bounds().Right() - maximizeOffset |
| 408 | return x >= start && x < start+boxWidth |
| 409 | } |
| 410 | |
| 411 | // requestClose asks the owner to close the window, if it agreed to be asked. |
| 412 | func (w *Window) requestClose() { |
| 413 | if w.OnClose != nil { |
| 414 | w.OnClose() |
| 415 | } |
| 416 | } |
| 417 | |
| 418 | // beginDrag records where a move or resize started. |
| 419 | func (w *Window) beginDrag(mode dragMode, x, y int) { |
| 420 | w.drag = dragState{mode: mode, startX: x, startY: y, origin: w.Bounds()} |
| 421 | } |
| 422 | |
| 423 | // continueDrag applies the movement of an in-progress drag and ends it when |
| 424 | // the button comes back up. |
| 425 | func (w *Window) continueDrag(ev *tcell.EventMouse) bool { |
| 426 | x, y := ev.Position() |
| 427 | dx, dy := x-w.drag.startX, y-w.drag.startY |
| 428 | |
| 429 | if w.drag.mode == dragMove { |
| 430 | w.SetBounds(w.drag.origin.Move(dx, dy)) |
| 431 | } else { |
| 432 | w.SetBounds(w.drag.origin.WithSize( |
| 433 | max(w.drag.origin.W+dx, MinWindowWidth), |
| 434 | max(w.drag.origin.H+dy, MinWindowHeight), |
| 435 | )) |
| 436 | } |
| 437 | |
| 438 | if ev.Buttons() == tcell.ButtonNone { |
| 439 | w.drag = dragState{} |
| 440 | } |
| 441 | return true |
| 442 | } |
| 443 | |
| 444 | // Dragging reports whether a move or resize is in progress, which the desktop |
| 445 | // needs in order to keep sending it events that fall outside the window. |
| 446 | func (w *Window) Dragging() bool { return w.drag.mode != dragNone } |