client/src/components/Board.vue

   1 <script>
   2 import { getSquareId, getSquareFromId } from "@/utils/squareId";
   3 import { ArrayFun } from "@/utils/array";
   4 import { store } from "@/store";
   5 export default {
   6   name: "my-board",
   7   // Last move cannot be guessed from here, and is required for highlights.
   8   // vr: object to check moves, print board...
   9   // userColor is left undefined for an external observer
  10   props: [
  11     "vr",
  12     "lastMove",
  13     "analyze",
  14     "score",
  15     "incheck",
  16     "orientation",
  17     "userColor",
  18     "vname"
  19   ],
  20   data: function() {
  21     return {
  22       mobileBrowser: ("ontouchstart" in window),
  23       possibleMoves: [], //filled after each valid click/dragstart
  24       choices: [], //promotion pieces, or checkered captures... (as moves)
  25       containerPos: null,
  26       selectedPiece: null, //moving piece (or clicked piece)
  27       start: null, //pixels coordinates + id of starting square (click or drag)
  28       startArrow: null,
  29       movingArrow: null,
  30       arrows: [], //object of {start: x,y / end: x,y}
  31       circles: {}, //object of squares' ID --> true (TODO: use a set?)
  32       click: "",
  33       clickTime: 0,
  34       settings: store.state.settings
  35     };
  36   },
  37   render(h) {
  38     if (!this.vr) {
  39       // Return empty div of class 'game' to avoid error when setting size
  40       return h(
  41         "div",
  42         { "class": { game: true } }
  43       );
  44     }
  45     const [sizeX, sizeY] = [V.size.x, V.size.y];
  46     // Precompute hints squares to facilitate rendering
  47     let hintSquares = ArrayFun.init(sizeX, sizeY, false);
  48     this.possibleMoves.forEach(m => {
  49       hintSquares[m.end.x][m.end.y] = true;
  50     });
  51     // Also precompute in-check squares
  52     let incheckSq = ArrayFun.init(sizeX, sizeY, false);
  53     this.incheck.forEach(sq => {
  54       incheckSq[sq[0]][sq[1]] = true;
  55     });
  56
  57     let lm = this.lastMove;
  58     // Precompute lastMove highlighting squares
  59     const lmHighlights = {};
  60     if (!!lm) {
  61       if (!Array.isArray(lm)) lm = [lm];
  62       lm.forEach(m => {
  63         if (!m.start.noHighlight && V.OnBoard(m.start.x, m.start.y))
  64           lmHighlights[m.start.x + sizeX * m.start.y] = true;
  65         if (!m.end.noHighlight && V.OnBoard(m.end.x, m.end.y))
  66           lmHighlights[m.end.x + sizeX * m.end.y] = true;
  67         if (!!m.start.toplay)
  68           // For Dice variant (at least?)
  69           lmHighlights[m.start.toplay[0] + sizeX * m.start.toplay[1]] = true;
  70       });
  71     }
  72     const showLight = (
  73       this.settings.highlight &&
  74       ["all", "highlight"].includes(V.ShowMoves)
  75     );
  76     const showCheck = (
  77       this.settings.highlight &&
  78       ["all", "highlight", "byrow"].includes(V.ShowMoves)
  79     );
  80     const orientation = !V.CanFlip ? "w" : this.orientation;
  81     // Ensure that squares colors do not change when board is flipped
  82     const lightSquareMod = (sizeX + sizeY) % 2;
  83     const showPiece = (x, y) => {
  84       return (
  85         this.vr.board[x][y] != V.EMPTY &&
  86         (!this.vr.enlightened || this.analyze || this.score != "*" ||
  87           (!!this.userColor && this.vr.enlightened[this.userColor][x][y]))
  88       );
  89     };
  90     const inHighlight = (x, y) => {
  91       return showLight && !!lmHighlights[x + sizeX * y];
  92     };
  93     const inShadow = (x, y) => {
  94       return (
  95         !this.analyze &&
  96         this.score == "*" &&
  97         this.vr.enlightened &&
  98         (!this.userColor || !this.vr.enlightened[this.userColor][x][y])
  99       );
 100     };
 101     // Create board element (+ reserves if needed by variant)
 102     let elementArray = [];
 103     const gameDiv = h(
 104       "div",
 105       {
 106         attrs: { id: "gamePosition" },
 107         "class": {
 108           game: true,
 109           clearer: true
 110         }
 111       },
 112       [...Array(sizeX).keys()].map(i => {
 113         const ci = orientation == "w" ? i : sizeX - i - 1;
 114         return h(
 115           "div",
 116           {
 117             "class": {
 118               row: true
 119             },
 120             style: { opacity: this.choices.length > 0 ? "0.5" : "1" }
 121           },
 122           [...Array(sizeY).keys()].map(j => {
 123             const cj = orientation == "w" ? j : sizeY - j - 1;
 124             const squareId = "sq-" + ci + "-" + cj;
 125             let elems = [];
 126             if (showPiece(ci, cj)) {
 127               let pieceSpecs = {
 128                 "class": {
 129                   piece: true,
 130                   ghost:
 131                     !!this.selectedPiece &&
 132                     this.selectedPiece.parentNode.id == squareId
 133                 },
 134                 attrs: {
 135                   src:
 136                     "/images/pieces/" +
 137                     this.vr.getPpath(
 138                       this.vr.board[ci][cj],
 139                       // Extra args useful for some variants:
 140                       this.userColor,
 141                       this.score,
 142                       this.orientation) +
 143                     V.IMAGE_EXTENSION
 144                 }
 145               };
 146               if (this.arrows.length == 0)
 147                 pieceSpecs["style"] = { position: "absolute" };
 148               elems.push(h("img", pieceSpecs));
 149             }
 150             if (this.settings.hints && hintSquares[ci][cj]) {
 151               elems.push(
 152                 h("img", {
 153                   "class": {
 154                     "mark-square": true
 155                   },
 156                   attrs: {
 157                     src: "/images/mark.svg"
 158                   }
 159                 })
 160               );
 161             }
 162             if (!!this.circles[squareId]) {
 163               elems.push(
 164                 h("img", {
 165                   "class": {
 166                     "circle-square": true
 167                   },
 168                   attrs: {
 169                     src: "/images/circle.svg"
 170                   }
 171                 })
 172               );
 173             }
 174             const oddity = (ci + cj) % 2;
 175             const lightSquare = (
 176               (!V.DarkBottomRight && oddity == lightSquareMod) ||
 177               (V.DarkBottomRight && oddity != lightSquareMod)
 178             );
 179             return h(
 180               "div",
 181               {
 182                 "class": {
 183                   board: true,
 184                   ["board" + sizeY]: true,
 185                   "light-square":
 186                     !V.Notoodark && lightSquare && !V.Monochrome,
 187                   "dark-square":
 188                     !V.Notoodark && (!lightSquare || !!V.Monochrome),
 189                   "middle-square": V.Notoodark,
 190                   [this.settings.bcolor]: true,
 191                   "in-shadow": inShadow(ci, cj),
 192                   "highlight": inHighlight(ci, cj),
 193                   "incheck-light":
 194                     showCheck && lightSquare && incheckSq[ci][cj],
 195                   "incheck-dark":
 196                     showCheck && !lightSquare && incheckSq[ci][cj],
 197                   "hover-highlight":
 198                     this.vr.hoverHighlight(
 199                       [ci, cj], !this.analyze ? this.userColor : null)
 200                 },
 201                 attrs: {
 202                   id: getSquareId({ x: ci, y: cj })
 203                 }
 204               },
 205               elems
 206             );
 207           })
 208         );
 209       })
 210     );
 211     if (!!this.vr.reserve) {
 212       const playingColor = this.userColor || "w"; //default for an observer
 213       const shiftIdx = playingColor == "w" ? 0 : 1;
 214       // Some variants have more than sizeY reserve pieces (Clorange: 10)
 215       const reserveSquareNb = Math.max(sizeY, V.RESERVE_PIECES.length);
 216       let myReservePiecesArray = [];
 217       if (!!this.vr.reserve[playingColor]) {
 218         for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 219           const qty = this.vr.reserve[playingColor][V.RESERVE_PIECES[i]];
 220           myReservePiecesArray.push(
 221             h(
 222               "div",
 223               {
 224                 "class": { board: true, ["board" + reserveSquareNb]: true },
 225                 attrs: { id: getSquareId({ x: sizeX + shiftIdx, y: i }) },
 226                 style: { opacity: qty > 0 ? 1 : 0.35 }
 227               },
 228               [
 229                 h("img", {
 230                   // NOTE: class "reserve" not used currently
 231                   "class": { piece: true, reserve: true },
 232                   attrs: {
 233                     src:
 234                       "/images/pieces/" +
 235                       this.vr.getReservePpath(i, playingColor, orientation) +
 236                       ".svg"
 237                   }
 238                 }),
 239                 h(
 240                   "sup",
 241                   {
 242                     "class": { "reserve-count": true },
 243                     style: { top: "calc(100% + 5px)" }
 244                   },
 245                   [ qty ]
 246                 )
 247               ]
 248             )
 249           );
 250         }
 251       }
 252       let oppReservePiecesArray = [];
 253       const oppCol = V.GetOppCol(playingColor);
 254       if (!!this.vr.reserve[oppCol]) {
 255         for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 256           const qty = this.vr.reserve[oppCol][V.RESERVE_PIECES[i]];
 257           oppReservePiecesArray.push(
 258             h(
 259               "div",
 260               {
 261                 "class": { board: true, ["board" + reserveSquareNb]: true },
 262                 attrs: { id: getSquareId({ x: sizeX + (1 - shiftIdx), y: i }) },
 263                 style: { opacity: qty > 0 ? 1 : 0.35 }
 264               },
 265               [
 266                 h("img", {
 267                   "class": { piece: true, reserve: true },
 268                   attrs: {
 269                     src:
 270                       "/images/pieces/" +
 271                       this.vr.getReservePpath(i, oppCol, orientation) +
 272                       ".svg"
 273                   }
 274                 }),
 275                 h(
 276                   "sup",
 277                   {
 278                     "class": { "reserve-count": true },
 279                     style: { top: "calc(100% + 5px)" }
 280                   },
 281                   [ qty ]
 282                 )
 283               ]
 284             )
 285           );
 286         }
 287       }
 288       const myReserveTop = (
 289         (playingColor == 'w' && orientation == 'b') ||
 290         (playingColor == 'b' && orientation == 'w')
 291       );
 292       const hasReserveTop = (
 293         (myReserveTop && !!this.vr.reserve[playingColor]) ||
 294         (!myReserveTop && !!this.vr.reserve[oppCol])
 295       );
 296       // "var" because must be reachable from outside this block
 297       var hasReserveBottom = (
 298         (myReserveTop && !!this.vr.reserve[oppCol]) ||
 299         (!myReserveTop && !!this.vr.reserve[playingColor])
 300       );
 301       // Center reserves, assuming same number of pieces for each side:
 302       const nbReservePieces = myReservePiecesArray.length;
 303       const marginLeft =
 304         ((100 - nbReservePieces * (100 / reserveSquareNb)) / 2) + "%";
 305       if (hasReserveTop) {
 306         var reserveTop =
 307           h(
 308             "div",
 309             {
 310               "class": {
 311                 game: true,
 312                 "reserve-div": true
 313               },
 314               style: {
 315                 "margin-left": marginLeft
 316               }
 317             },
 318             [
 319               h(
 320                 "div",
 321                 {
 322                   "class": {
 323                     row: true,
 324                     "reserve-row": true
 325                   }
 326                 },
 327                 myReserveTop ? myReservePiecesArray : oppReservePiecesArray
 328               )
 329             ]
 330           );
 331       }
 332       if (hasReserveBottom) {
 333         var reserveBottom =
 334           h(
 335             "div",
 336             {
 337               "class": {
 338                 game: true,
 339                 "reserve-div": true
 340               },
 341               style: {
 342                 "margin-left": marginLeft
 343               }
 344             },
 345             [
 346               h(
 347                 "div",
 348                 {
 349                   "class": {
 350                     row: true,
 351                     "reserve-row": true
 352                   }
 353                 },
 354                 myReserveTop ? oppReservePiecesArray : myReservePiecesArray
 355               )
 356             ]
 357           );
 358       }
 359       if (hasReserveTop) elementArray.push(reserveTop);
 360     }
 361     elementArray.push(gameDiv);
 362     if (!!this.vr.reserve && hasReserveBottom)
 363       elementArray.push(reserveBottom);
 364     const boardElt = document.getElementById("gamePosition");
 365     // boardElt might be undefine (at first drawing)
 366     if (this.choices.length > 0 && !!boardElt) {
 367       const squareWidth = boardElt.offsetWidth / sizeY;
 368       const offset = [boardElt.offsetTop, boardElt.offsetLeft];
 369       const maxNbeltsPerRow = Math.min(this.choices.length, sizeY);
 370       let topOffset = offset[0] + ((sizeX - 1) / 2) * squareWidth;
 371       let choicesHeight = squareWidth;
 372       if (this.choices.length >= sizeY) {
 373         // A second row is required (Eightpieces variant)
 374         topOffset -= squareWidth / 2;
 375         choicesHeight *= 2;
 376       }
 377       const choices = h(
 378         "div",
 379         {
 380           attrs: { id: "choices" },
 381           "class": { row: true },
 382           style: {
 383             top: topOffset + "px",
 384             left:
 385               offset[1] +
 386               (squareWidth * Math.max(sizeY - this.choices.length, 0)) / 2 +
 387               "px",
 388             width: (maxNbeltsPerRow * squareWidth) + "px",
 389             height: choicesHeight + "px"
 390           }
 391         },
 392         [ h(
 393           "div",
 394           {
 395             "class": { "full-width": true }
 396           },
 397           this.choices.map(m => {
 398             // A "choice" is a move
 399             const applyMove = (e) => {
 400               e.stopPropagation();
 401               // Force a delay between move is shown and clicked
 402               // (otherwise a "double-click" bug might occur)
 403               if (Date.now() - this.clickTime < 200) return;
 404               this.choices = [];
 405               this.play(m);
 406             };
 407             const stopPropagation = (e) => { e.stopPropagation(); }
 408             const onClick =
 409               this.mobileBrowser
 410                 // Must cancel mousedown logic:
 411                 ? { touchstart: stopPropagation, touchend: applyMove }
 412                 : { mousedown: stopPropagation, mouseup: applyMove };
 413             return h(
 414               "div",
 415               {
 416                 "class": {
 417                   board: true,
 418                   ["board" + sizeY]: true
 419                 },
 420                 style: {
 421                   width: (100 / maxNbeltsPerRow) + "%",
 422                   "padding-bottom": (100 / maxNbeltsPerRow) + "%"
 423                 }
 424               },
 425               [
 426                 h("img", {
 427                   attrs: {
 428                     src:
 429                       "/images/pieces/" +
 430                       // orientation: extra arg useful for some variants
 431                       this.vr.getPPpath(m, this.orientation) +
 432                       V.IMAGE_EXTENSION
 433                   },
 434                   "class": { "choice-piece": true },
 435                   on: onClick
 436                 })
 437               ]
 438             );
 439           })
 440         ) ]
 441       );
 442       elementArray.unshift(choices);
 443     }
 444     let onEvents = {};
 445     // NOTE: click = mousedown + mouseup
 446     if (this.mobileBrowser) {
 447       onEvents = {
 448         on: {
 449           touchstart: this.mousedown,
 450           touchmove: this.mousemove,
 451           touchend: this.mouseup
 452         }
 453       };
 454     }
 455     else {
 456       onEvents = {
 457         on: {
 458           mousedown: this.mousedown,
 459           mousemove: this.mousemove,
 460           mouseup: this.mouseup,
 461           contextmenu: this.blockContextMenu
 462         }
 463       };
 464     }
 465     return (
 466       h(
 467         "div",
 468         Object.assign({ attrs: { id: "rootBoardElement" } }, onEvents),
 469         elementArray
 470       )
 471     );
 472   },
 473   updated: function() {
 474     this.re_setDrawings();
 475   },
 476   methods: {
 477     blockContextMenu: function(e) {
 478       e.preventDefault();
 479       e.stopPropagation();
 480       return false;
 481     },
 482     cancelResetArrows: function() {
 483       this.startArrow = null;
 484       this.arrows = [];
 485       this.circles = {};
 486       const curCanvas = document.getElementById("arrowCanvas");
 487       if (!!curCanvas) curCanvas.parentNode.removeChild(curCanvas);
 488     },
 489     coordsToXY: function(coords, top, left, squareWidth) {
 490       return {
 491         // [1] for x and [0] for y because conventions in rules are inversed.
 492         x: (
 493           left + window.scrollX +
 494           (
 495             squareWidth *
 496             (this.orientation == 'w' ? coords[1] : (V.size.y - coords[1]))
 497           )
 498         ),
 499         y: (
 500           top + window.scrollY +
 501           (
 502             squareWidth *
 503             (this.orientation == 'w' ? coords[0] : (V.size.x - coords[0]))
 504           )
 505         )
 506       };
 507     },
 508     computeEndArrow: function(start, end, top, left, squareWidth) {
 509       const endCoords = this.coordsToXY(end, top, left, squareWidth);
 510       const delta = [endCoords.x - start.x, endCoords.y - start.y];
 511       const dist = Math.sqrt(delta[0] * delta[0] + delta[1] * delta[1]);
 512       // Simple heuristic for now, just remove 1/3 square.
 513       // TODO: should depend on the orientation.
 514       const fracSqWidth = squareWidth / 3;
 515       return {
 516         x: endCoords.x - delta[0] * fracSqWidth / dist,
 517         y: endCoords.y - delta[1] * fracSqWidth / dist
 518       };
 519     },
 520     drawCurrentArrow: function() {
 521       const boardElt = document.getElementById("gamePosition");
 522       const squareWidth = boardElt.offsetWidth / V.size.y;
 523       const bPos = boardElt.getBoundingClientRect();
 524       const aStart =
 525         this.coordsToXY(
 526           [this.startArrow[0] + 0.5, this.startArrow[1] + 0.5],
 527           bPos.top, bPos.left, squareWidth);
 528       const aEnd =
 529         this.computeEndArrow(
 530           aStart, [this.movingArrow[0] + 0.5, this.movingArrow[1] + 0.5],
 531           bPos.top, bPos.left, squareWidth);
 532       let currentArrow = document.getElementById("currentArrow");
 533       const d =
 534         "M" + aStart.x + "," + aStart.y + " " + "L" + aEnd.x + "," + aEnd.y;
 535       const arrowWidth = squareWidth / 4;
 536       if (!!currentArrow) currentArrow.setAttribute("d", d);
 537       else {
 538         let domArrow =
 539           document.createElementNS("http://www.w3.org/2000/svg", "path");
 540         domArrow.classList.add("svg-arrow");
 541         domArrow.id = "currentArrow";
 542         domArrow.setAttribute("d", d);
 543         domArrow.style = "stroke-width:" + arrowWidth + "px";
 544         document.getElementById("arrowCanvas")
 545           .insertAdjacentElement("beforeend", domArrow);
 546       }
 547     },
 548     addArrow: function(arrow) {
 549       this.arrows.push(arrow);
 550       // Also add to DOM:
 551       const boardElt = document.getElementById("gamePosition");
 552       const squareWidth = boardElt.offsetWidth / V.size.y;
 553       const bPos = boardElt.getBoundingClientRect();
 554       const newArrow =
 555         this.getSvgArrow(arrow, bPos.top, bPos.left, squareWidth);
 556       document.getElementById("arrowCanvas")
 557         .insertAdjacentElement("beforeend", newArrow);
 558     },
 559     getSvgArrow: function(arrow, top, left, squareWidth) {
 560       const aStart =
 561         this.coordsToXY(
 562           [arrow.start[0] + 0.5, arrow.start[1] + 0.5],
 563           top, left, squareWidth);
 564       const aEnd =
 565         this.computeEndArrow(
 566           aStart, [arrow.end[0] + 0.5, arrow.end[1] + 0.5],
 567           top, left, squareWidth);
 568       const arrowWidth = squareWidth / 4;
 569       let path =
 570         document.createElementNS("http://www.w3.org/2000/svg", "path");
 571       path.classList.add("svg-arrow");
 572       path.setAttribute(
 573         "d",
 574         "M" + aStart.x + "," + aStart.y + " " + "L" + aEnd.x + "," + aEnd.y
 575       );
 576       path.style = "stroke-width:" + arrowWidth + "px";
 577       return path;
 578     },
 579     re_setDrawings: function() {
 580       // Add some drawing on board (for some variants + arrows and circles)
 581       const boardElt = document.getElementById("gamePosition");
 582       if (!boardElt) return;
 583       // Remove current canvas, if any
 584       const curCanvas = document.getElementById("arrowCanvas");
 585       if (!!curCanvas) curCanvas.parentNode.removeChild(curCanvas);
 586       const squareWidth = boardElt.offsetWidth / V.size.y;
 587       const bPos = boardElt.getBoundingClientRect();
 588       let svgArrows = [];
 589       this.arrows.forEach(a => {
 590         svgArrows.push(this.getSvgArrow(a, bPos.top, bPos.left, squareWidth));
 591       });
 592       let vLines = [];
 593       if (!!V.Lines) {
 594         V.Lines.forEach(line => {
 595           const lStart =
 596             this.coordsToXY(line[0], bPos.top, bPos.left, squareWidth);
 597           const lEnd =
 598             this.coordsToXY(line[1], bPos.top, bPos.left, squareWidth);
 599           let path =
 600             document.createElementNS("http://www.w3.org/2000/svg", "path");
 601           if (line[0][0] == line[1][0] || line[0][1] == line[1][1])
 602             path.classList.add("svg-line");
 603           else
 604             // "Diagonals" are drawn with a lighter color (TODO: generalize)
 605             path.classList.add("svg-diag");
 606           path.setAttribute(
 607             "d",
 608             "M" + lStart.x + "," + lStart.y + " " +
 609               "L" + lEnd.x + "," + lEnd.y
 610           );
 611           vLines.push(path);
 612         });
 613       }
 614       let arrowCanvas =
 615         document.createElementNS("http://www.w3.org/2000/svg", "svg");
 616       arrowCanvas.id = "arrowCanvas";
 617       arrowCanvas.setAttribute("stroke", "none");
 618       let defs =
 619         document.createElementNS("http://www.w3.org/2000/svg", "defs");
 620       const arrowWidth = squareWidth / 4;
 621       let marker =
 622         document.createElementNS("http://www.w3.org/2000/svg", "marker");
 623       marker.id = "arrow";
 624       marker.setAttribute("markerWidth", (2 * arrowWidth) + "px");
 625       marker.setAttribute("markerHeight", (3 * arrowWidth) + "px");
 626       marker.setAttribute("markerUnits", "userSpaceOnUse");
 627       marker.setAttribute("refX", "0");
 628       marker.setAttribute("refY", (1.5 * arrowWidth) + "px");
 629       marker.setAttribute("orient", "auto");
 630       let head =
 631         document.createElementNS("http://www.w3.org/2000/svg", "path");
 632       head.classList.add("arrow-head");
 633       head.setAttribute(
 634         "d",
 635         "M0,0 L0," + (3 * arrowWidth) + " L" +
 636           (2 * arrowWidth) + "," + (1.5 * arrowWidth) + " z"
 637       );
 638       marker.appendChild(head);
 639       defs.appendChild(marker);
 640       arrowCanvas.appendChild(defs);
 641       svgArrows.concat(vLines).forEach(av => arrowCanvas.appendChild(av));
 642       document.getElementById("rootBoardElement").appendChild(arrowCanvas);
 643     },
 644     mousedown: function(e) {
 645       e.preventDefault();
 646       if (!this.mobileBrowser && e.which != 3)
 647         // Cancel current drawing and circles, if any
 648         this.cancelResetArrows();
 649       if (this.mobileBrowser || e.which == 1) {
 650         // Mouse left button
 651         if (!this.start) {
 652           this.containerPos =
 653             document.getElementById("boardContainer").getBoundingClientRect();
 654           // NOTE: classList[0] is enough: 'piece' is the first assigned class
 655           const withPiece = (e.target.classList[0] == "piece");
 656           // Show possible moves if current player allowed to play
 657           const startSquare =
 658             getSquareFromId(withPiece ? e.target.parentNode.id : e.target.id);
 659           this.possibleMoves = [];
 660           const color = this.analyze ? this.vr.turn : this.userColor;
 661           if (this.vr.canIplay(color, startSquare)) {
 662             // Emit the click event which could be used by some variants
 663             const targetId =
 664               (withPiece ? e.target.parentNode.id : e.target.id);
 665             const sq = getSquareFromId(targetId);
 666             this.$emit("click-square", sq);
 667             if (withPiece && !this.vr.onlyClick(sq)) {
 668               this.possibleMoves = this.vr.getPossibleMovesFrom(startSquare);
 669               if (this.possibleMoves.length > 0) {
 670                 // For potential drag'n drop, remember start coordinates
 671                 // (to center the piece on mouse cursor)
 672                 let parent = e.target.parentNode; //surrounding square
 673                 const rect = parent.getBoundingClientRect();
 674                 this.start = {
 675                   x: rect.x + rect.width / 2,
 676                   y: rect.y + rect.width / 2,
 677                   id: parent.id
 678                 };
 679                 // Add the moving piece to the board, just after current image
 680                 this.selectedPiece = e.target.cloneNode();
 681                 Object.assign(
 682                   this.selectedPiece.style,
 683                   {
 684                     position: "absolute",
 685                     top: 0,
 686                     display: "inline-block",
 687                     zIndex: 3000
 688                   }
 689                 );
 690                 parent.insertBefore(this.selectedPiece, e.target.nextSibling);
 691               }
 692             }
 693           }
 694         }
 695         else this.processMoveAttempt(e);
 696       }
 697       else if (e.which == 3) {
 698         // Mouse right button
 699         this.containerPos =
 700           document.getElementById("gamePosition").getBoundingClientRect();
 701         let elem = e.target;
 702         // Next loop because of potential marks
 703         while (elem.tagName == "IMG") elem = elem.parentNode;
 704         this.startArrow = getSquareFromId(elem.id);
 705       }
 706     },
 707     mousemove: function(e) {
 708       if (!this.selectedPiece && !this.startArrow) return;
 709       // Cancel if off boardContainer
 710       const [offsetX, offsetY] =
 711         this.mobileBrowser
 712           ? [e.changedTouches[0].clientX, e.changedTouches[0].clientY]
 713           : [e.clientX, e.clientY];
 714       if (
 715         offsetX < this.containerPos.left ||
 716         offsetX > this.containerPos.right ||
 717         offsetY < this.containerPos.top ||
 718         offsetY > this.containerPos.bottom
 719       ) {
 720         if (!!this.selectedPiece) {
 721           this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 722           delete this.selectedPiece;
 723           this.selectedPiece = null;
 724           this.start = null;
 725           this.possibleMoves = []; //in case of
 726           this.click = "";
 727           let selected = document.querySelector(".ghost");
 728           if (!!selected) selected.classList.remove("ghost");
 729         }
 730         else {
 731           this.startArrow = null;
 732           this.movingArrow = null;
 733           const currentArrow = document.getElementById("currentArrow");
 734           if (!!currentArrow)
 735             currentArrow.parentNode.removeChild(currentArrow);
 736         }
 737         return;
 738       }
 739       e.preventDefault();
 740       if (!!this.selectedPiece) {
 741         // There is an active element: move it around
 742         Object.assign(
 743           this.selectedPiece.style,
 744           {
 745             left: offsetX - this.start.x + "px",
 746             top: offsetY - this.start.y + "px"
 747           }
 748         );
 749       }
 750       else {
 751         let elem = e.target;
 752         // Next loop because of potential marks
 753         while (elem.tagName == "IMG") elem = elem.parentNode;
 754         // To center the arrow in square:
 755         const movingCoords = getSquareFromId(elem.id);
 756         if (
 757           movingCoords[0] != this.startArrow[0] ||
 758           movingCoords[1] != this.startArrow[1]
 759         ) {
 760           this.movingArrow = movingCoords;
 761           this.drawCurrentArrow();
 762         }
 763       }
 764     },
 765     mouseup: function(e) {
 766       e.preventDefault();
 767       if (this.mobileBrowser || e.which == 1) {
 768         if (!this.selectedPiece) return;
 769         // Drag'n drop. Selected piece is no longer needed:
 770         this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 771         delete this.selectedPiece;
 772         this.selectedPiece = null;
 773         this.processMoveAttempt(e);
 774       } else if (e.which == 3) {
 775         if (!this.startArrow) return;
 776         // Mouse right button
 777         this.movingArrow = null;
 778         this.processArrowAttempt(e);
 779       }
 780     },
 781     // Called by BaseGame after partially undoing multi-moves:
 782     resetCurrentAttempt: function() {
 783       this.possibleMoves = [];
 784       this.start = null;
 785       this.click = "";
 786       this.selectedPiece = null;
 787     },
 788     processMoveAttempt: function(e) {
 789       // Obtain the move from start and end squares
 790       const [offsetX, offsetY] =
 791         this.mobileBrowser
 792           ? [e.changedTouches[0].clientX, e.changedTouches[0].clientY]
 793           : [e.clientX, e.clientY];
 794       let landing = document.elementFromPoint(offsetX, offsetY);
 795       // Next condition: classList.contains(piece) fails because of marks
 796       while (landing.tagName == "IMG") landing = landing.parentNode;
 797       if (this.start.id == landing.id) {
 798         if (this.click == landing.id) {
 799           // Second click on same square: cancel current move
 800           this.possibleMoves = [];
 801           this.start = null;
 802           this.click = "";
 803         } else this.click = landing.id;
 804         return;
 805       }
 806       this.start = null;
 807       // OK: process move attempt, landing is a square node
 808       let endSquare = getSquareFromId(landing.id);
 809       let moves = this.findMatchingMoves(endSquare);
 810       this.possibleMoves = [];
 811       if (moves.length > 1) {
 812         this.clickTime = Date.now();
 813         this.choices = moves;
 814       } else if (moves.length == 1) this.play(moves[0]);
 815       // else: forbidden move attempt
 816     },
 817     processArrowAttempt: function(e) {
 818       // Obtain the arrow from start and end squares
 819       const [offsetX, offsetY] = [e.clientX, e.clientY];
 820       let landing = document.elementFromPoint(offsetX, offsetY);
 821       // Next condition: classList.contains(piece) fails because of marks
 822       while (landing.tagName == "IMG") landing = landing.parentNode;
 823       const landingCoords = getSquareFromId(landing.id);
 824       if (
 825         this.startArrow[0] == landingCoords[0] &&
 826         this.startArrow[1] == landingCoords[1]
 827       ) {
 828         // Draw (or erase) a circle
 829         this.$set(this.circles, landing.id, !this.circles[landing.id]);
 830       }
 831       else {
 832         // OK: add arrow, landing is a new square
 833         const currentArrow = document.getElementById("currentArrow");
 834         currentArrow.parentNode.removeChild(currentArrow);
 835         this.addArrow({
 836           start: this.startArrow,
 837           end: landingCoords
 838         });
 839       }
 840       this.startArrow = null;
 841     },
 842     findMatchingMoves: function(endSquare) {
 843       // Run through moves list and return the matching set (if promotions...)
 844       return (
 845         this.possibleMoves.filter(m => {
 846           return (endSquare[0] == m.end.x && endSquare[1] == m.end.y);
 847         })
 848       );
 849     },
 850     play: function(move) {
 851       this.$emit("play-move", move);
 852     }
 853   }
 854 };
 855 </script>
 856
 857 <style lang="sass">
 858 // SVG dynamically added, so not scoped
 859 #arrowCanvas
 860   pointer-events: none
 861   position: absolute
 862   top: 0
 863   left: 0
 864   width: 100%
 865   height: 100%
 866
 867 .svg-arrow
 868   opacity: 0.65
 869   stroke: #5f0e78
 870   fill: none
 871   marker-end: url(#arrow)
 872
 873 .svg-line
 874   stroke: black
 875
 876 .svg-diag
 877   stroke: grey
 878
 879 .arrow-head
 880   fill: #5f0e78
 881 </style>
 882
 883 <style lang="sass" scoped>
 884 @import "@/styles/_board_squares_img.sass";
 885
 886 //.game.reserve-div
 887   // TODO: would be cleaner to restrict width so that it doesn't overflow
 888   // Commented out because pieces would disappear over the board otherwise:
 889   //overflow: hidden
 890 .reserve-count
 891   width: 100%
 892   text-align: center
 893   display: inline-block
 894   position: absolute
 895 .reserve-row
 896   margin-bottom: 15px
 897
 898 .full-width
 899   width: 100%
 900
 901 .game
 902   user-select: none
 903   width: 100%
 904   margin: 0
 905   .board
 906     cursor: pointer
 907
 908 #choices
 909   user-select: none
 910   margin: 0
 911   position: absolute
 912   z-index: 300
 913   overflow-y: inherit
 914   background-color: rgba(0,0,0,0)
 915   img
 916     cursor: pointer
 917     background-color: #e6ee9c
 918     &:hover
 919       background-color: skyblue
 920     &.choice-piece
 921       width: 100%
 922       height: auto
 923       display: block
 924
 925 img.ghost
 926   // NOTE: no need to set z-index here, since opacity is low
 927   position: absolute
 928   opacity: 0.5
 929   top: 0
 930
 931 .incheck-light
 932   background-color: rgba(204, 51, 0, 0.7) !important
 933 .incheck-dark
 934   background-color: rgba(204, 51, 0, 0.9) !important
 935
 936 // TODO: no predefined highlight colors, but layers. How?
 937
 938 .hover-highlight:hover
 939   // TODO: color dependant on board theme, or inner border...
 940   background-color: #C571E6 !important
 941
 942 .highlight
 943   &.light-square
 944     &.lichess
 945       background-color: #cdd26a
 946     &.chesscom
 947       background-color: #f7f783
 948     &.chesstempo
 949       background-color: #9f9fff
 950     &.orangecc
 951       background-color: #fef273
 952   &.dark-square
 953     &.lichess
 954       background-color: #aaa23a
 955     &.chesscom
 956       background-color: #bacb44
 957     &.chesstempo
 958       background-color: #557fff
 959     &.orangecc
 960       background-color: #e8c525
 961   &.middle-square
 962     &.lichess
 963       background-color: #BCBA52
 964     &.chesscom
 965       background-color: #D9E164
 966     &.chesstempo
 967       background-color: #7A8FFF
 968     &.orangecc
 969       background-color: #F3DC4C
 970 </style>