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       const arrowIdx = this.arrows.findIndex(a => {
 550         return (
 551           a.start[0] == arrow.start[0] && a.start[1] == arrow.start[1] &&
 552           a.end[0] == arrow.end[0] && a.end[1] == arrow.end[1]
 553         );
 554       });
 555       if (arrowIdx >= 0)
 556         // Erase the arrow
 557         this.arrows.splice(arrowIdx, 1);
 558       else
 559         // Add to arrows vector:
 560         this.arrows.push(arrow);
 561       // NOTE: no need to draw here, will be re-draw
 562       // by updated() hook callong re_setDrawings()
 563     },
 564     getSvgArrow: function(arrow, top, left, squareWidth) {
 565       const aStart =
 566         this.coordsToXY(
 567           [arrow.start[0] + 0.5, arrow.start[1] + 0.5],
 568           top, left, squareWidth);
 569       const aEnd =
 570         this.computeEndArrow(
 571           aStart, [arrow.end[0] + 0.5, arrow.end[1] + 0.5],
 572           top, left, squareWidth);
 573       const arrowWidth = squareWidth / 4;
 574       let path =
 575         document.createElementNS("http://www.w3.org/2000/svg", "path");
 576       path.classList.add("svg-arrow");
 577       path.setAttribute(
 578         "d",
 579         "M" + aStart.x + "," + aStart.y + " " + "L" + aEnd.x + "," + aEnd.y
 580       );
 581       path.style = "stroke-width:" + arrowWidth + "px";
 582       return path;
 583     },
 584     re_setDrawings: function() {
 585       // Add some drawing on board (for some variants + arrows and circles)
 586       const boardElt = document.getElementById("gamePosition");
 587       if (!boardElt) return;
 588       // Remove current canvas, if any
 589       const curCanvas = document.getElementById("arrowCanvas");
 590       if (!!curCanvas) curCanvas.parentNode.removeChild(curCanvas);
 591       const squareWidth = boardElt.offsetWidth / V.size.y;
 592       const bPos = boardElt.getBoundingClientRect();
 593       let svgArrows = [];
 594       this.arrows.forEach(a => {
 595         svgArrows.push(this.getSvgArrow(a, bPos.top, bPos.left, squareWidth));
 596       });
 597       let vLines = [];
 598       if (!!V.Lines) {
 599         V.Lines.forEach(line => {
 600           const lStart =
 601             this.coordsToXY(line[0], bPos.top, bPos.left, squareWidth);
 602           const lEnd =
 603             this.coordsToXY(line[1], bPos.top, bPos.left, squareWidth);
 604           let path =
 605             document.createElementNS("http://www.w3.org/2000/svg", "path");
 606           if (line[0][0] == line[1][0] || line[0][1] == line[1][1])
 607             path.classList.add("svg-line");
 608           else
 609             // "Diagonals" are drawn with a lighter color (TODO: generalize)
 610             path.classList.add("svg-diag");
 611           path.setAttribute(
 612             "d",
 613             "M" + lStart.x + "," + lStart.y + " " +
 614               "L" + lEnd.x + "," + lEnd.y
 615           );
 616           vLines.push(path);
 617         });
 618       }
 619       let arrowCanvas =
 620         document.createElementNS("http://www.w3.org/2000/svg", "svg");
 621       arrowCanvas.id = "arrowCanvas";
 622       arrowCanvas.setAttribute("stroke", "none");
 623       let defs =
 624         document.createElementNS("http://www.w3.org/2000/svg", "defs");
 625       const arrowWidth = squareWidth / 4;
 626       let marker =
 627         document.createElementNS("http://www.w3.org/2000/svg", "marker");
 628       marker.id = "arrow";
 629       marker.setAttribute("markerWidth", (2 * arrowWidth) + "px");
 630       marker.setAttribute("markerHeight", (3 * arrowWidth) + "px");
 631       marker.setAttribute("markerUnits", "userSpaceOnUse");
 632       marker.setAttribute("refX", "0");
 633       marker.setAttribute("refY", (1.5 * arrowWidth) + "px");
 634       marker.setAttribute("orient", "auto");
 635       let head =
 636         document.createElementNS("http://www.w3.org/2000/svg", "path");
 637       head.classList.add("arrow-head");
 638       head.setAttribute(
 639         "d",
 640         "M0,0 L0," + (3 * arrowWidth) + " L" +
 641           (2 * arrowWidth) + "," + (1.5 * arrowWidth) + " z"
 642       );
 643       marker.appendChild(head);
 644       defs.appendChild(marker);
 645       arrowCanvas.appendChild(defs);
 646       svgArrows.concat(vLines).forEach(av => arrowCanvas.appendChild(av));
 647       document.getElementById("rootBoardElement").appendChild(arrowCanvas);
 648     },
 649     mousedown: function(e) {
 650       e.preventDefault();
 651       if (!this.mobileBrowser && e.which != 3)
 652         // Cancel current drawing and circles, if any
 653         this.cancelResetArrows();
 654       if (this.mobileBrowser || e.which == 1) {
 655         // Mouse left button
 656         if (!this.start) {
 657           this.containerPos =
 658             document.getElementById("boardContainer").getBoundingClientRect();
 659           // NOTE: classList[0] is enough: 'piece' is the first assigned class
 660           const withPiece = (e.target.classList[0] == "piece");
 661           // Show possible moves if current player allowed to play
 662           const startSquare =
 663             getSquareFromId(withPiece ? e.target.parentNode.id : e.target.id);
 664           this.possibleMoves = [];
 665           const color = this.analyze ? this.vr.turn : this.userColor;
 666           if (this.vr.canIplay(color, startSquare)) {
 667             // Emit the click event which could be used by some variants
 668             const targetId =
 669               (withPiece ? e.target.parentNode.id : e.target.id);
 670             const sq = getSquareFromId(targetId);
 671             this.$emit("click-square", sq);
 672             if (withPiece && !this.vr.onlyClick(sq)) {
 673               this.possibleMoves = this.vr.getPossibleMovesFrom(startSquare);
 674               if (this.possibleMoves.length > 0) {
 675                 // For potential drag'n drop, remember start coordinates
 676                 // (to center the piece on mouse cursor)
 677                 let parent = e.target.parentNode; //surrounding square
 678                 const rect = parent.getBoundingClientRect();
 679                 this.start = {
 680                   x: rect.x + rect.width / 2,
 681                   y: rect.y + rect.width / 2,
 682                   id: parent.id
 683                 };
 684                 // Add the moving piece to the board, just after current image
 685                 this.selectedPiece = e.target.cloneNode();
 686                 Object.assign(
 687                   this.selectedPiece.style,
 688                   {
 689                     position: "absolute",
 690                     top: 0,
 691                     display: "inline-block",
 692                     zIndex: 3000
 693                   }
 694                 );
 695                 parent.insertBefore(this.selectedPiece, e.target.nextSibling);
 696               }
 697             }
 698           }
 699         }
 700         else this.processMoveAttempt(e);
 701       }
 702       else if (e.which == 3) {
 703         // Mouse right button
 704         this.containerPos =
 705           document.getElementById("gamePosition").getBoundingClientRect();
 706         let elem = e.target;
 707         // Next loop because of potential marks
 708         while (elem.tagName == "IMG") elem = elem.parentNode;
 709         this.startArrow = getSquareFromId(elem.id);
 710       }
 711     },
 712     mousemove: function(e) {
 713       if (!this.selectedPiece && !this.startArrow) return;
 714       // Cancel if off boardContainer
 715       const [offsetX, offsetY] =
 716         this.mobileBrowser
 717           ? [e.changedTouches[0].clientX, e.changedTouches[0].clientY]
 718           : [e.clientX, e.clientY];
 719       if (
 720         offsetX < this.containerPos.left ||
 721         offsetX > this.containerPos.right ||
 722         offsetY < this.containerPos.top ||
 723         offsetY > this.containerPos.bottom
 724       ) {
 725         if (!!this.selectedPiece) {
 726           this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 727           delete this.selectedPiece;
 728           this.selectedPiece = null;
 729           this.start = null;
 730           this.possibleMoves = []; //in case of
 731           this.click = "";
 732           let selected = document.querySelector(".ghost");
 733           if (!!selected) selected.classList.remove("ghost");
 734         }
 735         else {
 736           this.startArrow = null;
 737           this.movingArrow = null;
 738           const currentArrow = document.getElementById("currentArrow");
 739           if (!!currentArrow)
 740             currentArrow.parentNode.removeChild(currentArrow);
 741         }
 742         return;
 743       }
 744       e.preventDefault();
 745       if (!!this.selectedPiece) {
 746         // There is an active element: move it around
 747         Object.assign(
 748           this.selectedPiece.style,
 749           {
 750             left: offsetX - this.start.x + "px",
 751             top: offsetY - this.start.y + "px"
 752           }
 753         );
 754       }
 755       else {
 756         let elem = e.target;
 757         // Next loop because of potential marks
 758         while (elem.tagName == "IMG") elem = elem.parentNode;
 759         // To center the arrow in square:
 760         const movingCoords = getSquareFromId(elem.id);
 761         if (
 762           movingCoords[0] != this.startArrow[0] ||
 763           movingCoords[1] != this.startArrow[1]
 764         ) {
 765           this.movingArrow = movingCoords;
 766           this.drawCurrentArrow();
 767         }
 768       }
 769     },
 770     mouseup: function(e) {
 771       e.preventDefault();
 772       if (this.mobileBrowser || e.which == 1) {
 773         if (!this.selectedPiece) return;
 774         // Drag'n drop. Selected piece is no longer needed:
 775         this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 776         delete this.selectedPiece;
 777         this.selectedPiece = null;
 778         this.processMoveAttempt(e);
 779       } else if (e.which == 3) {
 780         if (!this.startArrow) return;
 781         // Mouse right button
 782         this.movingArrow = null;
 783         this.processArrowAttempt(e);
 784       }
 785     },
 786     // Called by BaseGame after partially undoing multi-moves:
 787     resetCurrentAttempt: function() {
 788       this.possibleMoves = [];
 789       this.start = null;
 790       this.click = "";
 791       this.selectedPiece = null;
 792     },
 793     processMoveAttempt: function(e) {
 794       // Obtain the move from start and end squares
 795       const [offsetX, offsetY] =
 796         this.mobileBrowser
 797           ? [e.changedTouches[0].clientX, e.changedTouches[0].clientY]
 798           : [e.clientX, e.clientY];
 799       let landing = document.elementFromPoint(offsetX, offsetY);
 800       // Next condition: classList.contains(piece) fails because of marks
 801       while (landing.tagName == "IMG") landing = landing.parentNode;
 802       if (this.start.id == landing.id) {
 803         if (this.click == landing.id) {
 804           // Second click on same square: cancel current move
 805           this.possibleMoves = [];
 806           this.start = null;
 807           this.click = "";
 808         } else this.click = landing.id;
 809         return;
 810       }
 811       this.start = null;
 812       // OK: process move attempt, landing is a square node
 813       let endSquare = getSquareFromId(landing.id);
 814       let moves = this.findMatchingMoves(endSquare);
 815       this.possibleMoves = [];
 816       if (moves.length > 1) {
 817         this.clickTime = Date.now();
 818         this.choices = moves;
 819       } else if (moves.length == 1) this.play(moves[0]);
 820       // else: forbidden move attempt
 821     },
 822     processArrowAttempt: function(e) {
 823       // Obtain the arrow from start and end squares
 824       const [offsetX, offsetY] = [e.clientX, e.clientY];
 825       let landing = document.elementFromPoint(offsetX, offsetY);
 826       // Next condition: classList.contains(piece) fails because of marks
 827       while (landing.tagName == "IMG") landing = landing.parentNode;
 828       const landingCoords = getSquareFromId(landing.id);
 829       if (
 830         this.startArrow[0] == landingCoords[0] &&
 831         this.startArrow[1] == landingCoords[1]
 832       ) {
 833         // Draw (or erase) a circle
 834         this.$set(this.circles, landing.id, !this.circles[landing.id]);
 835       }
 836       else {
 837         // OK: add arrow, landing is a new square
 838         const currentArrow = document.getElementById("currentArrow");
 839         currentArrow.parentNode.removeChild(currentArrow);
 840         this.addArrow({
 841           start: this.startArrow,
 842           end: landingCoords
 843         });
 844       }
 845       this.startArrow = null;
 846     },
 847     findMatchingMoves: function(endSquare) {
 848       // Run through moves list and return the matching set (if promotions...)
 849       return (
 850         this.possibleMoves.filter(m => {
 851           return (endSquare[0] == m.end.x && endSquare[1] == m.end.y);
 852         })
 853       );
 854     },
 855     play: function(move) {
 856       this.$emit("play-move", move);
 857     }
 858   }
 859 };
 860 </script>
 861
 862 <style lang="sass">
 863 // SVG dynamically added, so not scoped
 864 #arrowCanvas
 865   pointer-events: none
 866   position: absolute
 867   top: 0
 868   left: 0
 869   width: 100%
 870   height: 100%
 871
 872 .svg-arrow
 873   opacity: 0.65
 874   stroke: #5f0e78
 875   fill: none
 876   marker-end: url(#arrow)
 877
 878 .svg-line
 879   stroke: black
 880
 881 .svg-diag
 882   stroke: grey
 883
 884 .arrow-head
 885   fill: #5f0e78
 886 </style>
 887
 888 <style lang="sass" scoped>
 889 @import "@/styles/_board_squares_img.sass";
 890
 891 //.game.reserve-div
 892   // TODO: would be cleaner to restrict width so that it doesn't overflow
 893   // Commented out because pieces would disappear over the board otherwise:
 894   //overflow: hidden
 895 .reserve-count
 896   width: 100%
 897   text-align: center
 898   display: inline-block
 899   position: absolute
 900 .reserve-row
 901   margin-bottom: 15px
 902
 903 .full-width
 904   width: 100%
 905
 906 .game
 907   user-select: none
 908   width: 100%
 909   margin: 0
 910   .board
 911     cursor: pointer
 912
 913 #choices
 914   user-select: none
 915   margin: 0
 916   position: absolute
 917   z-index: 300
 918   overflow-y: inherit
 919   background-color: rgba(0,0,0,0)
 920   img
 921     cursor: pointer
 922     background-color: #e6ee9c
 923     &:hover
 924       background-color: skyblue
 925     &.choice-piece
 926       width: 100%
 927       height: auto
 928       display: block
 929
 930 img.ghost
 931   // NOTE: no need to set z-index here, since opacity is low
 932   position: absolute
 933   opacity: 0.5
 934   top: 0
 935
 936 .incheck-light
 937   background-color: rgba(204, 51, 0, 0.7) !important
 938 .incheck-dark
 939   background-color: rgba(204, 51, 0, 0.9) !important
 940
 941 // TODO: no predefined highlight colors, but layers. How?
 942
 943 .hover-highlight:hover
 944   // TODO: color dependant on board theme, or inner border...
 945   background-color: #C571E6 !important
 946
 947 .highlight
 948   &.light-square
 949     &.lichess
 950       background-color: #cdd26a
 951     &.chesscom
 952       background-color: #f7f783
 953     &.chesstempo
 954       background-color: #9f9fff
 955     &.orangecc
 956       background-color: #fef273
 957   &.dark-square
 958     &.lichess
 959       background-color: #aaa23a
 960     &.chesscom
 961       background-color: #bacb44
 962     &.chesstempo
 963       background-color: #557fff
 964     &.orangecc
 965       background-color: #e8c525
 966   &.middle-square
 967     &.lichess
 968       background-color: #BCBA52
 969     &.chesscom
 970       background-color: #D9E164
 971     &.chesstempo
 972       background-color: #7A8FFF
 973     &.orangecc
 974       background-color: #F3DC4C
 975 </style>