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