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A userscript library for seamlessly adding chess move arrows to game boards on popular platforms like Chess.com and Lichess.org
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/470417/1455862/UniversalBoardDrawerjs.js
/* UniversalBoardDrawer.js
- Version: 1.3.4
- Author: Haka
- Description: A userscript library for seamlessly adding chess move arrows to game boards on popular platforms like Chess.com and Lichess.org
- GitHub: https://github.com/Hakorr/UniversalBoardDrawer
*/
class UniversalBoardDrawer {
constructor(boardElem, config) {
this.boardElem = boardElem;
this.window = config?.window || window;
this.document = this.window?.document;
this.parentElem = config?.parentElem || this.document.body;
this.boardDimensions = {
'width': config?.boardDimensions?.[0] || 8,
'height': config?.boardDimensions?.[1] || 8
};
this.adjustSizeByDimensions = config?.adjustSizeByDimensions || false;
this.adjustSizeConfig = config?.adjustSizeConfig;
this.orientation = config?.orientation || 'w';
this.zIndex = config?.zIndex || 1000; // container z-index
this.usePrepend = config?.prepend || false;
this.debugMode = config?.debugMode || false;
this.ignoreBodyRectLeft = config?.ignoreBodyRectLeft || false;
this.boardContainerElem = null;
this.singleSquareSize = null;
this.lastInputPositionStr = null;
this.lastInputPosition = null;
this.addedShapes = [];
this.squareSvgCoordinates = [];
this.observers = [];
this.customActivityListeners = [];
this.defaultFillColor = 'mediumseagreen';
this.defaultOpacity = 0.8;
this.updateInterval = 100;
this.isInputDown = false;
this.terminated = false;
if(!this.document) {
if(this.debugMode) console.error(`Inputted document element doesn't exist!`);
return;
}
if(!this.boardElem) {
if(this.debugMode) console.error(`Inputted board element doesn't exist!`);
return;
}
if(typeof this.boardDimensions != 'object') {
if(this.debugMode) console.error(`Invalid board dimensions value, please use array! (e.g. [8, 8])`);
return;
}
this.createOverlaySVG();
const handleMouseMove = e => {
if (this.terminated) {
this.document.removeEventListener('mousemove', handleMouseMove);
return;
}
this.handleMouseEvent.bind(this)(e);
};
const handleTouchStart = e => {
if (this.terminated) {
this.document.removeEventListener('touchstart', handleTouchStart);
return;
}
this.handleMouseEvent.bind(this)(e);
};
const handleMouseDown = () => {
if (this.terminated) {
this.document.removeEventListener('mousedown', handleMouseDown);
return;
}
this.isInputDown = true;
};
const handleMouseUp = () => {
if (this.terminated) {
this.document.removeEventListener('mouseup', handleMouseUp);
return;
}
this.isInputDown = false;
};
this.document.addEventListener('mousemove', handleMouseMove);
this.document.addEventListener('touchstart', handleTouchStart);
this.document.addEventListener('mousedown', handleMouseDown);
this.document.addEventListener('mouseup', handleMouseUp);
}
setOrientation(orientation) {
this.orientation = orientation;
this.updateDimensions();
}
setBoardDimensions(dimensionArr) {
const [width, height] = dimensionArr || [8, 8];
this.boardDimensions = { width, height };
this.updateDimensions();
}
setAdjustSizeByDimensions(boolean) {
this.adjustSizeByDimensions = boolean;
this.updateDimensions();
}
createArrowBetweenPositions(from, to, config) {
const fromCoordinateObj = this.squareSvgCoordinates.find(x => this.coordinateToFen(x.coordinates) == from);
const toCoordinateObj = this.squareSvgCoordinates.find(x => this.coordinateToFen(x.coordinates) == to);
if(!fromCoordinateObj || !toCoordinateObj) {
if(this.debugMode) console.error('Coordinates', from, to, 'do not exist. Possibly out of bounds?');
return;
}
const [fromX, fromY] = fromCoordinateObj?.positions;
const [toX, toY] = toCoordinateObj?.positions;
const distance = Math.sqrt(Math.pow(fromX - toX, 2) + Math.pow(fromY - toY, 2));
const angle = Math.atan2(fromY - toY, fromX - toX);
const scale = this.singleSquareSize / 100;
const lineWidth = (config?.lineWidth || 15) * scale;
const arrowheadWidth = (config?.arrowheadWidth || 55) * scale;
const arrowheadHeight = (config?.arrowheadHeight || 45) * scale;
const startOffset = (config?.startOffset || 20) * scale;
const existingArrowElem = config?.existingElem;
const arrowElem = typeof existingArrowElem === 'object'
? existingArrowElem
: this.document.createElementNS('http://www.w3.org/2000/svg', 'polygon');
arrowElem.setAttribute('transform', `rotate(${angle * (180 / Math.PI) - 90} ${fromX} ${fromY})`);
const arrowPoints = [
{ x: fromX - lineWidth / 2, y: fromY - startOffset },
{ x: fromX - lineWidth / 2, y: fromY - distance + arrowheadHeight },
{ x: fromX - arrowheadWidth / 2, y: fromY - distance + arrowheadHeight },
{ x: fromX, y: fromY - distance },
{ x: fromX + arrowheadWidth / 2, y: fromY - distance + arrowheadHeight },
{ x: fromX + lineWidth / 2, y: fromY - distance + arrowheadHeight },
{ x: fromX + lineWidth / 2, y: fromY - startOffset }
];
const pointsString = arrowPoints.map(point => `${point.x},${point.y}`).join(' ');
arrowElem.setAttribute('points', pointsString);
arrowElem.style.fill = this.defaultFillColor;
arrowElem.style.opacity = this.defaultOpacity;
const style = config?.style;
if(style) arrowElem.setAttribute('style', style);
return arrowElem;
}
createDotOnSVG(x, y) {
const dot = this.document.createElementNS('http://www.w3.org/2000/svg', 'circle');
dot.setAttribute('cx', x);
dot.setAttribute('cy', y);
dot.setAttribute('r', '1');
dot.setAttribute('fill', 'black');
this.addedShapes.push({ type: 'debugDot', 'element': dot });
this.boardContainerElem.appendChild(dot);
}
removeAllExistingShapes() {
this.addedShapes
.forEach(shapeObj => {
shapeObj.element?.remove();
});
}
removeAllDebugDots() {
this.addedShapes
.filter(shapeObj => shapeObj.type == 'debugDot')
.forEach(debugDotObj => {
debugDotObj.element?.remove();
});
}
updateShapes() {
if(this.debugMode) {
this.removeAllDebugDots();
this.squareSvgCoordinates.forEach(x => this.createDotOnSVG(...x.positions));
}
this.addedShapes
.filter(shapeObj => shapeObj.type != 'debugDot')
.forEach(shapeObj => {
const newShapeElem = this.createArrowBetweenPositions(...shapeObj.positions, shapeObj.config);
this.transferAttributes(newShapeElem, shapeObj.element);
});
}
coordinateToFen(coordinates) {
let [x, y] = coordinates;
x = this.orientation == 'w' ? x : this.boardDimensions.width - x + 1;
y = this.orientation == 'b' ? y : this.boardDimensions.height - y + 1;
const getCharacter = num => String.fromCharCode(96 + num);
const file = getCharacter(x);
const rank = y;
return file + rank;
}
updateCoords() {
this.squareSvgCoordinates = []; // reset coordinate array
// calculate every square center point coordinates relative to the svg
for(let y = 0; this.boardDimensions.height > y; y++) {
for(let x = 0; this.boardDimensions.width > x; x++) {
this.squareSvgCoordinates.push({
coordinates: [x + 1, y + 1],
positions: [this.squareWidth / 2 + (this.squareWidth * x),
this.squareHeight / 2 + (this.squareHeight * y)]
});
}
}
}
transferAttributes(fromElem, toElem) {
if(fromElem && fromElem?.attributes && toElem) {
[...fromElem.attributes].forEach(attr =>
toElem.setAttribute(attr.name, attr.value));
}
}
createShape(type, positions, config) {
if(this.terminated) {
if(this.debugMode) console.warn('Failed to create shape! Tried to create shape after termination!');
return false;
}
if(!this.boardContainerElem) {
if(this.debugMode) console.warn(`Failed to create shape! Board SVG doesn't exist yet! (createOverlaySVG() failed?)`);
return false;
}
switch(type) {
case 'arrow':
const element = this.createArrowBetweenPositions(...positions, config);
if(element) {
this.addedShapes.push({ type, positions, config, element });
if(this.usePrepend) {
this.boardContainerElem.prepend(element);
} else {
this.boardContainerElem.appendChild(element);
}
return element;
}
break;
}
return null;
}
updateDimensions() {
const boardRect = this.boardElem.getBoundingClientRect(),
bodyRect = this.document.body.getBoundingClientRect(); // https://stackoverflow.com/a/62106310
let boardWidth = boardRect.width,
boardHeight = boardRect.height;
let boardPositionTop = boardRect.top - bodyRect.top,
boardPositionLeft = boardRect.left - (this.ignoreBodyRectLeft ? 0 : bodyRect.left);
if(this.adjustSizeByDimensions) {
if(this.boardDimensions.width > this.boardDimensions.height) {
const multiplier = this.boardDimensions.height / this.boardDimensions.width,
newHeight = boardWidth * multiplier;
if(boardHeight !== newHeight) {
if(!this.adjustSizeConfig?.noTopAdjustment)
boardPositionTop += (boardHeight - newHeight) / 2;
boardHeight = newHeight;
}
}
else {
const multiplier = this.boardDimensions.width / this.boardDimensions.height,
newWidth = boardWidth * multiplier;
if(boardWidth !== newWidth) {
if(!this.adjustSizeConfig?.noLeftAdjustment)
boardPositionLeft += (boardWidth - newWidth) / 2;
boardWidth = newWidth;
}
}
}
this.boardContainerElem.style.width = boardWidth + 'px';
this.boardContainerElem.style.height = boardHeight + 'px';
this.boardContainerElem.style.left = boardPositionLeft + 'px';
this.boardContainerElem.style.top = boardPositionTop + 'px';
const squareWidth = boardWidth / this.boardDimensions.width;
const squareHeight = boardHeight / this.boardDimensions.height;
this.singleSquareSize = squareWidth;
this.squareWidth = squareWidth;
this.squareHeight = squareHeight;
this.updateCoords();
this.updateShapes();
}
createOverlaySVG() {
const svg = this.document.createElementNS('http://www.w3.org/2000/svg', 'svg');
svg.style.position = 'absolute';
svg.style.pointerEvents = 'none';
svg.style['z-index'] = this.zIndex;
this.boardContainerElem = svg;
this.updateDimensions();
this.parentElem.appendChild(this.boardContainerElem);
const rObs = new ResizeObserver(this.updateDimensions.bind(this));
rObs.observe(this.boardElem);
rObs.observe(this.document.body);
this.observers.push(rObs);
let oldBoardRect = JSON.stringify(this.boardElem.getBoundingClientRect());
const additionalCheckLoop = setInterval(() => {
if(this.terminated) {
clearInterval(additionalCheckLoop);
return;
}
const boardRect = JSON.stringify(this.boardElem.getBoundingClientRect());
if(boardRect !== oldBoardRect) {
oldBoardRect = boardRect;
this.updateDimensions();
}
}, this.updateInterval);
}
getCoordinatesFromInputPosition(e) {
const boardRect = this.boardElem.getBoundingClientRect();
const { clientX, clientY } = e.touches ? e.touches[0] : e;
const isOutOfBounds = clientX < boardRect.left || clientX > boardRect.right || clientY < boardRect.top || clientY > boardRect.bottom;
const relativeX = clientX - boardRect.left;
const relativeY = clientY - boardRect.top;
return isOutOfBounds
? [null, null]
: [Math.floor(relativeX / this.squareWidth) + 1, Math.floor(relativeY / this.squareHeight) + 1];
}
handleMouseEvent(e) {
if(this.isInputDown) return;
const position = this.getCoordinatesFromInputPosition(e),
positionStr = position?.toString();
if(positionStr != this.lastInputPositionStr) {
const enteredSquareListeners = this.customActivityListeners.filter(obj => obj.square == this.coordinateToFen(position));
enteredSquareListeners.forEach(obj => obj.cb('enter'));
if(this.lastInputPosition && this.lastInputPosition[0] != null) {
const leftSquareListeners = this.customActivityListeners.filter(obj => obj.square == this.coordinateToFen(this.lastInputPosition));
leftSquareListeners.forEach(obj => obj.cb('leave'));
}
this.lastInputPositionStr = positionStr;
this.lastInputPosition = position;
}
}
addSquareListener(square, cb) {
this.customActivityListeners.push({ square, cb });
return { remove: () => {
this.customActivityListeners = this.customActivityListeners.filter(obj => obj.square != square && obj.cb != cb);
}};
}
terminate() {
this.terminated = true;
this.observers.forEach(observer => observer.disconnect());
this.boardContainerElem.remove();
}
}