basant307/AI_Governance_Project

1/**2 * Explained by Blindman67 at https://stackoverflow.com/a/44856925/110288283 */4 5 6// Declare reused variable to avoid reallocating variables every time the function is called7let x, y, v1 = {}, v2 = {}, sinA, sinA90, radDirection, drawDirection, angle, halfAngle, cRadius, lenOut, radius, limit;8let startX, startY, stopX, stopY;9let lastPoint;10 11// convert 2 points into vector form, polar form, and normalised12const asVec = function (p, pp, v) {13  v.x = pp.x - p.x;14  v.y = pp.y - p.y;15  v.len = Math.sqrt(v.x * v.x + v.y * v.y);16  v.nx = v.x / v.len;17  v.ny = v.y / v.len;18  v.ang = Math.atan2(v.ny, v.nx);19};20 21const invertVec = function (originalV, invertedV) {22  invertedV.x = originalV.x * -1;23  invertedV.y = originalV.y * -1;24  invertedV.nx = originalV.nx * -1;25  invertedV.ny = originalV.ny * -1;26  invertedV.ang = originalV.ang > 0 ? -(Math.PI - originalV.ang) : Math.PI + originalV.ang;27};28 29const calcCornerArc = (previousPoint, currentPoint, nextPoint, radiusMax, isArcRadius) => {30  //-----------------------------------------31  // Part 132  previousPoint !== lastPoint ? asVec(currentPoint, previousPoint, v1) : invertVec(v2, v1); // Avoid recalculating vec if it is the invert of the last one calculated33  asVec(currentPoint, nextPoint, v2);34  sinA = v1.nx * v2.ny - v1.ny * v2.nx;35  sinA90 = v1.nx * v2.nx - v1.ny * -v2.ny;36  angle = Math.asin(Math.max(-1, Math.min(1, sinA)));37  if (Math.abs(angle) < 1e-6) {38    x = currentPoint.x;39    y = currentPoint.y;40    cRadius = radius = 0;41    return;42  }43  //-----------------------------------------44  radDirection = 1;45  drawDirection = false;46  if (sinA90 < 0) {47    if (angle < 0) {48      angle = Math.PI + angle;49    } else {50      angle = Math.PI - angle;51      radDirection = -1;52      drawDirection = true;53    }54  } else {55    if (angle > 0) {56      radDirection = -1;57      drawDirection = true;58    }59  }60  if (currentPoint.radius !== undefined) {61    radius = currentPoint.radius;62  } else {63    radius = radiusMax;64  }65  //-----------------------------------------66  // Part 267  halfAngle = angle / 2;68  //-----------------------------------------69 70 71  limit = Math.min(v1.len / 2, v2.len / 2);72  73  if (isArcRadius) {74    //-----------------------------------------75    // Part 376    lenOut = Math.abs(Math.cos(halfAngle) * radius / Math.sin(halfAngle));77 78    //-----------------------------------------79    // Special part A80    if (lenOut > limit) {81      lenOut = limit;82      cRadius = Math.abs(lenOut * Math.sin(halfAngle) / Math.cos(halfAngle));83    } else {84      cRadius = radius;85    }86  } else {87    lenOut = Math.min(limit, radius);88    cRadius = Math.abs(lenOut * Math.sin(halfAngle) / Math.cos(halfAngle));89  }90  //-----------------------------------------91 92 93 94  //-----------------------------------------95  // Part 496  stopX = currentPoint.x + v2.nx * lenOut;97  stopY = currentPoint.y + v2.ny * lenOut;98  //-----------------------------------------99  // Part 5100  x = stopX - v2.ny * cRadius * radDirection;101  y = stopY + v2.nx * cRadius * radDirection;102  //-----------------------------------------103  // Additional Part : calculate start point E104  startX = currentPoint.x + v1.nx * lenOut;105  startY = currentPoint.y + v1.ny * lenOut;106 107  // Save last point to avoid recalculating vector when not needed108  lastPoint = currentPoint;109};110 111 112/**113 * Draw round corner from a point and its previous and next neighbours in a path114 *115 * @param ctx :CanvasRenderingContext2D116 * @param previousPoint {{x: number, y:number, radius: number?}}117 * @param currentPoint {{x: number, y:number, radius: number?}}118 * @param nextPoint {{x: number, y:number, radius: number?}}119 * @param radiusMax :number120 * @param isArcRadius :boolean121 */122export function drawRoundCorner(ctx, previousPoint, currentPoint, nextPoint, radiusMax, isArcRadius) {123  calcCornerArc(previousPoint, currentPoint, nextPoint, radiusMax, isArcRadius);124  if (cRadius === 0) ctx.lineTo(currentPoint.x, currentPoint.y);125  else ctx.arc(x, y, cRadius, v1.ang + Math.PI / 2 * radDirection, v2.ang - Math.PI / 2 * radDirection, drawDirection);126 127}128 129/**130 * Draw corner provided by {@link getRoundCorner}131 *132 * @param ctx :CanvasRenderingContext2D133 * @param roundCorner {{cx:number, cy:number, radius:number, endAngle: number, startAngle: number, counterClockwise: boolean}}134 */135export function drawPreparedRoundCorner(ctx, roundCorner) {136  if (roundCorner.radius === 0) ctx.lineTo(roundCorner.cx, roundCorner.cy);137  else ctx.arc(roundCorner.cx, roundCorner.cy, roundCorner.radius, roundCorner.startAngle, roundCorner.endAngle, roundCorner.counterClockwise);138}139 140/**141 * Get round corner from a point and its previous and next neighbours in a path142 *143 * @param previousPoint {{x: number, y:number, radius: number?}}144 * @param currentPoint {{x: number, y:number, radius: number?}}145 * @param nextPoint {{x: number, y:number, radius: number?}}146 * @param radiusMax :number147 * @param isArcRadius :boolean148 * @return {{149 * cx:number, cy:number, radius:number,150 * startX:number, startY:number,151 * stopX:number, stopY: number,152 * endAngle: number, startAngle: number, counterClockwise: boolean153 * }}154 */155export function getRoundCorner(previousPoint, currentPoint, nextPoint, radiusMax, isArcRadius = true) {156  if (radiusMax === 0 || currentPoint.radius === 0) return {157    cx: currentPoint.x,158    cy: currentPoint.y,159    radius: 0,160    startX: currentPoint.x,161    startY: currentPoint.y,162    stopX: currentPoint.x,163    stopY: currentPoint.y,164    startAngle: undefined,165    endAngle: undefined,166    counterClockwise: undefined167  };168 169  calcCornerArc(previousPoint, currentPoint, nextPoint, radiusMax, isArcRadius);170  return {171    cx: x, cy: y, radius: cRadius,172    startX, startY,173    stopX, stopY,174    startAngle: v1.ang + Math.PI / 2 * radDirection,175    endAngle: v2.ang - Math.PI / 2 * radDirection,176    counterClockwise: drawDirection177  };178}179