Drawing the straps

All we have to do now is flip a bunch of points on the other side, and create one single path that follows our bib outline.

And as we now have one path to draw the bib, we can (and should) remove the earlier paths we drew to see what we are doing.

The round macro we added earlier is still required to calculate the points we need to construct the half-circle. But we don't want it to draw the half-circle path. As it happens, that is the default behaviour, so we merely have to remove its hidden: false property.

代码

function draftBib({
  Path,
  Point,
  paths,
  points,
  measurements,
  options,
  utils,
  macro,
  part,
}) {

  /*
   * Construct the neck opening
   */
  let tweak = 1
  let target = (measurements.head * options.neckRatio) /4
  let delta
  do {
    points.right = new Point(
      tweak * measurements.head / 10, 
      0
    )
    points.bottom = new Point(
      0, 
      tweak * measurements.head / 12
    )
  
    points.rightCp1 = points.right.shift(
      90, 
      points.bottom.dy(points.right) / 2
    )
    points.bottomCp2 = points.bottom.shift(
      0, 
      points.bottom.dx(points.right) / 2
    )
  
    paths.quarterNeck = new Path()
      .move(points.right)
      .curve(
        points.rightCp1, 
        points.bottomCp2, 
        points.bottom
      )
      .hide()

    delta = paths.quarterNeck.length() - target
    if (delta > 0) tweak = tweak * 0.99
    else tweak = tweak * 1.02
  } while (Math.abs(delta) > 1)

  /*
   * Construct the complete neck opening
   */
  points.rightCp2 = points.rightCp1.flipY()
  points.bottomCp1 = points.bottomCp2.flipX()
  points.left = points.right.flipX()
  points.leftCp1 = points.rightCp2.flipX()
  points.leftCp2 = points.rightCp1.flipX()
  points.top = points.bottom.flipY()
  points.topCp1 = points.bottomCp2.flipY()
  points.topCp2 = points.bottomCp1.flipY()

  /* Remove this path
  paths.neck = new Path()
    .move(points.top)
    .curve(points.topCp2, points.leftCp1, points.left)
    .curve(points.leftCp2, points.bottomCp1, points.bottom)
    .curve(points.bottomCp2, points.rightCp1, points.right)
    .curve(points.rightCp2, points.topCp1, points.top)
    .close()
    .addClass('fabric')
   */

  // Drawing the bib outline
  const width = measurements.head * options.widthRatio
  const length = measurements.head * options.lengthRatio

  points.topLeft = new Point(
    width / -2,
    points.top.y - (width / 2 - points.right.x)
  )
  points.topRight = points.topLeft.shift(0, width)
  points.bottomLeft = points.topLeft.shift(-90, length)
  points.bottomRight = points.topRight.shift(-90, length)

  /*
   * Shape the straps
   */
  points.edgeLeft = new Point(points.topLeft.x, points.left.y)
  points.edgeRight = new Point(points.topRight.x, points.right.y)
  points.edgeTop = new Point(0, points.topLeft.y)

  points.edgeLeftCp = points.edgeLeft.shiftFractionTowards(points.topLeft, 0.5)
  points.edgeRightCp = points.edgeLeftCp.flipX()
  points.edgeTopLeftCp = points.edgeTop.shiftFractionTowards(
    points.topLeft,
    0.5
  )
  points.edgeTopRightCp = points.edgeTopLeftCp.flipX()

  // Round the straps
  const strap = points.edgeTop.dy(points.top)

  points.提示Right = points.edgeTop.translate(strap / 2, strap / 2)
  points.提示RightTop = new Point(points.提示Right.x, points.edgeTop.y)
  points.提示RightBottom = new Point(points.提示Right.x, points.top.y)

  /*
   * Macros will return the auto-generated IDs
   */
  const ids1 = {
    提示RightTop: macro("round", {
      id: "提示RightTop",
      from: points.edgeTop,
      to: points.提示Right,
      via: points.提示RightTop,
      /* Remove this to have the macro
       * only create the points we need
       * and not draw a path
      hide: false
      */
    }),
    提示RightBottom: macro("round", {
      id: "提示RightBottom",
      from: points.提示Right,
      to: points.top,
      via: points.提示RightBottom,
      /* Remove this to have the macro
       * only create the points we need
       * and not draw a path
      hide: false
      */
    })
  }

  /*
   * Create points from them with easy names
   */
  for (const side in ids1) {
    for (const id of ['start', 'cp1', 'cp2', 'end']) {
      points[`${side}${utils.capitalize(id)}`] = points[ids1[side].points[id]].copy()
    }
  }

  /*
   * This is the list of points we need to rotate
   * to move our strap out of the way
   */

  const rotateThese = [
    "edgeTopLeftCp",
    "edgeTop",
    "提示Right",
    "提示RightTop",
    "提示RightTopStart",
    "提示RightTopCp1",
    "提示RightTopCp2",
    "提示RightTopEnd",
    "提示RightBottomStart",
    "提示RightBottomCp1",
    "提示RightBottomCp2",
    "提示RightBottomEnd",
    "提示RightBottom",
    "top",
    "topCp2"
  ]
    /*
     * We're rotating all the points in
     * the `rotateThese` array around
     * the `edgeLeft` point.
     *
     * We're using increments of 1 degree
     * until the `提示RightBottomStart` point
     * is 1 mm beyond the center of our bib.
     */
    while (points.提示RightBottomStart.x > -1) {
      for (const p of rotateThese) points[p] = points[p].rotate(1, points.edgeLeft)
    }

  /* Remove this repetition
  macro("round", {
    from: points.edgeTop,
    to: points.提示Right,
    via: points.提示RightTop,
    prefix: "提示RightTop",
    hide: false,
    class: 'contrast dotted',
  })
  macro("round", {
    from: points.提示Right,
    to: points.top,
    via: points.提示RightBottom,
    prefix: "提示RightBottom",
    hide: false,
    class: 'contrast dotted',
  })

  paths.rect = new Path()
    .move(points.edgeTop)
    .curve(points.edgeTopLeftCp, points.edgeLeftCp, points.edgeLeft)
    .line(points.bottomLeft)
    .line(points.bottomRight)
    .line(points.edgeRight)
    .curve(points.edgeRightCp, points.edgeTopRightCp, points.edgeTop)
    .close()
  */

  // Add points for second strap
  points.edgeTopRightCp = points.edgeTopLeftCp.flipX()
  points.topCp1 = points.topCp2.flipX()
  points.提示LeftTopStart = points.提示RightTopStart.flipX()
  points.提示LeftTopCp1 = points.提示RightTopCp1.flipX()
  points.提示LeftTopCp2 = points.提示RightTopCp2.flipX()
  points.提示LeftTopEnd = points.提示RightTopEnd.flipX()
  points.提示LeftBottomStart = points.提示RightBottomStart.flipX()
  points.提示LeftBottomCp1 = points.提示RightBottomCp1.flipX()
  points.提示LeftBottomCp2 = points.提示RightBottomCp2.flipX()
  points.提示LeftBottomEnd = points.提示RightBottomEnd.flipX()

  // Create one path for the bib outline
  paths.seam = new Path()
    .move(points.edgeLeft)
    .line(points.bottomLeft)
    .line(points.bottomRight)
    .line(points.edgeRight)
    .curve(
      points.edgeRightCp,
      points.edgeTopRightCp,
      points.提示LeftTopStart
    )
    .curve(
      points.提示LeftTopCp1,
      points.提示LeftTopCp2,
      points.提示LeftTopEnd
    )
    .curve(
      points.提示LeftBottomCp1,
      points.提示LeftBottomCp2,
      points.提示LeftBottomEnd
    )
    .curve(
      points.topCp1,
      points.rightCp2,
      points.right
    )
    .curve(
      points.rightCp1,
      points.bottomCp2,
      points.bottom
    )
    .curve(
      points.bottomCp1,
      points.leftCp2,
      points.left
    )
    .curve(
      points.leftCp1,
      points.topCp2,
      points.提示RightBottomEnd
    )
    .curve(
      points.提示RightBottomCp2,
      points.提示RightBottomCp1,
      points.提示RightBottomStart
    )
    .curve(
      points.提示RightTopCp2,
      points.提示RightTopCp1,
      points.提示RightTopStart
    )
    .curve(
      points.edgeTopLeftCp,
      points.edgeLeftCp,
      points.edgeLeft
    )
    .close()
    .addClass("fabric")

  return part
}

预览

透视

It is starting to look good. But this sharp corners at the bottom don't exactly say baby, do they?