@freesewing/brian/src/back.mjs

A FreeSewing pattern for a basic body block for menswear

import * as shared from './shared.mjs'
import { base } from './base.mjs'

export const back = {
  from: base,
  name: 'brian.back',
  draft: ({
    store,
    sa,
    points,
    Path,
    paths,
    Snippet,
    snippets,
    complete,
    macro,
    options,
    utils,
    part,
  }) => {
    points.anchor = points.hps.clone()

    // Adapt the shoulder seam according to the relevant options
    // Note: s3 stands for Shoulder Seam Shift
    // Don't bother with less than 10% as that's just asking for trouble
    if (options.s3Collar < 0.1 && options.s3Collar > -0.1) {
      points.s3CollarSplit = points.hps
      paths.backCollar = new Path().move(points.hps).curve_(points.neckCp2, points.cbNeck).hide()
    } else if (options.s3Collar > 0) {
      // Shift shoulder seam forward on the collar side
      points.s3CollarSplit = utils.curveIntersectsY(
        points.hps,
        points.mirroredNeckCp2Front,
        points.mirroredCfNeckCp1,
        points.mirroredCfNeck,
        store.get('s3CollarMaxFront') * -1 * options.s3Collar
      )
      paths.backCollar = new Path()
        .move(points.hps)
        ._curve(points.mirroredNeckCp2Front, points.mirroredCfNeckCp1, points.mirroredCfNeck)
        .split(points.s3CollarSplit)[0]
        .reverse()
        .join(new Path().move(points.hps).curve_(points.neckCp2, points.cbNeck))
        .hide()
    } else if (options.s3Collar < 0) {
      // Shift shoulder seam backward on the collar side
      points.s3CollarSplit = utils.curveIntersectsY(
        points.hps,
        points.neckCp2,
        points.cbNeck,
        points.cbNeck,
        store.get('s3CollarMaxBack') * -1 * options.s3Collar
      )
      paths.backCollar = new Path()
        .move(points.cbNeck)
        ._curve(points.neckCp2, points.neck)
        .split(points.s3CollarSplit)[0]
        .reverse()
        .hide()
    }
    // Don't bother with less than 10% as that's just asking for trouble
    if (options.s3Armhole < 0.1 && options.s3Armhole > -0.1) {
      points.s3ArmholeSplit = points.shoulder
      paths.backArmhole = new Path()
        .move(points.armholePitch)
        .curve(points.armholePitchCp2, points.shoulderCp1, points.shoulder)
        .hide()
    } else if (options.s3Armhole > 0) {
      // Shift shoulder seam forward on the armhole side
      points.s3ArmholeSplit = utils.curveIntersectsY(
        points.shoulder,
        points.mirroredShoulderCp1,
        points.mirroredFrontArmholePitchCp2,
        points.mirroredFrontArmholePitch,
        store.get('s3ArmholeMax') * -1 * options.s3Armhole + points.shoulder.y
      )
      paths.backArmhole = new Path()
        .move(points.armholePitch)
        .curve(points.armholePitchCp2, points.shoulderCp1, points.shoulder)
        .join(
          new Path()
            .move(points.shoulder)
            .curve(
              points.mirroredShoulderCp1,
              points.mirroredFrontArmholePitchCp2,
              points.mirroredFrontArmholePitch
            )
            .split(points.s3ArmholeSplit)[0]
        )
        .hide()
    } else if (options.s3Armhole < 0) {
      // Shift shoulder seam backward on the armhole side
      points.s3ArmholeSplit = utils.curveIntersectsY(
        points.shoulder,
        points.shoulderCp1,
        points.armholePitchCp2,
        points.armholePitch,
        store.get('s3ArmholeMax') * -1 * options.s3Armhole + points.shoulder.y
      )
      paths.backArmhole = new Path()
        .move(points.armholePitch)
        .curve(points.armholePitchCp2, points.shoulderCp1, points.shoulder)
        .split(points.s3ArmholeSplit)[0]
        .hide()
    }

    // Seamline
    paths.saBase = new Path()
      .move(points.cbHem)
      .line(points.hem)
      .line(points.armhole)
      .curve(points.armholeCp2, points.armholeHollowCp1, points.armholeHollow)
      .curve(points.armholeHollowCp2, points.armholePitchCp1, points.armholePitch)
      .join(paths.backArmhole)
      .line(points.s3CollarSplit)
      .join(paths.backCollar)
      .hide()
    paths.seam = new Path()
      .move(points.cbNeck)
      .line(points.cbHips)
      .join(paths.saBase)
      .attr('class', 'fabric')

    // Store lengths to fit sleeve
    store.set('backArmholeLength', shared.armholeLength(points, Path))
    store.set('backArmholeToArmholePitch', shared.armholeToArmholePitch(points, Path))

    if (sa) {
      paths.sa = paths.saBase
        .offset(sa)
        .attr('class', 'fabric sa')
        .line(points.cbNeck)
        .move(points.cbHips)
      paths.sa.line(paths.sa.start())
    }

    /*
     * Annotations
     */

    // Cut on fold
    macro('cutonfold', {
      from: points.cbNeck,
      to: points.cbHips,
      grainline: true,
    })

    // Cut list
    store.cutlist.addCut({ cut: 1, from: 'fabric', onFold: true })

    // Title
    macro('title', { at: points.title, nr: 2, title: 'back' })

    // Notches
    snippets.armholePitchNotch = new Snippet('bnotch', points.armholePitch)

    // Waist line
    if (complete)
      paths.waist = new Path().move(points.cbWaist).line(points.waist).attr('class', 'help')

    // Add notches if the shoulder seam is shifted
    shared.s3Notches(snippets, Snippet, points, options, 'bnotch')

    // Dimensions
    shared.dimensions(part, 'back')

    macro('hd', {
      id: 'wHem',
      from: points.cbHips,
      to: points.hips,
      y: points.hem.y + sa + 15,
    })
    macro('vd', {
      id: 'hHemToWaist',
      from: points.cbHem,
      to: points.cbWaist,
      x: points.cbHips.x - 15,
    })
    macro('vd', {
      id: 'hHemToNeckOpeningBottom',
      from: points.cbHem,
      to: points.cbNeck,
      x: points.cbHips.x - 30,
    })
    macro('hd', {
      id: 'wCFrontToHps',
      from: points.cbNeck,
      to: points.s3CollarSplit,
      y: points.s3CollarSplit.y - sa - 15,
    })
    macro('hd', {
      id: 'lShoulder',
      from: points.cbNeck,
      to: points.s3ArmholeSplit,
      y: points.s3CollarSplit.y - sa - 30,
    })

    return part
  },
}