City-Lifeline-Cockpit/.scratch/cockpit-real-data-wayfinding/research/fit-pin-path.mjs

// 一次性探针（票 47 DOM overlay 自绘母版）：
// ① 拟合母版下半收尖轮廓（假设=圆弧，检验残差）；② 量镂空版主版的孔洞几何。
// 输出直接嵌进 markerOverlay.js 的手绘 SVG path。
import { readFileSync } from 'node:fs'
import { inflateSync } from 'node:zlib'

function decodePng(path) {
    const buf = readFileSync(path)
    let pos = 8
    const idat = []
    let width = 0, height = 0, colorType = 0, trns = null
    while (pos < buf.length) {
        const len = buf.readUInt32BE(pos)
        const type = buf.toString('ascii', pos + 4, pos + 8)
        const data = buf.subarray(pos + 8, pos + 8 + len)
        if (type === 'IHDR') { width = data.readUInt32BE(0); height = data.readUInt32BE(4); colorType = data[9] }
        else if (type === 'tRNS') trns = Buffer.from(data)
        else if (type === 'IDAT') idat.push(data)
        else if (type === 'IEND') break
        pos += 12 + len
    }
    const channels = colorType === 6 ? 4 : colorType === 2 ? 3 : 1
    const stride = width * channels
    const raw = inflateSync(Buffer.concat(idat))
    const img = Buffer.alloc(height * stride)
    for (let y = 0; y < height; y++) {
        const filter = raw[y * (stride + 1)]
        const row = raw.subarray(y * (stride + 1) + 1, (y + 1) * stride)
        const prev = y > 0 ? img.subarray((y - 1) * stride, y * stride) : null
        const out = img.subarray(y * stride, (y + 1) * stride)
        for (let x = 0; x < stride; x++) {
            const a = x >= channels ? out[x - channels] : 0
            const b = prev ? prev[x] : 0
            const c = prev && x >= channels ? prev[x - channels] : 0
            let v = row[x]
            if (filter === 1) v += a
            else if (filter === 2) v += b
            else if (filter === 3) v += (a + b) >> 1
            else if (filter === 4) {
                const p = a + b - c
                const pa = Math.abs(p - a), pb = Math.abs(p - b), pc = Math.abs(p - c)
                v += pa <= pb && pa <= pc ? a : pb <= pc ? b : c
            }
            out[x] = v & 0xff
        }
    }
    const alphaAt = (x, y) => {
        if (colorType === 6) return img[y * stride + x * 4 + 3]
        if (colorType === 2) return 255
        const idx = img[y * stride + x]
        if (trns && idx < trns.length) return trns[idx]
        return 255
    }
    return { width, height, alphaAt }
}

const MINX = 67, MAXX = 444, MINY = 19, MAXY = 493
// 帽圆（实测）：圆心 (255.5, 208)，半径 189 —— 与 MASTER_GEOMETRY capCenter(0.499,0.397) 一致
const CAP = { cx: 255.5, cy: 208, r: 189 }

const file = process.argv[2] || 'public/cockpit/assets/icons/T_MarkPoint_WhiteFull.png'
const { alphaAt } = decodePng(file)
const edge = (y) => {
    for (let x = MINX; x <= MAXX; x++) if (alphaAt(x, y) > 8) return x
    return null
}

// ---- ① 下半段左缘采样 + 圆拟合 ----
const pts = []
for (let y = 380; y <= 490; y += 5) {
    const x = edge(y)
    if (x != null) pts.push([x, y])
}
function fitCircle(points) {
    const n = points.length
    let suu = 0, suv = 0, su = 0, svv = 0, sv = 0, suw = 0, svw = 0, sw = 0
    for (const [u, v] of points) {
        const w = u * u + v * v
        suu += u * u; suv += u * v; su += u; svv += v * v; sv += v
        suw += w * u; svw += w * v; sw += w
    }
    const A = [[suu, suv, su], [suv, svv, sv], [su, sv, n]]
    const b = [suw, svw, sw]
    for (let i = 0; i < 3; i++) {
        let p = i
        for (let k = i + 1; k < 3; k++) if (Math.abs(A[k][i]) > Math.abs(A[p][i])) p = k
        ;[A[i], A[p]] = [A[p], A[i]]; [b[i], b[p]] = [b[p], b[i]]
        for (let k = i + 1; k < 3; k++) {
            const f = A[k][i] / A[i][i]
            for (let j = i; j < 3; j++) A[k][j] -= f * A[i][j]
            b[k] -= f * b[i]
        }
    }
    const z = [0, 0, 0]
    for (let i = 2; i >= 0; i--) {
        z[i] = b[i]
        for (let j = i + 1; j < 3; j++) z[i] -= A[i][j] * z[j]
        z[i] /= A[i][i]
    }
    const [D, E, F] = z
    return { cx: -D / 2, cy: -E / 2, r: Math.sqrt((D * D) / 4 + (E * E) / 4 - F) }
}
const fit = fitCircle(pts)
let maxRes = 0
for (const [x, y] of pts) maxRes = Math.max(maxRes, Math.abs(Math.hypot(x - fit.cx, y - fit.cy) - fit.r))
console.log(`下半段圆弧拟合：圆心 (${fit.cx.toFixed(1)}, ${fit.cy.toFixed(1)}) 半径 ${fit.r.toFixed(1)}，最大残差 ${maxRes.toFixed(2)}px`)
const tip = { x: 255.5, y: 493 }
const dTip = Math.hypot(tip.x - fit.cx, tip.y - fit.cy)
console.log(`尖端到拟合圆心距离 ${dTip.toFixed(1)} vs 半径 ${fit.r.toFixed(1)}（差 ${(dTip - fit.r).toFixed(1)}px → ${Math.abs(dTip - fit.r) < 2 ? '尖端在圆上，A 命令直达' : '尖端不在圆上'}）`)
// 帽圆 ∩ 拟合圆 交点
const dx = fit.cx - CAP.cx, dy = fit.cy - CAP.cy, d = Math.hypot(dx, dy)
const a = (CAP.r * CAP.r - fit.r * fit.r + d * d) / (2 * d)
const h = Math.sqrt(Math.max(0, CAP.r * CAP.r - a * a))
const mx = CAP.cx + (a * dx) / d, my = CAP.cy + (a * dy) / d
console.log(`帽圆∩拟合圆：(${(mx + (h * dy) / d).toFixed(1)}, ${(my - (h * dx) / d).toFixed(1)}) / (${(mx - (h * dy) / d).toFixed(1)}, ${(my + (h * dx) / d).toFixed(1)})`)

// ---- ② 镂空版孔洞几何 ----
const hollow = decodePng('public/cockpit/assets/icons/T_MarkPoint_White.png')
const rowGaps = (y) => {
    const gaps = []
    let start = -1
    for (let x = MINX; x <= MAXX; x++) {
        const al = hollow.alphaAt(x, y)
        if (al <= 8 && start < 0) start = x
        if (al > 8 && start >= 0) { gaps.push([start, x - 1]); start = -1 }
    }
    if (start >= 0) gaps.push([start, MAXX])
    return gaps
}
const colGaps = () => {
    const gaps = []
    let start = -1
    for (let y = MINY; y <= MAXY; y++) {
        const al = hollow.alphaAt(256, y)
        if (al <= 8 && start < 0) start = y
        if (al > 8 && start >= 0) { gaps.push([start, y - 1]); start = -1 }
    }
    if (start >= 0) gaps.push([start, MAXY])
    return gaps
}
console.log('\n镂空版 y=208 透明段:', JSON.stringify(rowGaps(208)))
console.log('镂空版 y=190 透明段:', JSON.stringify(rowGaps(190)))
console.log('镂空版 x=256 透明段:', JSON.stringify(colGaps()))