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+/**
+ * The face artwork: everything that used to be a hand-drawn PNG in GIMP is now
+ * drawn from parameters onto a canvas, which is then used as the texture of the
+ * two overlay planes that already exist on the model.
+ *
+ * The plates have a linear UV mapping fitted to the original artwork, so drawing
+ * in "texture pixels" lands exactly where the original artwork did. Every constant
+ * below was measured from the original textures (see README for the numbers), so
+ * the defaults reproduce the 2022 artwork while every part of it stays editable.
+ *
+ * Texture space: the artwork WINDOW, 1024 x 380, origin at the top-left, y grows
+ * downwards. `canvasLayout` then says where that window sits on the bigger canvas
+ * a face plate actually needs (see below), and `Face` hands the bounds back as
+ * `limits`, so the drawing can clamp against the real edge instead of assuming
+ * the window is all there is.
+ *
+ * glTF stores v downwards too, and the textures are uploaded with flipY = false,
+ * so no flipping is needed anywhere.
+ */
+
+const TAU = Math.PI * 2;
+const clamp = (v, lo, hi) => Math.min(hi, Math.max(lo, v));
+const HUGE = 4000;
+
+/**
+ * The artwork window: the rectangle the 2022 hand-drawn textures occupied. Every
+ * constant below is written in this space.
+ */
+export const ART_WINDOW = { width: 1024, height: 380 };
+
+/** Keep this much clear at the canvas border, so filtering has room to breathe. */
+const EDGE_MARGIN = 8;
+
+/** What a drawing falls back to when no plate bounds are supplied. */
+const WINDOW_LIMITS = {
+ top: 0, bottom: ART_WINDOW.height, left: 0, right: ART_WINDOW.width,
+};
+
+/**
+ * The canvas a face plate's drawing needs, and where the artwork window sits on it.
+ *
+ * WHY: the plates are the *whole* front half of the body, so their UVs run far
+ * outside the 0..1 the artwork was drawn in (measured on the shipped model: the
+ * eye plate covers v -1.02..1.93, and 9 of 10 of its vertices sit within a
+ * twentieth of the border). Everything outside 0..1 used to clamp to the canvas
+ * edge row, so the moment a drawing reached the border - a tear dropped low, a
+ * brow lifted, a thick mouth pushed down - that edge row was copied across the
+ * rest of the plate and the mark stretched into a long smear.
+ *
+ * `Face` rewrites each plate's UVs so this range maps onto 0..1 instead, which
+ * removes the clamp altogether. The map is affine, so the artwork keeps its exact
+ * pixel size and position and merely shifts by `offset`; the canvas grows by the
+ * same factor, and those extra rows are the room a moved tear, brow or mouth
+ * needs (`limits` says where the real edge now is, in window coordinates).
+ *
+ * @param {{u0:number,u1:number,v0:number,v1:number}} range the plate's UV range
+ * @param {{width:number,height:number}} [window] the artwork window
+ */
+export function canvasLayout(range, window = ART_WINDOW) {
+ const u0 = Number.isFinite(range?.u0) ? range.u0 : 0;
+ const u1 = Number.isFinite(range?.u1) ? range.u1 : 1;
+ const v0 = Number.isFinite(range?.v0) ? range.v0 : 0;
+ const v1 = Number.isFinite(range?.v1) ? range.v1 : 1;
+ const du = Math.max(1e-6, u1 - u0);
+ const dv = Math.max(1e-6, v1 - v0);
+ const width = Math.max(1, Math.round(window.width * du));
+ const height = Math.max(1, Math.round(window.height * dv));
+ // `+ 0` turns a `-0` into a plain `0`, so the offsets compare cleanly.
+ const offsetX = Math.round(-u0 * window.width) + 0;
+ const offsetY = Math.round(-v0 * window.height) + 0;
+ return {
+ width,
+ height,
+ offsetX,
+ offsetY,
+ window,
+ // The canvas edges in the artwork's own coordinates. `top` is negative when
+ // the plate reaches above the window: that is the extra room.
+ limits: {
+ top: -offsetY + 0,
+ bottom: height - offsetY,
+ left: -offsetX + 0,
+ right: width - offsetX,
+ },
+ };
+}
+
+/** Fixed layout of the eye plane, measured from the original `eyes-open.png`. */
+export const EYE_LAYOUT = {
+ radius: 84,
+ irisRadius: 62.5,
+ highlightRadius: 28,
+ highlightOffset: { x: 29.5, y: -18 },
+ // The model's left eye (its own left, +x) sits in the u > 0.5 half.
+ eyes: [
+ { key: 'right', cx: 267.5, cy: 240, towardNose: 1 },
+ { key: 'left', cx: 755.5, cy: 240, towardNose: -1 },
+ ],
+ lidRadiusFactor: 1.35,
+ lidStroke: 14,
+ // Eyebrows are painted into the same texture as the eyes. The eye plane is a
+ // flat-ish patch on a round head, so only its lower part is really outside
+ // the head: a brow high on the forehead would be swallowed by it. The brow
+ // therefore sits just above the eyeball (row 156) and the eyeball is drawn
+ // over its lower edge afterwards.
+ // The brow sits just above the eyeball, and the eyeball is drawn over its
+ // lower edge. `lift` is that resting height, so `height: 0` is the brow's
+ // natural place and a POSITIVE height raises it (a negative one sinks it
+ // towards the eye, where the eyeball will cover it).
+ brow: { lift: 114, length: 134, thickness: 15, curve: 0.14, offsetX: 6 },
+ // A teardrop hangs well below the eye. The plate keeps the whole canvas, so
+ // the drop can sit low without being clipped (measured with a ruler grid).
+ tear: { size: 34, offsetX: 66, offsetY: 88 },
+ closedLine: {
+ // The single shut line is the *long* form of the eyelid, the same reach as
+ // the arms of the "ぎゅっ" below, so switching between 1 and 3 lines does not
+ // change how wide the eye reads.
+ length: 205,
+ offsetX: 6,
+ offsetY: -10,
+ slantDeg: 3.9,
+ bow: 3,
+ // 2- and 3-line shut eyes, copied from the original `eyes-close-tight`
+ // artwork: three strokes sharing one vertex that points at the nose, opening
+ // to a wide bird's foot / arrow shape. `spread` is half the height the arms
+ // open to at the far end.
+ armSpan: 205,
+ spread: 62,
+ vertex: 87.5,
+ armX: 104,
+ },
+ arch: { edgesUp: 8, apexUp: 44 },
+ // まつげ: a few strokes flicking out from the upper-outer lid (see drawEyes).
+ // `raise` lifts them a touch above the lid edge (2% of the lid slider).
+ lash: { length: 30, width: 8, angles: [46, 66, 86], raise: 0.04 },
+ // "ふつう"の目の瞳を、両目とも少し鼻側に寄せてかわいく見せる(px)。
+ irisInward: 7,
+};
+
+/**
+ * ほっぺ (a manga blush) and 頭の模様 (a mark on the head), both drawn into the eye
+ * plate next to the eyes and brows.
+ *
+ * They are deliberately *generic* manga devices, not a copy of any one character:
+ * a pink patch crossed by short diagonal strokes is a stock convention, and the
+ * head mark is one of a few simple shapes (a hook, a spiral, three strokes, a dot
+ * row) that starts off. Both stay editable through the panel. The cheek positions
+ * are tied to `EYE_LAYOUT` so they sit beside the eyes; the head mark sits up in
+ * the plate's upper area, i.e. on the forehead above the brows.
+ */
+export const CHEEK_LAYOUT = {
+ drop: 64, // how far below the eye centre the patch sits (artwork px)
+ outward: 66, // how far outwards, away from the midline, it sits
+ radius: 50, // half-width of the patch
+ squash: 0.55, // half-height, as a fraction of the half-width (a flat ellipse)
+ // The blush is *always* four strokes - the reference artwork has four - so
+ // there is no line-count control any more. The strokes are horizontal and
+ // hand-drawn: each wobbles a little and tapers to a point at both ends.
+ lines: 4,
+ lineWidth: 10, // the stroke thickness at its widest (artwork px)
+ spread: 0.62, // how far the outermost stroke sits from the centre (x half-height)
+ margin: 0.18, // clear gap left between a stroke's end and the patch outline
+ wobble: 0.32, // sideways wander, as a fraction of the stroke thickness
+};
+
+/**
+ * 頭の模様: a *hair-like covering* over the whole head, not a small forehead symbol.
+ *
+ * The face plate is a shell of the *whole* front half of the body, so the plate's
+ * own edge is the head's front silhouette. Filling the plate from its top edge
+ * down to an adjustable boundary therefore makes the covering's outline follow
+ * the silhouette for free - there is no separate ellipse to keep in step.
+ *
+ * It is a generic device: a colour cap, a fringe, a side part, or a left/right
+ * two-tone split. It is deliberately *not* a copy of any one character's hair.
+ * It starts off.
+ */
+export const HEAD_MARK_LAYOUT = {
+ // Where the boundary sits by default: on the forehead, just above the brows
+ // (EYE_LAYOUT.eyes[0].cy is the eye row and the brows reach ~114px above it).
+ cy: 120,
+ reach: 190, // artwork px the boundary moves per unit of `size`
+};
+
+/**
+ * 頭の模様 on the *hair plate*: the head's cover when the model carries a plate
+ * that wraps all the way round (material `hair-plate`, cylindrical UV).
+ *
+ * The front plate only reaches the head's silhouette, so hair drawn on it stops
+ * at the front half. The hair plate's UV is `u` = angle round the head (front at
+ * 0.5, back at the seam 0/1) and `v` = height (0 at the model's feet, 1 at the
+ * top of the head), so the covering is everything *above* a boundary line: a cap
+ * that is visible from behind as well.
+ */
+export const HAIR_WRAP_LAYOUT = {
+ // The wrap's v runs top-of-head (0) to the model's feet (1) after the GLB's
+ // V-flip, so `base` is how far down from the top the hairline sits at size 1.
+ // `reach` is how much a unit of `size` moves it; `offsetScale` converts the
+ // `offsetY` slider (artwork px) to the same units, so one slider drives both.
+ base: 0.30,
+ reach: 0.30,
+ offsetScale: 0.30 / 190,
+};
+
+/**
+ * ひげ: the mustaches and beards that hang under the nose. Drawn on the eye plate
+ * at the nose, the same spot the snot bubble uses. `shape` picks a well-known
+ * kind; `size` scales it about the nose, and the colours are adjustable.
+ */
+export const BEARD_LAYOUT = {
+ cx: 511.5,
+ cy: 352, // just under the nose
+ width: 240, // base width of the widest beard at size 1
+};
+
+/**
+ * 眼鏡 / サングラス, drawn into the same texture as the eyes and brows.
+ *
+ * Not measured off any artwork - the character has no glasses - but the numbers
+ * are tied to the eyeball so a lens is always a little wider than the eye it
+ * covers. The lens centre sits *below* the eye centre because the brow is drawn
+ * first, just above the eyeball (see `EYE_LAYOUT.brow`): a lens wide enough to
+ * read as glasses would otherwise cut straight through it.
+ *
+ * The two kinds get separate shapes on purpose. They used to share one ellipse
+ * and differ only in how dark the lens was filled, which made them hard to tell
+ * apart; the round 眼鏡 below and the wide, angular サングラス in
+ * `SUNGLASSES_LAYOUT` now read as different objects at a glance.
+ */
+const GLASSES_LAYOUT = {
+ widthFactor: 1.08, // lens half-width, as a multiple of the eyeball radius
+ heightFactor: 1.0, // a circle, so the round 眼鏡 stays round (a flatter
+ // ellipse used to drift towards the shades below)
+ drop: 20, // the lens centre hangs this far below the eye centre (artwork px)
+ bridgeRise: 8, // how much the bridge arcs up over the nose
+ bridgeWidth: 0.75, // bridge thickness, as a fraction of the frame stroke
+ templeLength: 1.5, // temple stub length, as a multiple of the eyeball radius
+ templeRise: 30, // how far the temple climbs towards the side of the head
+};
+
+/**
+ * サングラス: a long, pointed cat-eye rather than the round 眼鏡 lens. Each side is a
+ * slim wedge whose *outer end starts low*, rises to a *high, pointed outer corner*
+ * set further out (`tipX`), and whose top edge then sweeps back down towards the
+ * nose - the "外側が長くとがって上に上がる" shape the reference shows. The inner end is
+ * short, so the lens tapers inwards. The eye is allowed to poke out above and
+ * below it, so the lens no longer has to cover the whole eyeball. A level bar
+ * joins the two inner ends, so the pair still reads as one dark visor. The ratios
+ * are of the eyeball radius, exactly like `GLASSES_LAYOUT`, so `scale` means the
+ * same thing for both kinds.
+ */
+const SUNGLASSES_LAYOUT = {
+ widthFactor: 1.6, // a long lens: the outer end reaches well past the eyeball
+ heightFactor: 0.58, // slim, so the eye is free to show above and below it
+ drop: 8, // sits a little lower than the round pair
+ corner: 0.05, // corner rounding, as a fraction of the half-height; kept
+ // tiny so the outer corner stays pointed
+ topSkew: 1.0, // the pointed corner rises this far above the lens top (x half-height)
+ innerTop: 0.42, // the inner top is low, which is what makes the top edge climb
+ innerBottom: 0.34, // the inner bottom is pinched up towards the nose (x half-height)
+ outerEndX: 0.75, // the low outer end sits this far out (x half-width)
+ outerBottom: 0.82, // ...and this deep (x half-height)
+ tipX: 1.22, // the pointed corner juts this far out (x half-width)
+ bridgeWidth: 1.15, // a short, thick bar - thicker than the frame stroke
+ bridgeLift: 0.25, // the bar sits this far above the lens centre (x half-height)
+ templeLength: 1.15, // a short stub, like the round pair's but a little shorter
+ templeRise: 24,
+ // A heavy rim. It used to be slimmer than the round pair's stroke, which read
+ // as a thin pair of shades; the reference look is a chunky frame.
+ frameFactor: 1.6,
+};
+
+/** The mouth artwork is drawn on the `mouth-plate` shell, which covers the whole
+ * 1024 x 380 canvas (see tools/build-face-plates.py), so the drawing no longer
+ * has to be squeezed into a band. The only limit left is the canvas itself. */
+export const MOUTH_LAYOUT = {
+ centreX: 511.5,
+ chordY: 88,
+ halfChord: 420.5,
+ sag: 177,
+ // With the ends and the depth both fixed - which is what the slider promises -
+ // the only thing left to choose about the curve is *where* it bends. 1/3 is a
+ // quadratic Bézier (a parabola): it is flattest at the apex and falls away
+ // fastest near the ends. Pulling the cubic's control points in towards the ends
+ // makes the middle of the smile straighter still and lets the fall happen near
+ // the corners, which is what reads as a *gentler* curve at the same depth.
+ sagBend: 0.2,
+ thickness: 21,
+ // How big the round "O" oval gets at `round: 1`, as a multiple of the smile's
+ // own sag. The oval's size comes from this and `round` alone: `thickness` is
+ // only the stroke weight, so 口の太さ and 丸く開く no longer move together.
+ roundScale: 1.3,
+ // Kept for reference: the 2022 plane only showed these rows.
+ bandTop: 46,
+ bandBottom: 332,
+ // Only used to cap the *size* of the round "O" mouth, so the surprise face
+ // stays a mouth and not a hole. The mouth's travel no longer stops here: the
+ // drawing is given the plate's real edges through `limits`.
+ safeBottom: 372,
+ // The nose is a separate mesh that pokes out in front of the plate. The plate
+ // is depth tested, so the nose hides whatever is drawn behind it - but a frown
+ // arcs *up* into that hiding place, so slide the mouth down until the middle
+ // of the arc clears the nose. Only the middle is checked: a smile curves away
+ // from the nose, and checking its ends instead is what used to pin the whole
+ // mouth in place and make the height slider do nothing.
+ noseClear: 132,
+ // The original hand-drawn mouth is a *shallow* arc with tall corner strokes
+ // flicking up at the ends (measured from the artwork: the arc's own sag is
+ // ~0.13 of its chord, while the corners reach ~90px above it). Keeping that
+ // split is what makes `smile: 1` read as the original; making the arc itself
+ // deep instead looked too steep.
+ //
+ // The tongue rises from the lip line to a rounded top just above the corner
+ // strokes. Measured off the original: its crown is a *super-ellipse* -
+ // `rise = height * (1 - |dx/half|^2.5)` - so it is steep-sided with a smooth,
+ // almost flat top. It is convex upwards, but it is **not** a point.
+ tongue: { pos: 0.84, width: 126, height: 115, crown: 2.5 },
+ corner: { fromX: 26, fromY: 3, toX: 32, toY: 42, width: 11, curve: 26 },
+ openRise: 64,
+ // Was 0.25: opening the mouth used to flatten the smile to stay inside the
+ // texture band. There is no band to stay inside now.
+ openFlatten: 0,
+};
+
+/* ------------------------------------------------------------------ helpers */
+
+function circlePath(ctx, cx, cy, r) {
+ ctx.beginPath();
+ ctx.arc(cx, cy, r, 0, TAU);
+ ctx.closePath();
+}
+
+function fillCircle(ctx, cx, cy, r, color) {
+ circlePath(ctx, cx, cy, r);
+ ctx.fillStyle = color;
+ ctx.fill();
+}
+
+/**
+ * A heart, used for the "love" eyes. The path is wider than it is tall, which
+ * is what makes it read as a heart rather than a blob at small sizes.
+ */
+function heartPath(ctx, cx, cy, r) {
+ ctx.beginPath();
+ ctx.moveTo(cx, cy + r * 0.80);
+ ctx.bezierCurveTo(cx - r * 1.24, cy - r * 0.34, cx - r * 0.50, cy - r * 1.18, cx, cy - r * 0.40);
+ ctx.bezierCurveTo(cx + r * 0.50, cy - r * 1.18, cx + r * 1.24, cy - r * 0.34, cx, cy + r * 0.80);
+ ctx.closePath();
+}
+
+function fillHeart(ctx, cx, cy, r, color) {
+ heartPath(ctx, cx, cy, r);
+ ctx.fillStyle = color;
+ ctx.fill();
+}
+
+/** A teardrop, used by the crying expression. */
+function dropPath(ctx, cx, cy, size) {
+ ctx.beginPath();
+ ctx.moveTo(cx, cy - size * 1.32);
+ ctx.bezierCurveTo(cx + size * 0.95, cy - size * 0.34, cx + size * 0.95, cy + size * 0.78, cx, cy + size * 0.78);
+ ctx.bezierCurveTo(cx - size * 0.95, cy + size * 0.78, cx - size * 0.95, cy - size * 0.34, cx, cy - size * 1.32);
+ ctx.closePath();
+}
+
+function strokeCircle(ctx, cx, cy, r, color, width) {
+ circlePath(ctx, cx, cy, r);
+ ctx.strokeStyle = color;
+ ctx.lineWidth = width;
+ ctx.stroke();
+}
+
+function tracePolyline(ctx, points, closed) {
+ if (!points.length) return;
+ ctx.beginPath();
+ ctx.moveTo(points[0].x, points[0].y);
+ for (let i = 1; i < points.length; i++) ctx.lineTo(points[i].x, points[i].y);
+ if (closed) ctx.closePath();
+}
+
+function strokePolyline(ctx, points, { color, width, closed = false }) {
+ if (points.length < 2) return;
+ ctx.save();
+ ctx.strokeStyle = color;
+ ctx.lineWidth = width;
+ ctx.lineJoin = 'round';
+ ctx.lineCap = 'round';
+ tracePolyline(ctx, points, closed);
+ ctx.stroke();
+ ctx.restore();
+}
+
+function fillPolygon(ctx, points, color) {
+ if (points.length < 3) return;
+ ctx.save();
+ ctx.fillStyle = color;
+ tracePolyline(ctx, points, true);
+ ctx.fill();
+ ctx.restore();
+}
+
+/**
+ * Trace a closed polygon with rounded corners. Used for the squarish
+ * サングラス lens: an ellipse cannot be angular, and a plain polygon has cusps.
+ * Each corner is cut back by `radius` (clamped so short edges cannot overlap)
+ * and joined with a quadratic through the original vertex.
+ */
+function traceRoundedPolygon(ctx, points, radius) {
+ const n = points.length;
+ ctx.beginPath();
+ for (let i = 0; i < n; i++) {
+ const prev = points[(i + n - 1) % n];
+ const cur = points[i];
+ const next = points[(i + 1) % n];
+ const inLen = Math.hypot(cur.x - prev.x, cur.y - prev.y) || 1;
+ const outLen = Math.hypot(next.x - cur.x, next.y - cur.y) || 1;
+ const cut = Math.min(radius, inLen / 2, outLen / 2);
+ const from = { x: cur.x + ((prev.x - cur.x) / inLen) * cut, y: cur.y + ((prev.y - cur.y) / inLen) * cut };
+ const to = { x: cur.x + ((next.x - cur.x) / outLen) * cut, y: cur.y + ((next.y - cur.y) / outLen) * cut };
+ if (i === 0) ctx.moveTo(from.x, from.y);
+ else ctx.lineTo(from.x, from.y);
+ ctx.quadraticCurveTo(cur.x, cur.y, to.x, to.y);
+ }
+ ctx.closePath();
+}
+
+/** Points along a quadratic Bézier, `steps` segments (steps + 1 points). */
+function quadraticPoints(p0, p1, p2, steps) {
+ const out = [];
+ for (let i = 0; i <= steps; i++) {
+ const t = i / steps;
+ const u = 1 - t;
+ out.push({
+ x: u * u * p0.x + 2 * u * t * p1.x + t * t * p2.x,
+ y: u * u * p0.y + 2 * u * t * p1.y + t * t * p2.y,
+ });
+ }
+ return out;
+}
+
+/** A point on a cubic Bézier. */
+function cubicPoint(p0, p1, p2, p3, t) {
+ const u = 1 - t;
+ const a = u * u * u;
+ const b = 3 * u * u * t;
+ const c = 3 * u * t * t;
+ const d = t * t * t;
+ return {
+ x: a * p0.x + b * p1.x + c * p2.x + d * p3.x,
+ y: a * p0.y + b * p1.y + c * p2.y + d * p3.y,
+ };
+}
+
+/** Points along a cubic Bézier, `steps` segments (steps + 1 points). */
+function cubicPoints(p0, p1, p2, p3, steps) {
+ const out = [];
+ for (let i = 0; i <= steps; i++) out.push(cubicPoint(p0, p1, p2, p3, i / steps));
+ return out;
+}
+
+/**
+ * The four control points of the mouth's centreline: the same two ends, the same
+ * depth, but `bend` decides where the curve actually bends (see `sagBend`).
+ */
+function mouthControls(left, right, sag, bend) {
+ const width = right.x - left.x;
+ const y = left.y + (4 / 3) * sag;
+ return {
+ p0: left,
+ p1: { x: left.x + width * bend, y },
+ p2: { x: right.x - width * bend, y },
+ p3: right,
+ };
+}
+
+function rotate(points, pivot, degrees) {
+ if (!degrees) return points;
+ const a = (degrees * Math.PI) / 180;
+ const cos = Math.cos(a);
+ const sin = Math.sin(a);
+ return points.map((p) => {
+ const dx = p.x - pivot.x;
+ const dy = p.y - pivot.y;
+ return { x: pivot.x + dx * cos - dy * sin, y: pivot.y + dx * sin + dy * cos };
+ });
+}
+
+/* --------------------------------------------------------------------- eyes */
+
+/**
+ * Intersect the canvas clip with the eyeball disc and the (possibly closed)
+ * lids. Because the overlay plane is transparent and sits in front of the face,
+ * clipping is all that is needed: whatever is clipped away shows the real
+ * shaded face behind it. That is what makes the eyelid blend perfectly without
+ * baking a face-coloured background into the texture.
+ */
+/** Clip to the upper and lower lids only, without the eyeball circle. */
+function clipLids(ctx, eye, open, lowerLid, flat = false, tiltDeg = 0) {
+ const tilt = (clamp(tiltDeg, -45, 45) * Math.PI) / 180;
+ const rotated = Math.abs(tilt) > 1e-4;
+ const spin = () => {
+ ctx.translate(eye.cx, eye.cy);
+ ctx.rotate(tilt);
+ ctx.translate(-eye.cx, -eye.cy);
+ };
+ if (rotated) spin();
+
+ const lower = clamp(lowerLid, 0, 1);
+ // The upper and lower lids are independent: 上まぶたの高さ sets where the upper
+ // lid sits on its own, so raising 下まぶたの高さ does not drag the upper lid
+ // down with it. A blink still shuts the eye because `open` reaching 0 (or the
+ // upper lid dropping to the lower one) hands over to the shut-eye drawing
+ // before this clip is used.
+ const upper = 1 - clamp(open, 0, 1);
+ if (upper > 0.0005) {
+ const rl = eye.r * EYE_LAYOUT.lidRadiusFactor;
+ const lowest = eye.cy - eye.r + 2 * eye.r * upper;
+ ctx.beginPath();
+ if (flat) {
+ // A flat lid: a straight edge straight across the eye.
+ ctx.rect(eye.cx - HUGE, lowest, HUGE * 2, HUGE);
+ } else {
+ const cy = lowest - rl;
+ ctx.moveTo(eye.cx - HUGE, cy);
+ ctx.lineTo(eye.cx - rl, cy);
+ ctx.arc(eye.cx, cy, rl, Math.PI, 0, true); // lower semicircle: bulges down
+ ctx.lineTo(eye.cx + HUGE, cy);
+ ctx.lineTo(eye.cx + HUGE, cy + HUGE);
+ ctx.lineTo(eye.cx - HUGE, cy + HUGE);
+ }
+ ctx.closePath();
+ ctx.clip();
+ }
+
+ const bottom = lower;
+ if (bottom > 0.0005) {
+ const rl = eye.r * EYE_LAYOUT.lidRadiusFactor;
+ const highest = eye.cy + eye.r - 2 * eye.r * bottom;
+ ctx.beginPath();
+ if (flat) {
+ ctx.rect(eye.cx - HUGE, highest - HUGE, HUGE * 2, HUGE);
+ } else {
+ const cy = highest + rl;
+ ctx.moveTo(eye.cx - HUGE, cy);
+ ctx.lineTo(eye.cx - rl, cy);
+ ctx.arc(eye.cx, cy, rl, Math.PI, 0, false); // upper semicircle: bulges up
+ ctx.lineTo(eye.cx + HUGE, cy);
+ ctx.lineTo(eye.cx + HUGE, cy - HUGE);
+ ctx.lineTo(eye.cx - HUGE, cy - HUGE);
+ }
+ ctx.closePath();
+ ctx.clip();
+ }
+
+ if (rotated) {
+ // Undo the rotation for the caller, but keep the clip we just set.
+ ctx.translate(eye.cx, eye.cy);
+ ctx.rotate(-tilt);
+ ctx.translate(-eye.cx, -eye.cy);
+ }
+}
+
+/** Clip to the eyeball circle as well (the iris and heart are eyeball content). */
+function clipEye(ctx, eye, open, lowerLid, flat = false, tiltDeg = 0) {
+ circlePath(ctx, eye.cx, eye.cy, eye.r);
+ ctx.clip();
+ clipLids(ctx, eye, open, lowerLid, flat, tiltDeg);
+}
+
+function lidPath(ctx, eye, amount, lower, flat = false) {
+ ctx.beginPath();
+ if (flat) {
+ // A straight lid edge; the caller clips it to the eyeball.
+ const y = lower
+ ? eye.cy + eye.r - 2 * eye.r * amount
+ : eye.cy - eye.r + 2 * eye.r * (1 - amount);
+ ctx.moveTo(eye.cx - eye.r * 2, y);
+ ctx.lineTo(eye.cx + eye.r * 2, y);
+ return;
+ }
+ const rl = eye.r * EYE_LAYOUT.lidRadiusFactor;
+ if (!lower) {
+ const lowest = eye.cy - eye.r + 2 * eye.r * (1 - amount);
+ ctx.arc(eye.cx, lowest - rl, rl, Math.PI, 0, true);
+ } else {
+ const highest = eye.cy + eye.r - 2 * eye.r * amount;
+ ctx.arc(eye.cx, highest + rl, rl, Math.PI, 0, false);
+ }
+}
+
+/** The "eyes shut" artwork: a line, a chevron or a happy arch. */
+function drawShutEye(ctx, eye, spec, style, shapeScale = 1, maxHalf = Infinity) {
+ const layout = EYE_LAYOUT.closedLine;
+ const { line, width } = style;
+ // 形の大きさ is a multiplier on the shape's *fitting* size. With the white shown
+ // that fitting size is what just fits inside the eyeball, so the default (1)
+ // sits in the white; raising it may push the shape out past the white, which is
+ // allowed. `maxHalf` is Infinity when the white is hidden, so nothing is scaled
+ // back there.
+ const k = (unitHalf) => shapeScale * (maxHalf === Infinity ? 1 : Math.min(1, maxHalf / unitHalf));
+
+ if (spec.closed === 'chevron') {
+ // The chevron points *at* the nose, matching the original artwork.
+ const scale = k(layout.armX);
+ const vertex = { x: eye.cx + eye.towardNose * layout.vertex * scale, y: eye.cy + layout.offsetY * scale - 8 * scale };
+ const armX = eye.cx - eye.towardNose * layout.armX * scale;
+ const spread = layout.spread * (spec.spread ?? 1) * scale;
+ strokePolyline(ctx, [vertex, { x: armX, y: vertex.y - spread }], { color: line, width });
+ strokePolyline(ctx, [vertex, { x: armX, y: vertex.y + spread }], { color: line, width });
+ return;
+ }
+
+ if (spec.closed === 'three') {
+ // A real "3": an upper bowl and a lower bowl that meet at a single pinch on
+ // the nose side. Stacking two C's instead made the two lobes sit on top of
+ // each other; joining them at a point is what makes it read as the digit.
+ const r = 34 * k(1.7 * 34);
+ // Which way the digit faces. It used to follow the nose side, which made the
+ // pair a mirror image; each eye can now be set either way, because a pair of
+ // mirrored 3s does not always read the way you want.
+ const dir = (spec.threeFlip ? -1 : 1) * eye.towardNose;
+ const sx = eye.cx;
+ const cy = eye.cy + layout.offsetY;
+ const at = (x, y) => ({ x: sx + dir * r * x, y: cy + r * y });
+ const pinch = at(0.72, 0);
+ const upper = quadraticPoints(at(0.02, -1.62), at(2.05, -1.40), pinch, 26);
+ const lower = quadraticPoints(pinch, at(2.05, 1.46), at(0.02, 1.78), 26);
+ strokePolyline(ctx, upper, { color: line, width });
+ strokePolyline(ctx, lower, { color: line, width });
+ return;
+ }
+
+ if (spec.closed === 'arch') {
+ const scale = k(eye.r);
+ const edges = { x: eye.r * scale, y: EYE_LAYOUT.arch.edgesUp * scale };
+ const points = quadraticPoints(
+ { x: eye.cx - edges.x, y: eye.cy + edges.y },
+ { x: eye.cx, y: eye.cy + edges.y - EYE_LAYOUT.arch.apexUp * 2 * scale },
+ { x: eye.cx + edges.x, y: eye.cy + edges.y },
+ 24,
+ );
+ strokePolyline(ctx, points, { color: line, width });
+ return;
+ }
+
+ // Default: the gently slanted line of the original artwork, mirrored so it
+ // always slopes down towards the nose. With `closedLines` set to 2 or 3 the
+ // strokes share one endpoint instead - a ">" or bird's-foot shape, which is
+ // how manga draws a happily squeezed-shut eye.
+ const count = clamp(Math.round(spec.closedLines ?? 1), 1, 3);
+ const scale = k(layout.length / 2);
+ if (count >= 2) {
+ const vertex = { x: eye.cx + eye.towardNose * layout.vertex * scale, y: eye.cy + layout.offsetY * scale - 8 * scale };
+ // Reach as far as the single line does, not just a short stub: the arms are
+ // the *long* form of the same eyelid the one-line version covers.
+ const outX = -eye.towardNose * layout.armSpan * scale;
+ const spread = layout.spread * scale;
+ const arms = count === 2
+ ? [{ x: outX, y: -spread }, { x: outX, y: spread }]
+ : [
+ { x: outX, y: -spread },
+ { x: -eye.towardNose * Math.hypot(layout.armSpan, layout.spread) * scale, y: 0 },
+ { x: outX, y: spread },
+ ];
+ for (const arm of arms) {
+ strokePolyline(ctx, [vertex, { x: vertex.x + arm.x, y: vertex.y + arm.y }], { color: line, width });
+ }
+ return;
+ }
+
+ const half = (layout.length / 2) * (spec.length ?? 1) * scale;
+ const midX = eye.cx - eye.towardNose * layout.offsetX * scale;
+ const midY = eye.cy + layout.offsetY * scale;
+ const angle = ((layout.slantDeg * (spec.slant ?? 1) * eye.towardNose) * Math.PI) / 180;
+ const bow = (layout.bow ?? 0) * (spec.slant ?? 1) * scale;
+ const from = { x: midX - Math.cos(angle) * half, y: midY - Math.sin(angle) * half };
+ const to = { x: midX + Math.cos(angle) * half, y: midY + Math.sin(angle) * half };
+ const points = quadraticPoints(from, { x: midX, y: midY + bow * 2 }, to, 20);
+ strokePolyline(ctx, points, { color: line, width });
+}
+
+/**
+ * A stroke whose width runs from `w0` at the first point to `w1` at the last.
+ *
+ * Used for a ゴルゴ13-style brow: a filled wedge that comes to a point at one end
+ * reads as a heavy eyebrow, where a constant-width stroke reads as a soft arc.
+ */
+function taperedStroke(ctx, points, w0, w1, color) {
+ const count = points.length;
+ if (count < 2) return;
+ const side = [[], []];
+ for (let i = 0; i < count; i++) {
+ const t = i / (count - 1);
+ const w = (w0 + (w1 - w0) * t) / 2;
+ const before = points[Math.max(0, i - 1)];
+ const after = points[Math.min(count - 1, i + 1)];
+ const dx = after.x - before.x;
+ const dy = after.y - before.y;
+ const len = Math.hypot(dx, dy) || 1;
+ const nx = -dy / len;
+ const ny = dx / len;
+ side[0].push({ x: points[i].x + nx * w, y: points[i].y + ny * w });
+ side[1].push({ x: points[i].x - nx * w, y: points[i].y - ny * w });
+ }
+ ctx.save();
+ tracePolyline(ctx, [...side[0], ...side[1].reverse()], true);
+ ctx.fillStyle = color;
+ ctx.fill();
+ ctx.restore();
+}
+
+/** An eyebrow: a short arc above the eye, mirrored between the two eyes so a
+ * positive `angle` always means "inner end down" (an angry brow). */
+function drawBrow(ctx, eye, spec, style, limits = WINDOW_LIMITS) {
+ const brow = style.brow;
+ if (!brow?.enabled) return;
+ const layout = EYE_LAYOUT.brow;
+ // 0 is allowed: a zero-length stroke with round caps is a dot, which is what a
+ // length of 0 is asking for.
+ const length = Math.max(0, (brow.length ?? 1) * layout.length);
+ const thickness = Math.max(1, (brow.thickness ?? 1) * layout.thickness);
+ const cy = eye.cy - layout.lift - (brow.height ?? 0) - (spec.browHeight ?? 0);
+ // `spacing` widens the gap between the two brows: a positive value moves each
+ // one away from the nose. `layout.offsetX` is the resting inset from the
+ // artwork (which the old code read off the wrong object, so it never applied).
+ const cx = eye.cx + eye.towardNose * (layout.offsetX - (brow.spacing ?? 0));
+
+ // A supplied drawing (assets/brows/gol-right.png, the model's right brow only)
+ // replaces the strokes: like the textured ひげ it is drawn twice, mirrored, at
+ // `cx`, and tinted with the brow colour.
+ const entry = style.brows?.gol;
+ if (brow.image && entry?.image) {
+ const sprite = tintedSprite(entry.image, brow.color ?? '#2a1e33');
+ const sw = sprite.width || 1;
+ const sh = sprite.height || 1;
+ const drawW = Math.max(4, length);
+ const drawH = drawW * (sh / sw);
+ ctx.save();
+ ctx.translate(cx, cy);
+ // The drawing is the model's right brow, so the other eye gets it mirrored.
+ ctx.scale(eye.towardNose >= 0 ? 1 : -1, 1);
+ ctx.drawImage(sprite, -drawW / 2, -drawH / 2, drawW, drawH);
+ ctx.restore();
+ return;
+ }
+ const angle = (((brow.angle ?? 0) + (spec.browAngle ?? 0)) * eye.towardNose * Math.PI) / 180;
+ const half = length / 2;
+ const from = { x: cx - Math.cos(angle) * half, y: cy - Math.sin(angle) * half };
+ const to = { x: cx + Math.cos(angle) * half, y: cy + Math.sin(angle) * half };
+ const bow = (brow.curve ?? layout.curve) * length;
+ const points = quadraticPoints(from, { x: cx, y: cy - bow }, to, 16);
+ // A brow raised with the height slider used to run off the top of the canvas,
+ // where the clamped edge row was copied across the whole plate and the brow
+ // smeared upwards. Keep the whole stroke inside the artwork instead.
+ const top = limits.top + EDGE_MARGIN;
+ const highest = Math.min(...points.map((q) => q.y)) - thickness / 2;
+ if (highest < top) for (const q of points) q.y += top - highest;
+ // `taper` is how wide the *inner* (nose-side) end is: 1 = a plain stroke, and
+ // lower values turn the brow into a wedge that comes to a point at the nose.
+ const taper = clamp(brow.taper ?? 1, 0, 1);
+ const color = brow.color ?? style.line ?? '#55386e';
+ // A tapered wedge has no shape at zero length, so a dot always takes the plain
+ // round-capped stroke.
+ if (taper >= 0.999 || length < 2) {
+ strokePolyline(ctx, points, { color, width: thickness });
+ return;
+ }
+ const innerIsTo = eye.towardNose > 0;
+ taperedStroke(
+ ctx,
+ points,
+ thickness * (innerIsTo ? 1 : taper),
+ thickness * (innerIsTo ? taper : 1),
+ color,
+ );
+}
+
+/* ------------------------------------------------------- ほっぺ / 頭の模様 */
+
+/**
+ * ほっぺ: a soft pink patch crossed by short diagonal hatch strokes, the classic
+ * manga blush. Drawn once per cheek; the caller draws these before the eyes.
+ */
+function drawCheek(ctx, cx, cy, spec) {
+ const size = clamp(spec.size ?? 1, 0.2, 3);
+ const r = CHEEK_LAYOUT.radius * size;
+ const ry = r * CHEEK_LAYOUT.squash;
+
+ ctx.save();
+ ctx.beginPath();
+ ctx.ellipse(cx, cy, r, ry, 0, 0, TAU);
+ ctx.fillStyle = spec.color ?? '#f6a6b8';
+ ctx.fill();
+ // Clip the hatching to the patch, so a wobbly stroke keeps a clean edge.
+ ctx.clip();
+
+ // Four horizontal strokes, hand-drawn rather than ruled: each tapers to a
+ // point at both ends and wanders a little. Each one stops short of the patch
+ // outline - the margin is measured against the patch's own width at that
+ // height, so a stroke on the narrow top or bottom cannot reach the edge.
+ const thickness = Math.max(1.5, CHEEK_LAYOUT.lineWidth * size);
+ ctx.fillStyle = spec.hatchColor ?? '#e0708f';
+ for (let i = 0; i < CHEEK_LAYOUT.lines; i += 1) {
+ const t = CHEEK_LAYOUT.lines === 1 ? 0 : (i / (CHEEK_LAYOUT.lines - 1)) * 2 - 1; // -1..1
+ const dy = t * ry * CHEEK_LAYOUT.spread;
+ const chord = r * Math.sqrt(Math.max(0, 1 - (dy / ry) ** 2));
+ const half = chord - r * CHEEK_LAYOUT.margin;
+ if (half < 4) continue;
+ traceHandHatch(ctx, cx, cy + dy, half, thickness, i * 1.9);
+ }
+ ctx.restore();
+}
+
+/**
+ * One hand-drawn hatch stroke: a lens-shaped mark that tapers to a point at both
+ * ends, with a gentle wobble so it reads as drawn rather than printed.
+ */
+function traceHandHatch(ctx, cx, cy, half, thickness, seed) {
+ const steps = 12;
+ const top = [];
+ const bottom = [];
+ for (let i = 0; i <= steps; i += 1) {
+ const u = i / steps;
+ const x = cx + (u - 0.5) * 2 * half;
+ const wobble = Math.sin(u * Math.PI * 1.6 + seed) * thickness * CHEEK_LAYOUT.wobble;
+ const w = (thickness / 2) * Math.sin(u * Math.PI); // 0 at both ends
+ top.push({ x, y: cy + wobble - w });
+ bottom.push({ x, y: cy + wobble + w });
+ }
+ ctx.beginPath();
+ ctx.moveTo(top[0].x, top[0].y);
+ for (const point of top.slice(1)) ctx.lineTo(point.x, point.y);
+ for (let i = bottom.length - 1; i >= 0; i -= 1) ctx.lineTo(bottom[i].x, bottom[i].y);
+ ctx.closePath();
+ ctx.fill();
+}
+
+/** The pair of cheeks: symmetric about the face's midline (see `EYE_LAYOUT`). */
+function drawCheeks(ctx, spec) {
+ if (!spec?.enabled) return;
+ const drop = CHEEK_LAYOUT.drop + clamp(spec.offsetY ?? 0, -400, 400);
+ const outward = CHEEK_LAYOUT.outward + clamp(spec.spacing ?? 0, -400, 400);
+ for (const layout of EYE_LAYOUT.eyes) {
+ // Outwards is away from the midline, i.e. the opposite of `towardNose`.
+ const cx = layout.cx - layout.towardNose * outward;
+ drawCheek(ctx, cx, layout.cy + drop, spec);
+ }
+}
+
+/**
+ * 頭の模様: a hair-like covering over the whole head.
+ *
+ * The face plate is a shell of the front half of the body, so its own edge is
+ * the head's silhouette. This fills the plate from its top edge down to an
+ * adjustable boundary, which is what makes the covering follow the head outline
+ * without knowing the head's shape ahead of time. The boundary style, colour and
+ * size are all adjustable, and one style (`split`) divides the head into two
+ * colours along a vertical curve - a generic "two-tone head" device. It is not a
+ * copy of any particular character's hair.
+ */
+function drawHeadCover(ctx, spec, limits) {
+ const shape = spec?.shape ?? 'off';
+ if (shape === 'off' || shape === 'none' || shape === 'wave' || shape === 'side') return;
+
+ const size = clamp(spec.size ?? 1, 0.02, 3);
+ const left = limits.left;
+ const right = limits.right;
+ const top = limits.top;
+ const bottom = limits.bottom;
+ const width = right - left;
+ const cx = (left + right) / 2 + clamp(spec.offsetX ?? 0, -600, 600);
+ const color = spec.color ?? '#8a4fe0';
+ const color2 = spec.color2 ?? '#ffffff';
+
+ ctx.save();
+ // Stay on the plate: nothing may spill past the artwork's real edges.
+ ctx.beginPath();
+ ctx.rect(left, top, width, bottom - top);
+ ctx.clip();
+
+ if (shape === 'split') {
+ // Retired: the two-tone head was dropped, but an old saved state may still
+ // carry the shape, so treat it as off rather than drawing a two-tone head.
+ ctx.restore();
+ return;
+ }
+
+ // The boundary curve. `t` runs -1..1 across the plate, so each style is a
+ // small shape function; the covering is everything above it.
+ const base = HEAD_MARK_LAYOUT.cy + (size - 1) * HEAD_MARK_LAYOUT.reach
+ + clamp(spec.offsetY ?? 0, -600, 600);
+ const halfSpan = width / 2;
+ const boundary = (x) => {
+ const t = clamp((x - cx) / halfSpan, -1, 1);
+ // ぎざぎざ: a jagged, saw-toothed hairline. A triangle wave across the front
+ // gives the teeth; `teeth` is how far they reach down (its own slider), so
+ // the 大きさ slider only moves the hairline up and down.
+ if (shape === 'fringe') {
+ const teeth = 8;
+ const saw = Math.abs((((t * teeth) % 2) + 2) % 2 - 1); // 0..1 triangle
+ return base + (spec.teeth ?? 0.12) * 600 * saw;
+ }
+ // はちわれ: the same V upside down - a widow's peak.
+ if (shape === 'fringe-up') return base - 320 * Math.max(0, 1 - Math.abs(t) * 1.5);
+ // カーブ: a plain shallow curve, higher (more hair) round the sides.
+ if (shape === 'curve') return base + 160 * t * t;
+ // `cap`: a rounded helmet, lowest in the middle.
+ return base - 100 * (1 - t * t);
+ };
+
+ const steps = 48;
+ ctx.beginPath();
+ ctx.moveTo(left, top);
+ ctx.lineTo(right, top);
+ for (let i = steps; i >= 0; i -= 1) {
+ const x = left + (width * i) / steps;
+ ctx.lineTo(x, boundary(x));
+ }
+ ctx.closePath();
+ ctx.fillStyle = color;
+ ctx.fill();
+ ctx.restore();
+}
+
+/**
+ * 頭の模様 drawn onto the hair plate, which wraps right round the head.
+ *
+ * The plate's canvas is the cylindrical UV unrolled: `x` is the angle (front at
+ * the middle, the seam at the back at both ends) and `y` is the height. The GLB
+ * flips V on export, so the top of the head lands at the top of the canvas and
+ * the covering is everything above the boundary line - the same direction as
+ * `drawHeadCover`, which fills down from the top edge of the front plate.
+ *
+ * The same `shape` names are reused, with their front-to-back modulation tied to
+ * how far the column leans towards the front (`t`).
+ */
+export function drawHeadCoverWrap(ctx, spec, layout) {
+ const shape = spec?.shape ?? 'off';
+ // `split`, `wave` and `side` are retired front-plate shapes; they have no wrap
+ // equal. An old saved state may still carry one, so it simply draws no hair.
+ if (shape === 'off' || shape === 'none' || shape === 'split' || shape === 'wave' || shape === 'side') return;
+
+ const size = clamp(spec.size ?? 1, 0.02, 3);
+ const W = layout.width;
+ const H = layout.height;
+ // The horizontal axis is the angle. The *front* sits at u = 0.5, which is the
+ // middle of the artwork window (1024), not the middle of the canvas: after the
+ // seam heal the canvas is wider than the window, so using W/2 put the pattern
+ // a good way off centre.
+ const span = (layout.window ?? ART_WINDOW).width;
+ // After the GLB's V-flip the wrap's v is 0 at the top of the head and 1 at the
+ // model's feet, so a *larger* boundary means more hair (it reaches further
+ // down) - the same direction as `size` and `offsetY` on the front plate.
+ const base = HAIR_WRAP_LAYOUT.base
+ + (size - 1) * HAIR_WRAP_LAYOUT.reach
+ + clamp(spec.offsetY ?? 0, -600, 600) * HAIR_WRAP_LAYOUT.offsetScale;
+
+ ctx.save();
+ ctx.beginPath();
+ ctx.rect(0, 0, W, H);
+ ctx.clip();
+
+ // `t` is -1..1 across the front (+-90 deg around the front); everything behind
+ // is pinned to +-1, so the hairline runs flat round the back of the head.
+ const half = span * 0.25;
+ const cx = layout.offsetX + span * 0.5 + clamp(spec.offsetX ?? 0, -600, 600);
+ const vBound = (x) => {
+ const t = clamp((x - cx) / half, -1, 1);
+ // まえがみ: 富士額 / M字 (a widow's peak). The hairline comes down at the
+ // centre (the peak) and at the temples, with the corners between receded -
+ // the three peaks and two valleys of an "M". `t` is -1..1 across the front.
+ if (shape === 'fringe') {
+ // ぎざぎざ: a jagged, saw-toothed hairline. A triangle wave across the front
+ // gives the teeth; `teeth` is how far they reach down (its own slider), so
+ // the 大きさ slider only moves the hairline up and down.
+ const teeth = 8;
+ const saw = Math.abs((((t * teeth) % 2) + 2) % 2 - 1); // 0..1 triangle
+ return base + (spec.teeth ?? 0.12) * saw;
+ }
+ // はちわれ: the same V upside down - a widow's peak.
+ if (shape === 'fringe-up') return base - 0.18 * Math.max(0, 1 - Math.abs(t) * 1.5);
+ // カーブ: a deep round cover - low at the sides, high in the middle, like the
+ // blue of a certain robot cat's head.
+ if (shape === 'curve') return base + 0.42 * t * t;
+ return base - 0.07 * (1 - t * t); // `cap`
+ };
+
+ const steps = Math.max(96, Math.ceil(W / 2));
+ ctx.beginPath();
+ ctx.moveTo(0, 0);
+ for (let i = 0; i <= steps; i += 1) {
+ const x = (W * i) / steps;
+ ctx.lineTo(x, clamp(vBound(x), 0, 1) * H);
+ }
+ ctx.lineTo(W, 0);
+ ctx.closePath();
+ // A white mask: the colour is applied by the hair plate's material, so it goes
+ // through the same colour path as the body instead of being baked into the
+ // canvas (which shaded differently on iOS).
+ ctx.fillStyle = '#ffffff';
+ ctx.fill();
+ ctx.restore();
+}
+
+/**
+ * The shared extras (ほっぺ and 頭の模様) are drawn once per face, before the eyes,
+ * so the eyes, brows and glasses win any overlap and the cheeks are not doubled.
+ */
+function drawFaceExtras(ctx, style, lineOnly) {
+ drawCheeks(ctx, style.cheeks);
+ // The head covering fills out to the plate's real edges, so it needs `limits`.
+ drawHeadCover(ctx, style.headMark, style.limits ?? WINDOW_LIMITS);
+ drawBeard(ctx, style.beard, lineOnly, style.beards);
+}
+
+const BEARD_TINT_IDS = new WeakMap();
+const BEARD_TINT_CACHE = new Map();
+let beardTintSeq = 0;
+
+/**
+ * A copy of a beard drawing in the chosen colour.
+ *
+ * The supplied files are drawn in near-black, so repainting the ink with the
+ * beard colour (`source-in` keeps the anti-aliased alpha) is what lets the colour
+ * picker work on a drawing. Cached per (sprite, colour).
+ */
+function tintedSprite(image, color) {
+ let id = BEARD_TINT_IDS.get(image);
+ if (!id) {
+ beardTintSeq += 1;
+ id = beardTintSeq;
+ BEARD_TINT_IDS.set(image, id);
+ }
+ const key = `${id}|${color}`;
+ const cached = BEARD_TINT_CACHE.get(key);
+ if (cached) return cached;
+ const canvas = document.createElement('canvas');
+ canvas.width = image.width;
+ canvas.height = image.height;
+ const ctx = canvas.getContext('2d');
+ ctx.drawImage(image, 0, 0);
+ ctx.globalCompositeOperation = 'source-in';
+ ctx.fillStyle = color;
+ ctx.fillRect(0, 0, canvas.width, canvas.height);
+ BEARD_TINT_CACHE.set(key, canvas);
+ return canvas;
+}
+
+/**
+ * ひげ: a mustache or beard under the nose. Each kind is a small shape built on
+ * the spot; `scotch` and `cat` are drawn with round-capped strokes, and `kaiser`
+ * is a thick waving band with a curl at each tip. A kind that ships a drawing in
+ * `assets/beards/` is drawn from that instead (see `textures`), tinted with the
+ * beard colour. In a line drawing nothing is filled and only the outlines are inked.
+ */
+function drawBeard(ctx, spec, lineOnly = false, textures = null) {
+ const shape = spec?.shape ?? 'off';
+ if (shape === 'off' || shape === 'none') return;
+ const size = clamp(spec.size ?? 1, 0.2, 3);
+ const cx = BEARD_LAYOUT.cx;
+ const cy = BEARD_LAYOUT.cy + clamp(spec.offsetY ?? 0, -600, 600);
+ const w = BEARD_LAYOUT.width * size;
+ const color = spec.color ?? '#3a2a4a';
+
+ // A supplied drawing for this kind (assets/beards/<shape>.png) replaces the
+ // built-in strokes. The drawings are trimmed to their ink, so `w` is the
+ // beard's real width; it is centred on the nose and scaled by `size`, and it is
+ // tinted with the beard colour (the files are drawn in near-black).
+ const entry = textures?.[shape];
+ if (entry?.image) {
+ const sprite = tintedSprite(entry.image, color);
+ // Slightly wider than the built-in base: a moustache drawn to the same width
+ // as a beard's stroke sat mostly behind the nose.
+ const drawW = w * 1.4;
+ if (entry.half) {
+ // One side, mirrored to make the pair. The drawing is the model's own right
+ // side, which sits in the artwork's left half; `spacing` opens the middle
+ // (a negative value brings the two halves together).
+ const halfW = drawW / 2;
+ const dh = (halfW * (sprite.height || 1)) / (sprite.width || 1);
+ const gap = clamp(spec.spacing ?? 0, -400, 800);
+ const y = cy - dh / 2;
+ ctx.drawImage(sprite, cx - gap - halfW, y, halfW, dh);
+ ctx.save();
+ ctx.translate(cx + gap, cy);
+ ctx.scale(-1, 1);
+ // Draw into [-halfW, 0] so that, mirrored, it lands in [cx+gap, cx+gap+halfW].
+ ctx.drawImage(sprite, -halfW, -dh / 2, halfW, dh);
+ ctx.restore();
+ return;
+ }
+ const dh = (drawW * (sprite.height || 1)) / (sprite.width || 1);
+ ctx.drawImage(sprite, cx - drawW / 2, cy - dh / 2, drawW, dh);
+ return;
+ }
+
+ const line = spec.line ?? '#55386e';
+ const lw = Math.max(2, 9 * size);
+ const stroke = (points, width) => strokePolyline(ctx, points, {
+ color: lineOnly ? line : color, width,
+ });
+
+ if (shape === 'scotch') {
+ // ちょび髭: two short dashes under the nose, angled down and out so their tips
+ // clear the nose mesh (which hides anything drawn straight behind it).
+ stroke([{ x: cx - w * 0.07, y: cy + w * 0.02 }, { x: cx - w * 0.5, y: cy + w * 0.17 }], lw * 1.8);
+ stroke([{ x: cx + w * 0.07, y: cy + w * 0.02 }, { x: cx + w * 0.5, y: cy + w * 0.17 }], lw * 1.8);
+ return;
+ }
+ if (shape === 'kaiser') {
+ // カイゼル: a full, thick mustache whose ends turn up.
+ stroke([
+ { x: cx - w * 0.5, y: cy - w * 0.02 },
+ { x: cx - w * 0.28, y: cy + w * 0.07 },
+ { x: cx, y: cy + w * 0.09 },
+ { x: cx + w * 0.28, y: cy + w * 0.07 },
+ { x: cx + w * 0.5, y: cy - w * 0.02 },
+ ], lw * 2.6);
+ const curlAt = (dir) => {
+ // A little inward-turning spiral at the tip: the Dalí curl.
+ const ex = cx + dir * w * 0.5;
+ const ey = cy - w * 0.02;
+ const r0 = lw * 0.5;
+ const r1 = w * 0.17;
+ const steps = 22;
+ const points = [];
+ for (let i = 0; i <= steps; i += 1) {
+ const t = i / steps;
+ const a = -Math.PI / 2 + dir * Math.PI * 2 * 1.4 * t;
+ const r = r0 + (r1 - r0) * t;
+ points.push({ x: ex + dir * Math.cos(a) * r, y: ey + Math.sin(a) * r });
+ }
+ stroke(points, lw * 1.25);
+ };
+ curlAt(-1);
+ curlAt(1);
+ return;
+ }
+ if (shape === 'apron') {
+ // A filled bib was once a kind here; kept as a no-op so a saved state that
+ // still names it simply shows nothing rather than throwing.
+ return;
+ }
+ // ねこ: three whiskers a side, growing out of the cheeks with a gap left in the
+ // middle (like a cat's). The thickness is fixed, so `size` makes the whiskers
+ // longer and wider-spread without making them fatter, and `spacing` opens the
+ // gap between the left and right.
+ const whisker = 8;
+ const spacing = clamp(spec.spacing ?? 0, 0, 800);
+ const inner = w * 0.30 + spacing;
+ // `length` scales how far each whisker reaches out; `lineGap` opens the spacing
+ // between the three lines of one side. Neither changes the line's thickness.
+ const length = clamp(spec.length ?? 1, 0.2, 3);
+ const gap = w * 0.16 * clamp(spec.lineGap ?? 1, 0.2, 3);
+ const outer = inner + w * 0.38 * length;
+ for (const dir of [-1, 1]) {
+ for (let i = 0; i < 3; i += 1) {
+ stroke([
+ { x: cx + dir * inner, y: cy + (i - 1) * gap },
+ { x: cx + dir * outer, y: cy + (i - 1) * gap * 1.5 },
+ ], whisker);
+ }
+ }
+}
+
+/**
+ * One lens of a pair of 眼鏡 / サングラス, plus this eye's half of the bridge and its
+ * temple.
+ *
+ * Called once per eye from `drawEyes`, after the eyeball (or the shut-eye artwork)
+ * so the lens sits in front of the eye, and before that eye's tear so a teardrop
+ * falls past the lens. Nothing about a pair of glasses is per-eye, so the two
+ * halves are mirrored from `eye.towardNose` and meet at the face's midline. The
+ * kind picks the shape: a round 眼鏡 lens, or a wide angular サングラス one.
+ *
+ * `style.glasses` is the shared spec. In a line drawing the lens is left empty, so
+ * the paper behind shows through exactly as the eyeball's white does (see the note
+ * in `drawEyes`); the frames are then stroked in the line colour.
+ *
+ * @param {CanvasRenderingContext2D} ctx
+ * @param {{cx:number,cy:number,r:number,towardNose:number}} eye
+ * @param {boolean} line true in 線画 mode
+ * @param {object} style the bag `drawEyes` received
+ * @param {{top:number,bottom:number,left:number,right:number}} limits
+ */
+function drawGlasses(ctx, eye, line, style, limits) {
+ const spec = style.glasses;
+ if (!spec?.enabled) return;
+
+ const r = eye.r;
+ const scale = clamp(spec.scale ?? 1, 0.2, 3);
+ // The two kinds share everything about *where* they sit but not their shape:
+ // 眼鏡 is a round lens, サングラス a wide angular one (see the layouts above).
+ const shades = spec.kind === 'sunglasses';
+ const L = shades ? SUNGLASSES_LAYOUT : GLASSES_LAYOUT;
+ const rx = r * L.widthFactor * scale;
+ const ry = rx * L.heightFactor;
+ const frame = Math.max(
+ 1,
+ (spec.frameWidth ?? 1) * EYE_LAYOUT.lidStroke * (shades ? L.frameFactor : 1),
+ );
+ const colour = line ? (style.line ?? '#55386e') : (spec.frameColor ?? '#2a1e33');
+ // The outward direction (towards the temple) for this eye. The angular lens is
+ // built in a local frame whose u runs outwards, so the two sides mirror exactly.
+ const out = -eye.towardNose;
+ // The pointed outer corner makes the shades taller on that side; clamp against
+ // the full height so even that point cannot reach the canvas border.
+ const halfV = shades ? ry * Math.max(L.innerTop + L.topSkew, L.outerBottom) : ry;
+
+ // The face's midline: the two eyes are symmetric about it, so it is where the
+ // two halves of the bridge meet and what `tilt` turns the pair about.
+ const midX = (EYE_LAYOUT.eyes[0].cx + EYE_LAYOUT.eyes[1].cx) / 2;
+ // `lensGap` slides the two lenses apart (positive) or together (negative) along
+ // the face, symmetrically about the midline. It is clamped so the inner edges may
+ // meet at the midline but the two lenses can never cross each other.
+ const inwardRoom = Math.max(0, Math.abs(midX - eye.cx) - rx);
+ const gap = clamp(spec.lensGap ?? 0, -inwardRoom, HUGE);
+ // Keep the lens (and so everything that hangs off it) inside the artwork. The
+ // rest of the file clamps against `limits` for the same reason: a mark that
+ // reaches the canvas border gets the edge row copied across the whole plate.
+ const lensCx = clamp(
+ eye.cx + out * gap,
+ limits.left + EDGE_MARGIN + rx,
+ limits.right - EDGE_MARGIN - rx,
+ );
+ const lensCy = clamp(
+ eye.cy + L.drop + (spec.offsetY ?? 0),
+ limits.top + EDGE_MARGIN + halfV,
+ limits.bottom - EDGE_MARGIN - halfV,
+ );
+ // Local (u, v) -> canvas, with u outwards and v downwards.
+ const at = (u, v) => ({ x: lensCx + out * u, y: lensCy + v });
+
+ ctx.save();
+ // `tilt` leans the whole pair at once. Rotating about the midline keeps the
+ // bridge centred between the lenses instead of swinging it off to one side.
+ if (spec.tilt) {
+ ctx.translate(midX, lensCy);
+ ctx.rotate((clamp(spec.tilt, -90, 90) * Math.PI) / 180);
+ ctx.translate(-midX, -lensCy);
+ }
+
+ // --- lens ------------------------------------------------------------
+ // The one path is filled and then stroked, so the fill and the frame can never
+ // drift apart.
+ if (shades) {
+ // A long cat-eye, not an ellipse: the outer end starts low, rises to a
+ // pointed, lifted outer corner set further out, and the top edge sweeps back
+ // towards the nose. The inner end is short, so the lens tapers inwards.
+ const lens = [
+ at(-rx, -ry * L.innerTop), // inner top (near the nose)
+ at(rx * L.tipX, -ry * (L.innerTop + L.topSkew)), // pointed, lifted outer corner
+ at(rx * L.outerEndX, ry * L.outerBottom), // low outer end
+ at(-rx, ry * L.innerBottom), // inner bottom (pinched towards the nose)
+ ];
+ traceRoundedPolygon(ctx, lens, ry * L.corner);
+ if (!line) {
+ ctx.globalAlpha = clamp(spec.lensOpacity ?? 0, 0, 1);
+ ctx.fillStyle = spec.lensColor ?? '#2b2433';
+ ctx.fill();
+ ctx.globalAlpha = 1;
+ }
+ ctx.strokeStyle = colour;
+ ctx.lineWidth = frame;
+ ctx.stroke();
+ } else {
+ ctx.beginPath();
+ ctx.ellipse(lensCx, lensCy, rx, ry, 0, 0, TAU);
+ ctx.closePath();
+ if (!line) {
+ ctx.globalAlpha = clamp(spec.lensOpacity ?? 0, 0, 1);
+ ctx.fillStyle = spec.lensColor ?? '#2b2433';
+ ctx.fill();
+ ctx.globalAlpha = 1;
+ }
+ ctx.strokeStyle = colour;
+ ctx.lineWidth = frame;
+ ctx.stroke();
+ }
+
+ // --- bridge ----------------------------------------------------------
+ // Each eye draws the half of the bridge from its own lens to the midline.
+ const innerX = eye.towardNose > 0
+ ? Math.min(lensCx + rx, midX)
+ : Math.max(lensCx - rx, midX);
+ if (shades) {
+ // A short, thick, level bar high on the lenses: with the two lenses it reads
+ // as one continuous visor across the eyes.
+ const barY = lensCy - ry * L.bridgeLift;
+ strokePolyline(ctx, [{ x: innerX, y: barY }, { x: midX, y: barY }], {
+ color: colour,
+ width: frame * L.bridgeWidth,
+ });
+ } else {
+ // The two halves meet at the midline with a horizontal tangent, so the join is smooth.
+ const noseX = lensCy - L.bridgeRise;
+ strokePolyline(ctx, quadraticPoints(
+ { x: innerX, y: lensCy },
+ { x: (innerX + midX) / 2, y: noseX },
+ { x: midX, y: noseX },
+ 12,
+ ), { color: colour, width: frame * L.bridgeWidth });
+ }
+
+ // --- temple ----------------------------------------------------------
+ // A stub outwards from the outer edge of the lens. It stays short on purpose:
+ // the plate only reaches so far, and a temple that ran off it would smear. The
+ // round pair's outer edge is a vertical line at the lens centre height. The
+ // shades' outer end drops low, so their arm leaves from the *top* edge instead
+ // - from the pointed outer corner - which is where a cat-eye's arm attaches.
+ const outerX = shades
+ ? lensCx - eye.towardNose * rx * L.tipX
+ : lensCx - eye.towardNose * rx;
+ const outerY = shades ? lensCy - ry * (L.innerTop + L.topSkew) : lensCy;
+ const reach = clamp(
+ outerX - eye.towardNose * r * L.templeLength,
+ limits.left + EDGE_MARGIN,
+ limits.right - EDGE_MARGIN,
+ );
+ strokePolyline(ctx, [
+ { x: outerX, y: outerY },
+ {
+ x: eye.towardNose > 0 ? Math.min(reach, outerX) : Math.max(reach, outerX),
+ y: clamp(outerY - L.templeRise, limits.top + EDGE_MARGIN, limits.bottom - EDGE_MARGIN),
+ },
+ ], { color: colour, width: frame });
+
+ ctx.restore();
+}
+
+/**
+ * Draw the pair of eyes into a 1024 x 380 canvas.
+ *
+ * @param {CanvasRenderingContext2D} ctx
+ * @param {object} p
+ * @param {'paint'|'line'} [p.mode] paint = filled cartoon eyes, line = outline only
+ * @param {object} p.eyes `{ left, right }`, each `{ open, lookX, lookY, closed }`
+ * @param {object} [p.style] colours and shared shaping parameters
+ */
+/**
+ * Which artwork an eye shows: 'open', 'heart', 'line1'..'line3', 'three' or
+ * 'arch'. `shape` is the explicit choice; older saved states and the おまかせ
+ * rolls only set `open`/`closed`/`irisShape`, so this falls back to those.
+ */
+function eyeShapeKey(spec) {
+ const shape = spec.shape;
+ const explicitShut = shape === 'three' || shape === 'arch'
+ || (typeof shape === 'string' && shape.startsWith('line'));
+ // An explicit shut artwork is used as-is; the lid height only trims it.
+ if (explicitShut) return shape;
+ // A lowered lid on an open or heart eye reads as a shut line - a blink. It must
+ // NOT borrow a 3 or an arch from a stale `closed`, which used to flash on screen
+ // for a frame when blinking after picking 3/わらう and then switching to heart.
+ if ((spec.open ?? 1) <= 0.02) {
+ if (!shape) {
+ // Older saved states have no `shape`; derive the shut artwork from `closed`.
+ if (spec.closed === 'three') return 'three';
+ if (spec.closed === 'arch') return 'arch';
+ return `line${clamp(Math.round(spec.closedLines ?? 1), 1, 3)}`;
+ }
+ return 'line1';
+ }
+ if (shape) return shape;
+ return (spec.irisShape ?? 'circle') === 'heart' ? 'heart' : 'open';
+}
+
+export function drawEyes(ctx, p) {
+ const mode = p.mode ?? 'paint';
+ const line = mode === 'line';
+ const style = p.style ?? {};
+ const limits = style.limits ?? WINDOW_LIMITS;
+ const white = style.white ?? '#ffffff';
+ const irisColor = style.iris ?? '#150e1b';
+ const lineColor = style.line ?? '#55386e';
+ const lookMax = style.lookMax ?? 1;
+ const heartScale = 2;
+ const heartColor = style.heartColor ?? '#e0344f';
+ // A lens that is effectively opaque hides the eye completely, so a blink would
+ // show only as a flicker of the shut artwork through the lens. While such a
+ // lens is on, the eyes are drawn open and no blink is visible at all. This is a
+ // rendering decision, not an animation one - the blink still runs underneath.
+ const lensOpaque = style.glasses?.enabled === true
+ && clamp(style.glasses.lensOpacity ?? 0, 0, 1) >= 0.99;
+
+ // ほっぺ and 頭の模様 belong to the whole face, so they are drawn once here
+ // rather than inside the per-eye loop below. 鼻ちょうちん comes along too.
+ drawFaceExtras(ctx, style, line);
+
+ for (const layout of EYE_LAYOUT.eyes) {
+ const spec = (p.eyes ?? {})[layout.key] ?? {};
+ const eye = {
+ // `eyeX` slides this eye - and its lid, brow and tear - sideways on its own.
+ cx: layout.cx + clamp(spec.eyeX ?? 0, -400, 400),
+ cy: layout.cy,
+ r: EYE_LAYOUT.radius,
+ towardNose: layout.towardNose,
+ };
+ // Each lid can be set per eye, falling back to the shared value.
+ const lidWidth = spec.lidWidth ?? style.lidWidth ?? EYE_LAYOUT.lidStroke;
+ const lidFlat = (spec.lidShape ?? style.lidShape ?? 'curve') === 'flat';
+ // How much the whole narrowed eye is tilted (e.g. an angry or gentle squint).
+ const lidTilt = clamp(spec.lidTilt ?? style.lidTilt ?? 0, -45, 45);
+ const lineStyle = { line: lineColor, width: lidWidth };
+ // Which artwork this eye shows. `shape` is the explicit choice; older saved
+ // states and the おまかせ rolls only set `open`/`closed`, so fall back.
+ const shapeKey = eyeShapeKey(lensOpaque ? { ...spec, open: 1 } : spec);
+ const explicitShut = typeof spec.shape === 'string'
+ && (spec.shape === 'three' || spec.shape === 'arch' || spec.shape.startsWith('line'));
+ const isHeart = shapeKey === 'heart';
+ const isShutShape = shapeKey === 'three' || shapeKey === 'arch' || shapeKey.startsWith('line');
+ // The shut artwork reads `closed`/`closedLines`; build them from `shape` so a
+ // line, the 3 and the arch share one path with the older fields.
+ const shapeSpec = isShutShape
+ ? {
+ ...spec,
+ closed: shapeKey === 'three' ? 'three' : (shapeKey === 'arch' ? 'arch' : 'line'),
+ closedLines: shapeKey.startsWith('line') ? Number(shapeKey.slice(4)) : (spec.closedLines ?? 1),
+ }
+ : spec;
+ // The upper lid (`open`) and the lower lid are independent, and both shape
+ // every eye now: the shut artwork is drawn as the eye's content and is
+ // trimmed by them. A shut eye saved the old way stored open = 0 meaning
+ // "shut"; lift it or the artwork would be clipped away. An explicit shut
+ // `shape` keeps its own lid height, so the lid can be lowered onto it.
+ const rawOpen = spec.open ?? 1;
+ const open = lensOpaque
+ ? 1
+ : clamp(explicitShut ? rawOpen : (rawOpen <= 0.02 ? 1 : rawOpen), 0, 1);
+ const lowerLid = clamp(spec.lowerLid ?? style.lowerLid ?? 0, 0, 1);
+ // 大きさ: one knob for the iris, the heart and the shut artwork.
+ const shapeScale = clamp(style.irisScale ?? 1, 0.4, 2);
+ const irisRadius = EYE_LAYOUT.irisRadius * shapeScale;
+ // `white` is tri-state: only the plain open eye shows it by default.
+ const showWhite = spec.white != null ? spec.white === true : shapeKey === 'open';
+ // While the white is shown, a shape that would poke out of the eyeball is
+ // scaled back inside it; `shapeHalfLimit` is the half-size it may reach.
+ const shapeHalfLimit = showWhite ? eye.r * 0.92 : Infinity;
+
+ drawBrow(ctx, eye, spec, style, limits);
+
+ // --- tear ----------------------------------------------------------
+ // A teardrop hangs below the eye, so it is drawn on top of everything else
+ // (the opaque eyeball would otherwise cover it) and for a shut eye too. The
+ // amount, the height and the tilt are all *per eye*, because one eye crying
+ // while the other does not is a real expression.
+ const drawTear = () => {
+ if (spec.tearOn !== true) return;
+ const amount = clamp(spec.tear ?? 0.3, 0, 1.6);
+ if (amount <= 0.01) return;
+ const size = EYE_LAYOUT.tear.size * amount;
+ const tearX = eye.cx + clamp(spec.tearX ?? 0, -400, 400) - layout.towardNose * EYE_LAYOUT.tear.offsetX;
+ let tearY = eye.cy + EYE_LAYOUT.tear.offsetY + (spec.tearY ?? 0);
+ // The drop hangs from `cy - 1.32r` to `cy + 0.78r`. Keep its lower tip
+ // inside the artwork: a drop that reached the canvas border used to be
+ // smeared down the chin by the clamp.
+ const tearBottom = limits.bottom - EDGE_MARGIN;
+ if (tearY + size * 0.78 > tearBottom) tearY = tearBottom - size * 0.78;
+ ctx.save();
+ if (spec.tearTilt) {
+ ctx.translate(tearX, tearY);
+ ctx.rotate((spec.tearTilt * Math.PI) / 180);
+ ctx.translate(-tearX, -tearY);
+ }
+ dropPath(ctx, tearX, tearY, size);
+ if (!line) {
+ ctx.fillStyle = style.tearColor ?? '#8fd8ff';
+ ctx.fill();
+ }
+ ctx.strokeStyle = lineColor;
+ ctx.lineWidth = lidWidth * 0.55;
+ ctx.stroke();
+ ctx.restore();
+ };
+
+ // How far the gaze can push the content. A heart (or a shut line shown on the
+ // white) is much bigger than the iris, so it gets a smaller travel - and with
+ // the white shown the content is also clipped to the eyeball - so it never
+ // pokes outside the white.
+ const heartFit = isHeart && showWhite
+ ? Math.min(1, shapeHalfLimit / (EYE_LAYOUT.irisRadius * heartScale))
+ : 1;
+ const heartRadius = Math.min(
+ EYE_LAYOUT.irisRadius * heartScale * shapeScale * heartFit,
+ EYE_LAYOUT.radius * 2.1,
+ );
+ let travelBase = irisRadius;
+ if (isHeart) travelBase = heartRadius;
+ const eyeTravel = Math.max(0, EYE_LAYOUT.radius - travelBase) * lookMax;
+ let dx = clamp(spec.lookX ?? 0, -1, 1) * eyeTravel;
+ let dy = -clamp(spec.lookY ?? 0, -1, 1) * eyeTravel;
+ const dist = Math.hypot(dx, dy);
+ if (dist > eyeTravel && dist > 0) {
+ dx = (dx / dist) * eyeTravel;
+ dy = (dy / dist) * eyeTravel;
+ }
+
+ // --- the eye's content, clipped by the lids -------------------------
+ // Every shape is drawn the same way now: a white backing, then the artwork
+ // (iris, heart or the shut line/3/arch), trimmed by the upper and lower lids.
+ // The shut artwork and a heart both reach past the eyeball, so they are only
+ // lid-clipped - but once the white is shown they are clipped to the eyeball
+ // too, so they stay inside it. Clipping the heart by its *lids* rather than by
+ // the eyeball is also what lets a raised lower lid cover it from below: the
+ // heart replaces the eyeball, but it must still sit behind both lids.
+ ctx.save();
+ if ((isShutShape || isHeart) && !showWhite) {
+ clipLids(ctx, eye, open, lowerLid, lidFlat, lidTilt * eye.towardNose);
+ } else if (!isHeart || open < 0.999 || showWhite) {
+ clipEye(ctx, eye, open, lowerLid, lidFlat, lidTilt * eye.towardNose);
+ }
+ if (!line && showWhite) fillCircle(ctx, eye.cx, eye.cy, eye.r, white);
+ if (isShutShape) {
+ ctx.translate(dx, dy);
+ drawShutEye(ctx, eye, shapeSpec, lineStyle, shapeScale, shapeHalfLimit);
+ } else if (isHeart) {
+ fillHeart(ctx, eye.cx + dx, eye.cy + dy, heartRadius, line ? lineColor : heartColor);
+ } else {
+ const irisX = eye.cx + dx + eye.towardNose * EYE_LAYOUT.irisInward;
+ const irisY = eye.cy + dy;
+ fillCircle(ctx, irisX, irisY, irisRadius, line ? lineColor : irisColor);
+ // 光彩 (the white glint) is per eye, falling back to the shared switch.
+ const highlightOn = spec.highlight != null ? spec.highlight === true : style.highlight !== false;
+ if (highlightOn) {
+ const hx = irisX + layout.towardNose * EYE_LAYOUT.highlightOffset.x * shapeScale;
+ const hy = irisY + EYE_LAYOUT.highlightOffset.y * shapeScale;
+ const hr = EYE_LAYOUT.highlightRadius * shapeScale;
+ if (line) {
+ // Punch the sparkle out of the iris rather than painting it white. On
+ // screen the paper behind shows through, and in the SVG export (which
+ // only sees alpha) it stays a hole in the pupil.
+ ctx.save();
+ ctx.globalCompositeOperation = 'destination-out';
+ fillCircle(ctx, hx, hy, hr, '#000000');
+ ctx.restore();
+ } else {
+ fillCircle(ctx, hx, hy, hr, white);
+ }
+ }
+ }
+ ctx.restore();
+
+ // Between the eyeball and the tear: the lens covers the eye, and a tear still
+ // falls in front of it.
+ drawGlasses(ctx, eye, line, style, limits);
+
+ drawTear();
+
+ // --- lid strokes ---------------------------------------------------
+ // Faded in as the lid starts to cover the eye, so opening the eye all the
+ // way leaves the clean original artwork with no extra line.
+ const lidFade = clamp((0.95 - open) / 0.1, 0, 1);
+ // The tilt is mirrored between the eyes, so a positive value reads the same
+ // way on both (an inward, angry-looking squint).
+ const eyeTilt = lidTilt * eye.towardNose;
+ // The upper lid line has to sit where the clip put it - and that is set by
+ // `open` alone, so it stays put when the lower lid moves.
+ const upperAmt = clamp(open, 0, 1);
+ // A heart is a replacement for the eyeball, not an eye behind a lid: it keeps
+ // no lower-lid line, which used to cut across the heart.
+ const showLowerLid = lowerLid > 0.01;
+ if (lidFade > 0.01 || showLowerLid) {
+ ctx.save();
+ if (eyeTilt) {
+ ctx.translate(eye.cx, eye.cy);
+ ctx.rotate((eyeTilt * Math.PI) / 180);
+ ctx.translate(-eye.cx, -eye.cy);
+ }
+ circlePath(ctx, eye.cx, eye.cy, eye.r);
+ ctx.clip();
+ ctx.globalAlpha = line ? 1 : lidFade;
+ ctx.strokeStyle = lineColor;
+ ctx.lineWidth = lidWidth;
+ if (lidFade > 0.01) {
+ lidPath(ctx, eye, upperAmt, false, lidFlat);
+ ctx.stroke();
+ }
+ if (showLowerLid) {
+ ctx.globalAlpha = line ? 1 : lowerLid;
+ lidPath(ctx, eye, lowerLid, true, lidFlat);
+ ctx.stroke();
+ }
+ ctx.restore();
+ }
+
+ // --- まつげ --------------------------------------------------------
+ // Short strokes flicking outwards from the upper-outer lid. They sit outside
+ // the eyeball, so they are drawn after the lid block and are not clipped.
+ if (spec.lashes ?? style.lashes) {
+ // The lashes ride the upper lid: they drop as the lid lowers (2r per unit of
+ // open) and tilt with まぶたの傾き, so they stay on the lid edge. まつげの位置
+ // slides them along the lid, まつげの角度 tilts the strokes themselves.
+ const outDir = -eye.towardNose;
+ const lidDrop = 2 * eye.r * (1 - open);
+ const lashPos = clamp(spec.lashPos ?? style.lashPos ?? 0, -80, 80);
+ const lashAngle = clamp(spec.lashAngle ?? style.lashAngle ?? 0, -80, 80) * outDir;
+ const a = (lashAngle * Math.PI) / 180;
+ const ca = Math.cos(a);
+ const sa = Math.sin(a);
+ ctx.save();
+ if (eyeTilt) {
+ ctx.translate(eye.cx, eye.cy);
+ ctx.rotate((eyeTilt * Math.PI) / 180);
+ ctx.translate(-eye.cx, -eye.cy);
+ }
+ for (const deg of EYE_LAYOUT.lash.angles) {
+ const t = ((deg + lashPos) * Math.PI) / 180;
+ const ux = outDir * Math.cos(t);
+ const uy = -Math.sin(t);
+ // The stroke points along the radial direction, tilted by まつげの角度.
+ const dx = ux * ca - uy * sa;
+ const dy = ux * sa + uy * ca;
+ const r0 = eye.r * 0.96;
+ const bx = eye.cx + ux * r0;
+ const by = eye.cy + uy * r0 + lidDrop - eye.r * EYE_LAYOUT.lash.raise;
+ strokePolyline(ctx, [
+ { x: bx, y: by },
+ { x: bx + dx * EYE_LAYOUT.lash.length, y: by + dy * EYE_LAYOUT.lash.length },
+ ], { color: lineColor, width: EYE_LAYOUT.lash.width });
+ }
+ ctx.restore();
+ }
+
+ // --- outline (line-art mode only) ---------------------------------
+ if (line) strokeCircle(ctx, eye.cx, eye.cy, eye.r, lineColor, lidWidth * 0.75);
+ }
+}
+
+/* -------------------------------------------------------------------- mouth */
+
+/**
+ * Draw the mouth into a 1024 x 380 canvas.
+ *
+ * @param {CanvasRenderingContext2D} ctx
+ * @param {object} p
+ * @param {'paint'|'line'} [p.mode]
+ */
+export function drawMouth(ctx, p) {
+ const mode = p.mode ?? 'paint';
+ const line = mode === 'line';
+ const L = MOUTH_LAYOUT;
+ const limits = p.limits ?? WINDOW_LIMITS;
+ // The artwork's real edges, in the artwork's own coordinates, with a margin
+ // kept clear. `top` is negative when the plate reaches above the window, which
+ // is the room a moved mouth has to work with.
+ const edgeLeft = limits.left + EDGE_MARGIN;
+ const edgeRight = limits.right - EDGE_MARGIN;
+ const edgeTop = limits.top + EDGE_MARGIN;
+ const edgeBottom = limits.bottom - EDGE_MARGIN;
+
+ const openAmount = clamp(p.open ?? 0, 0, 1);
+ const thickness = L.thickness * clamp(p.thickness ?? 1, 0.2, 3);
+ const cornerAmount = clamp(p.corners ?? 1, 0, 1.6);
+ // The corner strokes flick out past the ends of the chord, so the ends cannot
+ // use the whole canvas: a very wide mouth used to smear sideways off the plate.
+ const cornerReach = L.corner.toX * cornerAmount;
+ const halfChord = Math.min(
+ L.halfChord * clamp(p.width ?? 1, 0.2, 1.6),
+ Math.min(L.centreX - (edgeLeft + cornerReach), (edgeRight - cornerReach) - L.centreX),
+ );
+
+ // A negative smile bulges the line upwards, which reads as a frown.
+ const sagRaw = L.sag * clamp(p.smile ?? 1, -0.55, 1.4);
+ // A frown's middle is the highest point of the mouth, and that is exactly
+ // where the nose is in the way, so slide the whole mouth down until the curve
+ // is in the open. The push is worked out from the *base* position and the
+ // height slider is added afterwards: adding it first made the push cancel the
+ // slider exactly, which is why dragging ‟口の高さ” did nothing at all on a
+ // frowning mouth like むっと.
+ const base = L.chordY + Math.max(0, L.noseClear - (L.chordY + sagRaw));
+ let y0 = base + (p.offsetY ?? 0);
+ // The smile flattens slightly as the mouth opens, so the whole mouth keeps
+ // fitting inside the band the mouth plane actually shows.
+ let sag = sagRaw * (1 - L.openFlatten * openAmount);
+ // Keep the whole mark on the canvas. The corner strokes sit *above* the ends of
+ // the chord, so the allowance is not symmetric - padding the bottom by the
+ // corner's depth used to cost most of the height slider's travel.
+ const cornerRise = L.corner.toY * cornerAmount + thickness;
+ const bottomEdge = y0 + Math.max(0, sag) + thickness;
+ if (bottomEdge > edgeBottom) y0 -= bottomEdge - edgeBottom;
+ const topEdge = y0 + Math.min(0, sag) - cornerRise;
+ if (topEdge < edgeTop) y0 += edgeTop - topEdge;
+ const pivot = { x: L.centreX, y: y0 + sag * 0.5 };
+ const tilt = p.tilt ?? 0;
+
+ const strokeColor = line ? (p.line ?? '#3a2a4a') : (p.color ?? '#ff1a44');
+ const innerColor = p.innerColor ?? '#4a0f1e';
+ const tongueColor = line ? (p.line ?? '#3a2a4a') : (p.tongueColor ?? '#ff2d2d');
+
+ const left = { x: L.centreX - halfChord, y: y0 };
+ const right = { x: L.centreX + halfChord, y: y0 };
+ const lip = mouthControls(left, right, sag, L.sagBend);
+ const arc = cubicPoints(lip.p0, lip.p1, lip.p2, lip.p3, 96);
+
+ const tongueAmount = clamp(p.tongue ?? 1, 0, 1.6);
+
+ // --- a round "O" mouth (surprised, singing) ---------------------------
+ const roundAmount = clamp(p.round ?? 0, 0, 1);
+ if (roundAmount > 0.004) {
+ let ry = L.sag * 1.05 * L.roundScale * roundAmount;
+ // Keep the oval below the nose and inside the plate, but allow it to grow to
+ // roughly half the head. The stroke's share is a fixed margin, not the live
+ // `thickness`: otherwise 口の太さ would quietly resize the oval too.
+ ry = Math.min(ry, (edgeBottom - L.thickness / 2 - L.noseClear) / 2.1);
+ const rx = Math.min(ry * 1.15 * clamp(p.width ?? 1, 0.2, 1.6), L.halfChord * 1.4);
+ const centreY = clamp(y0 + sag * 0.5, L.noseClear + ry * 1.02, edgeBottom - L.thickness / 2 - ry * 1.02);
+ if (ry > 5) {
+ ctx.save();
+ ctx.translate(pivot.x, pivot.y);
+ ctx.rotate((tilt * Math.PI) / 180);
+ ctx.translate(-pivot.x, -pivot.y);
+ ctx.beginPath();
+ ctx.ellipse(L.centreX, centreY, rx, ry, 0, 0, TAU);
+ if (!line) {
+ ctx.fillStyle = innerColor;
+ ctx.fill();
+ if (tongueAmount > 0.01) {
+ ctx.beginPath();
+ ctx.ellipse(L.centreX, centreY + ry * 0.46, rx * 0.52, ry * 0.4, 0, 0, TAU);
+ ctx.fillStyle = tongueColor;
+ ctx.fill();
+ }
+ }
+ ctx.strokeStyle = strokeColor;
+ ctx.lineWidth = line ? thickness * 0.8 : thickness;
+ ctx.stroke();
+ ctx.restore();
+ }
+ return;
+ }
+
+ // The smile line is the upper lip. Opening the mouth drops the lower jaw
+ // below it, and the room for that is limited by the texture band the mouth
+ // plane shows - otherwise the jaw is silently clipped away.
+ // Everything has to fit in the part of the plane that faces the camera.
+ let rise = L.openRise * openAmount;
+ const budget = edgeBottom - thickness / 2 - y0;
+ if (sag + rise > budget) {
+ rise = Math.max(0, budget - Math.min(sag, budget));
+ if (sag + rise > budget) sag = Math.max(-80, budget - rise);
+ }
+ const jawCubic = mouthControls(left, right, sag + rise, L.sagBend);
+ const jaw = cubicPoints(jawCubic.p0, jawCubic.p1, jawCubic.p2, jawCubic.p3, 96);
+ const jawAt = (t) => cubicPoint(jawCubic.p0, jawCubic.p1, jawCubic.p2, jawCubic.p3, t);
+ const lipAt = (t) => cubicPoint(lip.p0, lip.p1, lip.p2, lip.p3, t);
+ const openShape = rotate([...arc, ...jaw.slice(1, -1).reverse()], pivot, tilt);
+
+ const tonguePos = clamp(p.tonguePos ?? L.tongue.pos, 0.05, 0.95);
+ const tongueWidth = L.tongue.width * tongueAmount;
+ const tongueHeight = L.tongue.height * tongueAmount;
+
+ /**
+ * The tongue, rising from `curve` to `height` above its middle.
+ *
+ * `pointAt(t)` is that same curve as a function of t, so the tongue's foot can
+ * sit along it without this needing to know what kind of curve it is.
+ */
+ function drawTongue(pointAt, curve, height) {
+ const arcLength = Math.max(1, chordLength(curve));
+ const dt = clamp(tongueWidth / 2 / arcLength, 0.01, 0.45);
+ const t0 = clamp(tonguePos - dt, 0, 1);
+ const t1 = clamp(tonguePos + dt, 0, 1);
+ const base = [];
+ for (let i = 0; i <= 16; i++) base.push(pointAt(t0 + ((t1 - t0) * i) / 16));
+ const mid = pointAt(clamp(tonguePos, 0, 1));
+ const half = tongueWidth / 2;
+ // The foot runs left to right; the crown comes back right to left, so the two
+ // together are already a closed ring.
+ const footRight = base[base.length - 1];
+ const footLeft = base[0];
+ const crown = [];
+ const steps = 26;
+ for (let i = 0; i <= steps; i++) {
+ const f = i / steps;
+ const dx = 1 - 2 * f;
+ const footY = footRight.y + (footLeft.y - footRight.y) * f;
+ crown.push({
+ x: mid.x + dx * half,
+ y: footY - height * (1 - Math.pow(Math.abs(dx), L.tongue.crown)),
+ });
+ }
+ const shaped = rotate([...base, ...crown], pivot, tilt);
+ if (line) {
+ strokePolyline(ctx, shaped, { color: strokeColor, width: thickness * 0.8, closed: true });
+ return;
+ }
+ tracePolyline(ctx, shaped, true);
+ ctx.fillStyle = tongueColor;
+ ctx.fill();
+ }
+
+ if (openAmount > 0.004) {
+ if (!line) fillPolygon(ctx, openShape, innerColor);
+ // The tongue rises from the lower lip *into* the mouth, so it has to arrive
+ // with the opening: at a hair's width the jaw curve is a sliver, and the
+ // tongue used to burst straight out of it and sit on the chin.
+ const tongueOpen = clamp((openAmount - 0.06) / 0.24, 0, 1);
+ if (tongueAmount > 0.01 && tongueOpen > 0.01) {
+ ctx.save();
+ tracePolyline(ctx, openShape, true);
+ ctx.clip();
+ // Inside an open mouth the tongue sits on the lower jaw.
+ drawTongue(jawAt, jaw, tongueHeight * tongueOpen * (1 + openAmount * 0.3));
+ ctx.restore();
+ }
+ // One outline around the whole mouth reads as lips; the smile stroke alone
+ // would leave the lower edge as a bare colour change.
+ strokePolyline(ctx, openShape, { color: strokeColor, width: thickness, closed: true });
+ } else {
+ // Closed lips - but the tongue still pokes over the lip. That is what the
+ // original artwork does (the mouth reads as a smile with the tongue showing,
+ // like ペコちゃん), and it is why a plain line looked wrong there. The lip
+ // line goes on afterwards, so the tongue comes out from under it.
+ if (tongueAmount > 0.01) {
+ drawTongue(lipAt, arc, tongueHeight);
+ }
+ strokePolyline(ctx, rotate(arc, pivot, tilt), { color: strokeColor, width: thickness });
+ }
+
+ // --- corner marks ---------------------------------------------------
+ if (cornerAmount > 0.01) {
+ const C = L.corner;
+ const cornerAngle = p.cornerAngle ?? 0;
+ for (const [end, side] of [[left, -1], [right, 1]]) {
+ const from = { x: end.x + C.fromX * side * cornerAmount, y: end.y - C.fromY * cornerAmount };
+ const to = { x: end.x - C.toX * side * cornerAmount, y: end.y - C.toY * cornerAmount };
+ // A smooth curve, not a three-point kink. `mid` is the control point, so it
+ // is pulled twice as far as the bow should reach; both corners bow the same
+ // way (downwards on screen), which is what the original artwork does.
+ const control = {
+ x: (from.x + to.x) / 2,
+ y: (from.y + to.y) / 2 + (C.curve ?? 26) * cornerAmount,
+ };
+ const curve = quadraticPoints(from, control, to, 16);
+ // `cornerAngle` tilts the whole mark around the mouth corner, mirrored so
+ // both sides move together.
+ const shaped = cornerAngle ? rotate(curve, end, cornerAngle * side) : curve;
+ strokePolyline(ctx, rotate(shaped, pivot, tilt), {
+ color: line ? strokeColor : (p.cornerColor ?? '#725497'),
+ // The *length* of the corner mark follows `corners`, but its thickness
+ // does not: `corners: 0.71` is the length that matches the original, and
+ // the original's stroke is the full thickness.
+ width: C.width,
+ });
+ }
+ }
+}
+
+/** Approximate length of a polyline. */
+function chordLength(points) {
+ let total = 0;
+ for (let i = 1; i < points.length; i++) {
+ total += Math.hypot(points[i].x - points[i - 1].x, points[i].y - points[i - 1].y);
+ }
+ return total;
+}