Atelier

atelier — image studio driven by short Python scripts

Install (Python ≥ 3.11): pip install git+https://github.com/Wexop/atelier (update: pip install -U git+...) Check: atelier palette · atelier brushes · atelier fx (signatures).

Loop (always)

0. Pick the style guide (see Styles below) and read it; none fits → styles/new-style.md.
1. Write scene.py (30–80 lines, from atelier import *, build a Canvas c, end with c.save(__file__[:-3] + ".png")).
2. atelier render scene.py --preview → scene_prev.jpg (512 px, real low-res render, saves skipped). Read the image.
3. atelier inspect scene.py → scene_sheet.jpg: view, 5-value study + thirds/focal, clip map, histogram, palette, 4 auto zooms (aliasing, banding, noise, highlight) labelled --crop x,y,w,h, metrics + red flags. Read it. Zoom: atelier render scene.py --crop x,y,w,h.
4. ≥3 look-and-fix rounds (atelier compare old.png new.png for A/B), then atelier render scene.py (final; --scale 2, --seed N → SEED). Errors print one line scene.py:LINE: Type: message (--debug for traceback).

Conventions

• Drawing coords = canvas px (y down). Fields use normalised x, y ∈ [0,1]. Colours: "#hex", CSS names, (r,g,b) 0–1 or 0–255.
• Paint source (fill=, color=, stroke=) = colour | Field | f(x,y) | array H×W×3/4. Masks = Field | Shape | array | f(x,y).
• Everything random takes seed=. Previews render at low res: the picture is identical, only sharper at final.

Canvas & layers (core)

c = Canvas(w, h, bg=None, pixel=False)      # pixel=True: no AA, fixed scale, nearest-neighbour export
L = c.layer(blend="normal", opacity=1, mask=None)   # new layer, BECOMES CURRENT; c.use(L) to switch back
blends: normal multiply screen overlay soft_light hard_light add subtract color_dodge color_burn darken lighten difference hue saturation color luminosity
c.fill(src, mask=None) · c.erase(mask) · c.place(img|path, x=None, y=None, scale=None(cover), rot=0, fit="cover"|"contain", blend, opacity) -> layer
c.apply(*fx, mask=None)   # MERGES all layers, then effects (final grading);  L.apply(*fx, mask=None) = one layer
c.save(path, quality=92, scale=1, smooth=None) · c.preview(path, width=512) · c.crop_preview(path, x, y, w, h)
c.flatten() -> H×W×4 float · L.rgba (get/set) · c.w c.h (logical) c.W c.H c.s (raster scale)

Fields (field) — lazy, composable: + - * / ** > <, np.sin(f), f.ramp() f.warp() f.scale() f.rotate() f.move() f.remap(lo,hi) f.clip() f.within(shape|(x0,y0,x1,y1))

X Y radial(cx,cy) angle(cx,cy) · Field(lambda x, y: ...)
perlin/simplex/value(scale=4, seed) · fbm(scale=4, octaves=5, lacunarity=2, gain=.5, seed, base="perlin")
ridged(scale=3, ...) · turbulence(scale=4, ...) · worley(scale=6, mode="F1"|"F2"|"F2-F1"|"id", seed)
domain_warp(f, strength=.1, scale=2, seed) · aastep(f, edge=.5) · smoothstep(e0, e1, v) · mix(a, b, t)
patterns [0,1]: wood(rings=14, angle) marble() clouds(scale, cover=.5, sharp) terrain_height() water_ripples() fabric(scale=60) paper() stars(density=60, size)
gradient(stops, angle=90 (top→bottom; 0 = left→right), kind="linear"|"radial"|"conic", center, radius)
ramp(f, stops) / f.ramp("sunset") · stops = palette name | ["#..", ...] | [(pos, col), ...]   (OKLab interpolation)
palette("name") names: sunset night ocean forest desert earth fire ice pastel neon vapor viridis wood marble mono retro16 green4
cosine_palette(a, b, c, d, n=8) · rgb2hsv hsv2rgb rgb2oklab oklab2rgb
shade(height, light=(azimuth, elevation), strength=1, color=None, ambient=.25, spec=0)   # no color → grey, flat=0.5 (use on overlay layer)
masks: top(f) bottom(f) left(f) right(f) band(y0, y1) zone(x0, y0, x1, y1) disc(cx, cy, r)  (all soft=)
curves: f.ridge_line(y=.6, amp=.15) / curve(lambda x: y) → c.fill_below(curve, src) / fill_above · curve.below()

Vector & text (vector) — Shape = skia path, also a Field mask; booleans | & - ^

rect(x, y, w, h, r=0) ellipse(cx, cy, rx, ry) circle(cx, cy, r) polygon(pts) line(x1,y1,x2,y2 | pts) regular(cx,cy,r,n)
star(cx, cy, r, r2, n=5) arc(cx, cy, r, start, sweep) spline(pts, closed) svg("M .. C .. A .. Z") union(*shapes)
shape.move/rotate(deg)/scale/outline(width, dash)/soft(feather)/points(n)/bounds/length
c.draw(shape, fill="black", stroke=None, width=2, cap="round", join="round", dash=(on, off), feather=0, opacity=1)
c.rect/ellipse/circle/polygon/line/spline/path(d)(..., **same style)
c.text(txt, x, y, size=32, fill, font="sans"|"mono"|"serif"|family|path.ttf, weight="regular"|"semibold"|"bold"|int,
       align="left"|"center"|"right", valign="baseline"|"top"|"middle"|"bottom", spacing=em, line_height=1.2, italic, fit=width_px, kern=True)
text_shape(...) → Shape · text_size(txt, size) → (width, cap_height) · c.text_on_path(txt, shape|points, size, align, lift, fit, fill)
c.text_box(txt, x, y, w, h=None, size=18, align="left"|"justify"|"center", line_height=1.4, fit=True)   # **b** *i* [#c33]colour[/]
c.title(txt, x, y, size=96, style="shadow"|"extrude"|"outline"|"inline"|"neon", fill, color2)

Brushes (brush)

c.stroke(points|Shape, brush="round", size=12, color, pressure=[...]|f(t)|float, opacity, jitter, spacing, taper=(a, b), seed, **params)
brushes: round round_soft airbrush ink(speed) chalk(tooth) bristle(n, var, gaps) oil(impasto, pickup) watercolor(edge, granulation, bleed)
c.paint_like(ref, brush="oil", sizes=(48,24,12), tol=.08, angle=0, seed)   # repaint a reference (Canvas/Field/image) with strokes
c.scatter(what, n, region=mask, size=(a, b), color=col|list|palette|Field, color_jitter, rot=(a, b), seed)
   what: dot soft star grass leaf petal square person | Shape (unit size at 0,0)
c.hatch(region, angle=45, spacing=8, width=1.2, color, tone=Field (0=dark → thick), cross=False, wobble)
km_mix(a, b, t) pigment-like mixing (blue+yellow = green) · L.relief = 1.0 (oil impasto lighting strength)

Effects (fx) — c.apply(...) / L.apply(...); sizes in canvas px

blur(r) motion_blur(len, angle) sharpen(amt) bloom(threshold=.75, radius=12, strength=.8, tint) glow(r, strength, color)
drop_shadow(dx, dy, r, color, opacity) inner_shadow(...) vignette(amount=.35, softness=.6) grain(amount=.04, size=1, seed)
chromatic_aberration(px) lens_distortion(k) exposure(stops) contrast(amt) levels(black, white, gamma) curves([(in, out), ...], channel)
hue_sat(hue_deg, sat_mult, light) saturation(x) color_balance(shadows=(r,g,b), mids, highlights) gradient_map(stops) invert()
tone_map("agx"|"filmic"|"reinhard", exposure, look="punchy") displace(field, strength) posterize(levels)
pixelate(size, palette=name|list, colors=N, dither=None|"bayer"|"fs", strength=.6) halftone(size, angle, ink, paper, cmyk=False)
god_rays(x, y, rays=14, length=.9, strength=.45, color, threshold=.7, occlude=True) lens_flare(x, y, strength=.6, color, ghosts=6, streak=.5)
depth_of_field(depth, focus, aperture=8)   # depth from r = c.render(scene)
match_palette("ref.jpg", amount) transfer_tone(ref, amount)   # colour/tone transfer from a reference image

Stylize (stylize) — 3D → illustration + painterly filters (effects for c.apply / L.apply)

r = c.render(s, alpha=True); c.cur.apply(toon(r, bands=3, shadow=.45, colors={id: col}), shadow_dots(r, size=5, lo=.3), outlines(r, width=2.5, inner=1))
engraving: L.fill(PAPER, mask=r.alpha); L.apply(render_hatch(r, s, spacing=4.5, layers=3), outlines(r, width=2))  # hatches follow 3D surfaces
kuwahara(radius=6) oil · xdog(sigma=1, eps=.9, ink, paper) ink lines · pencil() · linocut(lines=7, angle) · edge_smooth(4)
watercolorize(bleed=2, edge=1, granulation=.4, ink=0..1) · stained_glass(cell=26, lead=3) · mosaic(tile=10) · shading(r) → (H,W) light

3D (sdf) — y up, units ≈ metres, primitives centred at origin

sphere(r) box(w, h, d) round_box(w, h, d, r) cylinder(r, h) capsule(a, b, r) torus(R, r) cone(r1, h, r2) plane(y, normal)
ellipsoid(rx, ry, rz) lathe([(radius, y), ...] bottom→top, thickness=None|shell) extrude([(x, y), ...], depth)
ops: a | b, a & b, a - b, a.union(b, k=smooth) .inter .sub · .move(x,y,z) .rotate(x,y,z deg) .scale(k|(kx,ky,kz))
     .onion(t) .round(r) .twist(k) .bend(k) .repeat(period, count) .mirror("x") .elongate() .displace(noise3(scale, octaves, seed), amount)
Mat(color | 2D Field (proj="tri"|"xz"|"xy"|"zy", tex_scale) | f(p, n)->(N,3), rough=.5|Field|f(p,n), metal=0, glass=0, ior=1.45,
    sss=0, sss_color, emit=None, power=1, bump=.3, bump_scale=60, local=True (textures follow the object), sheen=.6,
    wear=[smudges(.5), scratches(.5, density=40), dust(.3), edge_wear(.5, width=.01, color)])
s = Scene(); id = s.add(sdf, Mat(...)); s.camera(pos, target, fov=40)
s.sun(dir_toward_sun, color, power=3, soft=.04) · s.point(pos, color, power, radius) · s.area(pos, size=(w,h), normal, color, power, pattern="window"|"softbox", visible)
s.studio(key, target, size, power=45, window=True, fill=.2, bg) · s.sky(zenith, horizon, ground, power) · s.fog(color, density)
r = c.render(s, aa=1|2, exposure=0, look=None|"punchy", alpha=False)          # fast raymarcher (direct light + AO + 1 reflection)
r = c.pathtrace(s, spp=16, bounces=4, denoise=True, aperture=0, focus=None|dist|(x,y), seed=SEED)  # photoreal: GI, multi-refraction glass, adaptive AA
r.depth r.normal r.id r.mask(id) r.focus_at(x, y, c.s) r.linear r.spp r.time · denoise(img, albedo, normal, depth)

Nature (nature, terrain)

h = terrain(384, kind="alpine"|"hills"|"mesa"|"island"|"dunes", seed, erosion=1, flow=False)   # eroded heightmap [0,1]; erode() thermal()
c.terrain_map(h, style="relief"|"topo"|"shaded", water=.2)
v = c.landscape(h, cam=(x, alt, z), yaw, fov, horizon=.58, sun_elev=10, sun_az=30, haze=1, clouds=.35, water=.1, waves=.02, snow=.7, seed)
    v.depth v.water v.project(x, y, z) -> (px, py, px_per_m) v.ground(x, z)   # place 2D trees on the 3D terrain
c.sky(sun_elev=8, sun_az=0, horizon=.6, clouds=.3, haze=1) · c.sea(sun_elev=6, waves=.12, wave_len=60, foam=.5, clouds=.25)
c.tree(x, y, height_px, kind="oak"|"pine"|"birch"|"palm"|"bush"|"dead", season="summer"|"spring"|"autumn"|"winter", haze=0..1, seed)
c.grass(x, y, w, h, n) c.flower(x, y, size, kind="daisy"|"poppy"|"tulip"|"bell") c.fern(x, y, size) · tree3d("oak", 4, seed) → (trunk, leaves) SDFs
scene_sky(s, sun_elev, sun_az)   # physical sky on a 3D Scene
c.anime_cloud(x, y, w, h=.55w, palette="day"|"sunset"|"dusk"|"storm"|(shadow,mid,light,rim), light=(az, elev), bands=3, rim=.7, wisps, edge, bottom, seed)  # cel-shaded cumulus, flat base at (x, y)
c.anime_tree(x, y, height, kind="round"|"tall"|"umbrella", palette="summer"|"spring"|"autumn"|"sakura"|"dusk"|(sh,mid,lt,rim,trunk), light, width, leafy=.6, seed)  # cel-shaded tree
c.anime_mountains(y_foot, height, peaks=4, x0, x1, palette="day"|"dusk"|"autumn"|(sh,mid,lt,snow,snow_sh,haze), light, snow=.35, haze=.6, sharp=1, depth=.35, bands=3, seed)  # eroded relief, front view, cel tones
c.sparkles(n, region=mask, size=(6, 16), color, rays=4, glow=.6, seed)   # star glints (water, snow)

Figures (figure) — feet at (x, y), height = standing px (animals: withers)

c.figure(x, y, h, pose="stand", style="flat"|"line"|"silhouette"|"stick"|"ink"|"chalk", kind="human"|"cat"|"dog"|"horse"|"bird", seed)
   poses: stand idle walk run sit wave point cheer jump dance think hips phone reach · phase=0-1 (walk cycle) view="front"|"3q"|"side"|"back"
   body=adult|teen|child|elder build=slim|heavy outfit="tee pants|coat skirt|dress" hair=short|bob|long|bun|curly skin=SKIN name colors={...}
figure_shape(...) → Shape · figure_joints(...) → {"hand_r": (x, y), ...} (attach props) · figure_sdf(pose, height=1.75, style="mannequin")
c.crowd(n, box=(x0, y0, x1, y1), horizon=y, height=near_px, tint=(haze, .5), dogs=.1, seed)   # perspective-scaled crowd

Inspect (inspect) — judge numbers, not only the downscaled view

m = metrics(c|path|arr)   # noise (<1 clean, >4 grainy) aliasing (% hard steps, >35 jaggy) banding clip_shadows/highlights flags[...]
contact_sheet(c, "sheet.jpg") · compare(a, b, "ab.jpg") · guides(c) / composition(c) → focal, balance, tilt · analyze_reference("ref.jpg")

Styles — read the matching guide before writing the scene

Guides live in styles/ next to this file (if missing: https://raw.githubusercontent.com/Wexop/atelier/main/styles/<name>.md). Each gives recipe, rules, pitfalls and an example script. Several can be mixed (e.g. anime + flat).

• anime.md — painted anime landscapes: cel clouds, trees, mountains, rim light, god rays, sparkles
• oil.md — oil (paint_like) and watercolour washes
• photoreal.md — path-traced still life / product, terrain landscapes, sea and sky
• comic.md — ligne claire / toon from 3D, engraving, ink filters
• flat.md — flat vector, posters, typography, people, silhouette scenes
• pixel.md — pixel art with palettes and dithering
• abstract.md — generative abstracts from warped fields
• new-style.md — no guide fits: study the look, map it to primitives, paint, then save a new styles/<name>.md

Pitfalls

• c.layer() changes the current target: later c.text/... go to that layer (bad if it is multiply). Call c.layer() or c.use(L).
• c.apply() merges all layers. Use L.apply() to keep layers.
• shade(strength) depends on field frequency: ≈1 for big forms, ≈.05 for fine textures (fabric).
• tone_map on 2D art greys pure white — it is for HDR/3D; use curves/levels on illustrations.
• Hard thresholds alias: use aastep/smoothstep, not f > .5, for visible edges.
• Noise scale = features per canvas height. Shape coords = canvas px; Field coords = 0–1.
• Cost: pathtrace ≈ 30–60 µs/path (1200×800 @ 8 spp ≈ 5 min on 2 cores, previews 4× fewer spp) — draft with c.render; low spp sparkles on glossy metal/glass (raise spp). aa=2 ≈ 4×. Many SDF parts (figures, tree3d, displace) are slow to trace.
• Glass: rough=0 for clear (default rough .5 = frosted). In c.render glass bends once; use pathtrace for real refraction.
• Landscape: keep cloud cover ≤ .3 overhead (low clouds look boxy); bloom near the sun haloes clouds.