design: refresh marketplace icon (navy shield + teal accent)

.gitignore

@@ -149,3 +149,4 @@ out/
 
 # VS Code dev sandbox
 .vscode-test/
+.claude/

.vscodeignore

@@ -1,5 +1,6 @@
 .vscode/**
 .vscode-test/**
+.claude/**
 .github/**
 src/**
 test-fixtures/**
@@ -14,6 +15,7 @@ ROADMAP.md
 tsconfig.json
 tsconfig.integration.json
 vitest.config.ts
+media/icon-source.svg
 **/*.map
 **/*.ts
 **/tsconfig.json

scripts/gen_icon.py

@@ -1,111 +1,161 @@
-"""Generate the marketplace icon (128x128 PNG) from the brand SVG.
+"""Generate the marketplace icon (128×128 PNG) from the brand SVG.
 
-Re-run when the brand mark changes; the resulting ``icon.png`` is
-committed alongside this script so contributors don't need to install
-Pillow just to read it. The script depends on Pillow (``pip install
-pillow``); a single one-shot, not part of the extension build.
+The source of truth is ``media/icon-source.svg`` (concept B: navy
+shield with a teal accent border + teal check). This script is a
+pure-Python renderer that produces the matching PNG so contributors
+don't need to install Inkscape / Cairo / a browser to read the icon.
 
-The mark is the same shield + teal checkmark used in the
-pipeline-check docs hero. Path data lifted verbatim from
-``dmartinochoa/pipeline-check`` ``docs/index.md`` so the marketplace
-icon, the docs hero, and the favicon share a single visual identity.
+Implementation notes
+--------------------
+
+* Renders at 4× supersampling (512×512) and downsamples to 128×128
+  with Lanczos resampling. PIL's straight ``ImageDraw`` antialiasing is
+  blocky on diagonal strokes; the supersample → downsample pipeline
+  gives clean edges that match what a real SVG renderer would produce.
+
+* The shield path uses two quadratic Beziers (top-left and top-right
+  arcs at the base) — sampled into polygon points for ``ImageDraw``.
+
+* The check uses ``ImageDraw.line`` with ``joint="curve"`` for the
+  vertex join, plus explicit circles at the two endpoints to simulate
+  ``stroke-linecap="round"``.
+
+Dependencies: Pillow (``pip install pillow``). Run once after the
+brand mark changes; the resulting ``icon.png`` is committed alongside
+this script.
 """
 from __future__ import annotations
 
 from pathlib import Path
 
 from PIL import Image, ImageDraw
 
+# Output size + supersample factor. The renderer composes everything in
+# the supersampled space then downsizes — keeps the diagonal stroke of
+# the check from going staircase-blocky.
 ICON_SIZE = 128
-SCALE = 2  # viewBox is 64x64 in the brand SVG.
+SS = 4
+SCALE = SS  # design SVG viewBox is already 128×128, so we just scale by SS
 
-# Pipeline-Check design tokens (lifted from
-# pipeline_check/core/_design_tokens.css + extra.css).
+# Pipeline-Check design tokens (mirrors media/icon-source.svg and
+# pipeline_check/core/_design_tokens.css).
 NAVY_950 = "#04101a"
-WHITE = "#f0f2f5"
 TEAL = "#1ba3a9"
 
 OUT_DIR = Path(__file__).resolve().parent.parent
 OUT_PATH = OUT_DIR / "icon.png"
 
 
-def _cubic_bezier(
+def _quadratic_bezier(
     p0: tuple[float, float],
     p1: tuple[float, float],
     p2: tuple[float, float],
-    p3: tuple[float, float],
-    steps: int = 32,
+    steps: int = 48,
 ) -> list[tuple[float, float]]:
-    """Sample a cubic Bezier curve into ``steps + 1`` polygon points."""
-    points: list[tuple[float, float]] = []
+    """Sample a quadratic Bezier curve into ``steps + 1`` polygon points."""
+    out: list[tuple[float, float]] = []
     for i in range(steps + 1):
         t = i / steps
         mt = 1 - t
-        x = (
-            mt ** 3 * p0[0]
-            + 3 * mt ** 2 * t * p1[0]
-            + 3 * mt * t ** 2 * p2[0]
-            + t ** 3 * p3[0]
-        )
-        y = (
-            mt ** 3 * p0[1]
-            + 3 * mt ** 2 * t * p1[1]
-            + 3 * mt * t ** 2 * p2[1]
-            + t ** 3 * p3[1]
-        )
-        points.append((x, y))
-    return points
+        x = mt * mt * p0[0] + 2 * mt * t * p1[0] + t * t * p2[0]
+        y = mt * mt * p0[1] + 2 * mt * t * p1[1] + t * t * p2[1]
+        out.append((x, y))
+    return out
 
 
 def _shield_outline() -> list[tuple[float, float]]:
-    """Return the shield polygon in viewBox (64x64) coordinates.
-
-    Mirrors the SVG path::
+    """Shield polygon in the design's 128×128 viewBox coords.
 
-        M32 6 L54 13 V31
-        C54 44.5 44.5 53.5 32 58
-        C19.5 53.5 10 44.5 10 31
-        V13 Z
+    Mirrors media/icon-source.svg::
 
-    Two cubic Beziers form the bottom curve; the rest is straight.
+        M 64 12 L 110 26 L 110 62 Q 110 92 64 116 Q 18 92 18 62 L 18 26 Z
     """
     pts: list[tuple[float, float]] = [
-        (32.0, 6.0),    # top center
-        (54.0, 13.0),   # top right
-        (54.0, 31.0),   # vertical line down right side
+        (64.0, 12.0),     # top-centre cusp
+        (110.0, 26.0),    # top-right
+        (110.0, 62.0),    # right-side straight down
     ]
-    # First bezier: down-right curve to bottom apex.
-    pts.extend(_cubic_bezier(
-        (54.0, 31.0), (54.0, 44.5), (44.5, 53.5), (32.0, 58.0),
-    ))
-    # Second bezier: bottom apex back up to left side.
-    pts.extend(_cubic_bezier(
-        (32.0, 58.0), (19.5, 53.5), (10.0, 44.5), (10.0, 31.0),
-    ))
-    pts.append((10.0, 13.0))  # vertical line up left side
+    # Bottom-right curve down to the apex.
+    pts.extend(_quadratic_bezier((110.0, 62.0), (110.0, 92.0), (64.0, 116.0)))
+    # Bottom-left curve back up.
+    pts.extend(_quadratic_bezier((64.0, 116.0), (18.0, 92.0), (18.0, 62.0)))
+    pts.append((18.0, 26.0))  # left-side straight up
     return pts
 
 
-def _scaled(
-    points: list[tuple[float, float]],
-) -> list[tuple[float, float]]:
-    return [(x * SCALE, y * SCALE) for x, y in points]
+def _scaled(pts: list[tuple[float, float]]) -> list[tuple[float, float]]:
+    return [(x * SCALE, y * SCALE) for x, y in pts]
+
+
+def _round_cap(
+    draw: ImageDraw.ImageDraw,
+    centre: tuple[float, float],
+    width: float,
+    fill: str,
+) -> None:
+    """Draw a filled circle to simulate ``stroke-linecap="round"``."""
+    r = width / 2.0
+    draw.ellipse(
+        (centre[0] - r, centre[1] - r, centre[0] + r, centre[1] + r),
+        fill=fill,
+    )
 
 
 def main() -> None:
-    img = Image.new("RGBA", (ICON_SIZE, ICON_SIZE), NAVY_950)
-    draw = ImageDraw.Draw(img)
+    big_size = ICON_SIZE * SS
+    img = Image.new("RGBA", (big_size, big_size), (0, 0, 0, 0))
+    draw = ImageDraw.Draw(img, "RGBA")
 
-    # Shield outline, no fill, 5px stroke (≈2.5 in viewBox * SCALE).
     shield = _scaled(_shield_outline())
-    draw.line(shield + [shield[0]], fill=WHITE, width=5, joint="curve")
-
-    # Checkmark: M22 32 L29 39 L43 24, 6px stroke (3 in viewBox * SCALE).
-    check = _scaled([(22.0, 32.0), (29.0, 39.0), (43.0, 24.0)])
-    draw.line(check, fill=TEAL, width=6, joint="curve")
 
+    # Fill the navy shield.
+    draw.polygon(shield, fill=NAVY_950)
+
+    # Stroke the teal accent border (width 4 in viewBox space).
+    border_width = 4 * SCALE
+    draw.line(
+        shield + [shield[0]],
+        fill=TEAL,
+        width=border_width,
+        joint="curve",
+    )
+    # Round-cap the implicit "close path" join at the top cusp so it
+    # doesn't read as a notch.
+    _round_cap(draw, shield[0], border_width, TEAL)
+
+    # Inner ribbon at 25% opacity. Implemented by drawing the path at
+    # full opacity onto a transparent layer, then alpha-compositing
+    # with reduced opacity onto the main image.
+    ribbon = _scaled(
+        [(64.0, 22.0), (100.0, 32.0), (100.0, 62.0)]
+        + _quadratic_bezier((100.0, 62.0), (100.0, 86.0), (64.0, 106.0))
+        + _quadratic_bezier((64.0, 106.0), (28.0, 86.0), (28.0, 62.0))
+        + [(28.0, 32.0)]
+    )
+    ribbon_layer = Image.new("RGBA", (big_size, big_size), (0, 0, 0, 0))
+    ribbon_draw = ImageDraw.Draw(ribbon_layer, "RGBA")
+    ribbon_draw.line(
+        ribbon + [ribbon[0]],
+        fill=TEAL,
+        width=1 * SCALE,
+        joint="curve",
+    )
+    # Reduce to 25% opacity.
+    alpha = ribbon_layer.split()[-1].point(lambda v: int(v * 0.25))
+    ribbon_layer.putalpha(alpha)
+    img.alpha_composite(ribbon_layer)
+
+    # Check mark.
+    check_pts = _scaled([(40.0, 64.0), (56.0, 80.0), (88.0, 48.0)])
+    check_width = 11 * SCALE
+    draw.line(check_pts, fill=TEAL, width=check_width, joint="curve")
+    _round_cap(draw, check_pts[0], check_width, TEAL)
+    _round_cap(draw, check_pts[-1], check_width, TEAL)
+
+    # Downsample with Lanczos for smooth edges.
+    img = img.resize((ICON_SIZE, ICON_SIZE), Image.LANCZOS)
     img.save(OUT_PATH, "PNG", optimize=True)
-    print(f"wrote {OUT_PATH} ({ICON_SIZE}x{ICON_SIZE})")
+    print(f"wrote {OUT_PATH} ({ICON_SIZE}×{ICON_SIZE}) from media/icon-source.svg")
 
 
 if __name__ == "__main__":