tools: map a Canary UI draw log's blend states onto named sprites

Identifies each draw by the pixel size of its quad -- NDC extents times the
1280x720 surface -- matched against sprite dimensions read off the disc, since
the log names no elements.

Carries its own control: build 5 draws two rotated sweep strips whose heights
were measured independently at 1134 and 1303 px in
docs/re/data/title-sweep-drawn-at-rest.txt. If the conversion does not reproduce
those, every size it prints is wrong and it says so.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v

tools/re-capture/ui_blend_map.py

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+"""Which UI element is drawn with which BLEND state — from a Canary UI draw log.
+
+    ui_blend_map.py <xenia_re_ui_draws_NN.log> [--build 5]
+
+Canary's `CaptureUiDrawForRE` (patched 2026-08-31) logs RB_BLENDCONTROL0 per
+draw. The log does not name elements, so a draw is identified by the PIXEL SIZE
+of its quad: the vertices are in NDC, and (x_max-x_min)/2*1280 by
+(y_max-y_min)/2*720 is the on-screen size, which is matched against the sprite
+dimensions read straight off the disc.
+
+CONTROL, and it is not optional: GP_TITLE build 5 draws two rotated sweep
+strips whose heights were measured independently in
+docs/re/data/title-sweep-drawn-at-rest.txt as 1134 and 1303 px. If this script's
+NDC->pixel conversion does not reproduce those two numbers, its sizes are wrong
+and every identification below them is worthless. It prints the check.
+
+Blend states seen on this title's UI, decoded from the Xenos enum
+(xenos.h: kZero=0 kOne=1 kSrcAlpha=6 kOneMinusSrcAlpha=7; BlendOp kAdd=0):
+
+    0x00010001  src=ONE  dst=ZERO             opaque, blending effectively off
+    0x07010701  src=ONE  dst=ONE_MINUS_SRC_A  premultiplied alpha-over
+    0x01010101  src=ONE  dst=ONE              ADDITIVE
+"""
+import re
+import subprocess
+import sys
+
+W, H = 1280.0, 720.0
+FACTOR = {0: "ZERO", 1: "ONE", 4: "SRC_COLOR", 5: "1-SRC_COLOR", 6: "SRC_ALPHA",
+          7: "1-SRC_ALPHA", 8: "DST_COLOR", 9: "1-DST_COLOR", 10: "DST_ALPHA",
+          11: "1-DST_ALPHA"}
+
+
+def blend_name(raw):
+    src, op, dst = raw & 0x1F, (raw >> 5) & 7, (raw >> 8) & 0x1F
+    if (src, op, dst) == (1, 0, 0):
+        return "opaque"
+    if (src, op, dst) == (1, 0, 7):
+        return "alpha-over(premul)"
+    if (src, op, dst) == (1, 0, 1):
+        return "ADDITIVE"
+    if (src, op, dst) == (6, 0, 7):
+        return "alpha-over(straight)"
+    return "%s+%s" % (FACTOR.get(src, src), FACTOR.get(dst, dst))
+
+
+def sprite_sizes(build):
+    """name -> (w, h), straight off the disc via the formats crate."""
+    out = subprocess.run(
+        ["cargo", "run", "--release", "-q", "-p", "sylpheed-formats",
+         "--example", "frame_alpha_census"],
+        capture_output=True, text=True, cwd="/work",
+        env={**__import__("os").environ, "SYLPHEED_DISC": "/disc"}).stdout
+    sizes, cur = {}, None
+    for line in out.splitlines():
+        m = re.match(r"=== GP_TITLE build (\d+) ===", line)
+        if m:
+            cur = int(m.group(1))
+            continue
+        m = re.match(r"(\S+\.t32)\s+(\d+)x(\d+)", line)
+        if m and cur == build:
+            sizes[m.group(1)] = (int(m.group(2)), int(m.group(3)))
+    return sizes
+
+
+def main():
+    path = sys.argv[1]
+    build = int(sys.argv[sys.argv.index("--build") + 1]) if "--build" in sys.argv else 5
+    sizes = sprite_sizes(build)
+    lines = open(path).read().splitlines()
+    rows = []
+    for i, line in enumerate(lines):
+        m = re.search(r"^\s*(\d+) prim=(\d+) indices=(\d+).* blend=0x([0-9A-F]+)", line)
+        if not m:
+            continue
+        idx, prim, nidx, raw = int(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(4), 16)
+        tex = re.search(r"tex\[base=0x([0-9A-F]+) (\d+)x(\d+)", line)
+        verts = []
+        if i + 1 < len(lines):
+            for vm in re.finditer(r"\[(-?\d+\.\d+),(-?\d+\.\d+),z=", lines[i + 1]):
+                verts.append((float(vm.group(1)), float(vm.group(2))))
+        quads = [verts[k:k + 4] for k in range(0, len(verts) - 3, 4)]
+        rows.append((idx, prim, nidx, raw, tex.group(1) if tex else None, quads))
+
+    print("draw prim idx  blend      state                 quad px (w x h)   best name match")
+    heights = []
+    for idx, prim, nidx, raw, tex, quads in rows:
+        for q in quads:
+            xs = [p[0] for p in q]
+            ys = [p[1] for p in q]
+            w = (max(xs) - min(xs)) / 2 * W
+            h = (max(ys) - min(ys)) / 2 * H
+            heights.append(h)
+            best, bd = "-", 1e9
+            for n, (sw, sh) in sizes.items():
+                d = abs(sw - w) + abs(sh - h)
+                if d < bd:
+                    best, bd = n, d
+            tag = best if bd <= 6 else "(no match, nearest %s off %.0f)" % (best, bd)
+            print("%4d %4d %4d  0x%08X %-20s %7.1f x %7.1f   %s"
+                  % (idx, prim, nidx, raw, blend_name(raw), w, h, tag))
+    tall = sorted(h for h in heights if h > 900)
+    print("\nCONTROL — the two rotated sweep strips measured independently at 1134 and 1303 px:")
+    print("  tall quads found: %s" % ["%.0f" % t for t in sorted(set(round(t) for t in tall))])
+    print("  PASS" if any(abs(t - 1134) < 3 for t in tall) and any(abs(t - 1303) < 4 for t in tall)
+          else "  FAIL — the NDC->pixel conversion is wrong; ignore every size above")
+
+
+if __name__ == "__main__":
+    main()