midiviz: the wave is a watermark, not a backdrop

Behind the matrix it survived only in the margins — the cells' floor tints
are opaque on purpose, so 'behind' meant invisible. Painted over the
finished reading now, under the scanlines, brand magenta as atmosphere.

tools/bridge/midiviz.py

@@ -459,17 +459,23 @@ BASE_W, BASE_H = 420, 260
 # ── the two backdrops that are pictures, not measurements ─────────────────
 # PLN, 2026-09-24: "can we do a test (option menu toggle) with ParVagues
 # imagery (transparent parvagues wave) behind the midimon to style it
-# definitely ParVagues-y?"
+# definitely ParVagues-y?" — then, after the first cut painted it UNDER the
+# matrix: "i dont even see the parvagues wave its behind a grid of grids
+# somehow?" He was right, and it was structural, not a bug: the cells' floor
+# tints are OPAQUE on purpose (readability first), so anything painted behind
+# them survives only in the margins. A backdrop needs translucent layers
+# under it; this window has none.
 #
-# The wave is the brand mark itself — the Hokusai curl drawn in binary — and
-# brand magenta is a RESERVED colour in the Ship's Bridge design language,
-# which is exactly why it works here: at a wash this faint it is an
-# atmosphere, not a second reading competing with the cells. Vendored from
-# the SSOT asset (Perso/www/public/images/parvagues/logo_transparent.png,
-# downscaled to 640px) because midiviz must run standalone from a checkout
-# with no www tree on the box at all.
+# So the wave is a WATERMARK: painted over the finished reading, under the
+# scanline texture, faint enough to never compete with a digit. Brand magenta
+# is a RESERVED colour in the Ship's Bridge design language, which is exactly
+# why it works as atmosphere — nothing else on this canvas may use it, so the
+# wash says ParVagues and nothing else. Vendored from the SSOT asset
+# (Perso/www/public/images/parvagues/logo_transparent.png, downscaled to
+# 640px) because midiviz must run standalone from a checkout with no www
+# tree on the box at all.
 WAVE_PATH = Path(__file__).resolve().parent / "ui" / "parvagues_wave.png"
-WAVE_ALPHA = 0.13
+WAVE_ALPHA = 0.12
 
 # ── the HL feed ────────────────────────────────────────────────────────────
 # PLN, 2026-09-24: "please do indeed sub from the events, to indeed feed
@@ -1688,10 +1694,9 @@ def build_widget(port_label: str, reader: "Reader | None", scale: float = 1.0,
                                Qt.TransformationMode.SmoothTransformation)
             p.setOpacity(WAVE_ALPHA)
             try:
-                # Bottom-right, under the matrix and out of the header's way:
-                # the reading lives top-left, the brand lives where the eye
-                # rests. Painted between the background and everything else —
-                # the ordering IS the feature, same as the spectrum's.
+                # Bottom-right, over the finished reading: the digits live
+                # top-left, the brand lives where the eye rests. Under the
+                # scanlines, so the texture stays the canvas's own.
                 p.drawPixmap(w - scaled.width(), h - scaled.height(), scaled)
             finally:
                 p.setOpacity(1.0)
@@ -1841,8 +1846,6 @@ def build_widget(port_label: str, reader: "Reader | None", scale: float = 1.0,
                 # ordering IS the feature: PLN asked for it "behind".
                 if self.spectro:
                     self._paint_spectrum(p, w, h)
-                if self.wave:
-                    self._paint_wave(p, w, h)
                 self._paint_chrome(p, w, h, pulse)
                 self._paint_header(p, now, pulse)
                 self._paint_controls(p)
@@ -1850,6 +1853,11 @@ def build_widget(port_label: str, reader: "Reader | None", scale: float = 1.0,
                 self._paint_state(p)
                 self._paint_gutter(p, now, pulse)
                 self._paint_stream(p, now)
+                # The wave is a WATERMARK, not a backdrop: over the finished
+                # reading, under the texture. See the WAVE_PATH note — behind
+                # the opaque cells it survived only in the margins.
+                if self.wave:
+                    self._paint_wave(p, w, h)
                 self._scanlines_blit(p)
                 self.painted += 1
             finally: