Type-enforce the waveform overlay contract, narrow waveformLanes to LaneSplit, fix laneCount/cache/path-fallback bugs

src/shell/instrument/editor_paint_waveform.cpp

@@ -1,9 +1,7 @@
 // editor_paint_waveform.cpp — the WAVEFORM band's painter: the channel lane(s), the loop
 // span + start/loop markers, and the amp-envelope overlay. Windows-only.
 //
-// Overlays that ride the waveform (the envelope trace, its node handles, the markers) draw
-// ONCE into WaveformSurface::overlay — the full band, spanning both stacked lanes in
-// stereo. Never per lane; see waveform_view.h's overlay contract.
+// Overlay contract: see waveform_view.h's WaveformSurface.
 
 #include "shell/instrument/reasampler_editor.h"
 
@@ -76,13 +74,14 @@ void ReaSamplerEditor::paintWaveform(LICE_IBitmap* bmp, const Rect& band) {
 
     // Markers and the loop span are overlays: ONE draw across the full stacked height, so a
     // stereo view reads one loop region rather than two.
-    const Rect& overlay = surface.overlay;
+    const OverlayArea& overlay = surface.overlay;
+    const Rect& overlayRect = overlay.rect;
     const SetupMarkers m = pickedMarkers(frames);
     if (m.hasLoop && m.loopEnd > m.loopStart) {
         const int lx = frameToX(overlay, frames, m.loopStart);
         const int rx = frameToX(overlay, frames, m.loopEnd);
         if (rx > lx) {
-            LICE_FillRect(bmp, lx, overlay.y, rx - lx, overlay.height,
+            LICE_FillRect(bmp, lx, overlayRect.y, rx - lx, overlayRect.height,
                           toLice(roleColor(kRoleLoopMarker)), 0.20f, 0);
         }
     }
@@ -92,16 +91,17 @@ void ReaSamplerEditor::paintWaveform(LICE_IBitmap* bmp, const Rect& band) {
         const int mx = frameToX(overlay, frames, markerFrames[i]);
         const bool loopMarker = (i != 0);
         const float alpha = (loopMarker && !m.hasLoop) ? 0.4f : 1.0f;
-        LICE_FillRect(bmp, mx - 1, overlay.y, 2, overlay.height,
+        LICE_FillRect(bmp, mx - 1, overlayRect.y, 2, overlayRect.height,
                       toLice(roleColor(markerRoles[i])), alpha, 0);
     }
 
     paintEnvelopeOverlay(bmp, overlay, frames);
 }
 
-void ReaSamplerEditor::paintEnvelopeOverlay(LICE_IBitmap* bmp, const Rect& waveArea,
+void ReaSamplerEditor::paintEnvelopeOverlay(LICE_IBitmap* bmp, const OverlayArea& waveArea,
                                             std::int64_t frames) {
-    if (frames <= 0 || waveArea.width <= 0 || waveArea.height <= 0) return;
+    const Rect& area = waveArea.rect;
+    if (frames <= 0 || area.width <= 0 || area.height <= 0) return;
     const double rate = liveSampleRate();
     if (rate <= 0.0) return;
     const double totalSeconds = static_cast<double>(frames) / rate;
@@ -113,8 +113,8 @@ void ReaSamplerEditor::paintEnvelopeOverlay(LICE_IBitmap* bmp, const Rect& waveA
     // curve over the waveform. Clip x to the wave rect (a Gate release tail maps past the right).
     const LICE_pixel line = toLice(roleColor(Role::AccentSecondary));
     for (std::size_t i = 1; i < poly.size(); ++i) {
-        const int x0 = (std::max)(waveArea.x, (std::min)(waveArea.right() - 1, poly[i - 1].x));
-        const int x1 = (std::max)(waveArea.x, (std::min)(waveArea.right() - 1, poly[i].x));
+        const int x0 = (std::max)(area.x, (std::min)(area.right() - 1, poly[i - 1].x));
+        const int x1 = (std::max)(area.x, (std::min)(area.right() - 1, poly[i].x));
         LICE_Line(bmp, x0, poly[i - 1].y, x1, poly[i].y, line, 1.0f, 0, true);
     }
     // Draggable node handles: a small square per draggable node (Origin + ReleaseStart are
@@ -128,8 +128,8 @@ void ReaSamplerEditor::paintEnvelopeOverlay(LICE_IBitmap* bmp, const Rect& waveA
         if (v.node == EnvNode::Origin || v.node == EnvNode::ReleaseStart) continue;
         const bool grabbed = (drag_ == DragKind::kEnvNode && envNode_ == v.node);
         const int r = 3;
-        const int hx = (std::max)(waveArea.x + r, (std::min)(waveArea.right() - 1 - r, v.x));
-        const int hy = (std::max)(waveArea.y + r, (std::min)(waveArea.bottom() - 1 - r, v.y));
+        const int hx = (std::max)(area.x + r, (std::min)(area.right() - 1 - r, v.x));
+        const int hy = (std::max)(area.y + r, (std::min)(area.bottom() - 1 - r, v.y));
         LICE_FillRect(bmp, hx - r, hy - r, 2 * r, 2 * r, grabbed ? handleHot : handle, 1.0f, 0);
     }
 }