fix(waveform): 4x-oversampled min/max envelope, columnMinMax homed in peaks, panel routed through shared drawWaveform — one gap-free algorithm on all surfaces

src/draw_kit.cpp

@@ -8,8 +8,7 @@
 
 #include <cstddef>
 
-#include "bank_grid.h"      // compressAmplitudeForDisplay — the shared dB display curve (pure)
-#include "vst/waveform_view.h"  // columnMinMax — per-pixel-column envelope merge (pure)
+#include "bank_grid.h"  // compressAmplitudeForDisplay — the shared dB display curve (pure)
 
 // SWELL / LICE. On Windows use native Win32 (windows.h first); on mac/linux SWELL is
 // provided by the host. Mirrors bank_panel.cpp's include discipline.
@@ -278,6 +277,11 @@ void drawListRow(LICE_IBitmap* bmp, const ListRowBox& row, const char* label,
     }
 }
 
+int waveformColumnCount(const KitBox& box) {
+    const int w = box.width - 4;  // fixed 2px inset each side (matches drawWaveform below)
+    return w > 0 ? w : 0;
+}
+
 void drawWaveform(LICE_IBitmap* bmp, const KitBox& box, const Envelope& env) {
     if (!bmp || box.empty()) return;
 
@@ -293,7 +297,7 @@ void drawWaveform(LICE_IBitmap* bmp, const KitBox& box, const Envelope& env) {
 
     const int channels = static_cast<int>(env.size());
     const int bandH = box.height / channels;
-    const int innerW = box.width - 4;  // drawable pixel columns: box.x+2 .. box.x+2+innerW-1
+    const int innerW = waveformColumnCount(box);  // columns: box.x+2 .. box.x+2+innerW-1
 
     for (int ch = 0; ch < channels; ++ch) {
         const ChannelEnvelope& bins = env[static_cast<std::size_t>(ch)];
@@ -306,12 +310,14 @@ void drawWaveform(LICE_IBitmap* bmp, const KitBox& box, const Envelope& env) {
 
         if (bins.empty() || innerW <= 0) continue;
 
-        // Render one filled vertical span per pixel column.  columnMinMax merges all
-        // bins that project to column `col` under the same partition as computeEnvelope,
-        // so every pixel column is covered with no gaps regardless of the bins-to-pixels
-        // ratio.  Same dB display compression as the panel thumbnail (bank_grid, pure).
+        // Render one filled vertical span per pixel column. peaks::columnMinMax merges
+        // all bins that project to column `col` under the same partition as
+        // computeEnvelope, so every pixel column is covered with no gaps regardless of
+        // the bins-to-pixels ratio — callers oversample (kWaveformOversample bins per
+        // column) so each span shows true extremes. Same dB display compression
+        // everywhere (bank_grid, pure).
         for (int col = 0; col < innerW; ++col) {
-            const MinMax mm = vst::columnMinMax(bins, innerW, col);
+            const MinMax mm = columnMinMax(bins, innerW, col);
             const int x = box.x + 2 + col;
             int yMax = midY - static_cast<int>(
                 compressAmplitudeForDisplay(mm.max) * halfSpan);