Revert optimisation

src/activities/reader/EpubReaderActivity.cpp

@@ -104,62 +104,6 @@ void logReaderMemSnapshot(const char* stage) {
 inline void logReaderMemSnapshot(const char*) {}
 #endif
 
-bool computePageDynamicYBand(const Page& page, const GfxRenderer& renderer, const int fontId, const int viewportHeight,
-                             int* outTop, int* outBottom) {
-  if (viewportHeight <= 0 || !outTop || !outBottom) {
-    return false;
-  }
-
-  bool hasRange = false;
-  int minY = viewportHeight;
-  int maxY = -1;
-  const int lineHeight = std::max(1, renderer.getLineHeight(fontId));
-
-  for (const auto& el : page.elements) {
-    if (!el) continue;
-
-    const int elementTop = el->yPos;
-    int elementBottom = elementTop;
-    switch (el->getTag()) {
-      case TAG_PageLine:
-        elementBottom = el->yPos + lineHeight;
-        break;
-      case TAG_PageImage: {
-        const auto& img = static_cast<const PageImage&>(*el);
-        elementBottom = el->yPos + img.getImageBlock().getHeight();
-        break;
-      }
-      case TAG_PageTable: {
-        const auto& table = static_cast<const PageTableFragment&>(*el);
-        elementBottom = el->yPos + table.getTotalHeight();
-        break;
-      }
-      default:
-        continue;
-    }
-
-    minY = std::min(minY, elementTop);
-    maxY = std::max(maxY, elementBottom);
-    hasRange = true;
-  }
-
-  if (!hasRange) {
-    return false;
-  }
-
-  constexpr int BAND_PAD_PX = 2;
-  minY = std::max(0, minY - BAND_PAD_PX);
-  maxY = std::min(viewportHeight, maxY + BAND_PAD_PX);
-
-  if (minY >= maxY) {
-    return false;
-  }
-
-  *outTop = minY;
-  *outBottom = maxY;
-  return true;
-}
-
 // Computes the [0..100] EPUB progress percent. Returns 0 when pageCount is unknown (sync/bookmark
 // pre-render writes), in which case the next saveProgress() will overwrite progress.bin with the
 // real value before the user can leave the reader.
@@ -2093,20 +2037,22 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   logReaderMemSnapshot("bw_store_begin");
   bool bwBufferStored = false;
   if (shouldAttemptBwSnapshot) {
+    // Snapshot must cover every BW pixel drawn outside the grayscale text region —
+    // status bar (in top/bottom margins), truncated-section hint, edge progress bars.
+    // The AA pass clears the whole BW buffer to 0x00, renders text-only, and pushes
+    // grayscale; rows outside the restored band end up zero, causing a BW/grayscale
+    // mismatch in the status bar area on the next page turn — visible as ghosting
+    // at the bottom in Landscape CCW (issue #256).
+    //
+    // The X argument is only meaningful in portrait (where panel rows map to logical
+    // X); in landscape, panel rows map to logical Y and the X range doesn't affect
+    // the saved row band. So spanning the full logical Y always saves the full panel
+    // rows in landscape (≈ full framebuffer), while in portrait we keep the
+    // optimization by clipping to the content X band — the status bar still fits
+    // since it's anchored to the same content margins.
     const int contentLeft = orientedMarginLeft;
     const int contentRight = std::max(contentLeft, renderer.getScreenWidth() - orientedMarginRight);
-    const int contentBottom = std::max(contentTop, renderer.getScreenHeight() - orientedMarginBottom);
+    bwBufferStored = renderer.storeBwBufferRect(contentLeft, 0, contentRight - contentLeft, renderer.getScreenHeight());
-
-    int bandTop = 0;
-    int bandBottom = std::max(0, contentBottom - contentTop);
-    if (!computePageDynamicYBand(*page, renderer, getEffectiveReaderFontId(), bandBottom, &bandTop, &bandBottom)) {
-      bandTop = 0;
-      bandBottom = std::max(0, contentBottom - contentTop);
-    }
-
-    const int snapshotTop = contentTop + bandTop;
-    const int snapshotHeight = std::max(0, bandBottom - bandTop);
-    bwBufferStored = renderer.storeBwBufferRect(contentLeft, snapshotTop, contentRight - contentLeft, snapshotHeight);
   } else {
     LOG_INF("ERS", "Skipping BW snapshot precheck (free=%lu contig=%lu, need free>=%lu contig>=%lu)", bwStoreFreeHeap,
             bwStoreContigHeap, static_cast<uint32_t>(BW_SNAPSHOT_MIN_FREE_HEAP_BYTES),