Revert "feat: closest-pt size selection instead of ordinal slot" (#1949)

Reverts crosspoint-reader/crosspoint-reader#1912

This was meant to be more robust with partial SD card fonts, but causes
trouble for folks using custom font sizes. We need a better approach to
decouple numeric font sizes from S/M/L/XL settings.

lib/EpdFont/SdCardFontManager.cpp

@@ -28,21 +28,25 @@ int SdCardFontManager::computeFontId(uint32_t contentHash, const char* familyNam
   return id != 0 ? id : 1;  // 0 is reserved as "not found" sentinel
 }
 
-bool SdCardFontManager::loadFamily(const SdCardFontFamilyInfo& family, GfxRenderer& renderer, uint8_t targetPtSize) {
+bool SdCardFontManager::loadFamily(const SdCardFontFamilyInfo& family, GfxRenderer& renderer, uint8_t fontSizeEnum) {
   // Unload any previously loaded family first
   if (!loadedFamilyName_.empty()) {
     unloadAll(renderer);
   }
 
-  // Pick the single file whose size is closest to targetPtSize. Loading
-  // only one size bounds resident memory (intervals + kern/ligature tables
-  // per style) to one file's worth, vs. N_sizes × per-file overhead.
-  const SdCardFontFileInfo* selected = family.pickClosestSize(targetPtSize);
-  if (!selected) {
+  // Select by ordinal position: sort available sizes, then map the font size
+  // enum (SMALL=0 .. EXTRA_LARGE=3) to the corresponding slot. When the
+  // family has fewer sizes than 4, clamp to the last available size.
+  auto sizes = family.availableSizes();
+  if (sizes.empty()) {
     LOG_ERR("SDMGR", "Family %s has no files to load", family.name.c_str());
     return false;
   }
 
+  uint8_t idx = fontSizeEnum;
+  if (idx >= sizes.size()) idx = sizes.size() - 1;
+  const SdCardFontFileInfo* selected = family.findFile(sizes[idx]);
+
   auto* font = new (std::nothrow) SdCardFont();
   if (!font) {
     LOG_ERR("SDMGR", "Failed to allocate SdCardFont for %s", selected->path.c_str());
@@ -66,8 +70,8 @@ bool SdCardFontManager::loadFamily(const SdCardFontFamilyInfo& family, GfxRender
   renderer.registerSdCardFont(fontId, font);
   loaded_.push_back({font, fontId, selected->pointSize});
 
-  LOG_DBG("SDMGR", "Loaded %s size=%u id=%d styles=%u (target=%u)", selected->path.c_str(), selected->pointSize, fontId,
-          font->styleCount(), targetPtSize);
+  LOG_DBG("SDMGR", "Loaded %s size=%u id=%d styles=%u (sizeEnum=%u)", selected->path.c_str(), selected->pointSize,
+          fontId, font->styleCount(), fontSizeEnum);
 
   EpdFontFamily fontFamily(font->getEpdFont(0), font->getEpdFont(1), font->getEpdFont(2), font->getEpdFont(3));
   renderer.insertFont(fontId, fontFamily);

lib/EpdFont/SdCardFontManager.h

@@ -15,16 +15,12 @@ class SdCardFontManager {
   SdCardFontManager(const SdCardFontManager&) = delete;
   SdCardFontManager& operator=(const SdCardFontManager&) = delete;
 
-  // Load the single size whose pointSize is closest to targetPtSize. Only one
-  // .cpfont file is loaded; other sizes remain on disk. This keeps resident
-  // interval + kern/ligature tables to one size's worth of memory.
-  //
-  // Closest-pt selection is robust against families that don't ship the
-  // canonical {12,14,16,18}: a family with only [10,14,18] still resolves
-  // any reasonable target, where ordinal slot-mapping by SMALL..EXTRA_LARGE
-  // would mis-select.
+  // Load the font file matching fontSizeEnum (SMALL=0 .. EXTRA_LARGE=3) by
+  // ordinal position in the family's sorted size list. Only one .cpfont file
+  // is loaded; other sizes remain on disk. This keeps resident interval +
+  // kern/ligature tables to one size's worth of memory.
   // Returns true on success.
-  bool loadFamily(const SdCardFontFamilyInfo& family, GfxRenderer& renderer, uint8_t targetPtSize);
+  bool loadFamily(const SdCardFontFamilyInfo& family, GfxRenderer& renderer, uint8_t fontSizeEnum);
 
   // Unload everything, unregister from renderer.
   void unloadAll(GfxRenderer& renderer);

lib/EpdFont/SdCardFontRegistry.cpp

@@ -4,8 +4,6 @@
 #include <Logging.h>
 
 #include <algorithm>
-#include <climits>
-#include <cstdlib>
 #include <cstring>
 
 // --- SdCardFontFamilyInfo helpers ---
@@ -40,21 +38,6 @@ std::vector<uint8_t> SdCardFontFamilyInfo::availableSizes() const {
   return sizes;
 }
 
-const SdCardFontFileInfo* SdCardFontFamilyInfo::pickClosestSize(uint8_t targetPtSize) const {
-  const SdCardFontFileInfo* selected = nullptr;
-  int bestDiff = INT_MAX;
-  for (const auto& f : files) {
-    int diff = std::abs(static_cast<int>(f.pointSize) - static_cast<int>(targetPtSize));
-    // Strict < ensures the first scan wins on ties; then tie-break by smaller
-    // pointSize to make the choice independent of filesystem enumeration order.
-    if (diff < bestDiff || (diff == bestDiff && selected && f.pointSize < selected->pointSize)) {
-      bestDiff = diff;
-      selected = &f;
-    }
-  }
-  return selected;
-}
-
 // --- SdCardFontRegistry ---
 
 bool SdCardFontRegistry::parseFilename(const char* filename, uint8_t& size, uint8_t& style) {

lib/EpdFont/SdCardFontRegistry.h

@@ -20,15 +20,6 @@ struct SdCardFontFamilyInfo {
   const SdCardFontFileInfo* findFile(uint8_t size, uint8_t style = 0) const;
   bool hasSize(uint8_t size) const;
   std::vector<uint8_t> availableSizes() const;
-
-  // Pick the file whose pointSize is closest to targetPtSize. On ties (equal
-  // distance) prefers the smaller pointSize so behaviour is deterministic
-  // across SD card layouts. Returns nullptr when files is empty.
-  //
-  // Robust against families that don't ship the canonical {12,14,16,18} set:
-  // a family with only [10,14,18] resolves target 12 → 10 (or 14 on tie),
-  // target 16 → 14 or 18, etc., instead of mis-indexing by ordinal slot.
-  const SdCardFontFileInfo* pickClosestSize(uint8_t targetPtSize) const;
 };
 
 class SdCardFontRegistry {