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Crosspoint/lib/EpdFont/SdCardFontManager.cpp
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#include "SdCardFontManager.h"
#include <EpdFontFamily.h>
#include <GfxRenderer.h>
#include <Logging.h>
#include <SdCardFont.h>
#include <SdCardFontRegistry.h>
#include <cstdlib>
SdCardFontManager::~SdCardFontManager() {
if (renderer_) {
unloadAll(*renderer_);
} else {
for (auto& lf : loaded_) {
delete lf.font;
}
loaded_.clear();
}
}
// FNV-1a continuation: seeds with contentHash, then hashes family name + point size.
// Produces a deterministic ID that is stable across load/unload cycles and reboots,
// and changes when font content changes (different header/TOC = different contentHash).
int SdCardFontManager::computeFontId(uint32_t contentHash, const char* familyName, uint8_t pointSize) {
static constexpr uint32_t FNV_PRIME = 16777619u;
uint32_t hash = contentHash;
while (*familyName) {
hash ^= static_cast<uint8_t>(*familyName++);
hash *= FNV_PRIME;
}
hash ^= pointSize;
hash *= FNV_PRIME;
int id = static_cast<int>(hash);
return id != 0 ? id : 1; // 0 is reserved as "not found" sentinel
}
bool SdCardFontManager::loadFamily(const SdCardFontFamilyInfo& family, GfxRenderer& renderer, uint8_t targetPtSize) {
if (!renderer_) {
renderer_ = &renderer;
}
// 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) {
LOG_ERR("SDMGR", "Family %s has no files to load", family.name.c_str());
return false;
}
auto* font = new (std::nothrow) SdCardFont();
if (!font) {
LOG_ERR("SDMGR", "Failed to allocate SdCardFont for %s", selected->path.c_str());
return false;
}
if (!font->load(selected->path.c_str())) {
LOG_ERR("SDMGR", "Failed to load %s", selected->path.c_str());
delete font;
return false;
}
int fontId = computeFontId(font->contentHash(), family.name.c_str(), selected->pointSize);
// Guard against collision with built-in font IDs (astronomically unlikely
// with FNV-1a hashes, but provides a safety net)
if (renderer.getFontMap().count(fontId) != 0) {
LOG_ERR("SDMGR", "Font ID %d collides with existing font, skipping %s", fontId, selected->path.c_str());
delete font;
return false;
}
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);
EpdFontFamily fontFamily(font->getEpdFont(0), font->getEpdFont(1), font->getEpdFont(2), font->getEpdFont(3));
renderer.insertFont(fontId, fontFamily);
loadedFamilyName_ = family.name;
loadedPointSize_ = selected->pointSize;
return true;
}
void SdCardFontManager::unloadAll(GfxRenderer& renderer) {
if (!renderer_) {
renderer_ = &renderer;
}
renderer.clearSdCardFonts();
for (auto& lf : loaded_) {
renderer.removeFont(lf.fontId);
delete lf.font;
}
loaded_.clear();
loadedFamilyName_.clear();
loadedPointSize_ = 0;
}
int SdCardFontManager::getFontId(const std::string& familyName) const {
if (familyName != loadedFamilyName_ || loaded_.empty()) return 0;
return loaded_.front().fontId;
}