Files
crosspoint-reader-mod/lib/Epub/Epub/Section.cpp
martin brook 6c3a615fac feat: add png jpeg support (#556)
## Summary
- Add embedded image support to EPUB rendering with JPEG and PNG
decoders
- Implement pixel caching system to cache decoded/dithered images to SD
card for faster re-rendering
- Add 4-level grayscale support for display
## Changes
### New Image Rendering System
- Add `ImageBlock` class to represent an image with its cached path and
display dimensions
- Add `PageImage` class as a new `PageElement` type for images on pages
- Add `ImageToFramebufferDecoder` interface for format-specific image
decoders
- Add `JpegToFramebufferConverter` - JPEG decoder with Bayer dithering
and scaling
- Add `PngToFramebufferConverter` - PNG decoder with Bayer dithering and
scaling
- Add `ImageDecoderFactory` to select appropriate decoder based on file
extension
- Add `getRenderMode()` to GfxRenderer for grayscale render mode queries
### Dithering and Grayscale
- Implement 4x4 Bayer ordered dithering for 4-level grayscale output
- Stateless algorithm works correctly with MCU block decoding
- Handles scaling without artifacts
- Add grayscale render mode support (BW, GRAYSCALE_LSB, GRAYSCALE_MSB)
- Image decoders and cache renderer respect current render mode
- Enables proper 4-level e-ink grayscale when anti-aliasing is enabled
### Pixel Caching
- Cache decoded/dithered images to `.pxc` files on SD card
- Cache format: 2-bit packed pixels (4 pixels per byte) with
width/height header
- On subsequent renders, load directly from cache instead of re-decoding
- Cache renderer supports grayscale render modes for multi-pass
rendering
- Significantly improves page navigation speed for image-heavy EPUBs
### HTML Parser Integration
- Update `ChapterHtmlSlimParser` to process `<img>` tags and extract
images from EPUB
- Resolve relative image paths within EPUB ZIP structure
- Extract images to cache directory before decoding
- Create `PageImage` elements with proper scaling to fit viewport
- Fall back to alt text display if image processing fails
### Build Configuration
- Add `PNG_MAX_BUFFERED_PIXELS=6402` to support up to 800px wide images

  ### Test Script
                                
  - Generate test EPUBs with annotated JPEG and PNG images
- Test cases cover: grayscale (4 levels), centering, scaling, cache
performance
  
## Test plan
- [x] Open EPUB with JPEG images - verify images display with proper
grayscale
- [x] Open EPUB with PNG images - verify images display correctly and no
crash
- [x] Navigate away from image page and back - verify faster load from
cache
- [x] Verify grayscale tones render correctly (not just black/white
dithering)
- [x] Verify large images are scaled down to fit screen
- [x] Verify images are centered horizontally
- [x] Verify page serialization/deserialization works with images
  - [x] Verify images rendered in landscape mode        

## Test Results
[png](https://photos.app.goo.gl/5zFUb8xA8db3dPd19)
[jpeg](https://photos.app.goo.gl/SwtwaL2DSQwKybhw7)


![20260128_231123790](https://github.com/user-attachments/assets/78855971-4bb8-441a-b207-0a292b9739f5)

![20260128_231012253](https://github.com/user-attachments/assets/f08fb63f-1b73-41d9-a25e-78232ec0c495)

![20260128_231004209](https://github.com/user-attachments/assets/06c94acc-8a06-4955-978e-6e583399478d)

![20260128_230954997](https://github.com/user-attachments/assets/49bc44d5-0f2c-416b-9199-4d680fb0f4c3)

![20260128_230945717](https://github.com/user-attachments/assets/93446da5-2e07-410c-89c9-6a21d14e5acb)

![20260128_230938313](https://github.com/user-attachments/assets/4c74c72a-3d40-4a25-b0f3-acc703f42c00)

![20260128_230925546](https://github.com/user-attachments/assets/8d8f62ee-c8fc-4f19-a12c-da29083bb766)

![20260128_230918374](https://github.com/user-attachments/assets/f007d5db-41cc-4fa6-bb22-9e767ee7b00d)


                                                                       
---

### AI Usage

Did you use AI tools to help write this code? _**< YES  >**_

---------

Co-authored-by: Matthías Páll Gissurarson <mpg@mpg.is>
Co-authored-by: Dave Allie <dave@daveallie.com>
2026-02-16 19:56:59 +11:00

264 lines
9.4 KiB
C++

#include "Section.h"
#include <HalStorage.h>
#include <Logging.h>
#include <Serialization.h>
#include "Page.h"
#include "hyphenation/Hyphenator.h"
#include "parsers/ChapterHtmlSlimParser.h"
namespace {
constexpr uint8_t SECTION_FILE_VERSION = 13;
constexpr uint32_t HEADER_SIZE = sizeof(uint8_t) + sizeof(int) + sizeof(float) + sizeof(bool) + sizeof(uint8_t) +
sizeof(uint16_t) + sizeof(uint16_t) + sizeof(uint16_t) + sizeof(bool) + sizeof(bool) +
sizeof(uint32_t);
} // namespace
uint32_t Section::onPageComplete(std::unique_ptr<Page> page) {
if (!file) {
LOG_ERR("SCT", "File not open for writing page %d", pageCount);
return 0;
}
const uint32_t position = file.position();
if (!page->serialize(file)) {
LOG_ERR("SCT", "Failed to serialize page %d", pageCount);
return 0;
}
LOG_DBG("SCT", "Page %d processed", pageCount);
pageCount++;
return position;
}
void Section::writeSectionFileHeader(const int fontId, const float lineCompression, const bool extraParagraphSpacing,
const uint8_t paragraphAlignment, const uint16_t viewportWidth,
const uint16_t viewportHeight, const bool hyphenationEnabled,
const bool embeddedStyle) {
if (!file) {
LOG_DBG("SCT", "File not open for writing header");
return;
}
static_assert(HEADER_SIZE == sizeof(SECTION_FILE_VERSION) + sizeof(fontId) + sizeof(lineCompression) +
sizeof(extraParagraphSpacing) + sizeof(paragraphAlignment) + sizeof(viewportWidth) +
sizeof(viewportHeight) + sizeof(pageCount) + sizeof(hyphenationEnabled) +
sizeof(embeddedStyle) + sizeof(uint32_t),
"Header size mismatch");
serialization::writePod(file, SECTION_FILE_VERSION);
serialization::writePod(file, fontId);
serialization::writePod(file, lineCompression);
serialization::writePod(file, extraParagraphSpacing);
serialization::writePod(file, paragraphAlignment);
serialization::writePod(file, viewportWidth);
serialization::writePod(file, viewportHeight);
serialization::writePod(file, hyphenationEnabled);
serialization::writePod(file, embeddedStyle);
serialization::writePod(file, pageCount); // Placeholder for page count (will be initially 0 when written)
serialization::writePod(file, static_cast<uint32_t>(0)); // Placeholder for LUT offset
}
bool Section::loadSectionFile(const int fontId, const float lineCompression, const bool extraParagraphSpacing,
const uint8_t paragraphAlignment, const uint16_t viewportWidth,
const uint16_t viewportHeight, const bool hyphenationEnabled, const bool embeddedStyle) {
if (!Storage.openFileForRead("SCT", filePath, file)) {
return false;
}
// Match parameters
{
uint8_t version;
serialization::readPod(file, version);
if (version != SECTION_FILE_VERSION) {
file.close();
LOG_ERR("SCT", "Deserialization failed: Unknown version %u", version);
clearCache();
return false;
}
int fileFontId;
uint16_t fileViewportWidth, fileViewportHeight;
float fileLineCompression;
bool fileExtraParagraphSpacing;
uint8_t fileParagraphAlignment;
bool fileHyphenationEnabled;
bool fileEmbeddedStyle;
serialization::readPod(file, fileFontId);
serialization::readPod(file, fileLineCompression);
serialization::readPod(file, fileExtraParagraphSpacing);
serialization::readPod(file, fileParagraphAlignment);
serialization::readPod(file, fileViewportWidth);
serialization::readPod(file, fileViewportHeight);
serialization::readPod(file, fileHyphenationEnabled);
serialization::readPod(file, fileEmbeddedStyle);
if (fontId != fileFontId || lineCompression != fileLineCompression ||
extraParagraphSpacing != fileExtraParagraphSpacing || paragraphAlignment != fileParagraphAlignment ||
viewportWidth != fileViewportWidth || viewportHeight != fileViewportHeight ||
hyphenationEnabled != fileHyphenationEnabled || embeddedStyle != fileEmbeddedStyle) {
file.close();
LOG_ERR("SCT", "Deserialization failed: Parameters do not match");
clearCache();
return false;
}
}
serialization::readPod(file, pageCount);
file.close();
LOG_DBG("SCT", "Deserialization succeeded: %d pages", pageCount);
return true;
}
// Your updated class method (assuming you are using the 'SD' object, which is a wrapper for a specific filesystem)
bool Section::clearCache() const {
if (!Storage.exists(filePath.c_str())) {
LOG_DBG("SCT", "Cache does not exist, no action needed");
return true;
}
if (!Storage.remove(filePath.c_str())) {
LOG_ERR("SCT", "Failed to clear cache");
return false;
}
LOG_DBG("SCT", "Cache cleared successfully");
return true;
}
bool Section::createSectionFile(const int fontId, const float lineCompression, const bool extraParagraphSpacing,
const uint8_t paragraphAlignment, const uint16_t viewportWidth,
const uint16_t viewportHeight, const bool hyphenationEnabled, const bool embeddedStyle,
const std::function<void()>& popupFn) {
const auto localPath = epub->getSpineItem(spineIndex).href;
const auto tmpHtmlPath = epub->getCachePath() + "/.tmp_" + std::to_string(spineIndex) + ".html";
// Create cache directory if it doesn't exist
{
const auto sectionsDir = epub->getCachePath() + "/sections";
Storage.mkdir(sectionsDir.c_str());
}
// Retry logic for SD card timing issues
bool success = false;
uint32_t fileSize = 0;
for (int attempt = 0; attempt < 3 && !success; attempt++) {
if (attempt > 0) {
LOG_DBG("SCT", "Retrying stream (attempt %d)...", attempt + 1);
delay(50); // Brief delay before retry
}
// Remove any incomplete file from previous attempt before retrying
if (Storage.exists(tmpHtmlPath.c_str())) {
Storage.remove(tmpHtmlPath.c_str());
}
FsFile tmpHtml;
if (!Storage.openFileForWrite("SCT", tmpHtmlPath, tmpHtml)) {
continue;
}
success = epub->readItemContentsToStream(localPath, tmpHtml, 1024);
fileSize = tmpHtml.size();
tmpHtml.close();
// If streaming failed, remove the incomplete file immediately
if (!success && Storage.exists(tmpHtmlPath.c_str())) {
Storage.remove(tmpHtmlPath.c_str());
LOG_DBG("SCT", "Removed incomplete temp file after failed attempt");
}
}
if (!success) {
LOG_ERR("SCT", "Failed to stream item contents to temp file after retries");
return false;
}
LOG_DBG("SCT", "Streamed temp HTML to %s (%d bytes)", tmpHtmlPath.c_str(), fileSize);
if (!Storage.openFileForWrite("SCT", filePath, file)) {
return false;
}
writeSectionFileHeader(fontId, lineCompression, extraParagraphSpacing, paragraphAlignment, viewportWidth,
viewportHeight, hyphenationEnabled, embeddedStyle);
std::vector<uint32_t> lut = {};
// Derive the content base directory and image cache path prefix for the parser
size_t lastSlash = localPath.find_last_of('/');
std::string contentBase = (lastSlash != std::string::npos) ? localPath.substr(0, lastSlash + 1) : "";
std::string imageBasePath = epub->getCachePath() + "/img_" + std::to_string(spineIndex) + "_";
CssParser* cssParser = nullptr;
if (embeddedStyle) {
cssParser = epub->getCssParser();
if (cssParser) {
if (!cssParser->loadFromCache()) {
LOG_ERR("SCT", "Failed to load CSS from cache");
}
}
}
ChapterHtmlSlimParser visitor(
epub, tmpHtmlPath, renderer, fontId, lineCompression, extraParagraphSpacing, paragraphAlignment, viewportWidth,
viewportHeight, hyphenationEnabled,
[this, &lut](std::unique_ptr<Page> page) { lut.emplace_back(this->onPageComplete(std::move(page))); },
embeddedStyle, contentBase, imageBasePath, popupFn, cssParser);
Hyphenator::setPreferredLanguage(epub->getLanguage());
success = visitor.parseAndBuildPages();
Storage.remove(tmpHtmlPath.c_str());
if (!success) {
LOG_ERR("SCT", "Failed to parse XML and build pages");
file.close();
Storage.remove(filePath.c_str());
if (cssParser) {
cssParser->clear();
}
return false;
}
const uint32_t lutOffset = file.position();
bool hasFailedLutRecords = false;
// Write LUT
for (const uint32_t& pos : lut) {
if (pos == 0) {
hasFailedLutRecords = true;
break;
}
serialization::writePod(file, pos);
}
if (hasFailedLutRecords) {
LOG_ERR("SCT", "Failed to write LUT due to invalid page positions");
file.close();
Storage.remove(filePath.c_str());
return false;
}
// Go back and write LUT offset
file.seek(HEADER_SIZE - sizeof(uint32_t) - sizeof(pageCount));
serialization::writePod(file, pageCount);
serialization::writePod(file, lutOffset);
file.close();
if (cssParser) {
cssParser->clear();
}
return true;
}
std::unique_ptr<Page> Section::loadPageFromSectionFile() {
if (!Storage.openFileForRead("SCT", filePath, file)) {
return nullptr;
}
file.seek(HEADER_SIZE - sizeof(uint32_t));
uint32_t lutOffset;
serialization::readPod(file, lutOffset);
file.seek(lutOffset + sizeof(uint32_t) * currentPage);
uint32_t pagePos;
serialization::readPod(file, pagePos);
file.seek(pagePos);
auto page = Page::deserialize(file);
file.close();
return page;
}