Xteink-X4-crosspoint-reader/src/activities/reader/ReaderActivity.h
Eunchurn Park 49f97b69ca
Add TXT file reader support (#240)
## Summary

* **What is the goal of this PR?** 

Add support for reading plain text (.txt) files, enabling users to
browse, read, and track progress in TXT documents alongside existing
EPUB and XTC formats.

* **What changes are included?**

- New Txt library for loading and parsing plain text files
- New TxtReaderActivity with streaming page rendering using 8KB chunks
to handle large files without memory issues on ESP32-C3
- Page index caching system (index.bin) for instant re-open after sleep
or app restart
- Progress bar UI during initial file indexing (matching EPUB style)
- Word wrapping with proper UTF-8 support
- Cover image support for TXT files:
- Primary: image with same filename as TXT (e.g., book.jpg for book.txt)
  - Fallback: cover.bmp/jpg/jpeg in the same folder
  - JPG to BMP conversion using existing converter
  - Sleep screen cover mode now works with TXT files
- File browser now shows .txt files

## Additional Context

* Add any other information that might be helpful for the reviewer

* Memory constraints: The streaming approach was necessary because
ESP32-C3 only has 320KB RAM. A 700KB TXT file cannot be loaded entirely
into memory, so we read 8KB chunks and build a page offset index
instead.

* Cache invalidation: The page index cache automatically invalidates
when file size, viewport width, or lines per page changes (e.g., font
size or orientation change).

* Performance: First open requires indexing (with progress bar),
subsequent opens load from cache instantly.

* Cover image format: PNG is detected but not supported for conversion
(no PNG decoder available). Only BMP and JPG/JPEG work.
2026-01-14 21:36:40 +11:00

35 lines
1.3 KiB
C++

#pragma once
#include <memory>
#include "../ActivityWithSubactivity.h"
class Epub;
class Xtc;
class Txt;
class ReaderActivity final : public ActivityWithSubactivity {
std::string initialBookPath;
std::string currentBookPath; // Track current book path for navigation
const std::function<void()> onGoBack;
static std::unique_ptr<Epub> loadEpub(const std::string& path);
static std::unique_ptr<Xtc> loadXtc(const std::string& path);
static std::unique_ptr<Txt> loadTxt(const std::string& path);
static bool isXtcFile(const std::string& path);
static bool isTxtFile(const std::string& path);
static std::string extractFolderPath(const std::string& filePath);
void onSelectBookFile(const std::string& path);
void onGoToFileSelection(const std::string& fromBookPath = "");
void onGoToEpubReader(std::unique_ptr<Epub> epub);
void onGoToXtcReader(std::unique_ptr<Xtc> xtc);
void onGoToTxtReader(std::unique_ptr<Txt> txt);
public:
explicit ReaderActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::string initialBookPath,
const std::function<void()>& onGoBack)
: ActivityWithSubactivity("Reader", renderer, mappedInput),
initialBookPath(std::move(initialBookPath)),
onGoBack(onGoBack) {}
void onEnter() override;
};