# Fix: Cover/Thumbnail Pipeline on Home Screen

**Date:** 2026-02-15

## Task Description

Multiple issues with book cover thumbnails on the home screen:
1. After clearing a book's cache, the home screen showed a placeholder instead of the real cover.
2. Books without covers showed blank rectangles instead of generated placeholder covers.

## Root Cause

`Epub::generateThumbBmp()` wrote an empty 0-byte BMP file as a "don't retry" sentinel when a book had no cover. This empty file:
- Blocked the placeholder fallback in `EpubReaderActivity::onEnter()` (file exists check passes)
- Tricked the home screen into thinking a valid thumbnail exists (skips regeneration)
- Failed to parse in `LyraTheme::drawRecentBookCover()` resulting in a blank gray rectangle

## Changes Made

- **`lib/Epub/Epub.cpp`**: Removed the empty sentinel file write from `generateThumbBmp()`. Now it simply returns `false` when there's no cover, letting callers generate valid placeholder BMPs that serve the same "don't retry" purpose.
- **`src/activities/home/HomeActivity.cpp`**: Changed placeholder fallback in `loadRecentCovers()` from `if (!success && !Storage.exists(coverPath))` to `if (!success)` as defense-in-depth for edge cases like global cache clear.
- **`src/RecentBooksStore.h`**: Added `removeBook(const std::string& path)` method declaration.
- **`src/RecentBooksStore.cpp`**: Implemented `removeBook()` — finds and erases the book by path, then persists the updated list.
- **`src/activities/reader/EpubReaderActivity.cpp`**: After clearing cache in the `DELETE_CACHE` handler, calls `RECENT_BOOKS.removeBook(epub->getPath())` so the book is cleanly removed from recents when its cache is wiped.

## Follow-up Items

- None.