- Add isValidThumbnailBmp(), generateInvalidFormatCoverBmp(), and
generateInvalidFormatThumbBmp() methods to Epub class for validating
BMP files and generating X-pattern marker images when cover extraction
fails (e.g., progressive JPG).
- Restore prerender block in EpubReaderActivity::onEnter() that checks
for missing cover BMPs (fit + cropped) and thumbnail BMPs at each
PRERENDER_THUMB_HEIGHTS size, showing a "Preparing book..." popup
with progress. Falls back to PlaceholderCoverGenerator, then to
invalid-format marker BMPs as last resort.
Made-with: Cursor
a5ca15df4f
