Files

mod: Phase 1 - bring forward mod-exclusive files with ActivityManager migration

Brings ~55 mod-exclusive files to the upstream-based mod/master-resync branch:

Activities (migrated to new ActivityManager pattern):
- Clock/Time: SetTimeActivity, SetTimezoneOffsetActivity, NtpSyncActivity
- Dictionary: DictionaryDefinitionActivity, DictionarySuggestionsActivity,
  DictionaryWordSelectActivity, LookedUpWordsActivity
- Bookmark: EpubReaderBookmarkSelectionActivity
- Book management: BookManageMenuActivity, EndOfBookMenuActivity
- OPDS: OpdsServerListActivity, OpdsSettingsActivity
- Utility: DirectoryPickerActivity, NumericStepperActivity

Utilities (unchanged):
- BookManager, BookSettings, BookmarkStore, BootNtpSync
- Dictionary, LookupHistory, TimeSync, OpdsServerStore

Libraries: PlaceholderCover, TableData, ChapterXPathIndexer
Scripts: inject_mod_version, generate_book_icon, preview_placeholder_cover
Docs: KOReader sync XPath mapping

Migration changes:
- ActivityWithSubactivity -> Activity base class
- Callback constructors -> finish()/setResult() pattern
- enterNewActivity() -> startActivityForResult()
- Activity::RenderLock&& -> RenderLock&&

These files won't compile yet - they reference mod settings and I18n
strings that will be added in subsequent phases.

Made-with: Cursor

2026-03-07 15:10:00 -05:00

3.5 KiB

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Placeholder Cover Generation for Books Without Covers

Task

Implement placeholder cover BMP generation for books that have no embedded cover image (or have covers in unsupported formats). Previously, these books showed empty rectangles on the home screen and fell back to the default sleep screen.

Root Cause

Cover generation failed silently in three cases:

EPUB: No coverItemHref in metadata, or cover is non-JPG format (PNG/SVG/GIF)
TXT: No matching image file on the SD card
XTC: First-page render failure (rare)

When generateCoverBmp() returned false, no BMP was created, and no fallback was attempted.

Changes Made

New Files

lib/PlaceholderCover/PlaceholderCoverGenerator.h - Header for the placeholder generator
lib/PlaceholderCover/PlaceholderCoverGenerator.cpp - Implementation: allocates a 1-bit pixel buffer, renders title/author text using EpdFont glyph data (ported from GfxRenderer::renderChar), writes a 1-bit BMP file with word-wrapped centered text, border, and separator line

Modified Files

src/activities/reader/EpubReaderActivity.cpp - Added placeholder fallback after generateCoverBmp() and generateThumbBmp() fail during first-open prerender
src/activities/reader/TxtReaderActivity.cpp - Added placeholder fallback, added thumbnail generation (previously TXT had none), now passes thumb path to RECENT_BOOKS.addBook() instead of empty string
src/activities/reader/XtcReaderActivity.cpp - Added placeholder fallback after cover/thumb generation fail (rare case)
src/activities/boot_sleep/SleepActivity.cpp - Added placeholder generation before falling back to default sleep screen (handles books opened before this feature was added)
lib/Txt/Txt.h - Added getThumbBmpPath() and getThumbBmpPath(int height) methods
lib/Txt/Txt.cpp - Implemented the new thumb path methods

Architecture

Option B approach: shared PlaceholderCoverGenerator utility called from reader activities
Generator is independent of GfxRenderer (no display framebuffer dependency)
Includes Ubuntu 10 Regular and Ubuntu 12 Bold font data directly for self-contained rendering
Memory: 48KB for full cover (480x800), 4-12KB for thumbnails; allocated and freed per call

Flash Impact

Before: 96.4% flash usage (6,317,250 bytes)
After: 97.3% flash usage (6,374,546 bytes)
Delta: ~57KB (mostly from duplicate font bitmap data included in the generator)

Layout Revision (traditional book cover style)

Border: moved inward with proportional edge padding (~10px at full size) and thickened to ~5px, keeping it visible within the device bezel
Title: 2x integer-scaled Ubuntu 12 Bold (effectively ~24pt) for full-size covers, positioned in the top 2/3 zone, max 5 lines
Author: positioned in the bottom 1/3 zone, max 3 lines with word wrapping
Book icon: 48x48 1-bit bitmap (generated by scripts/generate_book_icon.py), displayed at 2x for full covers, 1x for medium thumbnails, omitted for small thumbnails
Separator line between title and author zones
All dimensions scale proportionally for thumbnails

Follow-up Items

Books opened before this feature was added won't get home screen thumbnails until re-opened (SleepActivity handles the sleep cover case by generating on demand)
Font data duplication adds ~57KB flash; could be reduced by exposing shared font references instead of including headers directly
Preview scripts in scripts/ can regenerate the icon and layout previews: generate_book_icon.py, preview_placeholder_cover.py

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