Maru, Arar ars apps that allows you to open text files, comic files, compressed files, PDF, epub files stored on your Android phone or web server and view them as if they were books.

It does not provide content (novel/manga files) by default.
Only Google Play Protect-certified devices are supported.

The main features are as follows.

1. text viewer

  - Support TXT, CSV, SMI, SUB, SRT
  - Support EPUB  (text and picture display), support built-in font
  - Open compressed text (ZIP, RAR, 7Z, ALZ/EGG) directly
  - Changeable fonts (san-serif/serif/custom font), adjust size/spacing/margins etc
  - Changeable character encoding (Auto/UTF-8,...)
  - Changeable text/background color/background image
  - Page turning method: arrow/screen tap/screen drag/volume button
  - Page turning effect (animation) : roll over, slide, swipe, scroll
  - Various Quick navigation: navigation bar, dial, page input
  - Add/rename/sort/lookup bookmarks
  - Text-to-Speech: language selection, speed control, special characters/kanji exclusion
  - Slideshow: adjustable speed
  - Search text: one by one, search all
  - Edit text: edit, add new file
  - Text alignment: left, justified, 2-sheet horizontal view
  - Quick brightness
  - Sentence organization
 

2. comic viewer

  - Support JPG, PNG, GIF, BMP, WEBP, TIFF, HEIC, AVIF, ZIP, RAR, 7Z, CBZ, CBR, CB7, ALZ/EGG, PDF files
  - Open compressed pictures (ZIP, RAR, 7Z, ALZ/EGG) directly
  - Support zip streaming
  - Support double compression
  - PDF: zoom up to 8x and sharpen option when zooming in
  - Left-right order/shuffle: left -> right, right->left (Japanese style), landscape 2-page view
  - Support zoom in-out, magnify
  - Page turning method: arrow/scroll tab/scroll drag/volume button
  - Page turning effect (animation): left/right scroll, up/down scroll, webtoon scroll
   Webtoon scroll can smoothly scroll very long pictures.
  - Quick navigation: navigation bar, dial, page input
  - Add/rename/sort/lookup bookmarks
  - Slideshow: set in seconds
  - Keep picture zoomed in
  - Support animated gif/webp/avif
  - Support picture rotation (manual rotation, Auto rotation of JPEG/Webp)
  - Double filter(inversion, sepia, sharpen, ...)
  - Support cropping edge

3. file function

  - Color mark of reading history: red(recent), green(partially read), blue(fully read)
  - Picture Preview: Tiled(Large, Small), Detail
  - Selectable file extension
  - Sorting : Name, Size, Date
  - Support delete rename, copy, move
  - Searching: file name, content, picture
  - Support uncompressing manually
  - Support read or write of USB storage(FAT32,NTFS,exFAT)

4. other

  - Theme/Color
  - Support language selection (Korean, Chinese, Japanese, English, ...)
  - Support Auto Synchornization of reading history
  - Support SFTP (secure file transport protocol)
  - Support FTP (file transport protocol)
  - Support SMB (Windows Shared Folder, Samba)
  - Support WebDAV
  - Support Google Drive
  - Support Dropbox
  - Support MS OneDrive
  - Password lock
  - Support S-pen of Samsung Note 9 and above: page turning, pausing slideshow
  - Headset button support: pausing slideshow
  - Media button (Bluetooth earphone, etc.) support: pausing TTS
  - Backup/restore settings (Maru, Arar compatible)
  - Shortcut management (e.g. add/delete shortcut of other apps)