An Android reader app committed to improving reading experience.

PDF, EPUB, MOBI, CBZ, FB2, XPS, TXT, HTML, OFFICE(DOCX,XLSX,PPTX) and ZIP/GZIP are supported.

Or download the latest APK from the Releases Section.

• Flip Vertical

  Flip Vertical and Flip Horizontal modes are supported.

• RtL Text

  In top-to-bottom, right-to-left script (TB-RL or vertical), writing starts from the top of the page and continues to the bottom, proceeding from right to left for new lines, pages numbered from right to left (from Wikipedia). The RtL Text mode can be applied to some traditional Chinese, Japanese and Korean books.

• Single Column

  Some PDF books were scanned in a way that left and right pages were put in one image, resulting in a so called dual-spread page. In the scenario, Single Column mode plays a role. It splits a dual-spread page into two pages.

  Single Column mode can also be a conveniency for magazines and scientific papers that have two columns in a page.

  In Single Column mode, all pages except first and last page are splitted.

• Continuous scroll

  Continuous scroll has been perfectly implemented in all scenarios.

• Lock Stray

  When flinging or scrolling a zoomed page, it can hardly move in straight horizontal/vertical direction, and be annoying reading experience. Here the Lock Stray mode will make a help.

• Crop Margin

  Crop page margins to get more efficient reading space. All document types are supported.

• Focus

  Focus mode will keep page position across zoomed pages. On moving to a definite page, eg. tapping to next/prev page, choosing on Toc/bookmark table, navigating through links or searching text, and skimming on page slider, it will present visible content area of new page in same position as the old one. Note that scroll/fling operation is an exception.

  On entering Focus mode, current page will zoom automatically to match screen in shorter dimension and center itself.

• Smart Focus

  With scanned PDF books, content area scarcely appear exactly centered in a page. More probable it inclines toward left or right side. Smart Focus deals with the scenario. By adjusting the position of even or odd pages accordingly, it makes Focus mode behave smartly.

  Smart Focus must work with Focus mode to make sense.

• Copy Text

  Text copy can be accomplished by selecting text and tap Copy Selection button. In Vertical Flip mode, text selection can cross page boundary.

  During text selecting, page navigation operations still work.

• Color Palette

  Color Palette are for maxmium legibility and are ideal for reducing eye strain conductive to focused reading.

• Font Size

  Currenet font size can be changed in Font Size menu.

• Contents

  Contents menu includes following two functions:

• Table of Contents

  Table of Contents will show up if the document has one. It supports multi-level headings, heading collapsing and expanding. It always keep sync with current page.

• Bookmarks

  Bookmarks works across reading sessions. To bookmark a page, just long press on blank area.

• Activate Links

  Activate Links and make them navigable.

• Search

  Search text and navigate through search goals.

• Share Book

  Call Android Share menu.

• Scrollable Toobar

  Scrollable Toolbar can accommodate more buttons for extended funtions.

• Pros and Cons

  In case of big books(thousands of pages), PDFs were opened very quick, and EPUBs badly slow.

• A function button will show up in Toolbar when the corresponding function is applicable, otherwise it will be hidden.
• Long press a Toolbar button, to show it's tooltip.
• Tap in left/top side, to move a page backward (when in not RtL Text mode)
• Tap in right/bottom side, to move a page forward (when in not RtL Text mode)
• Tap in middle, to show/hide Toolbar and Page Indicator
• Press down one finger and move in any direction, to scrol a page
• Press down two fingers and move one, to zoom in/out pages
• Fling horizontally/vertically, to Scroll Continuously
• Under the combination of Flip Horizontal and not Rtl Text mode, or of Flip Vertical and Rtl Text mode, when pages are leaved between two pages, it will slide slowly into the near page that guarantees any page contents will not be cut off.
• Under the combination of Flip Horizontal and Rtl Text mode, or of Flip Vertical and not Rtl Text mode, pages can stay at any position which will never cut off page contents that makes reading across two pages comfortably.
• Long press one finger on text, to trigger a text selection session. Then press on left/right handles and move, to change selection area. Tap in selection area, to show/hide Toolbar. Then tap Copy Selection button, to copy the selected text to system clipboard and end the selection session. Tap out of selection area, to cancel the selection session.
• Double tap in middle to Bookmark current page.
• All reading status as of page scale, position, last read page number, as well as all enable button states will be remembered across reading sessions for per book.
• In general, to get the best reading experience mutiple function modes can be employed, adding appropriate screen orientation if needed.

• MuPDF Android Viewer and developers
• MarkedView for help document rendering

• GitHub repo: https://github.com/elementdavv/chaka
• Email: [email protected]
• Telegram: @elementdavv
• X(Twitter): @elementdavv

If you love Chaka, consider supporting or hiring the maintainer @elementdavv