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KOReader is a document viewer application, originally created for Kindle e-ink readers. It currently runs on Kindle, Kobo, PocketBook, Ubuntu Touch and Android devices. Developers can also run a KOReader emulator for development purposes on desktop PCs with Linux, Windows and Mac OSX.

Main features for users

• supports multi-format documents including:
  • paged fixed-layout formats: PDF, DjVu, CBT, and CBZ
  • reflowable e-book formats: ePub, fb2, mobi, doc, chm and plain text
  • scanned PDF/DjVu documents can also be reflowed with built-in K2pdfopt
• use StarDict dictionaries / Wikipedia to lookup words
• highlights can be exported to Evernote cloud account
• highly customizable reader view and typesetting
  • setting arbitrary page margins / line space
  • choosing external fonts and styles
  • built-in multi-lingual hyphenation dictionaries
• supports adding custom online OPDS catalogs
• calibre integration
  • search calibre metadata on your koreader device
  • send ebooks from calibre library to your koreader device wirelessly
  • browser calibre library and download ebooks via calibre OPDS server
• can share ebooks with other koreader devices wirelessly
• various optimizations for e-ink devices
  • paginated menus without animation
  • adjustable text contrast
• multi-lingual user interface
• online Over-The-Air software update

Highlights for developers

• frontend written in Lua scripting language
  • multi-platform support through a single code-base
  • you can help develop KOReader in any editor without compilation
  • high runtime efficiency through LuaJIT acceleration
  • light-weight self-contained widget toolkit with small memory footprint
  • extensible with plugin system
• interfaced backends for documents parsing and rendering
  • high quality document backend libraries like MuPDF, DjvuLibre and CREngine
  • interacting with frontend via LuaJIT FFI for best performence
• in active development
  • with contributions from developers around the world
  • continuous integration with CircleCI
  • with unit tests (busted), static code analysis (luacheck) and code coverage test (luacov/coveralls)
  • automated nightly builds available at http://build.koreader.rocks/download/nightly/
• free as in free speech
  • licensed under Affero GPL v3
  • all dependencies are free software

Check out the KOReader wiki to learn more about this project.

Building Prerequisites

These instructions for how to get and compile the source are intended for a Linux OS. Windows users are suggested to develop in a Linux VM or use Wubi.

To get and compile the source you must have patch, wget, unzip, git, cmake and luarocks installed, as well as a version of autoconf greater than 2.64. You also need nasm and of course a compiler like gcc or clang. If you want to cross-compile for other architectures, you need a proper cross-compile toolchain. Your GCC should be at least version 4.8.

Users of Debian and Ubuntu can install the required packages using:

sudo apt-get install build-essential git patch wget unzip \
gettext autoconf automake cmake libtool nasm luarocks \
libssl-dev libffi-dev libsdl2-dev libc6-dev-i386 xutils-dev linux-libc-dev:i386 zlib1g:i386

If you are running Fedora, be sure to install the package libstdc++-static.

That's all you need to get the emulator up and running with ./kodev build and ./kodev run.

Cross compile toolchains are available for Ubuntu users through these commands:

# for Kindle
sudo apt-get install gcc-arm-linux-gnueabi g++-arm-linux-gnueabi
# for Kobo and Ubuntu touch
sudo apt-get install gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf
# for Win32
sudo apt-get install gcc-mingw-w64-i686 g++-mingw-w64-i686

The packages pkg-config-arm-linux-gnueabihf and pkg-config-arm-linux-gnueabi may block you from building for Kobo or Kindle. Remove them if you get an ld error, /usr/lib/gcc-cross/arm-linux-gnueabihf/4.8/../../../../arm-linux-gnueabihf/bin/ ld: cannot find -lglib-2.0

On Mac OS X you may need to install the following tools using Homebrew:

brew install nasm binutils libtool autoconf automake cmake makedepend sdl2 lua51 gettext pkg-config wget md5sha1sum
echo 'export PATH="/usr/local/opt/gettext/bin:$PATH"' >> "$HOME"/.bash_profile

If you run into a gettext error while building glib, try brew link --force gettext to override the built-in Mac OS BSD gettext with GNU GetText.

The KOReader Android build requires ant, openjdk-8-jdk and p7zip-full. A compatible version of the Android NDK and SDK will be downloaded automatically by ./kodev build android if no NDK or SDK is provided in environment variables. For that purpose you can use NDK=/ndk/location SDK=/sdk/location ./kodev build android.

Users of Debian Jessie first need to configure the backports repository:

sudo echo "deb http://ftp.debian.org/debian jessie-backports main" > /etc/apt/sources.list.d/backports.list
sudo apt-get update

For both Ubuntu and Debian, install the packages:

sudo apt-get install ant openjdk-8-jdk

Users on Debian finally need to remove JRE version 7:

sudo apt-get remove openjdk-7-jre-headless

In order to build KOReader package for Ubuntu Touch, the click package management tool is needed, Ubuntu users can install it with:

sudo apt-get install click

You might also need SDL library packages if you want to compile and run KOReader on Linux PC. Fedora users can install SDL and SDL-devel package. Ubuntu users probably need to install the libsdl2-dev package:

Getting the source

git clone https://github.com/koreader/koreader.git
cd koreader && ./kodev fetch-thirdparty

Building, Running and Testing

For emulating KOReader on Linux, Windows and Mac OSX

To build an emulator on your current Linux or OSX machine:

./kodev build

If you want to compile the emulator for Windows run:

./kodev build win32

To run KOReader on your development machine:

./kodev run

To automatically set up a number of primarily luarocks-related environment variables:

./kodev activate

To run unit tests:

./kodev test base
./kodev test front

To run a specific unit test (for test development):

./kodev test front readerbookmark_spec.lua

NOTE: Extra dependencies for tests: busted and ansicolors from luarocks.

To run Lua static analysis:

make static-check

NOTE: Extra dependencies for tests: luacheck from luarocks

You may need to checkout the circleci config file to setup up a proper testing environment. Briefly, you need to install luarocks and then install busted with luarocks. The "eng" language data file for tesseract-ocr is also need to test OCR functionality. Finally, make sure that luajit in your system is at least of version 2.0.2.

You can also specify the size and DPI of the emulator's screen using -w=X (width), -h=X (height), and -d=X (DPI). There is also a convenience -s (simulate) flag with some presets like kobo-aura-one, kindle3, and hidpi. The latter is a fictional device with --screen_width=1500, --screen_height=2000 and --screen_dpi=600 to help ensure DPI scaling works correctly. Sample usage:

./kodev run -s=kobo-aura-one

To use your own koreader-base repo instead of the default one change the KOR_BASE environment variable:

make KOR_BASE=../koreader-base

This will be handy if you are developing koreader-base and you want to test your modifications with the KOReader frontend. NOTE: this only supports relative path for now.

For EReader devices (kindle, kobo, pocketbook, ubuntu-touch)

To build an installable package for Kindle:

./kodev release kindle

To build an installable package for Kobo:

./kodev release kobo

To build an installable package for PocketBook:

./kodev release pocketbook

To build an installable package for Ubuntu Touch

./kodev release ubuntu-touch

You may checkout our nightlybuild script to see how to build a package from scratch.

For Android devices

A compatible version of the Android NDK and SDK will be downloaded automatically by the kodev command. If you already have an Android NDK and SDK installed that you would like to use instead, make sure that the android and ndk-build tools can be found in your PATH environment variable. Additionally, the NDK and SDK variables should point to the root directory of the Android NDK and SDK respectively.

Then, run this command to build an installable package for Android:

./kodev release android

Translation

Please refer to l10n's README to grab the latest translations from the KOReader project on Transifex with this command:

make po

If your language is not listed on the Transifex project, please don't hesitate to send a language request here.

Variables in translation

Some strings contain variables that should remain unaltered in translation. For example:

The title of the book is %1 and its author is %2.

This might be displayed as:

The title of the book is The Republic and its author is Plato.

To aid localization the variables may be freely positioned:

De auteur van het boek is %2 en de titel is %1.

That would result in:

De auteur van het boek is Plato en de titel is The Republic.

Use ccache

Ccache can speed up recompilation by caching previous compilations and detecting when the same compilation is being repeated. In other words, it will decrease build time when the sources have been built before. Ccache support has been added to KOReader's build system. To install ccache:

• in Ubuntu use:sudo apt-get install ccache
• in Fedora use:sudo yum install ccache
• from source:
  • download the latest ccache source from http://ccache.samba.org/download.html
  • extract the source package in a directory
  • cd to that directory and use:./configure && make && sudo make install
• to disable ccache, use export USE_NO_CCACHE=1 before make.
• for more information about ccache, visit: https://ccache.samba.org/