because studying PDF compress, I collected some open source Jbig2 Encoder and Decoder.

This encoder can:

• Generate JBIG2 files, or fragments for embedding in PDFs
• Generic region encoding
• Perform symbol extraction, classification and text region coding
• Perform refinement coding and,
• Compress multipage documents

Lossless JBIG2 Encoder Windows Dynamic Libary: bases on Jbig2, but easily integrate with your own application.

The JPedal JBIG2 Image Decoder is a 100% pure Java image decoder for the JBIG2 file format. The decoder takes the JBIG2 image processing technology developed for the Java PDF viewer and makes it available as a generic library for more general usage.

It offers the ability to allow developers to add JBIG2 image rendering capabilities to their own applications, through a simple and easy to use API. In its simplest form it allows developers to load in a JBIG2 encoded datastream and convert that into a BufferedImage.

Version 1 is available under a BSD license to provide a JBig2 decoder. It is used in many projects, including some of our competitors.

Version 2 is a faster, enhanced version available under a commerical license only. It is used in the commercial versions of JPedal from 4.21 onwards.

JBIG2-Image-Decoder:is a fork of JPedal’s JBIG2 library, which aims to improve the performance of the original code.

jbig2.js:JavaScript implementation of the JBIG2 specification.

jbig2dec is a decoder implementation of the JBIG2 image compression format. JBIG2 is designed for lossy or lossless encoding of ‘bilevel’ (1-bit monochrome) images at moderately high resolution, and in particular scanned paper documents. In this domain it is very efficient, offering compression ratios on the order of 100:1.

This is a decoder only implementation, and currently is in the alpha stage, meaning it doesn’t completely work yet. However, we are maintaining parity with available encoders, so it is useful for real work.

JBIG-KIT is a software implementation of the JBIG1 data compression standard (ITU-T T.82), which was designed for bi-level high-resolution image data such as scanned documents. This library is available in portable C code and has been widely used in fax products, printer firmware and drivers, and document management systems. The package includes a variant implementation of just the ITU-T T.85 profile, with memory management optimized for embedded and fax applications.

P.S.

JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group. It is suitable for both lossless and lossy compression. According to a press release[1] from the Group, in its lossless mode JBIG2 typically generates files one third to one fifth the size of Fax Group 4 and one half to one quarter the size of JBIG, the previous bi-level compression standard released by the Group. JBIG2 has been published in 2000 as the international standard ITU T.88[2], and in 2001 as ISO/IEC 14492[3].

A couple of days ago we released the latest version of Adobe Reader for iOS and Android, and we’re pleased to share a summary of the great new functionality in this update.

All New Look!

Adobe Reader now sports a branch new look, with a split panel that makes it extremely easy to navigate across different functions, such as viewing Recently viewed files, browsing the list of all documents, as well as taking a look at what’s new in this release. On Android phones, given the smaller screen space, the split pane animates to the left when you select an item. On iPhone and iPod Touch, the Reader UI provides a tab bar at the bottom of the screen instead of a split pane view, just like a standard iPhone app. All in all, it’s a brand new look and an engaging experience across devices and form factors!

Manage your files and folders, all within Adobe Reader

Adobe Reader now allows you to manage your documents right within the Reader. You can create & manage folders, and rename, delete and move files seamlessly on both Android and iOS (*). On Android, we’ve provided two viewing modes – while we’ve added the new Folder View that allows you to browse folders up and down the hierarchy just like any file browser, we’ve also retained the existing flat-list view that gives you very convenient view of all your PDF documents on the device storage. What’s more – you can manage files from either of the views. See below a series of screenshots illustrating some of these new capabilities.

(*) On iOS, file management is available on devices running iOS 5 and above.

Field Validation of forms

With this update of Adobe Reader, we’ve enhanced support for forms that have Field Validation, Calculation, and Formatting built in the form fields. Refer the screenshot below that illustrates this with a simple numerical form field.

Add Text Tool

Adobe Reader now supports adding arbitrary text using the Add Text tool (also popularly known as the ‘Typewriter tool’). This is available in the Commenting Toolbar along with the rest of the commenting tools, and can be very useful in filling static forms as well as adding text to arbitrary locations on the page.

Dictionary Support on iOS

Adobe Reader on iOS now allows you to look up definitions of selected terms in a PDF by invoking the built-in dictionary. This feature is available on all devices running iOS version 5 and above.

for details, please visit here.