Embolden font for PDF rendering

On E-ink devices, PDF seems to be rendered a little light, the readability will improve if it can be rendered a little darker. I found a way to do that, with the "FT_Outline_Embolden", the patch for poppler can be downloaded from here.

Screenshots are as follow:

Hope useful for E-ink PDF viewer or PDF to image converter.

IBSuite

To read book on my PRS505 e-book reader, I write some tools. Now I collect these tools into IBSuite (Image Book Suite), and put that on sourceforge. You can download the source code from the git of sourceforge project. Hope that can be useful for somebody.

http://sourceforge.net/projects/ibsuite/

IBSUITE

ibsuite stands for image book suite. It contains a set of tools to convert ebook in various format (pdf, chm, html) into a set of images, reformat the images (crop, embold, divide, etc), and assemble the result images into a new ebook.


COMPONENTS

• ibhtml2img: convert html to image with xulrunner
• ibhtml2pdf: convert html to pdf with xulrunner
• iblineparser: parser input image, extract line information
• ibpdfinfo: get some meta-information from pdf file, such as title, author, table of contents etc.
• ibpy: python module, which is the driver of the whole system, it uses above programs to convert input file to image, extract line information from image, dilate image, and re-assemble lines into a new image, generate output e-book.
• ibtools: A set of utilities and tools, some of them are used internal by ibsuite, others are user command provided by ibsuite.

USAGE

The most important command of ibsuite is ibreformat, the basic usage is as follow:

ibreformat [options] <input file>

In most cases, something like following:

ibreformat -o <output file>

--iprof=<iprof> --oprof=

<oprof>
--pprof=<pprof> <input file>

Where <input file> is input file name, <output file>

is output file name,

<iprof>

is input profile,

<pprof>

is output profile, is

<pprof>

processing profile.

Available input/output/processing profiles are as follow:

input profiles:

img: for scanned book

output profiles:

prs505p: for Sony PRS505 in portrait mode

prs505l: for Sony PRS505 in landscape mode

processing profiles:

divide2: divide one line into two line (a kind of simple reflow)

resize: Resize and dilate pages

repage: Re-page input book, without much other processing such as dilate.

For other command line options, please refer to "ibreformat -h".


Some useful command line option combinations:

For scanned book on PRS505:

ibsuite -o

-iprof=img -pprof=resize -oprof=prs505l

<input file>

For chm file on PRS505:

ibchm2imb .chm

When it finishs, .imb will be generated, then

ibsuite -o

-pprof=repage --oprof=prs505l .imb

INSTALL

Currently, only Linux is supported, but I think it may work on some unix enviroment (including cygwin on Windows) after some work. Currently only install from source code is supported.

Pre-requirement:

• gcc, g++, bash, make
• libfontconfig-dev, libnetpbm-dev, libgtk-dev
• python, python-imaging
• imagemagick
• for HTML/CHM support: python-chm, xulrunner
• for scanned book: unpaper

Build:

./configure [--prefix=]
make [PREFIX=] [NO_XUL=1]

Install:

# become root
make install [PREFIX=]

An algorithm to render PDF on small devices

I am interested in ebook reader for quite a while. But after trying with a 6-inch e-ink reader (Hanlin V3), I found it is almost useless to read normal PDF files (A4 size) on these devices. The font size is too small, while the page size is too wide. So, a method to render PDF for these small devices is thought about and prototyped. The details are as follow:

1. Convert pdf to image. I use pdftoppm of xpdf. Such as: pdftoppm -r 180 -f 245 -l 245 -gray -aa yes a.pdf a
2. Analyze the generated images. Break page into lines.
3. Divide each line long enough to two segments.
4. Rearrange the segments into a new page, with half of the width.

A full functional PDF re-flow algorithm is very difficult to implemented. But a more simplified version as above is much easier.