I am well aware of what calibre can do, and know some who use it on the
desktop.
the question is, if a compile of Calibre is possible for dos...you know
the focus of this list? smiles.
The qt idea came from a member of the calibre forum at mobileread.
regardless, the question desire and focus is possibly running the program
in DOS.
Kare
On Sat, 25 Jan 2020, dmccunney wrote:
On Sat, Jan 25, 2020 at 8:10 PM Karen Lewellen <klewel...@shellworld.net> wrote:
Hi folks,
Anyone know if the qt platform can be used to create DOS ports of programs?
www.qt.io
I don't believe the Qt framework can be used to create DOS
applications. And it wouldn't help you because it exists to create
cross-platform *UIs*. The code the UI will be a wrapper for will be
entirely separate. (There is a DOS FLTK toolkit with a similar
usage.)
The discussion is tied to the calibre ebook reading platform, with my
wondering if it might be possible to create a DOS edition, there is a
Linux one, strong in command line options, but I am not a developer.
I make extensive use of Calibre, and have it here under Windows and
Linux. (It's available for OS/X, too, but I don't have Apple gear to
run it on.) Calibre is cross platform because it's written in Python.
The Python runtime abstracts away the platform differences, and it
looks and acts identically on all OSes. (Calibre's author, Kovid
Goyal, is one the the official maintainers of the 2.X branch of
Python. Python is at v3 now, but v3 introduced enough differences
that migrating Python 2 code to Python 3 is non-trivial, and many
efforts refuse to try.)
What became Calibre began when Kovid, who was a PhD candidate in
Computer Science at the time, got a Sony Reader dedicated eBook
viewer. The Reader used a proprietary eBook format called BBLF, and
the only place to get BBLF formatted books was the Sony Store. Kovid
reverse-engineered the BBLF format to create software that could put
texts into the Sony format so he could view them on his Reader. (Sony
later switched to the ePub format that is the standard for everything
except Amazon Kindles.)
Calibre evolved into a Swiss Army Knife for eBooks. It's principal
purpose is to create and maintain an eBook library. It stores volumes
imported into it in a directory structure it maintains. Volumes are
stored in sub-directories by author name. If there is more than one
book by an author, each volume is in a sub-directory under their main
directory. It can also display books in the Library, but the assumption
is that you will use a dedicated eBook viewer device. Calibre knows
how to talk to almost all viewer devices, and can put books onto a
connected device. I use it here to put books on a 7" Android tablet
that I connect via a USB cable.
As well as maintaining the books, Calibre maintains extensive metadata
about the books, like publisher, issue date, category, publisher's
blurb, keywords describing the book, and series data for books in a
series). It can look up metadata online and store it for each book. The
database uses the public domain SQLite program, which provides an SQL
compliant relational database in a single library. SQLite is used under the
hood in a*lot* of things. (I'm composing this reply in the Firefox browser,
and Firefox uses and SQLite database called places.sqlite to store
bookmarks and browsing history, as well as other things.) Calibre's UI
does not use a third party graphics toolkit.
Aside from creating and maintaining a library, Calibre can convert
between eBook formats. I first used it to convert volumes I got in
ePub to Amazon's Mobi format, for a Palm OS device that had a Mobi
viewer but not one for ePub. (Palm devices were Mobipocket's first
target when the got into eBook publishing. Amazon bought Mobipocket
and used their efforts as the basis of the format used by the Amazon
Kindle. ePub did not exist at the time. Palm went belly-up before
ePub came around.) How well conversion works depends upon the
eBook format. PDF generally does *not* convert well. There isn't a
lot Calibre can do about that.
The command line options exist in Windows, too, but most folks have no
need to use them. Everything they need to do can be accomplished
through the GUI.
Calibre scratched a huge itch. Calibre is open source and can be
downloaded and used free of charge, but you can donate money if you
like it. Kovid has his PhD, but gets enough in donations he doesn't
have to get a regular job, and Calibre is his full time occupation.
(It costs a lot less to live in India, which helps.)
I don't believe it's *possible* to do a DOS port of Calibre. You would
need a DOS port of SQLite and a full version of Python 2.7 for DOS
as a starter. And if it could be done at all, it would require DOS
apps built for a 386 or better platform to get the required memory.
It could not be built to run on any earlier Intel CPU.
I believe Kovid has an experimental effort to rewrite Calibre in C#.
C# uses the Microsoft .NET framework, and C# code will run on anything
that has a .NET runtime. Linux has a longstanding effort called Mono
to create a cross platform .NET framework. Microsoft decided to make
.NET open source a while back, and Microsoft .NET engineers are major
contributors to current Mono development. I suspect Calibre in C#
will have better performance than Calibre in Python on the same
hardware, and that's a major reason for trying it.
But meanwhile, forget Calibre under DOS. If you really want to use
it, run Linux.
Thoughts?
See above.
Kare
______
Dennis
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