[File Type Plugin] FB2 Poetry Reflow

[microtic]

FB2 Poetry Reflow makes ordinary FB2 poetry easier to read on small screens.

When calibre converts an FB2 book, poems normally get a wide left margin. This plugin removes that extra margin and gives wrapped verses a hanging indent, making it easier to distinguish the continuation of a verse from the beginning of the next one.

It runs automatically when converting from FB2 to formats such as EPUB or AZW3. The original FB2 file is not modified.

Example

Before:

        The evening wind carries
        the sound of the sea
        A small light waits at
        the end of the quay

After:

The evening wind carries the sound
   of the sea
A small light waits at the end of
   the quay

These are invented example lines. Actual wrapping depends on your screen, font size, and reader settings.

What it preserves

• Separate verses and gaps between stanzas.
• Poem titles, inline emphasis, and internal links.
• Normal prose formatting.

Limitations

The source FB2 must identify the text as poetry. The plugin does not guess which ordinary paragraphs are poems, and it does not process existing EPUB or AZW3 files as input.

Poems with detectable explicit styling, alignment, or deliberate spacing are skipped and left to calibre’s normal conversion. This is a conservative heuristic, so please preview books containing visual or unusually arranged poetry.

For zipped FB2 files, extract the .fb2 before converting.

Compatibility

Tested with calibre 9.13 on Linux, producing EPUB and AZW3. The result has also been checked on a physical e-reader.

The plugin allows installation on calibre 5.0 and newer, but versions 5–8 are unverified. Windows and macOS are supported platforms; full conversion testing so far has been on Linux.

Installation

1. Download the plugin ZIP attached to this post. Do not unzip it.
2. Open calibre → Preferences → Plugins → Load plugin from file.
3. Select the ZIP and accept calibre’s third-party plugin warning.
4. Restart calibre if prompted.

Usage

Convert a book normally, making sure the input format is FB2. There is no additional button or configuration step.

To disable it, go to Preferences → Plugins → File type plugins → FB2 Poetry Reflow. Reconvert from the original FB2 to obtain calibre’s default output.

Source and license

Source code and README
GitHub releases

License: MIT.

Version History

Spoiler:

2.0.1
• Reflows ordinary FB2 poetry with hanging indentation.
• Preserves poem titles and links when anchors overlap.
• Skips detectable visual layouts.
• Includes regression tests and automated release builds.

Feedback is welcome. When reporting a problem, please include your calibre version, output format, and reader model or application. A small example that you have permission to share is especially helpful.

[JSWolf]

Is there any advantage to using FB2?

[Sarmat89]

Unlike EPUB, it supports headings, epigraphs, footnotes, and poetry.

[JSWolf]

Originally Posted by Sarmat89

Unlike EPUB, it supports headings, epigraphs, footnotes, and poetry.

So does ePub. You just have to code for it.

In your first post in this thread, your after sample is trivial to do in ePub.

[theducks]

Agree with Jon

It is called an 'outdent'
You set a wider margin:

margin-left:2em;
text-indent: -2em;

[Sarmat89]

With FB2, you are not limited to hanging indents. You can have proper right justification for the wrapped part.

[DNSB]

With the correct CSS, you can do pretty much anything in an ePub. Once you have created the needed CSS, it just becomes a matter of copy/paste. I have multiple sets for headings, chapter headers, epigraphs, poetry, screen plays and even footnotes in ePub2 or ePub3 when I'm not looking for backwards compatibility.


OTOH, IMNSHO, this is much like any other conversion tool for those who are not willing/able to down and dirty with the internals of an ePub file. It may not be the prettiest but it works in translating FB2's poetry tags (<poem>, <stanza>, <v> and likely others that I am not aware of) which have no direct equivalents in ePub.