[GUI Plugin] TextDiff

[Comfy.n]

Originally Posted by feuille

Hello Comfy.n,

I implemented two of your hints (see history).

In order to calculate the display time of a progress bar, I stopped intermediate times in the program flow. To my surprise, the HTML rendering of the text browser widget consumes 2/3 of the total runtime! I may implement in a future release a workaround like stepwise asynchronous loading with a timer or so, but I need to do some research on that.

Thank you for the mention, I appreciate it!
Just did a quick test and confirmed that I had two identical books (Ratio 0):



Then I found both are sourced from Gutenberg (one is a StandardEbooks edition).
Dark theme on-screen output is fine now, and it's great to have a one-click TextDiff tool within Calibre, thank you again.

[feuille]

The ratio is described in https://docs.python.org/3/library/difflib.html: »Note that this is 1.0 if the sequences are identical, and 0.0 if they have nothing in common.« Hmmm...

[Comfy.n]

Originally Posted by feuille

The ratio is described in https://docs.python.org/3/library/difflib.html: »Note that this is 1.0 if the sequences are identical, and 0.0 if they have nothing in common.« Hmmm...

yes I found it interesting to be zero, because when i did previous comparisons with very similar texts (translation variations), ratio would be like 0.95 or so

then I thought it was the other way -- the lower, the closer to identical

[Robert1a]

Hello, I tried the Plugin today by using it on similar ebooks and got the error meaasge:
AttributeError: 'TextDiffDialog' object has no attribute 'diff'

I'm using Calibre 6.20, Plugin 1.2.1 on Win 11.

[feuille]

Hello Robert1a,
I'm sorry, but I can't take care of it until next week. In the meantime, please send the complete Python stack trace with the line number of the error (if necessary, start Calibre in debug mode).

[Robert1a]

Sorry for my error message. I tried the tool for the first time and chose the save result to a file without having explicitely hit the compare before. So, the error massage appears when there is no result available. Maybe room for a small improvement, by checking if there is a comparision done before allowing to save the result.

The plugin works.

[feuille]

Thanks for the clarification! Version 1.2.2 next week 😊

[Zillion_]

Hello,
love your plugin ! May I make the following suggestions / remarks ?
- sometimes (= not always, and I haven't been able to determine why) if using the plugin (with a comparison displayed on screen) while editing the text of one of the compared files, it is not possible to "refresh" the comparison. It says "Error: no books selected", then the cursor starts spinning and never stops until Calibre is restarted (but everything keeps working).

- as above, sometimes, clicking "refresh books formats list" causes the same book to appear twice, instead of the two originally selected books.
- would it be possible to customize the colors used in the compare results ?

Also, question: what's the difference in the context handling between plugin and htmldiff ?

[Zillion_]

seems that the issue occurs when clicking anywhere in the Calibre main windows or booklist while the Compare window is open... not sure yet.

[Zillion_]

Hello, may I suggest a feature enhancement ? Would it be possible to configure parameters for the plugin, e.g. the "wrap columns at" (default=60, I like to set it higher), Tab size, Context handling, etc.

[feuille]

Originally Posted by Zillion_

Hello, may I suggest a feature enhancement ? Would it be possible to configure parameters for the plugin, e.g. the "wrap columns at" (default=60, I like to set it higher), Tab size, Context handling, etc.

Hello Zillion_,

wrap columns and tab size works as expected (see attached images with wraps at 60 resp. 100 Characters).

> Also, question: what's the difference in the context handling between plugin and htmldiff ?

Handling by htmldiff (quote from the documentation):

context and numlines are both optional keyword arguments. Set context to True when contextual differences are to be shown, else the default is False to show the full files. numlines defaults to 5. When context is True numlines controls the number of context lines which surround the difference highlights. When context is False numlines controls the number of lines which are shown before a difference highlight when using the “next” hyperlinks (setting to zero would cause the “next” hyperlinks to place the next difference highlight at the top of the browser without any leading context).
https://docs.python.org/3/library/difflib.html
Strategy is:
- Put diff without table body in new text blob with marker for revised table body
- Loop thru table body rows and build another text blob
- Replace marker in text blob 1 with text blob 2

Context handling by the plugin:

The plugin strips identical lines from the diff result, preserving n context lines (as set by user):

abc ...
[18 identical line(s).]
def...

BTW, there is a new version out (1.2.3).

[Zillion_]

Hello, while using this great plugin I noticed the following (on Calibre 7.2 and 7.3):
- choosing any font other that "sans serif" doesn't do anything
- choosing any display format other than HTML (e.g. context, unified or ndiff) causes the following error: "ERROR: Unhandled Exception" - "NameError:name 'self' is not defined".

From the Details screen:
Traceback (most recent call last):

File "calibre_plugins.textdiff.main", line 785, in compare
File "calibre_plugins.textdiff.main", line 1280, in create_diff
File "calibre_plugins.textdiff.main", line 1311, in diff_lines_to_string
NameError: name 'self' is not defined

[Zillion_]

Hello, thanks for the explanations. I still don't see what the "tab size" (tabulatorweite) does, I've tried multiple settings and can't see any difference in the output.

[feuille]

Originally Posted by Zillion_

Hello, while using this great plugin I noticed the following (on Calibre 7.2 and 7.3):
- choosing any font other that "sans serif" doesn't do anything
- choosing any display format other than HTML (e.g. context, unified or ndiff) causes the following error:
[/INDENT]

Thanks for your patient testing. The error has been fixed in the just released version 1.2.4.
The tab width is used internally by Difflib when converting tabs to spaces and vice versa (see Difflib documentation). Probably only makes sense when comparing source codes.

[Zillion_]

Thanks for the fix !!