Highlight changed parts in "Correct Texts"

[sbraz]

Sometimes it's hard to see what changed, especially when it's only whitespace. You could probably take advantage of difflib's SequenceMatcher to do this. I looked around but I don't see another library which would make it easier.
Feel free to re-use my code if it helps:

#!/usr/bin/env python3

import sys
import difflib

import colorama

def highlight_diff(a, b, a_delim_start, a_delim_end, b_delim_start, b_delim_end):
  s = difflib.SequenceMatcher(a=a, b=b)
  matching_block = s.get_matching_blocks()
  previous_index_a, previous_index_b = (0, 0)
  highlighted_a, highlighted_b = ("", "")
  for block in matching_block:
    highlighted_a += (a_delim_start + a[previous_index_a:block.a] +
            a_delim_end + a[block.a:block.a + block.size])
    previous_index_a = block.a + block.size
    highlighted_b += (b_delim_start + b[previous_index_b:block.b] +
            b_delim_end + b[block.b:block.b + block.size])
    previous_index_b = block.b + block.size
  return highlighted_a, highlighted_b

if __name__ == "__main__":
    a, b = sys.argv[1:]
    print("\n".join(highlight_diff(a, b, colorama.Style.BRIGHT + colorama.Fore.RED,
        colorama.Style.RESET_ALL, colorama.Style.BRIGHT + colorama.Fore.GREEN,
        colorama.Style.RESET_ALL)))

[otsaloma]

This could be very useful. I haven't used difflib, but if it works well enough, the bigger task is probably doing the GTK+ styling -- probably with the markup property of Gtk.CellRendererText and CSS classes (<span class="gaupol-diff-added">...</span> maybe?), somehow accounting for light vs. dark themes.

I don't have any immediate plans to do this. If someone's interested in contributing, this should be doable without needing to be familiar with or learning to understand Gaupol's codebase as a whole.

[sbraz]

I would help but I never work with GUIs so I wouldn't know where to start.

[otsaloma]

[otsaloma]

Done now. Used SequenceMatcher.get_opcodes so that added, removed and changed parts are colored different. Colors are done with opacity, so should hopefully work about OK with different themes. Colors are also configurable by editing the config file. Not tested much yet, so open to feedback.

[sbraz]

Great, thanks! I'm going to try using the git version and I'll let you know if I run into issues.