Completion percentage not precise enough with relatively large objects

[cristian64]

Problem:

Currently, it is difficult to determine if a specific change has improved or worsened the results because the two-decimal figures shown in the completion percentage may not reflect minor changes.

The visibility of these changes depends heavily on the size of the object being matched. For large objects, once matching reaches ~99%, the progress increments are often too small to trigger a visual change in the decimal output.

Solutions:

• Option 1 - Increase precision: Use more decimal places so users can identify minor progress. This could include a setting to choose the number of decimal places displayed.
• Option 2 - Show fractions: Show a fraction instead of a rounded percentage (e.g. 75773 / 75781 instead of 99.99%). Users could toggle between fraction and percentage modes.
• Option 3 - Add directional indicators: Include a small up/down arrow to indicate whether the latest rebuild improved or worsened the matching results.

Some mockups for the little arrows:

Description	Image
Worsened
No change
Improved

In terms of implementation, Option 3 would simply involve adding a character (in a distinct color) immediately following the percentage: ↑, ↓, or =.

Option 1 and 2 are arguably mutually exclusive, as you choose either more decimal places or the fraction mode (but it would be great to have both available as options). Option 3 applies to both modes equally.

[cristian64]

It could be down to lack of practice (I'm still new in this space), but yesterday not having a precise completion percentage led me astray as I wrongly discarded a good change because I didn't appreciate a gain.

[cristian64]

It seems to me this alone is already an improvement:

diff --git a/objdiff-gui/src/views/diff.rs b/objdiff-gui/src/views/diff.rs
index 76da8aa..a5d602f 100644
--- a/objdiff-gui/src/views/diff.rs
+++ b/objdiff-gui/src/views/diff.rs
@@ -425,7 +425,7 @@ pub fn diff_view_ui(
                     let mut needs_separator = false;
                     if let Some(match_percent) = symbol_diff.match_percent {
                         let response = ui.label(
-                            RichText::new(format!("{match_percent:.2}%"))
+                            RichText::new(format!("{match_percent:.4}%"))
                                 .font(appearance.code_font.clone())
                                 .color(match_color_for_symbol(match_percent, appearance)),
                         );
@@ -437,6 +437,13 @@ pub fn diff_view_ui(
                                         .color(appearance.text_color),
                                 );
                             });
+
+                            let score = max_score - diff_score;
+                            ui.label(
+                                RichText::new(format!("{score}/{max_score}"))
+                                    .font(appearance.code_font.clone())
+                                    .color(match_color_for_symbol(match_percent, appearance)),
+                            );
                         }
                         needs_separator = true;
                     }