From 7365ed9b05b2e512d8279d2faed72b7a1cc3996c Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 8 May 2018 23:02:00 +0530
Subject: [PATCH] diff: Better title rendering

---
 kittens/diff/collect.py |  4 ++--
 kittens/diff/main.py    |  2 +-
 kittens/diff/render.py  | 17 +++++++++++++----
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/kittens/diff/collect.py b/kittens/diff/collect.py
index 8209e35ff..5a489b522 100644
--- a/kittens/diff/collect.py
+++ b/kittens/diff/collect.py
@@ -150,8 +150,8 @@ def create_collection(left, right):
         collect_files(collection, left, right)
     else:
         pl, pr = os.path.abspath(left), os.path.abspath(right)
-        path_name_map[left] = pl
-        path_name_map[right] = pr
+        path_name_map[pl] = left
+        path_name_map[pr] = right
         collection.add_change(pl, pr)
     collection.finalize()
     return collection
diff --git a/kittens/diff/main.py b/kittens/diff/main.py
index 283c006b6..e72d7ac39 100644
--- a/kittens/diff/main.py
+++ b/kittens/diff/main.py
@@ -46,7 +46,7 @@ class DiffHandler(Handler):
     def __init__(self, args, opts, left, right):
         self.state = INITIALIZING
         self.opts = opts
-        self.left, self.right = map(os.path.abspath, (left, right))
+        self.left, self.right = left, right
         self.report_traceback_on_exit = None
         self.args = args
         self.scroll_pos = self.max_scroll_pos = 0
diff --git a/kittens/diff/render.py b/kittens/diff/render.py
index 1dad3495b..bd0747fd0 100644
--- a/kittens/diff/render.py
+++ b/kittens/diff/render.py
@@ -120,9 +120,18 @@ def highlight_boundaries(ltype):
     return start, stop
 
 
-def title_lines(left_path, args, columns, margin_size):
-    name = fit_in(sanitize(path_name_map[left_path]), columns - 2 * margin_size)
-    yield title_format(place_in(' ' + name, columns))
+def title_lines(left_path, right_path, args, columns, margin_size):
+    m = ' ' * margin_size
+    left_name, right_name = map(path_name_map.get, (left_path, right_path))
+    if right_name and right_name != left_name:
+        n1 = fit_in(m + sanitize(left_name), columns // 2 - margin_size)
+        n1 = place_in(n1, columns // 2)
+        n2 = fit_in(m + sanitize(right_name), columns // 2 - margin_size)
+        n2 = place_in(n2, columns // 2)
+        name = n1 + n2
+    else:
+        name = place_in(m + sanitize(left_name), columns)
+    yield title_format(place_in(name, columns))
     yield title_format('━' * columns)
 
 
@@ -354,7 +363,7 @@ def render_diff(collection, diff_map, args, columns):
     for path, item_type, other_path in collection:
         item_ref = Reference(path)
         is_binary = isinstance(data_for_path(path), bytes)
-        yield from yield_lines_from(title_lines(path, args, columns, margin_size), item_ref)
+        yield from yield_lines_from(title_lines(path, other_path, args, columns, margin_size), item_ref)
         if item_type == 'diff':
             if is_binary:
                 ans = yield_lines_from(binary_lines(path, other_path, columns, margin_size), item_ref)