diff: Start work on image display

kittens/diff/images.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
+
+import shutil
+import warnings
+
+
+class ImageSupportWarning(Warning):
+    pass
+
+
+def images_supported():
+    ans = getattr(images_supported, 'ans', None)
+    if ans is None:
+        ans = shutil.which('convert') is not None
+        images_supported.ans = ans
+        if not ans:
+            warnings.warn('ImageMagick not found images cannot be displayed', ImageSupportWarning)
+    return ans

kittens/diff/main.py

@@ -4,6 +4,7 @@
 
 import os
 import sys
+import warnings
 from collections import defaultdict
 from functools import partial
 from gettext import gettext as _
@@ -17,6 +18,7 @@ from ..tui.handler import Handler
 from ..tui.loop import Loop
 from .collect import create_collection, data_for_path, set_highlight_data
 from .config import init_config
+from .images import ImageSupportWarning
 from .patch import Differ, set_diff_command
 from .render import LineRef, render_diff
 
@@ -305,7 +307,16 @@ Syntax: |_ name=value|. For example: |_ -o background=gray|
 '''.format, config_help=CONFIG_HELP.format(conf_name='diff', appname=appname))
 
 
+def showwarning(message, category, filename, lineno, file=None, line=None):
+    if category is ImageSupportWarning:
+        showwarning.warnings.append(message)
+
+
+showwarning.warnings = []
+
+
 def main(args):
+    warnings.showwarning = showwarning
     msg = 'Show a side-by-side diff of the specified files/directories'
     args, items = parse_args(args[1:], OPTIONS, 'file_or_directory file_or_directory', msg, 'kitty +kitten diff')
     if len(items) != 2:
@@ -319,6 +330,9 @@ def main(args):
     loop = Loop()
     handler = DiffHandler(args, opts, left, right)
     loop.loop(handler)
+    for message in showwarning.warnings:
+        from kitty.utils import safe_print
+        safe_print(message, file=sys.stderr)
     if loop.return_code != 0:
         if handler.report_traceback_on_exit:
             print(handler.report_traceback_on_exit, file=sys.stderr)

kittens/diff/render.py

@@ -8,11 +8,12 @@ from itertools import repeat
 from kitty.fast_data_types import truncate_point_for_length, wcswidth
 
 from .collect import (
-    Segment, data_for_path, highlights_for_path, lines_for_path, path_name_map,
+    Segment, data_for_path, highlights_for_path, is_image, lines_for_path,
-    sanitize
+    path_name_map, sanitize
 )
 from .config import formats
 from .diff_speedup import split_with_highlights as _split_with_highlights
+from .images import images_supported
 
 
 class Ref:
@@ -352,6 +353,11 @@ def rename_lines(path, other_path, args, columns, margin_size):
         yield m + line
 
 
+def image_lines(left_path, right_path, columns, margin_size):
+    if False:
+        yield 0
+
+
 def render_diff(collection, diff_map, args, columns):
     largest_line_number = 0
     for path, item_type, other_path in collection:
@@ -366,20 +372,30 @@ def render_diff(collection, diff_map, args, columns):
     for i, (path, item_type, other_path) in enumerate(collection):
         item_ref = Reference(path)
         is_binary = isinstance(data_for_path(path), bytes)
+        is_img = is_binary and is_image(path) and images_supported()
         yield from yield_lines_from(title_lines(path, other_path, args, columns, margin_size), item_ref, False)
         if item_type == 'diff':
             if is_binary:
-                ans = yield_lines_from(binary_lines(path, other_path, columns, margin_size), item_ref)
+                if is_img:
+                    ans = image_lines(path, other_path, columns, margin_size)
+                else:
+                    ans = yield_lines_from(binary_lines(path, other_path, columns, margin_size), item_ref)
             else:
                 ans = lines_for_diff(path, other_path, diff_map[path], args, columns, margin_size)
         elif item_type == 'add':
             if is_binary:
-                ans = yield_lines_from(binary_lines(None, path, columns, margin_size), item_ref)
+                if is_img:
+                    ans = image_lines(None, path, columns, margin_size)
+                else:
+                    ans = yield_lines_from(binary_lines(None, path, columns, margin_size), item_ref)
             else:
                 ans = all_lines(path, args, columns, margin_size, is_add=True)
         elif item_type == 'removal':
             if is_binary:
-                ans = yield_lines_from(binary_lines(path, None, columns, margin_size), item_ref)
+                if is_img:
+                    ans = image_lines(path, None, columns, margin_size)
+                else:
+                    ans = yield_lines_from(binary_lines(path, None, columns, margin_size), item_ref)
             else:
                 ans = all_lines(path, args, columns, margin_size, is_add=False)
         elif item_type == 'rename':