Add a regression test for issue #14 (load supposedly "truncated" imag…

…e saved by GIMP).

data_for_tests.py

@@ -0,0 +1,21 @@
+import os
+
+from collections import OrderedDict
+
+REPO_DIR = os.path.dirname(os.path.realpath(__file__))
+TESTS_DIR = os.path.join(REPO_DIR, "tests")
+TESTS_DATA_DIR = os.path.join(TESTS_DIR, "data")
+
+image_group_dirs = OrderedDict()
+image_group_dirs['pil-compatible'] = \
+    os.path.join(TESTS_DATA_DIR, "pil-compatible")
+image_group_dirs['pil-incompatible'] = \
+    os.path.join(TESTS_DATA_DIR, "pil-incompatible")
+image_groups = OrderedDict()
+for key, parent in image_group_dirs.items():
+    image_groups[key] = []
+    for sub in os.listdir(parent):
+        sub_path = os.path.join(parent, sub)
+        if not os.path.isfile(sub_path):
+            continue
+        image_groups[key].append(sub_path)

tests/channeltinkerpil/test_incompatible_pngs_tkinter.py

@@ -0,0 +1,100 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Based on
+# <https://geeksforgeeks.org/python-display-images-with-pygame/>
+# importing required library
+from __future__ import division
+import os
+import sys
+
+import tkinter as tk
+# import PIL
+from PIL import (
+    ImageTk,
+    Image,
+    ImageFile,
+)
+
+ImageFile.LOAD_TRUNCATED_IMAGES = True
+# ^ Avoids issue #14 (GIMP images with
+#   "Raw profile type exif"), and image is displayed
+#   (often image isn't really broken,
+#   such as if saved with GIMP)
+TEST_SUBMODULE_DIR = os.path.dirname(os.path.realpath(__file__))
+TESTS_DIR = os.path.dirname(TEST_SUBMODULE_DIR)
+REPO_DIR = os.path.dirname(TESTS_DIR)
+sys.path.insert(0, REPO_DIR)
+
+from data_for_tests import image_groups  # noqa: E402
+# group_key = 'pil-compatible'  # never triggers issue #14
+group_key = 'pil-incompatible'
+
+root = None
+path = None
+paths = None
+path_i = 0
+
+
+def load():
+    global path_i
+    if path_i >= len(paths):
+        return False
+    try:
+        # image1.show()
+        # show just opens it with the default application (or xv), so:
+        image1 = Image.open(paths[path_i])
+        # ^ causes:
+        # PIL.UnidentifiedImageError: cannot identify image file '...'
+        # where ... is the path of a PIL-incompatible image (issue #14)
+        # *unless* ImageFile.LOAD_TRUNCATED_IMAGES = True
+        test = ImageTk.PhotoImage(image1)
+        label1 = tk.Label(root, image=test)
+        label1.image = test
+        label1.pack()
+        path_i += 1
+        root.after(200, load)
+    except Exception as ex:
+        label1 = tk.Label(
+            root,
+            text="{}: {}".format(type(ex).__name__, ex)
+        )
+        label1.pack()
+        raise
+
+
+def exit_window():
+    root.destroy()
+
+
+def main():
+    global root
+    global path
+    global paths
+    path = None
+    if len(sys.argv) > 1:
+        path = sys.argv[1]
+        if len(sys.argv) > 2:
+            print("Error: Got extra arg.", file=sys.stderr)
+            return 1
+    if not path:
+        image_paths = sorted(image_groups[group_key])
+        if image_paths:
+            paths = image_paths
+            path = image_paths[-1]
+            print('Automatically selected "{}"'.format(path))
+    else:
+        paths = [path]
+    root = tk.Tk()
+    root.title("Tkinter Image Loading Test")
+    W = root.winfo_screenwidth() // 4
+    H = root.winfo_screenheight() // 4
+
+    root.geometry("{}x{}".format(W, H))
+    root.after(1, load)
+    root.after(2000, exit_window)
+    root.mainloop()
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())