From a141acc152fa58ef24fd7383a35bcc0c024177c7 Mon Sep 17 00:00:00 2001
From: David Manthey <david.manthey@kitware.com>
Date: Thu, 4 Mar 2021 09:33:30 -0500
Subject: [PATCH] Increase the priority level of the PIL tile source.

The PIL tilesource was a fallback source, but sources with the same
priority level are used in an arbitrary order, and it was desired to
make it higher priority than the bioformats source for small tiff files.
This introduces more resolution into the fallback priority ordering.
---
 CHANGELOG.md                                        |  3 +++
 large_image/constants.py                            |  5 +++--
 .../large_image_source_bioformats/__init__.py       |  2 +-
 sources/pil/large_image_source_pil/__init__.py      | 13 ++++++++++---
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80d8e872e..2c167a416 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@
 - Reduce gdal warning about projection strings (#559)
 - Don't report needless frame information for some single frame files (#558)
 
+### Changes
+- The PIL tilesource priority is slightly higher than other fallback sources (#560)
+
 ### Bug Fixes
 - Fix compositing when using different frame numbers and partial tiles (#557)
 
diff --git a/large_image/constants.py b/large_image/constants.py
index 9df3f9c7f..fa3277669 100644
--- a/large_image/constants.py
+++ b/large_image/constants.py
@@ -23,8 +23,9 @@ class SourcePriority:
     MEDIUM = 4
     LOW = 5
     LOWER = 6
-    FALLBACK = 7
-    MANUAL = 8   # Will never be selected automatically
+    FALLBACK_HIGH = 7
+    FALLBACK = 8
+    MANUAL = 9   # Will never be selected automatically
 
 
 TILE_FORMAT_IMAGE = 'image'
diff --git a/sources/bioformats/large_image_source_bioformats/__init__.py b/sources/bioformats/large_image_source_bioformats/__init__.py
index e4f5b71cb..17c3ae9f6 100644
--- a/sources/bioformats/large_image_source_bioformats/__init__.py
+++ b/sources/bioformats/large_image_source_bioformats/__init__.py
@@ -145,7 +145,7 @@ def __init__(self, path, **kwargs):  # noqa
             raise TileSourceException(
                 'File cannot be opened via bioformats because it has no '
                 'extension to specify the file type (%s).' % largeImagePath)
-        if ext.lower() in ('.jpg', '.jpeg', '.jpe', '.png', '.tif', '.tiff'):
+        if ext.lower() in ('.jpg', '.jpeg', '.jpe', '.png'):
             raise TileSourceException('File will not be opened by bioformats reader')
 
         if not _startJavabridge(self._logger):
diff --git a/sources/pil/large_image_source_pil/__init__.py b/sources/pil/large_image_source_pil/__init__.py
index 85079a5aa..23381eb0a 100644
--- a/sources/pil/large_image_source_pil/__init__.py
+++ b/sources/pil/large_image_source_pil/__init__.py
@@ -24,7 +24,7 @@
 
 from large_image import config
 from large_image.cache_util import LruCacheMetaclass, methodcache, strhash
-from large_image.constants import TILE_FORMAT_PIL
+from large_image.constants import TILE_FORMAT_PIL, SourcePriority
 from large_image.exceptions import TileSourceException
 from large_image.tilesource import FileTileSource
 
@@ -65,8 +65,15 @@ class PILFileTileSource(FileTileSource, metaclass=LruCacheMetaclass):
 
     cacheName = 'tilesource'
     name = 'pilfile'
-    # No extensions or mime types are explicitly added for the PIL tile source,
-    # as it should always be a fallback source
+
+    # Although PIL is always a fallback source, prefer it to other fallback
+    # sources
+    extensions = {
+        None: SourcePriority.FALLBACK_HIGH
+    }
+    mimeTypes = {
+        None: SourcePriority.FALLBACK_HIGH
+    }
 
     def __init__(self, path, maxSize=None, **kwargs):
         """