Merge branch 'joe-rice-image-displayer-registry'

2 files changed, 37 insertions, 23 deletions

diff --git a/ranger/core/fm.py b/ranger/core/fm.py
index 43001e8b..7d23c9b6 100644
--- a/ranger/core/fm.py
+++ b/ranger/core/fm.py
@@ -22,11 +22,7 @@ from ranger.container.tags import Tags, TagsDummy
 from ranger.gui.ui import UI
 from ranger.container.bookmarks import Bookmarks
 from ranger.core.runner import Runner
-from ranger.ext.img_display import (W3MImageDisplayer, ITerm2ImageDisplayer,
-                                    TerminologyImageDisplayer,
-                                    URXVTImageDisplayer, URXVTImageFSDisplayer,
-                                    KittyImageDisplayer, UeberzugImageDisplayer,
-                                    ImageDisplayer)
+from ranger.ext.img_display import get_image_displayer
 from ranger.core.metadata import MetadataManager
 from ranger.ext.rifle import Rifle
 from ranger.container.directory import Directory
@@ -104,7 +100,7 @@ class FM(Actions,  # pylint: disable=too-many-instance-attributes
         def set_image_displayer():
             if self.image_displayer:
                 self.image_displayer.quit()
-            self.image_displayer = self._get_image_displayer()
+            self.image_displayer = get_image_displayer(self.settings.preview_images_method)
         set_image_displayer()
         self.settings.signal_bind('setopt.preview_images_method', set_image_displayer,
                                   priority=settings.SIGNAL_PRIORITY_AFTER_SYNC)
@@ -227,23 +223,6 @@ class FM(Actions,  # pylint: disable=too-many-instance-attributes
             for line in entry.splitlines():
                 yield line
 
-    def _get_image_displayer(self):  # pylint: disable=too-many-return-statements
-        if self.settings.preview_images_method == "w3m":
-            return W3MImageDisplayer()
-        elif self.settings.preview_images_method == "iterm2":
-            return ITerm2ImageDisplayer()
-        elif self.settings.preview_images_method == "terminology":
-            return TerminologyImageDisplayer()
-        elif self.settings.preview_images_method == "urxvt":
-            return URXVTImageDisplayer()
-        elif self.settings.preview_images_method == "urxvt-full":
-            return URXVTImageFSDisplayer()
-        elif self.settings.preview_images_method == "kitty":
-            return KittyImageDisplayer()
-        elif self.settings.preview_images_method == "ueberzug":
-            return UeberzugImageDisplayer()
-        return ImageDisplayer()
-
     def _get_thisfile(self):
         return self.thistab.thisfile
 
diff --git a/ranger/ext/img_display.py b/ranger/ext/img_display.py
index 2cce5c7a..7e911848 100644
--- a/ranger/ext/img_display.py
+++ b/ranger/ext/img_display.py
@@ -23,6 +23,7 @@ import warnings
 import json
 import threading
 from subprocess import Popen, PIPE
+from collections import defaultdict
 
 import termios
 from contextlib import contextmanager
@@ -72,6 +73,33 @@ class ImgDisplayUnsupportedException(Exception):
     pass
 
 
+def fallback_image_displayer():
+    """Simply makes some noise when chosen. Temporary fallback behavior."""
+
+    raise ImgDisplayUnsupportedException
+
+
+IMAGE_DISPLAYER_REGISTRY = defaultdict(fallback_image_displayer)
+
+
+def register_image_displayer(nickname=None):
+    """Register an ImageDisplayer by nickname if available."""
+
+    def decorator(image_displayer_class):
+        if nickname:
+            registry_key = nickname
+        else:
+            registry_key = image_displayer_class.__name__
+        IMAGE_DISPLAYER_REGISTRY[registry_key] = image_displayer_class
+        return image_displayer_class
+    return decorator
+
+
+def get_image_displayer(registry_key):
+    image_displayer_class = IMAGE_DISPLAYER_REGISTRY[registry_key]
+    return image_displayer_class()
+
+
 class ImageDisplayer(object):
     """Image display provider functions for drawing images in the terminal"""
 
@@ -90,6 +118,7 @@ class ImageDisplayer(object):
         pass
 
 
+@register_image_displayer("w3m")
 class W3MImageDisplayer(ImageDisplayer, FileManagerAware):
     """Implementation of ImageDisplayer using w3mimgdisplay, an utilitary
     program from w3m (a text-based web browser). w3mimgdisplay can display
@@ -243,6 +272,7 @@ class W3MImageDisplayer(ImageDisplayer, FileManagerAware):
 # ranger-independent libraries.
 
 
+@register_image_displayer("iterm2")
 class ITerm2ImageDisplayer(ImageDisplayer, FileManagerAware):
     """Implementation of ImageDisplayer using iTerm2 image display support
     (http://iterm2.com/images.html).
@@ -351,6 +381,7 @@ class ITerm2ImageDisplayer(ImageDisplayer, FileManagerAware):
         return width, height
 
 
+@register_image_displayer("terminology")
 class TerminologyImageDisplayer(ImageDisplayer, FileManagerAware):
     """Implementation of ImageDisplayer using terminology image display support
     (https://github.com/billiob/terminology).
@@ -390,6 +421,7 @@ class TerminologyImageDisplayer(ImageDisplayer, FileManagerAware):
         self.clear(0, 0, 0, 0)
 
 
+@register_image_displayer("urxvt")
 class URXVTImageDisplayer(ImageDisplayer, FileManagerAware):
     """Implementation of ImageDisplayer working by setting the urxvt
     background image "under" the preview pane.
@@ -474,6 +506,7 @@ class URXVTImageDisplayer(ImageDisplayer, FileManagerAware):
         self.clear(0, 0, 0, 0)  # dummy assignments
 
 
+@register_image_displayer("urxvt-full")
 class URXVTImageFSDisplayer(URXVTImageDisplayer):
     """URXVTImageDisplayer that utilizes the whole terminal."""
 
@@ -486,6 +519,7 @@ class URXVTImageFSDisplayer(URXVTImageDisplayer):
         return self._get_centered_offsets()
 
 
+@register_image_displayer("kitty")
 class KittyImageDisplayer(ImageDisplayer, FileManagerAware):
     """Implementation of ImageDisplayer for kitty (https://github.com/kovidgoyal/kitty/)
     terminal. It uses the built APC to send commands and data to kitty,
@@ -681,6 +715,7 @@ class KittyImageDisplayer(ImageDisplayer, FileManagerAware):
         #         continue
 
 
+@register_image_displayer("ueberzug")
 class UeberzugImageDisplayer(ImageDisplayer):
     """Implementation of ImageDisplayer using ueberzug.
     Ueberzug can display images in a Xorg session.