Add OpenRaster (.ora) thumbnailer.

Pix can open but xviewer can't currently (gdk-pixbuf support)

Author: mtwebster

debian/control

@@ -56,3 +56,10 @@ Architecture: all
 Depends: xapp-thumbnailers-common
 Description: Gimp thumbnailer
  Produces thumbnails for Gimp xcf files.
+
+Package: xapp-ora-thumbnailer
+Architecture: all
+Depends: xapp-thumbnailers-common
+Description: OpenRaster thumbnailer
+ Produces thumbnails for OpenRaster (.ora) files.
+

debian/xapp-ora-thumbnailer.install

@@ -0,0 +1,2 @@
+usr/bin/xapp-ora-thumbnailer
+usr/share/thumbnailers/xapp-ora-thumbnailer.thumbnailer

files/usr/bin/xapp-ora-thumbnailer

@@ -0,0 +1,27 @@
+#!/usr/bin/python3
+
+import os
+import sys
+import tempfile
+import zipfile
+import gi
+
+gi.require_version("XApp", "1.0")
+from gi.repository import XApp, GdkPixbuf
+
+import XappThumbnailers
+t = XappThumbnailers.Thumbnailer()
+
+# https://www.openraster.org/baseline/file-layout-spec.html
+# OpenRaster files are normal zip files, with a pre-generated thumbnail file you can extract.
+try:
+    with zipfile.PyZipFile(t.args.input) as z:
+        with tempfile.TemporaryDirectory(dir=XApp.get_tmp_dir(), prefix="xapp-ora-thumbnailer-") as tempd:
+            z.extract("Thumbnails/thumbnail.png", path=tempd)
+            pixbuf = GdkPixbuf.Pixbuf.new_from_file_at_size(os.path.join(tempd, "Thumbnails", "thumbnail.png"), t.args.size, t.args.size)
+            pixbuf.savev(t.args.output, "png")
+except Exception as e:
+    print("Could not generate thumbnail for '%s': %s" % (t.args.input, e), file=sys.stderr, flush=True)
+    sys.exit(1)
+
+sys.exit(0)

files/usr/share/thumbnailers/xapp-ora-thumbnailer.thumbnailer

@@ -0,0 +1,4 @@
+[Thumbnailer Entry]
+TryExec=xapp-ora-thumbnailer
+Exec=xapp-ora-thumbnailer -i %i -o %o -s %s
+MimeType=image/openraster;