image magic: add bmp and tiff + Readme

README.md

@@ -120,6 +120,24 @@ The following packages are optional:
  Python bindings of fontconfig are required for displaying
  genealogical symbols
 
+* **magic**
+
+ Python magic bindings required to have better performances with image
+ processing.
+ If this module is not available, we continue to use Gdk.
+ This avoid to load the image in memory. This is a real improvement
+ when we have many big images.
+ Used in odfdoc, rtfdoc and webreport and tested with png, gif, jpeg, bmp, tiff
+ #
+ #            file size     with magic  without (Gdk)   ratio
+ # example 1 :     256k        0.00080        0.00575       7
+ # example 2 :      21M        0.00171        0.55860     326
+
+ Debian, Ubuntu, ... : python3-magic
+ Fedora, Redhat, ... : python3-magic
+ openSUSE            : python-magic
+ ArchLinux           : python-magic
+
 Optional packages required by Third-party Addons
 ------------------------------------------------
 

gramps/gen/utils/image.py

@@ -168,12 +168,18 @@ def image_size(source):
         # For performance reasons, we'll try to get image size from magic.
         # This avoid to load the image in memory. This is a real improvement
         # when we have many big images.
-        # Used in odfdoc, rtfdoc and webreport and tested with png, gif, jpeg
+        # Used in odfdoc, rtfdoc and webreport and tested with png, gif, jpeg,
+        # bmp, tiff
         #
         #            file size     with magic  without (Gdk)   ratio
         # example 1 :     256k        0.00080        0.00575       7
         # example 2 :      21M        0.00171        0.55860     326
         img = magic.from_file(source)
+        found = img.find("TIFF")
+        if found == 0:
+            width = re.search('width=(\d+)', img).groups()
+            height = re.search('height=(\d+)', img).groups()
+            return (int(width[0]), int(height[0]))
         found = img.find("precision")
         if found > 0:
             img = img[found:]