# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1444675530 -7200
# Node ID 93aaf33edc7325b6e0c446e30078c9a8035b82fa
# Parent  fcd8939da191eb0931fb3f221e2a22edc3adf193# Parent  0d27eee1a2bba27589f4d4cc0901ac7626987328
Made more thorough fixes to the scaling of images.

diff -r fcd8939da191 -r 93aaf33edc73 optimiser.py
--- a/optimiser.py	Mon Oct 12 18:10:28 2015 +0200
+++ b/optimiser.py	Mon Oct 12 20:45:30 2015 +0200
@@ -67,12 +67,17 @@
         im = im.rotate(270)
 
     w, h = im.size
-    if w > h:
-        height = (width * h) / w
+
+    width_scale_factor = float(width) / w
+    height_scale_factor = float(height) / h
+    scale_factor = min(width_scale_factor, height_scale_factor)
+
+    if scale_factor < 1:
+        width = int(scale_factor * w)
+        height = int(scale_factor * h)
+        return im.resize((width, height))
     else:
-        width = (height * w) / h
-
-    return im.resize((width, height))
+        return im
 
 def get_parameter(options, flag, conversion, default, missing):
 
@@ -157,6 +162,8 @@
     number_of_colours = get_parameter(options, "-C", int, 4, 4)
     preserve_aspect_ratio = "-A" in options
 
+    # Determine whether the height will need adjusting before conversion.
+
     scale_factor = float(width) / base_width
     height = int(base_height * scale_factor)
 
@@ -192,6 +199,7 @@
 
         if scale_factor != 1:
             im = im.resize((image_width, int(image_height / scale_factor)))
+            image_width, image_height = im.size
 
         process_image(im, saturate, desaturate, darken, brighten)
 
@@ -208,7 +216,7 @@
         # Scale images to a height determined by the aspect ratio.
 
         if preserve_aspect_ratio and scale_factor != 1:
-            imp = imp.resize((image_width, image_height))
+            imp = imp.resize((image_width, int(image_height * scale_factor)))
 
         imp.save(preview_filename)
 
@@ -220,7 +228,7 @@
         # Scale images to a height determined by the aspect ratio.
 
         if preserve_aspect_ratio and scale_factor != 1:
-            im = im.resize((image_width, image_height))
+            im = im.resize((image_width, int(image_height * scale_factor)))
 
         im.save(output_filename)