# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1444347038 -7200
# Node ID 14cf81e93dd46340b35daf7f72b521beaef9fe25
# Parent  4d2f52b71f3c4df24177139ddb70520fed8db762
Added parameterisation of the darken and brighten options.

diff -r 4d2f52b71f3c -r 14cf81e93dd4 optimiser.py
--- a/optimiser.py	Fri Oct 09 00:40:59 2015 +0200
+++ b/optimiser.py	Fri Oct 09 01:30:38 2015 +0200
@@ -294,8 +294,8 @@
 
 -s - Saturate the input image (can be repeated)
 -d - Desaturate the input image (can be repeated)
--D - Darken the input image (can be repeated)
--B - Brighten the input image (can be repeated)
+-D - Darken the input image (can be repeated or followed by a float)
+-B - Brighten the input image (can be repeated or followed by a float)
 -2 - Square/diminish the bright corner colour contributions (experimental)
 
 -r - Rotate the input image clockwise
@@ -322,6 +322,15 @@
     darken = options.count("-D")
     brighten = options.count("-B")
 
+    if darken == 1:
+        i = options.index("-D")
+        if options[i+1].isdigit():
+            darken = float(options[i+1])
+    if brighten == 1:
+        i = options.index("-B")
+        if options[i+1].isdigit():
+            brighten = float(options[i+1])
+
     # Experimental colour distribution modification.
 
     use_square = "-2" in options
@@ -353,7 +362,7 @@
                     if saturate or desaturate:
                         rgb = saturate_rgb(rgb, saturate and math.pow(0.5, saturate) or math.pow(2, desaturate))
                     if darken or brighten:
-                        rgb = amplify_rgb(rgb, brighten and math.pow(0.5, brighten) or math.pow(2, darken))
+                        rgb = amplify_rgb(rgb, brighten and 0.5 / brighten or 2 * darken)
                     im.putpixel((x, y), rgb)
 
     # Generate a preview if requested.