Make Emacs on OSX treat all RGB colors as being within the sRGB color space

emacs-osx-srgb.patch

commit 3b63b2c6e9e93adab09eace60750ed981a8e528f
Author: Steve Purcell <steve@sanityinc.com>
Date:   Sat Dec 21 11:44:12 2013 +0000

    Treat hex colors as sRGB (see  http://debbugs.gnu.org/cgi/bugreport.cgi?bug=8402)

diff --git a/src/nsterm.m b/src/nsterm.m
index 733c05a..0c79186 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1373,6 +1373,13 @@ ns_fullscreen_hook (struct frame *f)
     Color management
 
    ========================================================================== */
+#if defined(NS_IMPL_COCOA) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
+#define NS_COLOR_FROM_RGB(r, g, b) [NSColor colorWithSRGBRed: r green: g blue: b alpha: 1.0]
+#define NS_COLOR_AS_RGB(c) [c colorUsingColorSpace: [NSColorSpace sRGBColorSpace]]
+#else
+#define NS_COLOR_FROM_RGB(r, g, b) [NSColor colorWithCalibratedRed: r green: g blue: b alpha: 1.0]
+#define NS_COLOR_AS_RGB(c) [c colorUsingColorSpaceName: NSCalibratedRGBColorSpace]
+#endif
 
 
 NSColor *
@@ -1551,7 +1558,7 @@ ns_get_color (const char *name, NSColor **col)
 
   if (r >= 0.0F)
     {
-      *col = [NSColor colorWithCalibratedRed: r green: g blue: b alpha: 1.0];
+      *col = NS_COLOR_FROM_RGB(r, g, b);
       unblock_input ();
       return 0;
     }
@@ -1583,7 +1590,7 @@ ns_get_color (const char *name, NSColor **col)
   }
 
   if (new)
-    *col = [new colorUsingColorSpaceName: NSCalibratedRGBColorSpace];
+    *col = NS_COLOR_AS_RGB(new);
   unblock_input ();
   return new ? 0 : 1;
 }
@@ -1624,7 +1631,7 @@ ns_color_to_lisp (NSColor *col)
           return build_string ((char *)str);
         }
 
-    [[col colorUsingColorSpaceName: NSCalibratedRGBColorSpace]
+      [NS_COLOR_AS_RGB(col)
         getRed: &red green: &green blue: &blue alpha: &alpha];
   if (red ==green && red ==blue)
     {
@@ -4252,10 +4259,9 @@ ns_term_init (Lisp_Object display_name)
             name = SSDATA (XCAR (color));
             c = XINT (XCDR (color));
             [cl setColor:
-                  [NSColor colorWithCalibratedRed: RED_FROM_ULONG (c) / 255.0
-                                            green: GREEN_FROM_ULONG (c) / 255.0
-                                             blue: BLUE_FROM_ULONG (c) / 255.0
-                                            alpha: 1.0]
+                  NS_COLOR_FROM_RGB(RED_FROM_ULONG (c) / 255.0,
+                                    GREEN_FROM_ULONG (c) / 255.0,
+                                    BLUE_FROM_ULONG (c) / 255.0)
                   forKey: [NSString stringWithUTF8String: name]];
           }
         [cl writeToFile: nil];

An alternative formulation in this patch is now in Emacs trunk, and should be part of the Emacs 24.4 release.