[gimp] libgimpcolor: add API to create profile variants with linear/sRGB gamma

[Michael Natterer <mitch src gnome org>]

commit 6eb9f9d4aab93909bfafcc21f82719b4f366927b
Author: Michael Natterer <mitch gimp org>
Date:   Tue Oct 20 20:12:18 2015 +0200

    libgimpcolor: add API to create profile variants with linear/sRGB gamma
    
    and the original profile's RGB chromacities and whitepoint.

 libgimpcolor/gimpcolor.def      |    2 +
 libgimpcolor/gimpcolorprofile.c |   79 +++++++++++++++++++++++++++++++++------
 libgimpcolor/gimpcolorprofile.h |    5 ++
 3 files changed, 74 insertions(+), 12 deletions(-)
---
diff --git a/libgimpcolor/gimpcolor.def b/libgimpcolor/gimpcolor.def
index 7819e61..897575a 100644
--- a/libgimpcolor/gimpcolor.def
+++ b/libgimpcolor/gimpcolor.def
@@ -43,7 +43,9 @@ EXPORTS
        gimp_color_profile_new_from_icc_profile
        gimp_color_profile_new_from_lcms_profile
        gimp_color_profile_new_linear_rgb
+       gimp_color_profile_new_linear_rgb_from_color_profile
        gimp_color_profile_new_srgb
+       gimp_color_profile_new_srgb_gamma_from_color_profile
        gimp_hsl_get_type
        gimp_hsl_set
        gimp_hsl_set_alpha
diff --git a/libgimpcolor/gimpcolorprofile.c b/libgimpcolor/gimpcolorprofile.c
index cbd44f2..819c43b 100644
--- a/libgimpcolor/gimpcolorprofile.c
+++ b/libgimpcolor/gimpcolorprofile.c
@@ -704,13 +704,9 @@ gimp_color_profile_get_rgb_matrix_colorants (GimpColorProfile *profile,
 }
 
 static GimpColorProfile *
-gimp_color_profile_new_from_profile (GimpColorProfile *profile,
-                                     gboolean          linear)
+gimp_color_profile_new_from_color_profile (GimpColorProfile *profile,
+                                           gboolean          linear)
 {
-  /* Make the target RGB working space.  Until the ICC allows other
-   * illuminants, and corresponding LCMS code has been added, use the
-   * D50 color space reference white and illuminant.
-   */
   GimpColorProfile *new_profile;
   cmsHPROFILE       target_profile;
   GimpMatrix3       matrix;
@@ -719,6 +715,8 @@ gimp_color_profile_new_from_profile (GimpColorProfile *profile,
   cmsCIEXYZ         blue;
   cmsCIEXYZ        *whitepoint;
   cmsToneCurve     *curve;
+  const gchar      *model;
+  gchar            *new_model;
 
   g_return_val_if_fail (GIMP_IS_COLOR_PROFILE (profile), NULL);
 
@@ -758,8 +756,8 @@ gimp_color_profile_new_from_profile (GimpColorProfile *profile,
       /* linear light */
       curve = cmsBuildGamma (NULL, 1.00);
 
-      gimp_color_profile_set_tag (profile, cmsSigProfileDescriptionTag,
-                                  "GIMP generated with linear gamma TRC");
+      gimp_color_profile_set_tag (target_profile, cmsSigProfileDescriptionTag,
+                                  "linear variant generated by GIMP");
     }
   else
     {
@@ -769,8 +767,8 @@ gimp_color_profile_new_from_profile (GimpColorProfile *profile,
       /* sRGB curve */
       curve = cmsBuildParametricToneCurve (NULL, 4, srgb_parameters);
 
-      gimp_color_profile_set_tag (profile, cmsSigProfileDescriptionTag,
-                                  "GIMP generated with sRGB gamma TRC");
+      gimp_color_profile_set_tag (target_profile, cmsSigProfileDescriptionTag,
+                                  "sRGB gamma variant generated by GIMP");
     }
 
   cmsWriteTag (target_profile, cmsSigRedTRCTag,   curve);
@@ -779,11 +777,28 @@ gimp_color_profile_new_from_profile (GimpColorProfile *profile,
 
   cmsFreeToneCurve (curve);
 
-  gimp_color_profile_set_tag (profile, cmsSigDeviceMfgDescTag,
+  model = gimp_color_profile_get_model (profile);
+
+  if (model && g_str_has_prefix (model, "Generated from '"))
+    {
+      /* don't add multiple "Generated from 'foo'" */
+      new_model = g_strdup (model);
+    }
+  else
+    {
+      new_model = g_strdup_printf ("Generated from '%s'",
+                                   gimp_color_profile_get_description (profile));
+    }
+
+  gimp_color_profile_set_tag (target_profile, cmsSigDeviceMfgDescTag,
                               "GIMP");
-  gimp_color_profile_set_tag (profile, cmsSigCopyrightTag,
+  gimp_color_profile_set_tag (target_profile, cmsSigDeviceModelDescTag,
+                              new_model);
+  gimp_color_profile_set_tag (target_profile, cmsSigCopyrightTag,
                               "Public Domain");
 
+  g_free (new_model);
+
   new_profile = gimp_color_profile_new_from_lcms_profile (target_profile, NULL);
 
   cmsCloseProfile (target_profile);
@@ -791,6 +806,46 @@ gimp_color_profile_new_from_profile (GimpColorProfile *profile,
   return new_profile;
 }
 
+/**
+ * gimp_color_profile_new_srgb_gamma_from_color_profile:
+ * @profile: a #GimpColorProfile
+ *
+ * This function creates a new RGB #GimpColorProfile with a sRGB gamma
+ * TRC and @profile's RGB chromacities and whitepoint.
+ *
+ * Return value: the new #GimpColorProfile, or %NULL if @profile is not
+ *               an RGB profile or not matrix-based.
+ *
+ * Since: 2.10
+ **/
+GimpColorProfile *
+gimp_color_profile_new_srgb_gamma_from_color_profile (GimpColorProfile *profile)
+{
+  g_return_val_if_fail (GIMP_IS_COLOR_PROFILE (profile), NULL);
+
+  return gimp_color_profile_new_from_color_profile (profile, FALSE);
+}
+
+/**
+ * gimp_color_profile_new_linear_rgb_from_color_profile:
+ * @profile: a #GimpColorProfile
+ *
+ * This function creates a new RGB #GimpColorProfile with a linear TRC
+ * and @profile's RGB chromacities and whitepoint.
+ *
+ * Return value: the new #GimpColorProfile, or %NULL if @profile is not
+ *               an RGB profile or not matrix-based.
+ *
+ * Since: 2.10
+ **/
+GimpColorProfile *
+gimp_color_profile_new_linear_rgb_from_color_profile (GimpColorProfile *profile)
+{
+  g_return_val_if_fail (GIMP_IS_COLOR_PROFILE (profile), NULL);
+
+  return gimp_color_profile_new_from_color_profile (profile, TRUE);
+}
+
 static cmsHPROFILE *
 gimp_color_profile_new_srgb_internal (void)
 {
diff --git a/libgimpcolor/gimpcolorprofile.h b/libgimpcolor/gimpcolorprofile.h
index 04b123a..3c290d7 100644
--- a/libgimpcolor/gimpcolorprofile.h
+++ b/libgimpcolor/gimpcolorprofile.h
@@ -69,6 +69,11 @@ GimpColorProfile * gimp_color_profile_new_linear_rgb        (void);
 
 GimpColorProfile * gimp_color_profile_new_adobe_rgb         (void);
 
+GimpColorProfile *
+       gimp_color_profile_new_srgb_gamma_from_color_profile (GimpColorProfile  *profile);
+GimpColorProfile *
+       gimp_color_profile_new_linear_rgb_from_color_profile (GimpColorProfile  *profile);
+
 GimpColorProfile * gimp_color_profile_new_from_file         (GFile             *file,
                                                              GError           **error);