[gimp] Bug 756389 - Color-managing grayscale images

[Michael Natterer <mitch src gnome org>]

commit 11e8cacf7e185398e2517784961f6642e5ff65de
Author: Michael Natterer <mitch gimp org>
Date:   Sun Dec 13 23:36:31 2015 +0100

    Bug 756389 - Color-managing grayscale images
    
    Support creating linear/sRGB-gamma variants of gray profiles and
    rename gimp_color_profile_new_linear_rgb_from_color_profile() to
    gimp_color_profile_new_linear_gamma_from_color_profile() because it's
    not RGB-specific any longer.

 app/core/gimpimage-convert-precision.c |    2 +-
 app/core/gimplayer.c                   |    2 +-
 libgimpcolor/gimpcolor.def             |    2 +-
 libgimpcolor/gimpcolorprofile.c        |   74 ++++++++++++++++++++------------
 libgimpcolor/gimpcolorprofile.h        |    4 +-
 5 files changed, 51 insertions(+), 33 deletions(-)
---
diff --git a/app/core/gimpimage-convert-precision.c b/app/core/gimpimage-convert-precision.c
index fbd6f88..ab36fef 100644
--- a/app/core/gimpimage-convert-precision.c
+++ b/app/core/gimpimage-convert-precision.c
@@ -173,7 +173,7 @@ gimp_image_convert_precision (GimpImage     *image,
       if (gimp_babl_format_get_linear (new_format))
         {
           new_profile =
-            gimp_color_profile_new_linear_rgb_from_color_profile (old_profile);
+            gimp_color_profile_new_linear_gamma_from_color_profile (old_profile);
         }
       else
         {
diff --git a/app/core/gimplayer.c b/app/core/gimplayer.c
index a0f6c1a..1fce1ce 100644
--- a/app/core/gimplayer.c
+++ b/app/core/gimplayer.c
@@ -1136,7 +1136,7 @@ gimp_layer_convert_type (GimpDrawable      *drawable,
               if (gimp_babl_format_get_linear (new_format))
                 {
                   dest_profile =
-                    gimp_color_profile_new_linear_rgb_from_color_profile (src_profile);
+                    gimp_color_profile_new_linear_gamma_from_color_profile (src_profile);
                 }
               else
                 {
diff --git a/libgimpcolor/gimpcolor.def b/libgimpcolor/gimpcolor.def
index 1b1e384..6122cba 100644
--- a/libgimpcolor/gimpcolor.def
+++ b/libgimpcolor/gimpcolor.def
@@ -44,9 +44,9 @@ EXPORTS
        gimp_color_profile_new_from_file
        gimp_color_profile_new_from_icc_profile
        gimp_color_profile_new_from_lcms_profile
+       gimp_color_profile_new_linear_gamma_from_color_profile
        gimp_color_profile_new_linear_gray
        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_gray
        gimp_color_profile_new_srgb_gamma_from_color_profile
diff --git a/libgimpcolor/gimpcolorprofile.c b/libgimpcolor/gimpcolorprofile.c
index c60f7d5..785802d 100644
--- a/libgimpcolor/gimpcolorprofile.c
+++ b/libgimpcolor/gimpcolorprofile.c
@@ -788,10 +788,7 @@ gimp_color_profile_new_from_color_profile (GimpColorProfile *profile,
 {
   GimpColorProfile *new_profile;
   cmsHPROFILE       target_profile;
-  GimpMatrix3       matrix;
-  cmsCIEXYZ         red;
-  cmsCIEXYZ         green;
-  cmsCIEXYZ         blue;
+  GimpMatrix3       matrix = { 0, };
   cmsCIEXYZ        *whitepoint;
   cmsToneCurve     *curve;
   const gchar      *model;
@@ -799,37 +796,27 @@ gimp_color_profile_new_from_color_profile (GimpColorProfile *profile,
 
   g_return_val_if_fail (GIMP_IS_COLOR_PROFILE (profile), NULL);
 
-  if (! gimp_color_profile_get_rgb_matrix_colorants (profile, &matrix))
-    return NULL;
+  if (gimp_color_profile_is_rgb (profile))
+    {
+      if (! gimp_color_profile_get_rgb_matrix_colorants (profile, &matrix))
+        return NULL;
+    }
+  else if (! gimp_color_profile_is_gray (profile))
+    {
+      return NULL;
+    }
 
   whitepoint = cmsReadTag (profile->priv->lcms_profile,
                            cmsSigMediaWhitePointTag);
 
-  red.X = matrix.coeff[0][0];
-  red.Y = matrix.coeff[0][1];
-  red.Z = matrix.coeff[0][2];
-
-  green.X = matrix.coeff[1][0];
-  green.Y = matrix.coeff[1][1];
-  green.Z = matrix.coeff[1][2];
-
-  blue.X = matrix.coeff[2][0];
-  blue.Y = matrix.coeff[2][1];
-  blue.Z = matrix.coeff[2][2];
-
   target_profile = cmsCreateProfilePlaceholder (0);
 
   cmsSetProfileVersion (target_profile, 4.3);
   cmsSetDeviceClass (target_profile, cmsSigDisplayClass);
-  cmsSetColorSpace (target_profile, cmsSigRgbData);
   cmsSetPCS (target_profile, cmsSigXYZData);
 
   cmsWriteTag (target_profile, cmsSigMediaWhitePointTag, whitepoint);
 
-  cmsWriteTag (target_profile, cmsSigRedColorantTag,   &red);
-  cmsWriteTag (target_profile, cmsSigGreenColorantTag, &green);
-  cmsWriteTag (target_profile, cmsSigBlueColorantTag,  &blue);
-
   if (linear)
     {
       /* linear light */
@@ -850,9 +837,40 @@ gimp_color_profile_new_from_color_profile (GimpColorProfile *profile,
                                   "sRGB gamma variant generated by GIMP");
     }
 
-  cmsWriteTag (target_profile, cmsSigRedTRCTag,   curve);
-  cmsWriteTag (target_profile, cmsSigGreenTRCTag, curve);
-  cmsWriteTag (target_profile, cmsSigBlueTRCTag,  curve);
+  if (gimp_color_profile_is_rgb (profile))
+    {
+      cmsCIEXYZ red;
+      cmsCIEXYZ green;
+      cmsCIEXYZ blue;
+
+      cmsSetColorSpace (target_profile, cmsSigRgbData);
+
+      red.X = matrix.coeff[0][0];
+      red.Y = matrix.coeff[0][1];
+      red.Z = matrix.coeff[0][2];
+
+      green.X = matrix.coeff[1][0];
+      green.Y = matrix.coeff[1][1];
+      green.Z = matrix.coeff[1][2];
+
+      blue.X = matrix.coeff[2][0];
+      blue.Y = matrix.coeff[2][1];
+      blue.Z = matrix.coeff[2][2];
+
+      cmsWriteTag (target_profile, cmsSigRedColorantTag,   &red);
+      cmsWriteTag (target_profile, cmsSigGreenColorantTag, &green);
+      cmsWriteTag (target_profile, cmsSigBlueColorantTag,  &blue);
+
+      cmsWriteTag (target_profile, cmsSigRedTRCTag,   curve);
+      cmsWriteTag (target_profile, cmsSigGreenTRCTag, curve);
+      cmsWriteTag (target_profile, cmsSigBlueTRCTag,  curve);
+    }
+  else
+    {
+      cmsSetColorSpace (target_profile, cmsSigGrayData);
+
+      cmsWriteTag (target_profile, cmsSigGrayTRCTag, curve);
+    }
 
   cmsFreeToneCurve (curve);
 
@@ -906,7 +924,7 @@ gimp_color_profile_new_srgb_gamma_from_color_profile (GimpColorProfile *profile)
 }
 
 /**
- * gimp_color_profile_new_linear_rgb_from_color_profile:
+ * gimp_color_profile_new_linear_gamma_from_color_profile:
  * @profile: a #GimpColorProfile
  *
  * This function creates a new RGB #GimpColorProfile with a linear TRC
@@ -918,7 +936,7 @@ gimp_color_profile_new_srgb_gamma_from_color_profile (GimpColorProfile *profile)
  * Since: 2.10
  **/
 GimpColorProfile *
-gimp_color_profile_new_linear_rgb_from_color_profile (GimpColorProfile *profile)
+gimp_color_profile_new_linear_gamma_from_color_profile (GimpColorProfile *profile)
 {
   g_return_val_if_fail (GIMP_IS_COLOR_PROFILE (profile), NULL);
 
diff --git a/libgimpcolor/gimpcolorprofile.h b/libgimpcolor/gimpcolorprofile.h
index 34ebea4..e9767a6 100644
--- a/libgimpcolor/gimpcolorprofile.h
+++ b/libgimpcolor/gimpcolorprofile.h
@@ -72,9 +72,9 @@ GimpColorProfile * gimp_color_profile_new_srgb_gray         (void);
 GimpColorProfile * gimp_color_profile_new_linear_gray       (void);
 
 GimpColorProfile *
-       gimp_color_profile_new_srgb_gamma_from_color_profile (GimpColorProfile  *profile);
+     gimp_color_profile_new_srgb_gamma_from_color_profile   (GimpColorProfile  *profile);
 GimpColorProfile *
-       gimp_color_profile_new_linear_rgb_from_color_profile (GimpColorProfile  *profile);
+     gimp_color_profile_new_linear_gamma_from_color_profile (GimpColorProfile  *profile);
 
 GimpColorProfile * gimp_color_profile_new_from_file         (GFile             *file,
                                                              GError           **error);