[gegl] operations: improve the descriptions of the invert operations

[Michael Natterer <mitch src gnome org>]

commit e143214562e09e3757638cb1230aebece806292d
Author: Michael Natterer <mitch gimp org>
Date:   Mon Jun 5 20:38:36 2017 +0200

    operations: improve the descriptions of the invert operations
    
    They now show up in GIMP's UI, and should not be worse than the
    previous GIMP tooltips.

 operations/common/invert-gamma.c  |    4 ++--
 operations/common/invert-linear.c |    4 ++--
 operations/common/value-invert.c  |    4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)
---
diff --git a/operations/common/invert-gamma.c b/operations/common/invert-gamma.c
index bf64a59..dce4630 100644
--- a/operations/common/invert-gamma.c
+++ b/operations/common/invert-gamma.c
@@ -81,8 +81,8 @@ gegl_op_class_init (GeglOpClass *klass)
     "categories" , "color",
     "reference-hash", "db07b9d85f2786db29560bd50ae0e7a1",
     "description",
-       _("Inverts the components (except alpha), the result is the "
-         "corresponding \"negative\" image."),
+       _("Invert the components (except alpha) perceptually, "
+         "the result is the corresponding \"negative\" image."),
     NULL);
 }
 
diff --git a/operations/common/invert-linear.c b/operations/common/invert-linear.c
index 8fcc39d..d907286 100644
--- a/operations/common/invert-linear.c
+++ b/operations/common/invert-linear.c
@@ -76,8 +76,8 @@ gegl_op_class_init (GeglOpClass *klass)
     "categories" , "color",
     "reference-hash", "3fc7e35d7a5c45b9e55bc2d15890005a",
     "description",
-       _("Inverts the components (except alpha), the result is the "
-         "corresponding \"negative\" image."),
+       _("Invert the components (except alpha) in linear light, "
+         "the result is the corresponding \"negative\" image."),
     "cl-source"  , invert_linear_cl_source,
     NULL);
 }
diff --git a/operations/common/value-invert.c b/operations/common/value-invert.c
index 6154982..5c367e9 100644
--- a/operations/common/value-invert.c
+++ b/operations/common/value-invert.c
@@ -149,8 +149,8 @@ gegl_op_class_init (GeglOpClass *klass)
     "categories" , "color",
     "reference-hash", "489d46de415cb7308b59014449ff76af",
     "description",
-        _("Inverts just the value component, the result is the corresponding "
-          "'inverted' image."),
+        _("Invert the value component, the result has the brightness "
+          "inverted, keeping the color."),
     "cl-source"  , value_invert_cl_source,
     NULL);
 }