[gtk+] css: Implement font-variant-alternatives

[Matthias Clasen <matthiasc src gnome org>]

commit 8a7f2ca0bef63a5b637fbf3ca1fae1df48464f02
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Sep 18 10:01:05 2017 -0400

    css: Implement font-variant-alternatives
    
    This is only a partial implementation, since we don't support
    @font-feature-values. The only supported value is historical-forms,
    for now.

 gtk/gtkcssstyle.c             |   10 ++++++++++
 gtk/gtkcssstylepropertyimpl.c |   21 +++++++++++++++++++++
 gtk/gtkcsstypesprivate.h      |    1 +
 3 files changed, 32 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcssstyle.c b/gtk/gtkcssstyle.c
index 3396034..1fbe5e6 100644
--- a/gtk/gtkcssstyle.c
+++ b/gtk/gtkcssstyle.c
@@ -230,6 +230,7 @@ gtk_css_style_get_pango_attributes (GtkCssStyle *style)
   GtkCssValue *position;
   GtkCssValue *caps;
   GtkCssValue *numeric;
+  GtkCssValue *alternatives;
   GString *s;
   int i;
 
@@ -369,6 +370,15 @@ gtk_css_style_get_pango_attributes (GtkCssStyle *style)
         g_string_append (s, "zero 1");
     }
 
+  alternatives = gtk_css_style_get_value (style, GTK_CSS_PROPERTY_FONT_VARIANT_ALTERNATIVES);
+  for (i = 0; i < _gtk_css_array_value_get_n_values (alternatives); i++)
+    {
+      GtkCssValue *value = _gtk_css_array_value_get_nth (alternatives, i);
+      if (s->len > 0) g_string_append (s, ", ");
+      if (strcmp (_gtk_css_ident_value_get (value), "historical-forms") == 0)
+        g_string_append (s, "hist 1");
+    }
+
   attrs = add_pango_attr (attrs, pango_attr_font_features_new (s->str));
   g_string_free (s, TRUE);
 
diff --git a/gtk/gtkcssstylepropertyimpl.c b/gtk/gtkcssstylepropertyimpl.c
index a0311b3..25c66f9 100644
--- a/gtk/gtkcssstylepropertyimpl.c
+++ b/gtk/gtkcssstylepropertyimpl.c
@@ -737,6 +737,19 @@ parse_font_variant_numeric (GtkCssStyleProperty *property,
 }
 
 static GtkCssValue *
+parse_font_variant_alternatives (GtkCssStyleProperty *property,
+                                 GtkCssParser        *parser)
+{
+  GtkCssValue *value = NULL;
+
+  value = _gtk_css_ident_value_try (parser, "normal", "historical-forms", NULL);
+  if (value == NULL)
+    _gtk_css_parser_error (parser, "Not a valid value");
+
+  return value;
+}
+
+static GtkCssValue *
 box_shadow_value_parse (GtkCssStyleProperty *property,
                         GtkCssParser        *parser)
 {
@@ -1261,6 +1274,14 @@ _gtk_css_style_property_init_properties (void)
                                           parse_font_variant_numeric,
                                           NULL,
                                           _gtk_css_array_value_new (_gtk_css_ident_value_new ("normal")));
+  gtk_css_style_property_register        ("font-variant-alternatives",
+                                          GTK_CSS_PROPERTY_FONT_VARIANT_ALTERNATIVES,
+                                          G_TYPE_NONE,
+                                          0,
+                                          GTK_CSS_AFFECTS_TEXT | GTK_CSS_AFFECTS_TEXT_ATTRS,
+                                          parse_font_variant_alternatives,
+                                          NULL,
+                                          _gtk_css_array_value_new (_gtk_css_ident_value_new ("normal")));
   gtk_css_style_property_register        ("text-shadow",
                                           GTK_CSS_PROPERTY_TEXT_SHADOW,
                                           G_TYPE_NONE,
diff --git a/gtk/gtkcsstypesprivate.h b/gtk/gtkcsstypesprivate.h
index 5ca7b7a..6518a24 100644
--- a/gtk/gtkcsstypesprivate.h
+++ b/gtk/gtkcsstypesprivate.h
@@ -168,6 +168,7 @@ enum { /*< skip >*/
   GTK_CSS_PROPERTY_FONT_VARIANT_POSITION,
   GTK_CSS_PROPERTY_FONT_VARIANT_CAPS,
   GTK_CSS_PROPERTY_FONT_VARIANT_NUMERIC,
+  GTK_CSS_PROPERTY_FONT_VARIANT_ALTERNATIVES,
   GTK_CSS_PROPERTY_TEXT_SHADOW,
   GTK_CSS_PROPERTY_BOX_SHADOW,
   GTK_CSS_PROPERTY_MARGIN_TOP,