[gtk+] Add a function to turn a css style into pango attributes

[Matthias Clasen <matthiasc src gnome org>]

commit 7b0929ad388d26e7c24620c5b8e93f9401eb8859
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jun 3 00:19:24 2016 -0400

    Add a function to turn a css style into pango attributes
    
    This is _gtk_style_context_get_pango_attributes, decoupled
    from the GtkStyleContext. This will be used to drive css-styled
    text rendering from css subnodes of widgets, e.g. for the value
    in GtkScale.

 gtk/gtkcssstyle.c        |   76 ++++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkcssstyleprivate.h |    2 +
 gtk/gtkstylecontext.c    |   71 +------------------------------------------
 3 files changed, 79 insertions(+), 70 deletions(-)
---
diff --git a/gtk/gtkcssstyle.c b/gtk/gtkcssstyle.c
index d801c64..f4a84a1 100644
--- a/gtk/gtkcssstyle.c
+++ b/gtk/gtkcssstyle.c
@@ -28,6 +28,7 @@
 #include "gtkcssinheritvalueprivate.h"
 #include "gtkcssinitialvalueprivate.h"
 #include "gtkcssnumbervalueprivate.h"
+#include "gtkcssrgbavalueprivate.h"
 #include "gtkcsssectionprivate.h"
 #include "gtkcssshorthandpropertyprivate.h"
 #include "gtkcssstringvalueprivate.h"
@@ -188,3 +189,78 @@ gtk_css_style_to_string (GtkCssStyle *style)
   return g_string_free (string, FALSE);
 }
 
+static PangoUnderline
+get_pango_underline_from_style (GtkTextDecorationStyle style)
+{
+  switch (style)
+    {
+    case GTK_CSS_TEXT_DECORATION_STYLE_DOUBLE:
+      return PANGO_UNDERLINE_DOUBLE;
+    case GTK_CSS_TEXT_DECORATION_STYLE_WAVY:
+      return PANGO_UNDERLINE_ERROR;
+    case GTK_CSS_TEXT_DECORATION_STYLE_SOLID:
+    default:
+      return PANGO_UNDERLINE_SINGLE;
+    }
+
+  g_return_val_if_reached (PANGO_UNDERLINE_SINGLE);
+}
+
+static PangoAttrList *
+add_pango_attr (PangoAttrList  *attrs,
+                PangoAttribute *attr)
+{
+  if (attrs == NULL)
+    attrs = pango_attr_list_new ();
+
+  pango_attr_list_insert (attrs, attr);
+
+  return attrs;
+}
+
+PangoAttrList *
+gtk_css_style_get_pango_attributes (GtkCssStyle *style)
+{
+  PangoAttrList *attrs = NULL;
+  GtkTextDecorationLine decoration_line;
+  GtkTextDecorationStyle decoration_style;
+  const GdkRGBA *color;
+  const GdkRGBA *decoration_color;
+  gint letter_spacing;
+
+  /* text-decoration */
+  decoration_line = _gtk_css_text_decoration_line_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_TEXT_DECORATION_LINE));
+  decoration_style = _gtk_css_text_decoration_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_TEXT_DECORATION_STYLE));
+  color = _gtk_css_rgba_value_get_rgba (gtk_css_style_get_value (style, GTK_CSS_PROPERTY_COLOR));
+  decoration_color = _gtk_css_rgba_value_get_rgba (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_TEXT_DECORATION_COLOR));
+
+  switch (decoration_line)
+    {
+    case GTK_CSS_TEXT_DECORATION_LINE_UNDERLINE:
+      attrs = add_pango_attr (attrs, pango_attr_underline_new (get_pango_underline_from_style 
(decoration_style)));
+      if (!gdk_rgba_equal (color, decoration_color))
+        attrs = add_pango_attr (attrs, pango_attr_underline_color_new (decoration_color->red * 65535. + 0.5,
+                                                                       decoration_color->green * 65535. + 
0.5,
+                                                                       decoration_color->blue * 65535. + 
0.5));
+      break;
+    case GTK_CSS_TEXT_DECORATION_LINE_LINE_THROUGH:
+      attrs = add_pango_attr (attrs, pango_attr_strikethrough_new (TRUE));
+      if (!gdk_rgba_equal (color, decoration_color))
+        attrs = add_pango_attr (attrs, pango_attr_strikethrough_color_new (decoration_color->red * 65535. + 
0.5,
+                                                                           decoration_color->green * 65535. 
+ 0.5,
+                                                                           decoration_color->blue * 65535. + 
0.5));
+      break;
+    case GTK_CSS_TEXT_DECORATION_LINE_NONE:
+    default:
+      break;
+    }
+
+  /* letter-spacing */
+  letter_spacing = _gtk_css_number_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_LETTER_SPACING), 100);
+  if (letter_spacing != 0)
+    {
+      attrs = add_pango_attr (attrs, pango_attr_letter_spacing_new (letter_spacing * PANGO_SCALE));
+    }
+
+  return attrs;
+}
diff --git a/gtk/gtkcssstyleprivate.h b/gtk/gtkcssstyleprivate.h
index f1d165f..049574a 100644
--- a/gtk/gtkcssstyleprivate.h
+++ b/gtk/gtkcssstyleprivate.h
@@ -74,6 +74,8 @@ gboolean                gtk_css_style_print                     (GtkCssStyle
                                                                  GString                *string,
                                                                  guint                   indent,
                                                                  gboolean                skip_initial);
+PangoAttrList *         gtk_css_style_get_pango_attributes      (GtkCssStyle            *style);
+
 
 G_END_DECLS
 
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index f5da8ca..a6191bd 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -3034,79 +3034,10 @@ _gtk_style_context_get_icon_extents (GtkStyleContext *context,
                                          x, y, width, height);
 }
 
-static PangoUnderline
-get_pango_underline_from_style (GtkTextDecorationStyle style)
-{
-  switch (style)
-    {
-    case GTK_CSS_TEXT_DECORATION_STYLE_DOUBLE:
-      return PANGO_UNDERLINE_DOUBLE;
-    case GTK_CSS_TEXT_DECORATION_STYLE_WAVY:
-      return PANGO_UNDERLINE_ERROR;
-    case GTK_CSS_TEXT_DECORATION_STYLE_SOLID:
-    default:
-      return PANGO_UNDERLINE_SINGLE;
-    }
-
-  g_return_val_if_reached (PANGO_UNDERLINE_SINGLE);
-}
-
-static PangoAttrList *
-add_pango_attr(PangoAttrList *attrs, PangoAttribute *attr)
-{
-  if (attrs == NULL)
-    attrs = pango_attr_list_new ();
-
-  pango_attr_list_insert (attrs, attr);
-
-  return attrs;
-}
-
 PangoAttrList *
 _gtk_style_context_get_pango_attributes (GtkStyleContext *context)
 {
-  PangoAttrList *attrs = NULL;
-  GtkTextDecorationLine decoration_line;
-  GtkTextDecorationStyle decoration_style;
-  const GdkRGBA *color;
-  const GdkRGBA *decoration_color;
-  gint letter_spacing;
-
-  /* text-decoration */
-  decoration_line = _gtk_css_text_decoration_line_value_get (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_TEXT_DECORATION_LINE));
-  decoration_style = _gtk_css_text_decoration_style_value_get (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_TEXT_DECORATION_STYLE));
-  color = _gtk_css_rgba_value_get_rgba (_gtk_style_context_peek_property (context, GTK_CSS_PROPERTY_COLOR));
-  decoration_color = _gtk_css_rgba_value_get_rgba (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_TEXT_DECORATION_COLOR));
-
-  switch (decoration_line)
-    {
-    case GTK_CSS_TEXT_DECORATION_LINE_UNDERLINE:
-      attrs = add_pango_attr (attrs, pango_attr_underline_new (get_pango_underline_from_style 
(decoration_style)));
-      if (!gdk_rgba_equal (color, decoration_color))
-        attrs = add_pango_attr (attrs, pango_attr_underline_color_new (decoration_color->red * 65535. + 0.5,
-                                                                       decoration_color->green * 65535. + 
0.5,
-                                                                       decoration_color->blue * 65535. + 
0.5));
-      break;
-    case GTK_CSS_TEXT_DECORATION_LINE_LINE_THROUGH:
-      attrs = add_pango_attr (attrs, pango_attr_strikethrough_new (TRUE));
-      if (!gdk_rgba_equal (color, decoration_color))
-        attrs = add_pango_attr (attrs, pango_attr_strikethrough_color_new (decoration_color->red * 65535. + 
0.5,
-                                                                           decoration_color->green * 65535. 
+ 0.5,
-                                                                           decoration_color->blue * 65535. + 
0.5));
-      break;
-    case GTK_CSS_TEXT_DECORATION_LINE_NONE:
-    default:
-      break;
-    }
-
-  /* letter-spacing */
-  letter_spacing = _gtk_css_number_value_get (_gtk_style_context_peek_property (context, 
GTK_CSS_PROPERTY_LETTER_SPACING), 100);
-  if (letter_spacing != 0)
-    {
-      attrs = add_pango_attr (attrs, pango_attr_letter_spacing_new (letter_spacing * PANGO_SCALE));
-    }
-
-    return attrs;
+  return gtk_css_style_get_pango_attributes (gtk_style_context_lookup_style (context));
 }
 
 static AtkAttributeSet *