st-shadow: Parse the 'inset' keyword

The box-shadow property in the CSS3 draft[0] supports the optional
'inset' keyword for inner shadows cast onto the background. Add
support for the keyword to the shadow parsing code.

[0] http://www.w3.org/TR/css3-background/#box-shadow

https://bugzilla.gnome.org/show_bug.cgi?id=642334

src/st/st-icon.c

@@ -291,6 +291,13 @@ st_icon_style_changed (StWidget *widget)
     }
   priv->shadow_spec = st_theme_node_get_shadow (theme_node, "icon-shadow");
 
+  if (priv->shadow_spec && priv->shadow_spec->inset)
+    {
+      g_warning ("The icon-shadow property does not support inset shadows");
+      st_shadow_unref (priv->shadow_spec);
+      priv->shadow_spec = NULL;
+    }
+
   priv->theme_icon_size = (int)(0.5 + st_theme_node_get_length (theme_node, "icon-size"));
   st_icon_update_icon_size (self);
   st_icon_update (self);

src/st/st-shadow.c

@@ -39,6 +39,7 @@
  * @yoffset: vertical offset
  * @blur: blur radius
  * @spread: spread radius
+ * @inset: whether the shadow should be inset
  *
  * Creates a new #StShadow
  *
@@ -49,7 +50,8 @@ st_shadow_new (ClutterColor *color,
                gdouble       xoffset,
                gdouble       yoffset,
                gdouble       blur,
-               gdouble       spread)
+               gdouble       spread,
+               gboolean      inset)
 {
   StShadow *shadow;
 
@@ -60,6 +62,7 @@ st_shadow_new (ClutterColor *color,
   shadow->yoffset   = yoffset;
   shadow->blur      = blur;
   shadow->spread    = spread;
+  shadow->inset     = inset;
   shadow->ref_count = 1;
 
   return shadow;
@@ -129,7 +132,8 @@ st_shadow_equal (StShadow *shadow,
           shadow->xoffset == other->xoffset &&
           shadow->yoffset == other->yoffset &&
           shadow->blur == other->blur &&
-          shadow->spread == other->spread);
+          shadow->spread == other->spread &&
+          shadow->inset == other->inset);
 }
 
 /**
@@ -150,6 +154,17 @@ st_shadow_get_box (StShadow              *shadow,
   g_return_if_fail (actor_box != NULL);
   g_return_if_fail (shadow_box != NULL);
 
+  /* Inset shadows are drawn below the border, so returning
+   * the original box is not actually correct; still, it's
+   * good enough for the purpose of determing additional space
+   * required outside the actor box.
+   */
+  if (shadow->inset)
+    {
+      *shadow_box = *actor_box;
+      return;
+    }
+
   shadow_box->x1 = actor_box->x1 + shadow->xoffset
                    - shadow->blur - shadow->spread;
   shadow_box->x2 = actor_box->x2 + shadow->xoffset

src/st/st-shadow.h

@@ -48,6 +48,7 @@ struct _StShadow {
     gdouble      yoffset;
     gdouble      blur;
     gdouble      spread;
+    gboolean     inset;
     volatile int ref_count;
 };
 
@@ -57,7 +58,8 @@ StShadow *st_shadow_new      (ClutterColor   *color,
                               gdouble         xoffset,
                               gdouble         yoffset,
                               gdouble         blur,
-                              gdouble         spread);
+                              gdouble         spread,
+                              gboolean        inset);
 StShadow *st_shadow_ref      (StShadow       *shadow);
 void      st_shadow_unref    (StShadow       *shadow);
 

src/st/st-theme-node.c

@@ -2649,9 +2649,9 @@ parse_shadow_property (StThemeNode       *node,
                        gdouble           *xoffset,
                        gdouble           *yoffset,
                        gdouble           *blur,
-                       gdouble           *spread)
+                       gdouble           *spread,
+                       gboolean          *inset)
 {
-  /* Set value for width/color/blur in any order */
   GetFromTermResult result;
   CRTerm *term;
   int n_offsets = 0;
@@ -2662,7 +2662,17 @@ parse_shadow_property (StThemeNode       *node,
   *yoffset = 0.;
   *blur = 0.;
   *spread = 0.;
+  *inset = FALSE;
 
+  /* The CSS3 draft of the box-shadow property[0] is a lot stricter
+   * regarding the order of terms:
+   * If the 'inset' keyword is specified, it has to be first or last,
+   * and the color may not be mixed with the lengths; while we parse
+   * length values in the correct order, we allow for arbitrary
+   * placement of the color and 'inset' keyword.
+   *
+   * [0] http://www.w3.org/TR/css3-background/#box-shadow
+   */
   for (term = decl->value; term; term = term->next)
     {
       if (term->type == TERM_NUMBER)
@@ -2707,6 +2717,12 @@ parse_shadow_property (StThemeNode       *node,
               continue;
             }
         }
+      else if (term->type == TERM_IDENT &&
+               strcmp (term->content.str->stryng->str, "inset") == 0)
+        {
+          *inset = TRUE;
+          continue;
+        }
 
       result = get_color_from_term (node, term, color);
 
@@ -2766,6 +2782,7 @@ st_theme_node_lookup_shadow (StThemeNode  *node,
   gdouble yoffset = 0.;
   gdouble blur = 0.;
   gdouble spread = 0.;
+  gboolean inset = FALSE;
 
   int i;
 
@@ -2783,10 +2800,14 @@ st_theme_node_lookup_shadow (StThemeNode  *node,
                                                             &xoffset,
                                                             &yoffset,
                                                             &blur,
-                                                            &spread);
+                                                            &spread,
+                                                            &inset);
           if (result == VALUE_FOUND)
             {
-              *shadow = st_shadow_new (&color, xoffset, yoffset, blur, spread);
+              *shadow = st_shadow_new (&color,
+                                       xoffset, yoffset,
+                                       blur, spread,
+                                       inset);
               return TRUE;
             }
           else if (result == VALUE_INHERIT)
@@ -2865,6 +2886,14 @@ st_theme_node_get_box_shadow (StThemeNode *node)
                                    FALSE,
                                    &shadow))
     {
+      if (shadow->inset)
+        {
+          g_warning ("Inset shadows are not implemented for the box-shadow "
+                     "property");
+          st_shadow_unref (shadow);
+          shadow = NULL;
+        }
+
       node->box_shadow = shadow;
 
       return node->box_shadow;
@@ -2898,6 +2927,14 @@ st_theme_node_get_background_image_shadow (StThemeNode *node)
                                    FALSE,
                                    &shadow))
     {
+      if (shadow->inset)
+        {
+          g_warning ("The -st-background-image-shadow property does not "
+                     "support inset shadows");
+          st_shadow_unref (shadow);
+          shadow = NULL;
+        }
+
       node->background_image_shadow = shadow;
 
       return node->background_image_shadow;
@@ -2938,6 +2975,13 @@ st_theme_node_get_text_shadow (StThemeNode *node)
         }
     }
 
+  if (result && result->inset)
+    {
+      g_warning ("The text-shadow property does not support inset shadows");
+      st_shadow_unref (result);
+      result = NULL;
+    }
+
   node->text_shadow = result;
   node->text_shadow_computed = TRUE;