[gtksourceview] StyleScheme: style cursors with CSS

[Sébastien Wilmet <swilmet src gnome org>]

commit be943d94f15e1e0dbe3b89c8a1e4388571d95bb7
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed Mar 4 14:47:17 2015 +0100

    StyleScheme: style cursors with CSS
    
    To avoid using gtk_widget_override_cursor() (deprecated).
    
    CSS example:
    
    GtkSourceView {
            -GtkWidget-cursor-color: red;
            -GtkWidget-secondary-cursor-color: green;
    }

 gtksourceview/gtksourcestylescheme.c |  117 ++++++++++++++++++++++++++--------
 1 files changed, 91 insertions(+), 26 deletions(-)
---
diff --git a/gtksourceview/gtksourcestylescheme.c b/gtksourceview/gtksourcestylescheme.c
index ad59b81..1ff05c1 100644
--- a/gtksourceview/gtksourcestylescheme.c
+++ b/gtksourceview/gtksourcestylescheme.c
@@ -84,6 +84,7 @@ struct _GtkSourceStyleSchemePrivate
        GHashTable *named_colors;
 
        GtkCssProvider *css;
+       GtkCssProvider *css_provider_cursors;
 };
 
 G_DEFINE_TYPE_WITH_PRIVATE (GtkSourceStyleScheme, gtk_source_style_scheme, G_TYPE_OBJECT)
@@ -113,6 +114,7 @@ gtk_source_style_scheme_dispose (GObject *object)
 
        g_clear_object (&scheme->priv->parent);
        g_clear_object (&scheme->priv->css);
+       g_clear_object (&scheme->priv->css_provider_cursors);
 
        G_OBJECT_CLASS (gtk_source_style_scheme_parent_class)->dispose (object);
 }
@@ -627,50 +629,95 @@ _gtk_source_style_scheme_get_background_pattern_color (GtkSourceStyleScheme *sch
        return get_color (style, FALSE, color);
 }
 
-static void
-update_cursor_colors (GtkWidget      *widget,
-                     GtkSourceStyle *style_primary,
-                     GtkSourceStyle *style_secondary)
+static gchar *
+get_cursors_css_style (GtkSourceStyleScheme *scheme,
+                      GtkWidget            *widget)
 {
+       GtkSourceStyle *primary_style;
+       GtkSourceStyle *secondary_style;
        GdkRGBA primary_color;
        GdkRGBA secondary_color;
-       GdkRGBA *primary = NULL;
-       GdkRGBA *secondary = NULL;
+       gchar *primary_color_str;
+       gchar *secondary_color_str;
+       gchar *css;
 
-       if (get_color (style_primary, TRUE, &primary_color))
-       {
-               primary = &primary_color;
-       }
+       primary_style = gtk_source_style_scheme_get_style (scheme, STYLE_CURSOR);
+       secondary_style = gtk_source_style_scheme_get_style (scheme, STYLE_SECONDARY_CURSOR);
 
-       if (get_color (style_secondary, TRUE, &secondary_color))
+       if (!get_color (primary_style, TRUE, &primary_color))
        {
-               secondary = &secondary_color;
+               return NULL;
        }
 
-       if (primary != NULL && secondary == NULL)
+       if (!get_color (secondary_style, TRUE, &secondary_color))
        {
                GtkStyleContext *context;
 
                context = gtk_widget_get_style_context (widget);
-               gtk_style_context_get_background_color (context, GTK_STATE_FLAG_NORMAL,
+
+               gtk_style_context_get_background_color (context,
+                                                       GTK_STATE_FLAG_NORMAL,
                                                        &secondary_color);
 
                /* shade the secondary cursor */
                secondary_color.red *= 0.5;
                secondary_color.green *= 0.5;
                secondary_color.blue *= 0.5;
-
-               secondary = &secondary_color;
        }
 
-       if (primary != NULL)
+       primary_color_str = gdk_rgba_to_string (&primary_color);
+       secondary_color_str = gdk_rgba_to_string (&secondary_color);
+
+       css = g_strdup_printf ("GtkSourceView {\n"
+                              "\t-GtkWidget-cursor-color: %s;\n"
+                              "\t-GtkWidget-secondary-cursor-color: %s;\n"
+                              "}\n",
+                              primary_color_str,
+                              secondary_color_str);
+
+       g_free (primary_color_str);
+       g_free (secondary_color_str);
+
+       return css;
+}
+
+/* The CssProvider for the cursors depends only on @scheme, but it needs a
+ * @widget to shade the background color in case the secondary cursor color
+ * isn't defined. The background color is normally defined by @scheme, or if
+ * it's not defined it is taken from the GTK+ theme. So ideally, if the GTK+
+ * theme changes at runtime, we should regenerate the CssProvider for the
+ * cursors, but it isn't done.
+ */
+static GtkCssProvider *
+get_css_provider_cursors (GtkSourceStyleScheme *scheme,
+                         GtkWidget            *widget)
+{
+       gchar *css;
+       GtkCssProvider *provider;
+       GError *error = NULL;
+
+       css = get_cursors_css_style (scheme, widget);
+
+       if (css == NULL)
        {
-               gtk_widget_override_cursor (widget, primary, secondary);
+               return NULL;
        }
-       else
+
+       provider = gtk_css_provider_new ();
+
+       gtk_css_provider_load_from_data (provider, css, -1, &error);
+       g_free (css);
+
+       if (error != NULL)
        {
-               gtk_widget_override_cursor (widget, NULL, NULL);
+               g_warning ("Error when loading CSS for cursors: %s", error->message);
+               g_error_free (error);
+
+               g_object_unref (provider);
+               return NULL;
        }
+
+       return provider;
 }
 
 /**
@@ -686,7 +733,6 @@ void
 _gtk_source_style_scheme_apply (GtkSourceStyleScheme *scheme,
                                GtkWidget            *widget)
 {
-       GtkSourceStyle *style, *style2;
        GtkStyleContext *context;
 
        g_return_if_fail (GTK_SOURCE_IS_STYLE_SCHEME (scheme));
@@ -703,9 +749,24 @@ _gtk_source_style_scheme_apply (GtkSourceStyleScheme *scheme,
        gtk_style_context_invalidate (context);
        G_GNUC_END_IGNORE_DEPRECATIONS;
 
-       style = gtk_source_style_scheme_get_style (scheme, STYLE_CURSOR);
-       style2 = gtk_source_style_scheme_get_style (scheme, STYLE_SECONDARY_CURSOR);
-       update_cursor_colors (widget, style, style2);
+       /* The CssProvider for the cursors needs that the first provider is
+        * applied, to get the background color.
+        */
+       if (scheme->priv->css_provider_cursors == NULL)
+       {
+               scheme->priv->css_provider_cursors = get_css_provider_cursors (scheme, widget);
+       }
+
+       if (scheme->priv->css_provider_cursors != NULL)
+       {
+               gtk_style_context_add_provider (context,
+                                               GTK_STYLE_PROVIDER (scheme->priv->css_provider_cursors),
+                                               GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+
+               G_GNUC_BEGIN_IGNORE_DEPRECATIONS;
+               gtk_style_context_invalidate (context);
+               G_GNUC_END_IGNORE_DEPRECATIONS;
+       }
 }
 
 /**
@@ -730,12 +791,16 @@ _gtk_source_style_scheme_unapply (GtkSourceStyleScheme *scheme,
        gtk_style_context_remove_provider (context,
                                           GTK_STYLE_PROVIDER (scheme->priv->css));
 
+       if (scheme->priv->css_provider_cursors != NULL)
+       {
+               gtk_style_context_remove_provider (context,
+                                                  GTK_STYLE_PROVIDER (scheme->priv->css_provider_cursors));
+       }
+
        G_GNUC_BEGIN_IGNORE_DEPRECATIONS;
        /* See https://bugzilla.gnome.org/show_bug.cgi?id=708583 */
        gtk_style_context_invalidate (context);
        G_GNUC_END_IGNORE_DEPRECATIONS;
-
-       update_cursor_colors (widget, NULL, NULL);
 }
 
 /* --- PARSER ---------------------------------------------------------------- */