cairo: Add foreign mapping for Cairo.Surface

This allows one to pass a cairo_surface_t to API like
Gdk.pixbuf_new_from_surface().

Reported-by: Seif Lotfy <seif@lotfy.com>

https://bugzilla.gnome.org/show_bug.cgi?id=700529

3 files changed, 61 insertions, 0 deletions

diff --git a/modules/cairo-private.h b/modules/cairo-private.h
index 6edfb6d8..411c33ef 100644
--- a/modules/cairo-private.h
+++ b/modules/cairo-private.h
@@ -39,6 +39,7 @@ cairo_t *        gjs_cairo_context_get_context          (JSContext       *contex
 JSObject *       gjs_cairo_context_from_context         (JSContext       *context,
                                                          cairo_t         *cr);
 void             gjs_cairo_context_init                 (JSContext       *context);
+void             gjs_cairo_surface_init                 (JSContext       *context);
 
 
 /* cairo_path_t */
diff --git a/modules/cairo-surface.c b/modules/cairo-surface.c
index 5f4d7a89..c38308c9 100644
--- a/modules/cairo-surface.c
+++ b/modules/cairo-surface.c
@@ -24,6 +24,7 @@
 
 #include <gjs/gjs-module.h>
 #include <gjs/compat.h>
+#include <gi/foreign.h>
 #include <cairo.h>
 #include "cairo-private.h"
 
@@ -243,3 +244,61 @@ gjs_cairo_surface_get_surface(JSContext *context,
     return priv->surface;
 }
 
+static JSBool
+surface_to_g_argument(JSContext      *context,
+                      jsval           value,
+                      const char     *arg_name,
+                      GjsArgumentType argument_type,
+                      GITransfer      transfer,
+                      gboolean        may_be_null,
+                      GArgument      *arg)
+{
+    JSObject *obj;
+    cairo_surface_t *s;
+
+    obj = JSVAL_TO_OBJECT(value);
+    s = gjs_cairo_surface_get_surface(context, obj);
+    if (!s)
+        return JS_FALSE;
+    if (transfer == GI_TRANSFER_EVERYTHING)
+        cairo_surface_destroy(s);
+
+    arg->v_pointer = s;
+    return JS_TRUE;
+}
+
+static JSBool
+surface_from_g_argument(JSContext  *context,
+                        jsval      *value_p,
+                        GArgument  *arg)
+{
+    JSObject *obj;
+
+    obj = gjs_cairo_surface_from_surface(context, (cairo_surface_t*)arg->v_pointer);
+    if (!obj)
+        return JS_FALSE;
+
+    *value_p = OBJECT_TO_JSVAL(obj);
+    return JS_TRUE;
+}
+
+static JSBool
+surface_release_argument(JSContext  *context,
+                         GITransfer  transfer,
+                         GArgument  *arg)
+{
+    cairo_surface_destroy((cairo_surface_t*)arg->v_pointer);
+    return JS_TRUE;
+}
+
+static GjsForeignInfo foreign_info = {
+    surface_to_g_argument,
+    surface_from_g_argument,
+    surface_release_argument
+};
+
+void
+gjs_cairo_surface_init(JSContext *context)
+{
+    gjs_struct_foreign_register("cairo", "Surface", &foreign_info);
+}
diff --git a/modules/cairo.c b/modules/cairo.c
index 6cde95de..d72e39c4 100644
--- a/modules/cairo.c
+++ b/modules/cairo.c
@@ -55,6 +55,7 @@ gjs_js_define_cairo_stuff(JSContext *context,
     if (JSVAL_IS_NULL(obj))
         return JS_FALSE;
     gjs_cairo_context_init(context);
+    gjs_cairo_surface_init(context);
 
     obj = gjs_cairo_surface_create_proto(context, module,
                                          "Surface", NULL);