callbacks: Optimize cairo logic for Gtk 3

With Gtk 3, we don't need to implement the funtion
gdk_cairo_surface_create_from_pixbuf() ourselves, as it is
available there. So, just call the right function.

Also, with Gtk 3.22 and above, the old way of calling
gdk_cairo_create() is obsolete, as all windows already have
it. So, instead, just instance it.

That supresses a deprecated function warning:

callbacks.c:604:5: warning: ‘gdk_cairo_create’ is deprecated: Use 'gdk_window_begin_draw_frame() and gdk_drawing_context_get_cairo_context()' instead [-Wdeprecated-declarations]
     cr = gdk_cairo_create(window);
     ^~
In file included from /usr/include/gtk-3.0/gdk/gdk.h:33,
                 from /usr/include/gtk-3.0/gtk/gtk.h:30,
                 from v4l.h:24,
                 from callbacks.h:4,
                 from callbacks.c:1:
/usr/include/gtk-3.0/gdk/gdkcairo.h:35:12: note: declared here
 cairo_t  * gdk_cairo_create             (GdkWindow          *window);
            ^~~~~~~~~~~~~~~~

While here, add a missing surface destroy in order to avoid
possible memory leaks.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 24 insertions, 2 deletions

diff --git a/src/callbacks.c b/src/callbacks.c
index d731b86..f8a378e 100644
--- a/src/callbacks.c
+++ b/src/callbacks.c
@@ -500,6 +500,9 @@ static void apply_filters(cam_t *cam)
 static cairo_surface_t *create_from_pixbuf(const GdkPixbuf *pixbuf,
                                            GdkWindow *for_window)
 {
+#if GTK_MAJOR_VERSION >= 3
+    return gdk_cairo_surface_create_from_pixbuf(pixbuf, 1, for_window);
+#else
     gint width = gdk_pixbuf_get_width(pixbuf);
     gint height = gdk_pixbuf_get_height(pixbuf);
     guchar *gdk_pixels = gdk_pixbuf_get_pixels(pixbuf);
@@ -564,6 +567,7 @@ static cairo_surface_t *create_from_pixbuf(const GdkPixbuf *pixbuf,
 
     cairo_surface_mark_dirty(surface);
     return surface;
+#endif
 }
 
 static void show_buffer(cam_t *cam)
@@ -579,6 +583,10 @@ static void show_buffer(cam_t *cam)
         .x = 0, .y = 0,
         .width = cam->width, .height = cam->height
     };
+#if GTK_MAJOR_VERSION >= 3 && GTK_MINOR_VERSION >= 22
+    GdkDrawingContext *context;
+    cairo_region_t *region;
+#endif
 
     /*
      * refer the frame
@@ -601,13 +609,27 @@ static void show_buffer(cam_t *cam)
     window = gtk_widget_get_window(widget);
 
     surface = create_from_pixbuf(pb, window);
+
+#if GTK_MAJOR_VERSION >= 3 && GTK_MINOR_VERSION >= 22
+    region = cairo_region_create();
+    context = gdk_window_begin_draw_frame(window, region);
+    cr = gdk_drawing_context_get_cairo_context(context);
+#else
     cr = gdk_cairo_create(window);
-    cairo_set_source_surface(cr, surface, 0, 0);
+#endif
 
+    cairo_set_source_surface(cr, surface, 0, 0);
     gdk_cairo_rectangle(cr, &rect);
-
     cairo_fill(cr);
+
+#if GTK_MAJOR_VERSION >= 3 && GTK_MINOR_VERSION >= 22
+    gdk_window_end_draw_frame(window, context);
+#else
     cairo_destroy(cr);
+    cairo_region_destroy(region);
+#endif
+
+    cairo_surface_destroy(surface);
 
     frames++;
     frames2++;