[clutter] wayland: Use wl_cursor_theme to provide a buffer for the Wayland cursor

[Rob Bradford <rbradford src gnome org>]

commit fce43c420e4fff2b8cbed5eee4dce740689df637
Author: Rob Bradford <rob linux intel com>
Date:   Mon Oct 8 13:25:36 2012 +0100

    wayland: Use wl_cursor_theme to provide a buffer for the Wayland cursor
    
    This change switches to the new mechanism for loading a cursor into a buffer.
    It no longer relies on having a PNG stored in a known location and instead
    loads from the Wayland cursor theme.
    
    Signed-off-by: Rob Bradford <rob linux intel com>

 clutter/wayland/clutter-backend-wayland.c |  174 +++--------------------------
 clutter/wayland/clutter-backend-wayland.h |    4 +
 2 files changed, 22 insertions(+), 156 deletions(-)
---
diff --git a/clutter/wayland/clutter-backend-wayland.c b/clutter/wayland/clutter-backend-wayland.c
index 3717d4f..56b5b57 100644
--- a/clutter/wayland/clutter-backend-wayland.c
+++ b/clutter/wayland/clutter-backend-wayland.c
@@ -48,6 +48,7 @@
 #include "cogl/clutter-stage-cogl.h"
 
 #include <wayland-client.h>
+#include <wayland-cursor.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <cogl/cogl.h>
@@ -76,6 +77,12 @@ clutter_backend_wayland_dispose (GObject *gobject)
       backend_wayland->cursor_buffer = NULL;
     }
 
+  if (backend_wayland->cursor_theme)
+    {
+      wl_cursor_theme_destroy (backend_wayland->cursor_theme);
+      backend_wayland->cursor_theme = NULL;
+    }
+
   G_OBJECT_CLASS (clutter_backend_wayland_parent_class)->dispose (gobject);
 }
 
@@ -277,175 +284,30 @@ clutter_backend_wayland_class_init (ClutterBackendWaylandClass *klass)
   backend_class->get_display = clutter_backend_wayland_get_display;
 }
 
-/*
- * clutter_backend_wayland_load_cursor and the two functions below were copied
- * from GTK+ and adapted for clutter
- */
-static void
-set_pixbuf (GdkPixbuf     *pixbuf,
-            unsigned char *map,
-            int            width,
-            int            height)
-{
-  int stride, i, n_channels;
-  unsigned char *pixels, *end, *argb_pixels, *s, *d;
-
-  stride = gdk_pixbuf_get_rowstride (pixbuf);
-  pixels = gdk_pixbuf_get_pixels (pixbuf);
-  n_channels = gdk_pixbuf_get_n_channels (pixbuf);
-  argb_pixels = map;
-
-#define MULT(_d,c,a,t) \
-  do { t = c * a + 0x7f; _d = ((t >> 8) + t) >> 8; } while (0)
-
-  if (n_channels == 4)
-    {
-      for (i = 0; i < height; i++)
-        {
-          s = pixels + i * stride;
-          end = s + width * 4;
-          d = argb_pixels + i * width * 4;
-          while (s < end)
-            {
-              unsigned int t;
-
-              MULT(d[0], s[2], s[3], t);
-              MULT(d[1], s[1], s[3], t);
-              MULT(d[2], s[0], s[3], t);
-              d[3] = s[3];
-              s += 4;
-              d += 4;
-            }
-        }
-    }
-  else if (n_channels == 3)
-    {
-      for (i = 0; i < height; i++)
-        {
-          s = pixels + i * stride;
-          end = s + width * 3;
-          d = argb_pixels + i * width * 4;
-          while (s < end)
-            {
-              d[0] = s[2];
-              d[1] = s[1];
-              d[2] = s[0];
-              d[3] = 0xff;
-              s += 3;
-              d += 4;
-            }
-        }
-    }
-}
-
-static struct wl_buffer *
-create_cursor (ClutterBackendWayland *backend_wayland,
-               GdkPixbuf             *pixbuf)
-{
-  int stride, fd;
-  char *filename;
-  GError *error = NULL;
-  struct wl_shm_pool *pool;
-  struct wl_buffer *buffer;
-  gint width, height;
-  gsize size;
-  unsigned char *map;
-
-  width = gdk_pixbuf_get_width (pixbuf);
-  height = gdk_pixbuf_get_height (pixbuf);
-  stride = width * 4;
-  size = stride * height;
-
-  fd = g_file_open_tmp ("wayland-shm-XXXXXX", &filename, &error);
-  if (fd < 0)
-    {
-      g_critical (G_STRLOC ": Opening temporary file failed: %s", error->message);
-      g_error_free (error);
-      return NULL;
-    }
-
-  unlink (filename);
-  g_free (filename);
-
-  if (ftruncate (fd, size) < 0)
-    {
-      g_critical (G_STRLOC ": Setting the size of temporary file failed: %s", g_strerror (errno));
-      close (fd);
-      return NULL;
-    }
-
-  map = mmap (NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-
-  if (map == MAP_FAILED)
-    {
-      g_critical (G_STRLOC ": Memory mapping file failed: %s", g_strerror (errno));
-      close (fd);
-      return NULL;
-   }
-
-  set_pixbuf (pixbuf, map, width, height);
-
-  pool = wl_shm_create_pool (backend_wayland->wayland_shm, fd, size);
-  close (fd);
-  buffer = wl_shm_pool_create_buffer (pool,
-                                      0,
-                                      width,
-                                      height,
-                                      stride,
-                                      WL_SHM_FORMAT_ARGB8888);
-  wl_shm_pool_destroy (pool);
-  munmap (map, size);
-
-  return buffer;
-}
-
 static void
 clutter_backend_wayland_load_cursor (ClutterBackendWayland *backend_wayland)
 {
-  const gchar * const *directories;
-  gint j;
-  GdkPixbuf *pixbuf = NULL;
-  GError *error = NULL;
+  struct wl_cursor *cursor;
 
-  directories = g_get_system_data_dirs();
+  backend_wayland->cursor_theme =
+    wl_cursor_theme_load (NULL, /* default */
+                          32,
+                          backend_wayland->wayland_shm);
 
-  for (j = 0; directories[j] != NULL; j++)
-    {
-      gchar *filename;
-      filename = g_build_filename (directories[j],
-                                   "weston",
-                                   "left_ptr.png",
-                                   NULL);
-      if (g_file_test (filename, G_FILE_TEST_EXISTS))
-        {
-          pixbuf = gdk_pixbuf_new_from_file (filename, &error);
-
-          if (error != NULL)
-            {
-              g_warning ("Failed to load cursor: %s: %s",
-                         filename, error->message);
-              g_error_free (error);
-              return;
-            }
-          break;
-        }
-    }
+  cursor = wl_cursor_theme_get_cursor (backend_wayland->cursor_theme,
+                                       "left_ptr");
 
-  if (!pixbuf)
-    return;
-
-  backend_wayland->cursor_buffer = create_cursor (backend_wayland, pixbuf);
+  backend_wayland->cursor_buffer =
+    wl_cursor_image_get_buffer (cursor->images[0]);
 
   if (backend_wayland->cursor_buffer)
     {
-      backend_wayland->cursor_x = 0;
-      backend_wayland->cursor_y = 0;
+      backend_wayland->cursor_x = cursor->images[0]->hotspot_x;
+      backend_wayland->cursor_y = cursor->images[0]->hotspot_y;
     }
 
   backend_wayland->cursor_surface =
     wl_compositor_create_surface (backend_wayland->wayland_compositor);
-
-  g_object_unref (pixbuf);
 }
 
 static void
diff --git a/clutter/wayland/clutter-backend-wayland.h b/clutter/wayland/clutter-backend-wayland.h
index 5788a45..5cbaa3b 100644
--- a/clutter/wayland/clutter-backend-wayland.h
+++ b/clutter/wayland/clutter-backend-wayland.h
@@ -32,6 +32,9 @@
 #include <clutter/clutter-backend.h>
 #include <clutter/clutter-device-manager.h>
 
+#include <wayland-client.h>
+#include <wayland-cursor.h>
+
 #include "clutter-backend-private.h"
 
 G_BEGIN_DECLS
@@ -59,6 +62,7 @@ struct _ClutterBackendWayland
   struct wl_surface *cursor_surface;
   struct wl_buffer *cursor_buffer;
   struct wl_output *wayland_output;
+  struct wl_cursor_theme *cursor_theme;
 
   gint cursor_x, cursor_y;
   gint output_width, output_height;