docs: Add example of a border added through ClutterEffect

Add a basic example showing how to implement a ClutterEffect post_paint() function to overlay a highlight border over a rectangular actor.
2025-06-13 16:59:30 +00:00 · 2011-03-08 11:19:13 +00:00
parent 1d14e7468b
commit a81dbcf483
4 changed files with 479 additions and 0 deletions
--- a/doc/cookbook/examples/effects-basic.c
+++ b/doc/cookbook/examples/effects-basic.c
@ -0,0 +1,106 @@
+#include <stdlib.h>
+#include <clutter/clutter.h>
+
+#include "cb-border-effect.h"
+
+static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
+static ClutterColor red_color = { 0xff, 0x00, 0x00, 0xff };
+
+static gboolean
+add_highlight (ClutterActor *actor,
+               ClutterEvent *event,
+               gpointer      user_data)
+{
+  ClutterActorMeta *meta = CLUTTER_ACTOR_META (user_data);
+
+  gboolean effect_enabled = clutter_actor_meta_get_enabled (meta);
+
+  clutter_actor_meta_set_enabled (meta, !effect_enabled);
+
+  clutter_actor_queue_redraw (actor);
+
+  return TRUE;
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  ClutterActor *stage;
+  ClutterActor *box;
+  ClutterLayoutManager *layout_manager;
+  ClutterActor *texture;
+  ClutterEffect *effect;
+  gchar *filename;
+  guint i;
+  GError *error = NULL;
+
+  if (argc < 2)
+    {
+      g_print ("Usage: %s <image files>\n", argv[0]);
+      return EXIT_FAILURE;
+    }
+
+  if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
+    return EXIT_FAILURE;
+
+  stage = clutter_stage_new ();
+  clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
+  clutter_stage_set_user_resizable (CLUTTER_STAGE (stage), TRUE);
+  clutter_actor_set_size (stage, 600, 400);
+  g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
+
+  layout_manager = clutter_flow_layout_new (CLUTTER_FLOW_HORIZONTAL);
+  clutter_flow_layout_set_column_spacing (CLUTTER_FLOW_LAYOUT (layout_manager),
+                                          10);
+  clutter_flow_layout_set_row_spacing (CLUTTER_FLOW_LAYOUT (layout_manager),
+                                       10);
+
+  box = clutter_box_new (layout_manager);
+  clutter_actor_add_constraint (box, clutter_bind_constraint_new (stage, CLUTTER_BIND_WIDTH, 0.0));
+
+  /* loop through the files specified on the command line, adding
+   * each one into the box
+   */
+  for (i = 1; i < argc; i++)
+    {
+      filename = argv[i];
+
+      texture = clutter_texture_new ();
+      clutter_texture_set_keep_aspect_ratio (CLUTTER_TEXTURE (texture), TRUE);
+      clutter_actor_set_width (texture, 150);
+      clutter_actor_set_reactive (texture, TRUE);
+
+      clutter_texture_set_from_file (CLUTTER_TEXTURE (texture),
+                                     filename,
+                                     &error);
+
+      if (error != NULL)
+        g_warning ("Error loading file %s:\n%s",
+                   filename,
+                   error->message);
+
+      /* create a 5 pixel red border effect */
+      effect = cb_border_effect_new (5.0, &red_color);
+
+      /* add the effect to the actor, but disabled */
+      clutter_actor_add_effect (texture, effect);
+      clutter_actor_meta_set_enabled (CLUTTER_ACTOR_META (effect), FALSE);
+
+      /* on mouse click, toggle the "enabled" property of the border effect */
+      g_signal_connect (texture,
+                        "button-press-event",
+                        G_CALLBACK (add_highlight),
+                        effect);
+
+      clutter_container_add_actor (CLUTTER_CONTAINER (box), texture);
+    }
+
+  clutter_container_add_actor (CLUTTER_CONTAINER (stage), box);
+
+  clutter_actor_show (stage);
+
+  clutter_main ();
+
+  return EXIT_SUCCESS;
+}