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#include <stdlib.h>
#include <glib.h>
#include <clutter/clutter.h>
static const char *menu_items_name[] = {
"Option 1",
"Option 2",
"Option 3",
"Option 4",
"Option 5",
"Option 6",
"Option 7",
"Option 8",
"Option 9",
"Option 10",
"Option 11",
};
static const guint menu_items_len = G_N_ELEMENTS (menu_items_name);
static void
select_item_at_index (ClutterActor *scroll,
int index_)
{
ClutterPoint point;
ClutterActor *menu, *item;
gpointer old_selected;
menu = clutter_actor_get_first_child (scroll);
old_selected = g_object_get_data (G_OBJECT (scroll), "selected-item");
if (old_selected != NULL)
{
item = clutter_actor_get_child_at_index (menu, GPOINTER_TO_INT (old_selected));
clutter_text_set_color (CLUTTER_TEXT (item), CLUTTER_COLOR_White);
}
/* wrap around the index */
if (index_ < 0)
index_ = clutter_actor_get_n_children (menu) - 1;
else if (index_ >= clutter_actor_get_n_children (menu))
index_ = 0;
item = clutter_actor_get_child_at_index (menu, index_);
clutter_actor_get_position (item, &point.x, &point.y);
/* scroll to the actor's position; the menu actor is always set at (0, 0),
* so it does not contribute any further offset, and we can use the position
* of its children to ask the ScrollActor to scroll the visible region; if
* the menu actor had an offset, or was transformed, we would have needed to
* get their relative transformed position instead.
*/
clutter_actor_save_easing_state (scroll);
clutter_scroll_actor_scroll_to_point (CLUTTER_SCROLL_ACTOR (scroll), &point);
clutter_actor_restore_easing_state (scroll);
clutter_text_set_color (CLUTTER_TEXT (item), CLUTTER_COLOR_LightSkyBlue);
/* store the index of the currently selected item, so that we can
* implement select_next_item() and select_prev_item()
*/
g_object_set_data (G_OBJECT (scroll), "selected-item",
GINT_TO_POINTER (index_));
}
static void
select_next_item (ClutterActor *scroll)
{
gpointer selected_ = g_object_get_data (G_OBJECT (scroll), "selected-item");
select_item_at_index (scroll, GPOINTER_TO_INT (selected_) + 1);
}
static void
select_prev_item (ClutterActor *scroll)
{
gpointer selected_ = g_object_get_data (G_OBJECT (scroll), "selected-item");
select_item_at_index (scroll, GPOINTER_TO_INT (selected_) - 1);
}
static ClutterActor *
create_menu_item (const char *name)
{
ClutterActor *text;
text = clutter_text_new ();
clutter_text_set_font_name (CLUTTER_TEXT (text), "Sans Bold 24");
clutter_text_set_text (CLUTTER_TEXT (text), name);
clutter_text_set_color (CLUTTER_TEXT (text), CLUTTER_COLOR_White);
clutter_actor_set_margin_left (text, 12.f);
clutter_actor_set_margin_right (text, 12.f);
return text;
}
static ClutterActor *
create_menu_actor (ClutterActor *scroll)
{
ClutterActor *menu;
ClutterLayoutManager *layout_manager;
guint i;
/* this is our menu; it contains items in a vertical layout */
layout_manager = clutter_box_layout_new ();
clutter_box_layout_set_orientation (CLUTTER_BOX_LAYOUT (layout_manager),
CLUTTER_ORIENTATION_VERTICAL);
clutter_box_layout_set_spacing (CLUTTER_BOX_LAYOUT (layout_manager), 12.f);
menu = clutter_actor_new ();
clutter_actor_set_layout_manager (menu, layout_manager);
clutter_actor_set_background_color (menu, CLUTTER_COLOR_Black);
/* these are the items */
for (i = 0; i < menu_items_len; i++)
clutter_actor_add_child (menu, create_menu_item (menu_items_name[i]));
return menu;
}
static ClutterActor *
create_scroll_actor (ClutterActor *stage)
{
ClutterActor *scroll;
/* our scrollable viewport */
scroll = clutter_scroll_actor_new ();
clutter_actor_set_name (scroll, "scroll");
/* give a vertical offset, and constrain the viewport so that its size
* is bound to the stage size
*/
clutter_actor_set_position (scroll, 0.f, 18.f);
clutter_actor_add_constraint (scroll, clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.5));
clutter_actor_add_constraint (scroll, clutter_bind_constraint_new (stage, CLUTTER_BIND_HEIGHT, -36.f));
/* we only want to scroll the contents vertically, and
* ignore any horizontal component
*/
clutter_scroll_actor_set_scroll_mode (CLUTTER_SCROLL_ACTOR (scroll),
CLUTTER_SCROLL_VERTICALLY);
clutter_actor_add_child (scroll, create_menu_actor (scroll));
/* select the first item */
select_item_at_index (scroll, 0);
return scroll;
}
static gboolean
on_key_press (ClutterActor *stage,
ClutterEvent *event,
gpointer unused)
{
ClutterActor *scroll;
guint key_symbol;
scroll = clutter_actor_get_first_child (stage);
key_symbol = clutter_event_get_key_symbol (event);
if (key_symbol == CLUTTER_KEY_Up)
select_prev_item (scroll);
else if (key_symbol == CLUTTER_KEY_Down)
select_next_item (scroll);
return CLUTTER_EVENT_STOP;
}
int
main (int argc, char *argv[])
{
ClutterActor *stage;
if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
return EXIT_FAILURE;
/* create a new stage */
stage = clutter_stage_new ();
clutter_stage_set_title (CLUTTER_STAGE (stage), "Scroll Actor");
clutter_stage_set_user_resizable (CLUTTER_STAGE (stage), TRUE);
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
g_signal_connect (stage, "key-press-event", G_CALLBACK (on_key_press), NULL);
clutter_actor_add_child (stage, create_scroll_actor (stage));
clutter_actor_show (stage);
clutter_main ();
return EXIT_SUCCESS;
}
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