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2008-01-18 Emmanuele Bassi <ebassi@openedhand.com>

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* subclassing-ClutterActor.sgml: Fix up the wording and the
	examples a bit; add a paragraph about the ClutterActor::pick()
	virtual method.
This commit is contained in:
Emmanuele Bassi 2008-01-18 11:45:12 +00:00
parent cbddf6aa1a
commit 5b6a9701e2
2 changed files with 56 additions and 12 deletions
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6
doc/reference/ChangeLog
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@ -1,3 +1,9 @@
2008-01-18 Emmanuele Bassi <ebassi@openedhand.com>
* subclassing-ClutterActor.sgml: Fix up the wording and the
examples a bit; add a paragraph about the ClutterActor::pick()
virtual method.
2008-01-18 Emmanuele Bassi <ebassi@openedhand.com>
* clutter-sections.txt: Add the new ClutterBehaviourOpacity

62
doc/reference/subclassing-ClutterActor.sgml
View file

@ -42,7 +42,7 @@ foo_actor_query_coords (ClutterActor *actor,
{
FooActor *foo_actor = FOO_ACTOR (actor);
GList *child;
guint width, height;
ClutterUnit width, height;
/* initialize our size */
width = height = 0;
@ -54,21 +54,17 @@ foo_actor_query_coords (ClutterActor *actor,
/* we return only visible actors */
if (CLUTTER_ACTOR_IS_VISIBLE (child_actor))
{
ClutterActorBox child_box;
ClutterActorBox child_box = { 0, };
clutter_actor_query_coords (child_actor, &amp;child_box);
width += child_box.x2 - child_box.x2;
width += child_box.x2 - child_box.x2;
height += child_box.y2 - child_box.y1;
}
}
/* internally, the coordinates are all expressed in generic
* "units", but the public API converts them into pixels,
* so we need to juggle around with conversions
*/
box-&gt;x2 = box-&gt;x1 + CLUTTER_UNITS_FROM_INT (width);
box-&gt;y2 = box-&gt;y1 + CLUTTER_UNITS_FROM_INT (height);
box-&gt;x2 = box-&gt;x1 + width
box-&gt;y2 = box-&gt;y1 + height;
}
</programlisting>
</example>
@ -97,16 +93,58 @@ foo_actor_paint (ClutterActor *actor)
FooActor *foo_actor = FOO_ACTOR (actor);
GList *child;
glPushMatrix ();
/* by including &lt;clutter/cogl.h&gt; it's possible to use the internal
* COGL abstraction API, which is also used by Clutter itself and avoids
* changing the GL calls depending on the target platform (GL or GL/ES).
*/
cogl_push_matrix ();
for (child = foo_actor-&gt;children; child != NULL; child = child-&gt;next)
{
ClutterActor *child_actor = child-&gt;data;
clutter_actor_paint (child_actor);
if (CLUTTER_ACTOR_IS_MAPPED (child_actor))
clutter_actor_paint (child_actor);
}
glPopMatrix ();
cogl_pop_matrix ();
}
</programlisting>
</example>
<para>If the actor has a non-rectangular shape, or it has internal childrens
that needs to be distinguished by the events delivery mechanism, the
ClutterActor::pick() method should also be overridden. The ::pick() method
works exactly like the ::paint() method, but the actor should paint just
its shape with the passed colour:</para>
<example id="clutter-actor-pick-example">
<programlisting>
static void
foo_actor_pick (ClutterActor *actor,
const ClutterColor *pick_color)
{
FooActor *foo_actor = FOO_ACTOR (actor);
guint width, height;
/* by including &lt;clutter/cogl.h&gt; it's possible to use the internal
* COGL abstraction API, which is also used by Clutter itself and avoids
* changing the GL calls depending on the target platform (GL or GL/ES).
*/
cogl_color (pick_color);
clutter_actor_get_size (actor, &amp;width, &amp;height);
glEnable (GL_BLEND);
/* draw a triangular shape */
glBegin (GL_POLYGON);
glVertex2i (width / 2, 0 );
glVertex2i (width , height);
glVertex2i (0 , height);
glEnd ();
cogl_pop_matrix ();
}
</programlisting>
</example>