previous page__: Creating a zoom effect
==== Creating Drop and Bounce Effects ====
To finish, we add drop and bounce effects to our buttons at application start.
To do this, we create one timeline per button after creating the buttons in
elm_main():
<code c>
drop and bounce effects
ecore_animator_timeline_add(2, _do_drop, bt1);
ecore_animator_timeline_add(2.3, _do_drop, bt2);
ecore_animator_timeline_add(2.5, _do_drop, bt3);
</code>
We call the same _do_drop() animation callback function for each timeline.
In this callback, instead of using an Evas Map, we simply change the position
of the target using the evas_object_move() function:
<code c>
static Eina_Bool
_do_drop(void *data, double pos)
{
Evas_Object *obj = data;
int x, y, w, h;
double frame = pos;
frame = ecore_animator_pos_map(pos, ECORE_POS_MAP_BOUNCE, 2, 4);
evas_object_geometry_get(obj, &x, &y, &w, &h);
evas_object_move(obj, x, 600 * frame);
return EINA_TRUE;
}
</code>
To get the bounce effect, we use the ecore_animator_pos_map() function,
which maps an input position from 0.0 to 1.0 along the timeline to a position
on a different curve. The curve can be of different types, such as LINEAR,
SINUSOIDAL, and BOUNCE. This function takes the following arguments:
* The input position to map
* The mapping to use (LINEAR, SINUSOIDAL, and so on)
* v1, which is the first parameter used by the mapping
* v2, which is the second parameter used by the mapping
The ECORE_POS_MAP_BOUNCE map we use starts at 0.0, then drops like a ball
bouncing to the ground at 1.0, bouncing v2 times with a decay factor of v1.
Here, we bounce 4 times with a decay factor of 2:
<code c>
frame = ecore_animator_pos_map(pos, ECORE_POS_MAP_BOUNCE, 2, 4);
</code>
This frame is used in the move function to create the animation. The value
increases on each _do_drop() call along the timeline, which produces a
nice drop of the buttons from their initial position to 600 pixels on the
vertical axis.
The whole code__: **ecore_animator.c