[UI Sample] Evas Map Rotation Sample Overview

The Evas Map Rotation sample demonstrates how to rotate a button in 3D using EFL map functions. A map consists of a set of points (currently only 4 are supported). Each of these points contains a set of canvas x and y coordinates that can be used to alter the geometry of the mapped object.

The following figure illustrates the Evas Map Rotation screen.

Figure: Evas Map Rotation screen

Implementation

The create_base_gui() function draws the button in 3D by creating a button and animating it with the ecore_animator_add() function.

#include "evasmaprotation.h"

static void
create_base_gui(appdata_s *ad)
{
   // Window
   ad->win = elm_win_util_standard_add(PACKAGE, PACKAGE);
   elm_win_autodel_set(ad->win, EINA_TRUE);

   evas_object_smart_callback_add(ad->win, "delete,request", win_delete_request_cb, NULL);
   eext_object_event_callback_add(ad->win, EEXT_CALLBACK_BACK, win_back_cb, ad);
   Evas_Object *btn;

   // Create a button
   btn = elm_button_add(ad->win);
   elm_object_text_set(btn, "Evas<br>Map<br> Rotation");
   evas_object_move(btn, 100, 100);
   evas_object_resize(btn, 300, 300);
   evas_object_show(btn);

   ecore_animator_add(evas_map_rotation_exam_animator_cb, btn);

   // Show the window after the base GUI is set up
   evas_object_show(ad->win);
}

The evas_object_geometry_get() function obtains the position of the button. The evas_map_new() function creates an Evas map and the evas_map_util_points_populate_from_object_full() function populates the source and destination map points to match the button. The button is rotated and a perspective transform is applied with the evas_map_util_3d_rotate() and evas_map_util_3d_perspective() functions. The evas_object_map_set() function applies the map to the button object.

Eina_Bool
evas_map_rotation_exam_animator_cb(void *data)
{
   static int i = 0;
   Evas_Map *map;
   Evas_Object *btn = data;
   Evas_Coord x, y, w, h;

   i++;
   if (i > 360) i = 0;

   evas_object_geometry_get(btn, &x, &y, &w, &h);
   // Create an Evas map
   map = evas_map_new(4);
   evas_map_util_points_populate_from_object_full(map, btn, 0);
   evas_map_util_3d_rotate(map, i, 0, 0, x + (w / 2), y + (h / 2), 0);
   evas_map_util_3d_perspective(map,  x + (w / 2), y + (h / 2), 0, 300);

   // Apply map to button object
   evas_object_map_set(btn, map);

   // Free map resource
   evas_map_free(map);

   // Enable map feature
   evas_object_map_enable_set(btn, EINA_TRUE);

   return ECORE_CALLBACK_RENEW;
}