Slideshow widget example

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Slideshow widget example

This application is aimed to exemplify the slideshow widget.

It consists of a window with a slideshow widget set as "resize object", along with a control bar, in the form of a notify. Those controls will exercise most of the slideshow's API functions.

We create the slideshow, itself, first, making it loop on its image items, when in slideshow mode:

slideshow = elm_slideshow_add(win);
elm_slideshow_loop_set(slideshow, EINA_TRUE);
evas_object_size_hint_weight_set(slideshow,
EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
elm_win_resize_object_add(win, slideshow);
evas_object_show(slideshow);
EVAS_HINT_EXPAND
#define EVAS_HINT_EXPAND
Use with evas_object_size_hint_weight_set(), evas_object_size_hint_weight_get(), evas_object_size_hin...
Definition: Evas_Common.h:297
EINA_TRUE
#define EINA_TRUE
boolean value TRUE (numerical value 1)
Definition: eina_types.h:539
elm_slideshow_add
Evas_Object * elm_slideshow_add(Evas_Object *parent)
Add a new slideshow widget to the given parent Elementary (container) object.
Definition: elm_slideshow.c:356
elm_win_resize_object_add
void elm_win_resize_object_add(Eo *obj, Evas_Object *subobj)
Add subobj as a resize object of window obj.
Definition: efl_ui_win.c:8997
evas_object_show
EVAS_API void evas_object_show(Evas_Object *eo_obj)
Makes the given Evas object visible.
Definition: evas_object_main.c:1814
evas_object_size_hint_weight_set
EVAS_API void evas_object_size_hint_weight_set(Evas_Object *obj, double x, double y)
Sets the hints for an object's weight.
Definition: evas_object_main.c:2638

Next, we define the item class for our slideshow items. Slideshow images are going to be Elementary photo widgets, here, as pointed by our `get` class function. We'll let the Elementary infrastructure to delete those objects for us, and, as there's no additional data attached to our slideshow items, the `del` class function can be left undefined:

static Elm_Slideshow_Item_Class itc;
_Elm_Slideshow_Item_Class
member definitions of Elm_Slideshow_Item_Class
Definition: elm_slideshow_common.h:26
itc.func.get = _get;
itc.func.del = NULL;
/* get our images to make slideshow items */
static Evas_Object *
_get(void *data, Evas_Object *obj)
{
Evas_Object *photo = elm_photo_add(obj);
elm_photo_file_set(photo, data);
elm_photo_fill_inside_set(photo, EINA_TRUE);
elm_object_style_set(photo, "shadow");
return photo;
}
elm_photo_file_set
Eina_Bool elm_photo_file_set(Eo *obj, const char *file)
Set the file that will be used as the photo widget's image.
Definition: elm_photo.c:409
elm_photo_fill_inside_set
void elm_photo_fill_inside_set(Evas_Object *obj, Eina_Bool fill)
Set if the photo should be completely visible or not.
Definition: elm_photo.c:452
elm_photo_add
Evas_Object * elm_photo_add(Evas_Object *parent)
Add a new photo to the parent.
Definition: elm_photo.c:310
elm_object_style_set
Eina_Bool elm_object_style_set(Evas_Object *obj, const char *style)
Set the style to used by a given widget.
Definition: elm_main.c:1583
Evas_Object
Efl_Canvas_Object Evas_Object
An Evas Object handle.
Definition: Evas_Common.h:185

We now get to populate the slideshow widget with items. Our images are going to be some randomly chosen from the Elementary package, nine of them. For the first eight, we insert them ordered in the widget, by using elm_slideshow_item_sorted_insert(). The comparing function will use the image names to sort items. The last item is inserted at the end of the slideshow's items list, with elm_slideshow_item_add(). We check out how that list ends with elm_slideshow_items_get(), than:

Elm_Object_Item *slide_first = NULL, *slide_last = NULL, *slide_it = NULL;
const char *transition, *layout;
const Eina_List *l, *list;
const char *data_dir;
char img[IMG_NUM][PATH_MAX];
char *img_files[] =
{
"logo.png", "plant_01.jpg", "rock_01.jpg", "rock_02.jpg", "sky_01.jpg",
"wood_01.jpg", "mystrale.jpg", "mystrale_2.jpg"
};
int i = 0;
elm_app_info_set(elm_main, "elementary", "images");
data_dir = elm_app_data_dir_get();
for (i = 0; i < IMG_NUM; i++)
snprintf(img[i], PATH_MAX, "%s/images/%s", data_dir, img_files[i]);
elm_policy_set(ELM_POLICY_QUIT, ELM_POLICY_QUIT_LAST_WINDOW_CLOSED);
win = elm_win_util_standard_add("slideshow", "Slideshow example");
elm_win_autodel_set(win, EINA_TRUE);
slideshow = elm_slideshow_add(win);
elm_slideshow_loop_set(slideshow, EINA_TRUE);
evas_object_size_hint_weight_set(slideshow,
EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
elm_win_resize_object_add(win, slideshow);
evas_object_show(slideshow);
itc.func.get = _get;
itc.func.del = NULL;
for (i = 0; i < IMG_NUM; i++)
{
slide_it = elm_slideshow_item_sorted_insert(slideshow, &itc, img[i],
_cmp_func);
if (!slide_first) slide_first = slide_it;
}
slide_last = slide_it;
list = elm_slideshow_items_get(slideshow);
printf("List of items in the slideshow:\n");
EINA_LIST_FOREACH(list, l, slide_it)
printf("\t%s\n",
(const char *)elm_object_item_data_get(slide_it));
EINA_LIST_FOREACH
#define EINA_LIST_FOREACH(list, l, _data)
Definition for the macro to iterate over a list.
Definition: eina_list.h:1415
elm_app_info_set
void elm_app_info_set(void *mainfunc, const char *dom, const char *checkfile)
Re-locate the application somewhere else after compilation, if the developer wishes for easier distri...
Definition: elm_main.c:496
elm_app_data_dir_get
const char * elm_app_data_dir_get(void)
Get the application's run time data prefix directory, as set by elm_app_info_set() and the way (envir...
Definition: elm_main.c:586
Elm_Object_Item
Eo Elm_Object_Item
An Elementary Object item handle.
Definition: elm_object_item.h:6
elm_object_item_data_get
void * elm_object_item_data_get(const Elm_Object_Item *it)
Get the data associated with an object item.
Definition: efl_ui_widget.c:3796
elm_policy_set
Eina_Bool elm_policy_set(unsigned int policy, int value)
Set a new policy's value (for a given policy group/identifier).
Definition: elm_main.c:1380
ELM_POLICY_QUIT_LAST_WINDOW_CLOSED
@ ELM_POLICY_QUIT_LAST_WINDOW_CLOSED
quit when the application's last window is closed
Definition: elm_general.h:248
ELM_POLICY_QUIT
@ ELM_POLICY_QUIT
under which circumstances the application should quit automatically.
Definition: elm_general.h:227
elm_win_util_standard_add
Evas_Object * elm_win_util_standard_add(const char *name, const char *title)
Adds a window object with standard setup.
Definition: efl_ui_win.c:9582
elm_win_autodel_set
void elm_win_autodel_set(Eo *obj, Eina_Bool autodel)
Set the window's autodel state.
Definition: efl_ui_win.c:6194
_Eina_List
Type for a generic double linked list.
Definition: eina_list.h:318

Note that we save the pointers to the first and last items in the slideshow, for future use.

What follows is the code creating a notify, to be shown over the slideshow's viewport, with knobs to act on it. We're not showing that boilerplate code, but only the callbacks attached to the interesting smart events of those knobs. The first four are buttons, which will:

- Select the next item in the slideshow
- Select the previous item in the slideshow
- Select the first item in the slideshow
- Select the last item in the slideshow

Check out the code for those four actions, being the two last `data` pointers the same `first` and `last` pointers we save before, respectively:

/* jump to next item, cyclically */
static void
_next(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
elm_slideshow_next(data);
}
EINA_UNUSED
#define EINA_UNUSED
Used to indicate that a function parameter is purposely unused.
Definition: eina_types.h:339
static void
_previous(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
elm_slideshow_previous(data);
}
static void
_first(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
elm_slideshow_item_show(data);
}
static void
_last(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
elm_slideshow_item_show(data);
}

What follow are two hoversels, meant for one to change the slideshow's transition and layout styles, respectively. We fetch all the available transition and layout names to populate those widgets and, when one selects any of them, we apply the corresponding setters on the slideshow:

hv = elm_hoversel_add(win);
elm_box_pack_end(bx, hv);
elm_hoversel_hover_parent_set(hv, win);
EINA_LIST_FOREACH(elm_slideshow_transitions_get(slideshow), l, transition)
elm_hoversel_item_add(hv, transition, NULL, 0, _transition_select,
transition);
elm_object_text_set(hv, eina_list_data_get(
elm_slideshow_transitions_get(slideshow)));
evas_object_show(hv);
elm_box_pack_end
void elm_box_pack_end(Elm_Box *obj, Efl_Canvas_Object *subobj)
Add an object at the end of the pack list.
Definition: elm_box_eo.legacy.c:57
elm_hoversel_add
Evas_Object * elm_hoversel_add(Evas_Object *parent)
Add a new Hoversel object.
Definition: elc_hoversel.c:703
hv = elm_hoversel_add(win);
elm_box_pack_end(bx, hv);
elm_hoversel_hover_parent_set(hv, win);
EINA_LIST_FOREACH(elm_slideshow_layouts_get(slideshow), l, layout)
elm_hoversel_item_add(hv, layout, NULL, 0, _layout_select, layout);
elm_object_text_set(hv, elm_slideshow_layout_get(slideshow));
evas_object_show(hv);
/* transition changed */
static void
_transition_select(void *data, Evas_Object *obj, void *event_info EINA_UNUSED)
{
elm_slideshow_transition_set(slideshow, data);
elm_object_text_set(obj, data);
}
static void
_layout_select(void *data, Evas_Object *obj, void *event_info EINA_UNUSED)
{
elm_slideshow_layout_set(slideshow, data);
elm_object_text_set(obj, data);
}

For one to change the transition time on the slideshow widget, we use a spinner widget. We set it to the initial value of 3 (seconds), which will be probed by the next knob – a button starting the slideshow, de facto. Note that changing the transition time while a slideshow is already happening will adjust its transition time:

spin = elm_spinner_add(win);
elm_spinner_label_format_set(spin, "%2.0f s");
evas_object_smart_callback_add(spin, "changed", _spin, spin);
elm_spinner_step_set(spin, 1);
elm_spinner_min_max_set(spin, 1, 30);
elm_spinner_value_set(spin, 3);
elm_box_pack_end(bx, spin);
evas_object_show(spin);
elm_spinner_add
Evas_Object * elm_spinner_add(Evas_Object *parent)
Add a new spinner widget to the given parent Elementary (container) object.
Definition: elm_spinner.c:1350
elm_spinner_label_format_set
void elm_spinner_label_format_set(Elm_Spinner *obj, const char *fmt)
Control the format string of the displayed label.
Definition: elm_spinner_eo.legacy.c:63
elm_spinner_min_max_set
void elm_spinner_min_max_set(Evas_Object *obj, double min, double max)
Control the minimum and maximum values for the spinner.
Definition: elm_spinner.c:1357
elm_spinner_step_set
void elm_spinner_step_set(Evas_Object *obj, double step)
Control the step used to increment or decrement the spinner value.
Definition: elm_spinner.c:1369
elm_spinner_value_set
void elm_spinner_value_set(Evas_Object *obj, double val)
Control the value the spinner displays.
Definition: elm_spinner.c:1381
evas_object_smart_callback_add
EVAS_API void evas_object_smart_callback_add(Evas_Object *eo_obj, const char *event, Evas_Smart_Cb func, const void *data)
Add (register) a callback function to the smart event specified by event on the smart object obj.
Definition: evas_object_smart.c:1040
/* slideshow transition time has changed */
static void
_spin(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
if (elm_slideshow_timeout_get(slideshow) > 0)
elm_slideshow_timeout_set(slideshow, elm_spinner_value_get(data));
}
elm_spinner_value_get
double elm_spinner_value_get(const Evas_Object *obj)
Control the value the spinner displays.
Definition: elm_spinner.c:1387

Finally, we have two buttons which will, respectively, start and stop the slideshow on our widget. Here are their "clicked" callbacks:

/* start the show! */
static void
_start(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
elm_slideshow_timeout_set(slideshow, elm_spinner_value_get(data));
elm_object_disabled_set(bt_start, EINA_TRUE);
elm_object_disabled_set(bt_stop, EINA_FALSE);
}
EINA_FALSE
#define EINA_FALSE
boolean value FALSE (numerical value 0)
Definition: eina_types.h:533
elm_object_disabled_set
void elm_object_disabled_set(Evas_Object *obj, Eina_Bool disabled)
Set the disabled state of an Elementary object.
Definition: elm_main.c:1613
static void
_stop(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
elm_slideshow_timeout_set(slideshow, 0.0);
elm_object_disabled_set(bt_start, EINA_FALSE);
elm_object_disabled_set(bt_stop, EINA_TRUE);
}

This is how the example program's window looks like:

See the full source code for this example.