Box example - custom layout

This example shows how to register a custom layout to be used by the Edje box part.

It will use edje_box_layout_register() for that.

To play with this example, use the keyboard modifier keys and number keys together. The Ctrl key is used for adding elements, and Shift is used for removing them. For instance, Ctrl + 3 will insert a new rectangle object in the 3rd position of the box, while Shift + 6 will try to remove the 6th element of the box.

This example is very similar to the other box example, has a structure with global data, a callback for key down events where we create or delete rectangle objects and add or remove them to/from the box part.

But the important part is the next one:

static void
custom_layout(Evas_Object *o, Evas_Object_Box_Data *p, void *data EINA_UNUSED)
{
Evas_Object_Box_Option *opt;
Eina_List *l;
int x, y, w, h;
int xx, yy, ww, hh;
int count;
evas_object_geometry_get(o, &x, &y, &w, &h);
count = eina_list_count(p->children);
ww = w / (count ? count : 1);
hh = h / (count ? count : 1);
if (ww < 1) ww = 1;
if (hh < 1) hh = 1;
xx = x;
yy = y;
EINA_LIST_FOREACH(p->children, l, opt)
{
evas_object_move(opt->obj, xx, yy);
xx += ww;
yy += hh;
}
eina_list_count
static unsigned int eina_list_count(const Eina_List *list)
Gets the count of the number of items in a list.
EINA_LIST_FOREACH
#define EINA_LIST_FOREACH(list, l, _data)
Definition for the macro to iterate over a list.
Definition: eina_list.h:1415
EINA_UNUSED
#define EINA_UNUSED
Used to indicate that a function parameter is purposely unused.
Definition: eina_types.h:339
evas_object_geometry_get
EVAS_API void evas_object_geometry_get(const Evas_Object *eo_obj, Evas_Coord *x, Evas_Coord *y, Evas_Coord *w, Evas_Coord *h)
Retrieves the position and (rectangular) size of the given Evas object.
Definition: evas_object_main.c:1335
evas_object_move
EVAS_API void evas_object_move(Evas_Object *obj, Evas_Coord x, Evas_Coord y)
Move the given Evas object to the given location inside its canvas' viewport.
Definition: evas_object_main.c:1171
Evas_Object
Efl_Canvas_Object Evas_Object
An Evas Object handle.
Definition: Evas_Common.h:185
_Eina_List
Type for a generic double linked list.
Definition: eina_list.h:318
_Evas_Object_Box_Data
This structure augments clipped smart object's instance data, providing extra members required by gen...
Definition: Evas_Common.h:2849
_Evas_Object_Box_Option
Evas_Object_Box_Option struct fields
Definition: Evas_Common.h:2872
_Evas_Object_Box_Option::obj
Evas_Object * obj
Pointer to the box child object, itself.
Definition: Evas_Common.h:2873

This code implements our custom layout, which will position every object added to the box in a diagonal through the size of the box part. Notice that it just calculates the position and offset based on the size of the box and number of children, and then moves each child to the respective position.

Later on the `main` function, everything we need to do is to register this custom layout function with edje:

edje_box_layout_register("custom_layout", custom_layout, NULL, NULL, NULL, NULL);
edje_box_layout_register
void edje_box_layout_register(const char *name, Evas_Object_Box_Layout func, void *(*layout_data_get)(void *), void(*layout_data_free)(void *), void(*free_data)(void *), void *data)
Registers a custom layout to be used in edje boxes.
Definition: edje_util.c:3478

And use it inside the box.edc file:

part {
name: "example/box";
type: BOX;
description {
state: "default" 0.0;
box {
layout: "custom_layout";
padding: 2 2;
align: 0.5 0.5;
min: 1 1;
}
rel1 {
relative: 0.0 0.2;
offset: 0 0;
to: "bg";
}
rel2 {
relative: 1.0 1.0;
offset: -1 -61;
to: "bg";
}
}
} // example/box

The example's window should look like this picture:

The full source code follows:

#ifdef HAVE_CONFIG_H
# include "config.h"
#else
# define EINA_UNUSED
#endif
#ifndef PACKAGE_DATA_DIR
#define PACKAGE_DATA_DIR "."
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <Ecore.h>
#include <Evas.h>
#include <Ecore_Evas.h>
#include <Edje.h>
static const char commands[] = \
"commands are:\n"
"\tShift + any key - remove box\n"
"\tCtrl + any key - insert box\n"
"\tEsc - exit\n"
"\th - print help\n";
static void
custom_layout(Evas_Object *o, Evas_Object_Box_Data *p, void *data EINA_UNUSED)
{
Evas_Object_Box_Option *opt;
Eina_List *l;
int x, y, w, h;
int xx, yy, ww, hh;
int count;
evas_object_geometry_get(o, &x, &y, &w, &h);
count = eina_list_count(p->children);
ww = w / (count ? count : 1);
hh = h / (count ? count : 1);
if (ww < 1) ww = 1;
if (hh < 1) hh = 1;
xx = x;
yy = y;
EINA_LIST_FOREACH(p->children, l, opt)
{
evas_object_move(opt->obj, xx, yy);
xx += ww;
yy += hh;
}
}
static Evas_Object *
new_greenie_block(Evas *e)
{
Evas_Object *o;
o = evas_object_rectangle_add(e);
evas_object_resize(o, 10, 10);
evas_object_color_set(o, 0, 255, 0, 255);
evas_object_show(o);
return o;
}
static void
on_keydown(void *data, Evas *evas, Evas_Object *o EINA_UNUSED, void *einfo)
{
Evas_Event_Key_Down *ev;
Evas_Object *edje_obj;
const Evas_Modifier *mods;
ev = (Evas_Event_Key_Down *)einfo;
edje_obj = (Evas_Object *)data;
mods = evas_key_modifier_get(evas);
if (!strcmp(ev->key, "h"))
{
printf(commands);
return;
}
if (evas_key_modifier_is_set(mods, "Shift"))
{
int pos;
Evas_Object *obj = NULL;
pos = atoi(ev->key);
obj = edje_object_part_box_remove_at(edje_obj, "example/box", pos);
if (obj)
evas_object_del(obj);
return;
}
if (evas_key_modifier_is_set(mods, "Control"))
{
Evas_Object *obj;
int pos;
pos = atoi(ev->key);
obj = new_greenie_block(evas);
if (!edje_object_part_box_insert_at(edje_obj, "example/box", obj, pos))
edje_object_part_box_append(edje_obj, "example/box", obj);
return;
}
if (!strcmp(ev->key, "Escape"))
ecore_main_loop_quit();
}
static Evas_Object *
box_new(Ecore_Evas *ee, const char *edje_file_path, const char *name, int x, int y, int w, int h)
{
Evas_Object *edje_obj;
edje_obj = edje_object_add(ecore_evas_get(ee));
evas_object_move(edje_obj, x, y);
evas_object_resize(edje_obj, w, h);
if (!edje_object_file_set(edje_obj, edje_file_path, "example/group2"))
{
printf("error: could not load file object.\n");
}
evas_object_show(edje_obj);
evas_object_name_set(edje_obj, name);
ecore_evas_data_set(ee, "edje_obj", edje_obj);
return edje_obj;
}
static void
on_resize(Ecore_Evas *ee)
{
Evas_Object *bg;
Evas_Object *edje_obj;
int w;
int h;
bg = ecore_evas_data_get(ee, "background");
edje_obj = ecore_evas_data_get(ee, "edje_obj");
ecore_evas_geometry_get(ee, NULL, NULL, &w, &h);
evas_object_resize(bg, w, h);
evas_object_resize(edje_obj, w, h);
}
static void
on_destroy(Ecore_Evas *ee EINA_UNUSED)
{
ecore_main_loop_quit();
}
int
main(int argc EINA_UNUSED, char *argv[] EINA_UNUSED)
{
const char *edje_file = PACKAGE_DATA_DIR"/box.edj";
Ecore_Evas *ee;
Evas *evas;
Evas_Object *bg;
Evas_Object *edje_obj;
Evas_Object *last;
Evas_Object *o;
int w;
int h;
int i;
if (!ecore_evas_init())
return EXIT_FAILURE;
if (!edje_init())
goto shutdown_ecore_evas;
/* this will give you a window with an Evas canvas under the first
* engine available */
ee = ecore_evas_new(NULL, 0, 0, 640, 480, NULL);
if (!ee) goto shutdown_edje;
ecore_evas_callback_resize_set(ee, on_resize);
ecore_evas_callback_destroy_set(ee, on_destroy);
ecore_evas_geometry_get(ee, NULL, NULL, &w, &h);
evas = ecore_evas_get(ee);
bg = evas_object_rectangle_add(evas);
evas_object_resize(bg, w, h);
evas_object_show(bg);
evas_object_focus_set(bg, 1);
ecore_evas_data_set(ee, "background", bg);
edje_box_layout_register("custom_layout", custom_layout, NULL, NULL, NULL, NULL);
edje_obj = box_new(ee, edje_file, "box", 0, 0, w, h);
evas_object_event_callback_add(bg, EVAS_CALLBACK_KEY_DOWN, on_keydown, edje_obj);
for (i = 1; i <= 5; i++)
{
o = last = evas_object_rectangle_add(evas);
evas_object_size_hint_min_set(o, 50, 50);
evas_object_resize(o, 50, 50);
evas_object_color_set(o, 128, 0, 0, 128);
evas_object_show(o);
if (!edje_object_part_box_append(edje_obj, "example/box", o))
{
fprintf(stderr, "error appending child object!\n");
return 1;
}
}
printf(commands);
ecore_evas_show(ee);
ecore_main_loop_begin();
ecore_evas_free(ee);
ecore_evas_shutdown();
edje_shutdown();
return EXIT_SUCCESS;
shutdown_edje:
edje_shutdown();
shutdown_ecore_evas:
ecore_evas_shutdown();
return EXIT_FAILURE;
}
Ecore_Evas.h
Evas wrapper functions.
Edje.h
Edje Graphical Design Library.
EVAS_CALLBACK_KEY_DOWN
@ EVAS_CALLBACK_KEY_DOWN
Key Press Event.
Definition: Evas_Common.h:430
ecore_evas_init
EAPI int ecore_evas_init(void)
Inits the Ecore_Evas system.
Definition: ecore_evas.c:602
ecore_evas_callback_destroy_set
EAPI void ecore_evas_callback_destroy_set(Ecore_Evas *ee, Ecore_Evas_Event_Cb func)
Sets a callback for Ecore_Evas destroy events.
Definition: ecore_evas.c:1185
ecore_evas_show
EAPI void ecore_evas_show(Ecore_Evas *ee)
Shows an Ecore_Evas' window.
Definition: ecore_evas.c:1480
ecore_evas_get
EAPI Evas * ecore_evas_get(const Ecore_Evas *ee)
Gets an Ecore_Evas's Evas.
Definition: ecore_evas.c:1300
ecore_evas_geometry_get
EAPI void ecore_evas_geometry_get(const Ecore_Evas *ee, int *x, int *y, int *w, int *h)
Gets the geometry of an Ecore_Evas.
Definition: ecore_evas.c:1362
ecore_evas_data_set
EAPI void ecore_evas_data_set(Ecore_Evas *ee, const char *key, const void *data)
Stores user data in an Ecore_Evas structure.
Definition: ecore_evas.c:1103
ecore_evas_callback_resize_set
EAPI void ecore_evas_callback_resize_set(Ecore_Evas *ee, Ecore_Evas_Event_Cb func)
Sets a callback for Ecore_Evas resize events.
Definition: ecore_evas.c:1140
ecore_evas_shutdown
EAPI int ecore_evas_shutdown(void)
Shuts down the Ecore_Evas system.
Definition: ecore_evas.c:666
ecore_evas_new
EAPI Ecore_Evas * ecore_evas_new(const char *engine_name, int x, int y, int w, int h, const char *extra_options)
Creates a new Ecore_Evas based on engine name and common parameters.
Definition: ecore_evas.c:1039
ecore_evas_free
EAPI void ecore_evas_free(Ecore_Evas *ee)
Frees an Ecore_Evas.
Definition: ecore_evas.c:1083
ecore_evas_data_get
EAPI void * ecore_evas_data_get(const Ecore_Evas *ee, const char *key)
Retrieves user data associated with an Ecore_Evas.
Definition: ecore_evas.c:1092
ecore_main_loop_quit
void ecore_main_loop_quit(void)
Quits the main loop once all the events currently on the queue have been processed.
Definition: ecore_main.c:1321
ecore_main_loop_begin
void ecore_main_loop_begin(void)
Runs the application main loop.
Definition: ecore_main.c:1311
edje_shutdown
int edje_shutdown(void)
Shuts down the Edje library.
Definition: edje_main.c:262
edje_init
int edje_init(void)
Initializes the Edje library.
Definition: edje_main.c:35
edje_object_add
Evas_Object * edje_object_add(Evas *evas)
Instantiates a new Edje object.
Definition: edje_smart.c:22
edje_object_file_set
Eina_Bool edje_object_file_set(Evas_Object *obj, const char *file, const char *group)
Sets the EDJ file (and group within it) to load an Edje object's contents from.
Definition: edje_smart.c:467
edje_object_part_box_insert_at
Eina_Bool edje_object_part_box_insert_at(Evas_Object *obj, const char *part, Evas_Object *child, unsigned int pos)
Inserts an object to the box.
Definition: edje_part_table.c:260
edje_object_part_box_remove_at
Evas_Object * edje_object_part_box_remove_at(Evas_Object *obj, const char *part, unsigned int pos)
Removes an object from the box.
Definition: edje_part_table.c:267
edje_object_part_box_append
Eina_Bool edje_object_part_box_append(Evas_Object *obj, const char *part, Evas_Object *child)
Appends an object to the box.
Definition: edje_part_table.c:232
Evas
Eo Evas
An opaque handle to an Evas canvas.
Definition: Evas_Common.h:163
evas_key_modifier_get
EVAS_API const Evas_Modifier * evas_key_modifier_get(const Evas *eo_e)
Returns a handle to the list of modifier keys registered in the canvas e.
Definition: evas_key.c:35
evas_key_modifier_is_set
EVAS_API Eina_Bool evas_key_modifier_is_set(const Evas_Modifier *m, const char *keyname)
Checks the state of a given modifier of the default seat, at the time of the call.
Definition: evas_key.c:76
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_name_set
EVAS_API void evas_object_name_set(Evas_Object *eo_obj, const char *name)
Sets the name of the given Evas object to the given name.
Definition: evas_name.c:5
evas_object_del
EVAS_API void evas_object_del(Evas_Object *obj)
Marks the given Evas object for deletion (when Evas will free its memory).
Definition: evas_object_main.c:928
evas_object_color_set
EVAS_API void evas_object_color_set(Evas_Object *obj, int r, int g, int b, int a)
Sets the general/main color of the given Evas object to the given one.
Definition: evas_object_main.c:2024
evas_object_event_callback_add
EVAS_API void evas_object_event_callback_add(Evas_Object *eo_obj, Evas_Callback_Type type, Evas_Object_Event_Cb func, const void *data)
Add (register) a callback function to a given Evas object event.
Definition: evas_callbacks.c:478
evas_object_focus_set
EVAS_API void evas_object_focus_set(Efl_Canvas_Object *obj, Eina_Bool focus)
Indicates that this object is the keyboard event receiver on its canvas.
Definition: efl_canvas_object_eo.legacy.c:39
evas_object_resize
EVAS_API void evas_object_resize(Evas_Object *obj, Evas_Coord w, Evas_Coord h)
Changes the size of the given Evas object.
Definition: evas_object_main.c:1236
evas_object_size_hint_min_set
EVAS_API void evas_object_size_hint_min_set(Evas_Object *obj, Evas_Coord w, Evas_Coord h)
Sets the hints for an object's minimum size.
Definition: evas_object_main.c:2611
evas_object_rectangle_add
EVAS_API Evas_Object * evas_object_rectangle_add(Evas *e)
Adds a rectangle to the given evas.
Definition: evas_object_rectangle.c:78
_Evas_Event_Key_Down
Key press event.
Definition: Evas_Legacy.h:314
_Evas_Event_Key_Down::key
const char * key
The logical key : (eg shift+1 == exclamation)
Definition: Evas_Legacy.h:320

To compile use this command:

    * gcc -o edje-box2 edje-box2.c -DPACKAGE_BIN_DIR=\"/Where/enlightenment/is/installed/bin\" -DPACKAGE_LIB_DIR=\"/Where/enlightenment/is/installed/lib\"
    * -DPACKAGE_DATA_DIR=\"/Where/enlightenment/is/installed/share\"
    * `pkg-config --cflags --libs evas ecore ecore-evas edje`
    *
    * edje_cc box.edc
    *