Ecore_Evas window size hints

On this example, we show you how to deal with Ecore_Evas window size hints, which are implemented per Evas engine.

We start by defining an initial size for our window and, after creating it, adding a background white rectangle and a text object to it, to be used to display the current window's sizes, at any given time:

#define WIDTH (300)
#define HEIGHT (300)
return EXIT_FAILURE;
/* this will give you a window with an Evas canvas under the first
* engine available */
ee = ecore_evas_new(NULL, 0, 0, WIDTH, HEIGHT, NULL);
if (!ee) goto error;
ecore_evas_title_set(ee, "Ecore_Evas window sizes example");
ecore_evas_callback_resize_set(ee, _canvas_resize_cb);
evas = ecore_evas_get(ee);
evas_object_color_set(bg, 255, 255, 255, 255); /* white bg */
evas_object_move(bg, 0, 0); /* at canvas' origin */
evas_object_resize(bg, WIDTH, HEIGHT); /* covers full canvas */
text = evas_object_text_add(evas);
evas_object_color_set(text, 0, 0, 0, 255);
evas_object_resize(text, 150, 50);
evas_object_text_font_set(text, "Sans", 20);
_canvas_resize_cb(ee);
printf(commands);
/* to inform current window's size */
static void
_canvas_resize_cb(Ecore_Evas *ee_)
{
int w, h;
char buf[1024];
ecore_evas_geometry_get(ee_, NULL, NULL, &w, &h);
snprintf(buf, sizeof(buf), "%d x %d", w, h);
evas_object_move(text, (w - 150) / 2, (h - 50) / 2);
evas_object_resize(bg, w, h);
}

The program has a command line interface, responding to the following keys:

static const char commands[] = \
"commands are:\n"
"\tm - impose a minumum size to the window\n"
"\tx - impose a maximum size to the window\n"
"\tb - impose a base size to the window\n"
"\ts - impose a step size (different than 1 px) to the window\n"
"\tg - get the screen geometry\n"
"\th - print help\n";

Use the 'm' key to impose a minimum size of half the initial ones on our window. Test it by trying to resize it to smaller sizes than that:

if (strcmp(ev->key, "m") == 0) /* impose a minimum size on the window */
{
min_set = !min_set;
if (min_set)
{
ecore_evas_size_min_set(ee, WIDTH / 2, HEIGHT / 2);
printf("Imposing a minimum size of %d x %d\n",
WIDTH / 2, HEIGHT / 2);
}
else
{
printf("Taking off minimum size restriction from the"
" window\n");
}
return;
}

The 'x' key will, in turn, set a maximum size on our window – to two times our initial size. Test it by trying to resize the window to bigger sizes than that:

if (strcmp(ev->key, "x") == 0) /* impose a maximum size on the window */
{
max_set = !max_set;
if (max_set)
{
ecore_evas_size_max_set(ee, WIDTH * 2, HEIGHT * 2);
printf("Imposing a maximum size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
printf("Taking off maximum size restriction from the"
" window\n");
}
return;
}

Window base sizes will override any minimum sizes set, so try it with the 'b' key. It will set a base size of two times the initial one:

if (strcmp(ev->key, "b") == 0) /* impose a base size on the window */
{
base_set = !base_set;
if (base_set)
{
ecore_evas_size_base_set(ee, WIDTH * 2, HEIGHT * 2);
printf("Imposing a base size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
printf("Taking off base size restriction from the"
" window\n");
}
return;
}

Finally, there's a key to impose a "step size" on our window, of 40 pixels. With than on ('s' key), you'll see the window will always be bound to multiples of that size, for dimensions on both axis:

if (strcmp(ev->key, "s") == 0) /* impose a step size on the window */
{
step_set = !step_set;
if (step_set)
{
printf("Imposing a step size of %d x %d\n", 40, 40);
}
else
{
printf("Taking off step size restriction from the"
" window\n");
}
return;
}

The full example follows.

#ifdef HAVE_CONFIG_H
#include "config.h"
#else
#define EINA_UNUSED
#endif
#include <Ecore.h>
#include <Ecore_Evas.h>
#define WIDTH (300)
#define HEIGHT (300)
static Ecore_Evas *ee;
static Evas_Object *text, *bg;
static Eina_Bool min_set = EINA_FALSE;
static Eina_Bool max_set = EINA_FALSE;
static Eina_Bool base_set = EINA_FALSE;
static Eina_Bool step_set = EINA_FALSE;
static const char commands[] = \
"commands are:\n"
"\tm - impose a minumum size to the window\n"
"\tx - impose a maximum size to the window\n"
"\tb - impose a base size to the window\n"
"\ts - impose a step size (different than 1 px) to the window\n"
"\tg - get the screen geometry\n"
"\th - print help\n";
/* to inform current window's size */
static void
_canvas_resize_cb(Ecore_Evas *ee_)
{
int w, h;
char buf[1024];
ecore_evas_geometry_get(ee_, NULL, NULL, &w, &h);
snprintf(buf, sizeof(buf), "%d x %d", w, h);
evas_object_move(text, (w - 150) / 2, (h - 50) / 2);
evas_object_resize(bg, w, h);
}
static void
_on_destroy(Ecore_Evas *ee_ EINA_UNUSED)
{
}
static void
_on_keydown(void *data EINA_UNUSED,
void *einfo)
{
Evas_Event_Key_Down *ev = einfo;
if (strcmp(ev->key, "h") == 0) /* print help */
{
printf(commands);
return;
}
if (strcmp(ev->key, "m") == 0) /* impose a minimum size on the window */
{
min_set = !min_set;
if (min_set)
{
ecore_evas_size_min_set(ee, WIDTH / 2, HEIGHT / 2);
printf("Imposing a minimum size of %d x %d\n",
WIDTH / 2, HEIGHT / 2);
}
else
{
printf("Taking off minimum size restriction from the"
" window\n");
}
return;
}
if (strcmp(ev->key, "x") == 0) /* impose a maximum size on the window */
{
max_set = !max_set;
if (max_set)
{
ecore_evas_size_max_set(ee, WIDTH * 2, HEIGHT * 2);
printf("Imposing a maximum size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
printf("Taking off maximum size restriction from the"
" window\n");
}
return;
}
if (strcmp(ev->key, "b") == 0) /* impose a base size on the window */
{
base_set = !base_set;
if (base_set)
{
ecore_evas_size_base_set(ee, WIDTH * 2, HEIGHT * 2);
printf("Imposing a base size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
printf("Taking off base size restriction from the"
" window\n");
}
return;
}
if (strcmp(ev->key, "s") == 0) /* impose a step size on the window */
{
step_set = !step_set;
if (step_set)
{
printf("Imposing a step size of %d x %d\n", 40, 40);
}
else
{
printf("Taking off step size restriction from the"
" window\n");
}
return;
}
if (strcmp(ev->key, "g") == 0) /* get screen geometry */
{
int x, y, w, h;
ecore_evas_screen_geometry_get(ee, &x, &y, &w, &h);
printf("screen geometry: %d,%d, %dx%d\n", x, y, w, h);
return;
}
}
int
main(void)
{
Evas *evas;
return EXIT_FAILURE;
/* this will give you a window with an Evas canvas under the first
* engine available */
ee = ecore_evas_new(NULL, 0, 0, WIDTH, HEIGHT, NULL);
if (!ee) goto error;
ecore_evas_title_set(ee, "Ecore_Evas window sizes example");
ecore_evas_callback_resize_set(ee, _canvas_resize_cb);
evas = ecore_evas_get(ee);
evas_object_color_set(bg, 255, 255, 255, 255); /* white bg */
evas_object_move(bg, 0, 0); /* at canvas' origin */
evas_object_resize(bg, WIDTH, HEIGHT); /* covers full canvas */
bg, EVAS_CALLBACK_KEY_DOWN, _on_keydown, NULL);
text = evas_object_text_add(evas);
evas_object_color_set(text, 0, 0, 0, 255);
evas_object_resize(text, 150, 50);
evas_object_text_font_set(text, "Sans", 20);
_canvas_resize_cb(ee);
printf(commands);
return 0;
error:
fprintf(stderr, "error: Requires at least one Evas engine built"
" and linked to ecore-evas for this example to run"
" properly.\n");
return -1;
}
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:1065
ecore_evas_shutdown
EAPI int ecore_evas_shutdown(void)
Shuts down the Ecore_Evas system.
Definition: ecore_evas.c:674
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:1388
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:1166
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:1300
_Evas_Event_Key_Down
Key press event.
Definition: Evas_Legacy.h:314
EINA_UNUSED
#define EINA_UNUSED
Definition: eina_types.h:339
ecore_evas_free
EAPI void ecore_evas_free(Ecore_Evas *ee)
Frees an Ecore_Evas.
Definition: ecore_evas.c:1109
ecore_evas_title_set
EAPI void ecore_evas_title_set(Ecore_Evas *ee, const char *t)
Sets the title of an Ecore_Evas' window.
Definition: ecore_evas.c:1553
ecore_evas_init
EAPI int ecore_evas_init(void)
Inits the Ecore_Evas system.
Definition: ecore_evas.c:606
ecore_evas_size_base_set
EAPI void ecore_evas_size_base_set(Ecore_Evas *ee, int w, int h)
Sets the base size for a given Ecore_Evas window.
Definition: ecore_evas.c:1658
EINA_FALSE
#define EINA_FALSE
Definition: eina_types.h:533
ecore_evas_screen_geometry_get
EAPI void ecore_evas_screen_geometry_get(const Ecore_Evas *ee, int *x, int *y, int *w, int *h)
Gets geometry of screen associated with this Ecore_Evas.
Definition: ecore_evas.c:2764
Evas_Object
Efl_Canvas_Object Evas_Object
Definition: Evas_Common.h:180
ecore_evas_callback_delete_request_set
EAPI void ecore_evas_callback_delete_request_set(Ecore_Evas *ee, Ecore_Evas_Event_Cb func)
Sets a callback for Ecore_Evas delete request events.
Definition: ecore_evas.c:1202
evas_object_resize
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
Ecore_Evas.h
Evas wrapper functions.
evas_object_text_text_set
void evas_object_text_text_set(Eo *obj, const char *text)
Sets the text string to be displayed by the given text object.
Definition: evas_object_text.c:2356
ecore_evas_get
EAPI Evas * ecore_evas_get(const Ecore_Evas *ee)
Gets an Ecore_Evas's Evas.
Definition: ecore_evas.c:1326
evas_object_event_callback_add
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:477
EVAS_CALLBACK_KEY_DOWN
@ EVAS_CALLBACK_KEY_DOWN
Key Press Event.
Definition: Evas_Common.h:419
_Evas_Event_Key_Down::key
const char * key
The logical key : (eg shift+1 == exclamation)
Definition: Evas_Legacy.h:320
ecore_main_loop_begin
void ecore_main_loop_begin(void)
Runs the application main loop.
Definition: ecore_main.c:1290
ecore_evas_size_min_set
EAPI void ecore_evas_size_min_set(Ecore_Evas *ee, int w, int h)
Sets the minimum size of a given Ecore_Evas window.
Definition: ecore_evas.c:1586
evas_object_focus_set
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_show
void evas_object_show(Evas_Object *eo_obj)
Makes the given Evas object visible.
Definition: evas_object_main.c:1814
Evas
Eo Evas
Definition: Evas_Common.h:158
EINA_TRUE
#define EINA_TRUE
Definition: eina_types.h:539
evas_object_text_add
Evas_Object * evas_object_text_add(Evas *e)
Creates a new text object on the provided canvas.
Definition: evas_object_text.c:366
Eina_Bool
unsigned char Eina_Bool
Definition: eina_types.h:527
evas_object_rectangle_add
Evas_Object * evas_object_rectangle_add(Evas *e)
Adds a rectangle to the given evas.
Definition: evas_object_rectangle.c:78
ecore_evas_size_max_set
EAPI void ecore_evas_size_max_set(Ecore_Evas *ee, int w, int h)
Sets the maximum size of a given Ecore_Evas window.
Definition: ecore_evas.c:1622
evas_object_move
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
ecore_evas_size_step_set
EAPI void ecore_evas_size_step_set(Ecore_Evas *ee, int w, int h)
Sets the "size step" for a given Ecore_Evas window.
Definition: ecore_evas.c:1692
ecore_evas_show
EAPI void ecore_evas_show(Ecore_Evas *ee)
Shows an Ecore_Evas' window.
Definition: ecore_evas.c:1506
evas_object_color_set
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_text_font_set
void evas_object_text_font_set(Eo *obj, const char *font, Evas_Font_Size size)
Set the font family or filename, and size on a given text object.
Definition: evas_object_text.c:2340