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)
if (!ecore_evas_init())
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_callback_delete_request_set(ee, _on_destroy);
ecore_evas_title_set(ee, "Ecore_Evas window sizes example");
ecore_evas_callback_resize_set(ee, _canvas_resize_cb);
ecore_evas_show(ee);
evas = ecore_evas_get(ee);
bg = evas_object_rectangle_add(evas);
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 */
evas_object_show(bg);
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);
evas_object_show(text);
_canvas_resize_cb(ee);
fprintf(stdout, commands);
ecore_main_loop_begin();
/* 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_text_text_set(text, buf);
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);
fprintf(stdout, "Imposing a minimum size of %d x %d\n",
WIDTH / 2, HEIGHT / 2);
}
else
{
ecore_evas_size_min_set(ee, 0, 0);
fprintf(stdout, "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);
fprintf(stdout, "Imposing a maximum size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
ecore_evas_size_max_set(ee, 0, 0);
fprintf(stdout, "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);
fprintf(stdout, "Imposing a base size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
ecore_evas_size_base_set(ee, 0, 0);
fprintf(stdout, "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)
{
ecore_evas_size_step_set(ee, 40, 40);
fprintf(stdout, "Imposing a step size of %d x %d\n", 40, 40);
}
else
{
ecore_evas_size_step_set(ee, 0, 0);
fprintf(stdout, "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_text_text_set(text, buf);
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)
{
ecore_main_loop_quit();
}
static void
_on_keydown(void *data EINA_UNUSED,
Evas *evas EINA_UNUSED,
Evas_Object *o EINA_UNUSED,
void *einfo)
{
Evas_Event_Key_Down *ev = einfo;
if (strcmp(ev->key, "h") == 0) /* print help */
{
fprintf(stdout, 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);
fprintf(stdout, "Imposing a minimum size of %d x %d\n",
WIDTH / 2, HEIGHT / 2);
}
else
{
ecore_evas_size_min_set(ee, 0, 0);
fprintf(stdout, "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);
fprintf(stdout, "Imposing a maximum size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
ecore_evas_size_max_set(ee, 0, 0);
fprintf(stdout, "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);
fprintf(stdout, "Imposing a base size of %d x %d\n",
WIDTH * 2, HEIGHT * 2);
}
else
{
ecore_evas_size_base_set(ee, 0, 0);
fprintf(stdout, "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)
{
ecore_evas_size_step_set(ee, 40, 40);
fprintf(stdout, "Imposing a step size of %d x %d\n", 40, 40);
}
else
{
ecore_evas_size_step_set(ee, 0, 0);
fprintf(stdout, "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);
fprintf(stdout, "screen geometry: %d,%d, %dx%d\n", x, y, w, h);
return;
}
}
int
main(void)
{
Evas *evas;
if (!ecore_evas_init())
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_callback_delete_request_set(ee, _on_destroy);
ecore_evas_title_set(ee, "Ecore_Evas window sizes example");
ecore_evas_callback_resize_set(ee, _canvas_resize_cb);
ecore_evas_show(ee);
evas = ecore_evas_get(ee);
bg = evas_object_rectangle_add(evas);
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 */
evas_object_show(bg);
evas_object_focus_set(bg, EINA_TRUE);
evas_object_event_callback_add(
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);
evas_object_show(text);
_canvas_resize_cb(ee);
fprintf(stdout, commands);
ecore_main_loop_begin();
ecore_evas_free(ee);
ecore_evas_shutdown();
return 0;
error:
fprintf(stderr, "You got to have at least one Evas engine built"
" and linked up to ecore-evas for this example to run"
" properly.\n");
ecore_evas_shutdown();
return -1;
}