Evas alignment, minimum size, maximum size, padding and weight hints example

In this code, we place a (vertical) box with two rectangles as child elements.

It has a command line interface with which to act on those rectangles' size hints:

static const char commands[] = \
"commands are:\n"
"\tShift + a - change alignment hints on top rectangle\n"
"\tShift + m - change min. size hint on top rectangle\n"
"\tShift + n - change max. size hint on top rectangle\n"
"\tShift + p - change padding hints on top rectangle\n"
"\tShift + w - change weight hints on top rectangle\n\n"
"\tControl + a - change alignment hints on bottom rectangle\n"
"\tControl + m - change min. size hint on bottom rectangle\n"
"\tControl + n - change max. size hint on bottom rectangle\n"
"\tControl + p - change padding hints on bottom rectangle\n"
"\tControl + w - change weight hints on bottom rectangle\n\n"
"\ts - print current hints information\n"
"\th - print help\n";

That should be self explanatory. Change those values (possibly resizing the box, which will resize together with the example's window) to get how size hints are honored by a container object, which in this case is the Evas box.

More on this smart object can be found on Evas box example. The full code for this example follows.

#ifdef HAVE_CONFIG_H
#include "config.h"
#else
#define PACKAGE_EXAMPLES_DIR "."
#endif
#include <Ecore.h>
#include <Ecore_Evas.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "evas-common.h"
#define WIDTH 320
#define HEIGHT 480
static const char commands[] = \
"commands are:\n"
"\tShift + a - change alignment hints on top rectangle\n"
"\tShift + m - change min. size hint on top rectangle\n"
"\tShift + n - change max. size hint on top rectangle\n"
"\tShift + p - change padding hints on top rectangle\n"
"\tShift + w - change weight hints on top rectangle\n\n"
"\tControl + a - change alignment hints on bottom rectangle\n"
"\tControl + m - change min. size hint on bottom rectangle\n"
"\tControl + n - change max. size hint on bottom rectangle\n"
"\tControl + p - change padding hints on bottom rectangle\n"
"\tControl + w - change weight hints on bottom rectangle\n\n"
"\ts - print current hints information\n"
"\th - print help\n";
static const char *border_img_path = PACKAGE_EXAMPLES_DIR EVAS_IMAGE_FOLDER "/red.png";
struct coord_tuple
{
Evas_Coord w, h;
};
struct weight_tuple
{
double x, y;
};
struct padding_tuple
{
Evas_Coord l, r, t, b;
};
struct rect_data
{
struct coord_tuple *min_ptr;
struct coord_tuple min[4];
struct coord_tuple *max_ptr;
struct coord_tuple max[4];
struct weight_tuple *align_ptr;
struct weight_tuple align[3];
struct weight_tuple *weight_ptr;
struct weight_tuple weight[3];
struct padding_tuple *padding_ptr;
struct padding_tuple padding[3];
};
struct test_data
{
Ecore_Evas *ee;
Evas *canvas;
struct rect_data t_data, b_data;
Evas_Object *bg, *box, *t_rect, *b_rect, *border;
};
static struct test_data d = {0};
/* Keep the example's window size in sync with the background image's size */
static void
_canvas_resize_cb(Ecore_Evas *ee)
{
int w, h;
ecore_evas_geometry_get(ee, NULL, NULL, &w, &h);
evas_object_resize(d.bg, w, h);
evas_object_move(d.box, (w / 4), (h / 4));
evas_object_resize(d.box, (w / 2), (h / 2));
evas_object_move(d.border, (w / 4) - 3, (h / 4) - 3);
evas_object_resize(d.border, (w / 2) + 6, (h / 2) + 6);
}
static void
_print_rect_stats(Evas_Object *rect)
{
Evas_Coord w, h, l, r, t, b;
Eina_Size2D cmin;
double x, y;
evas_object_size_hint_align_get(rect, &x, &y);
printf("\talign hints: h(%f), v(%f)\n",
x, y);
cmin = efl_gfx_hint_size_combined_min_get(rect);
printf("\tmin. size hints: h(%d), v(%d)\n",
cmin.w, cmin.h);
evas_object_size_hint_max_get(rect, &w, &h);
printf("\tmax. size hints: h(%d), v(%d)\n",
w, h);
evas_object_size_hint_padding_get(rect, &l, &r, &t, &b);
printf("\tpadding hints: l(%d), r(%d), t(%d), b(%d)\n",
l, r, t, b);
evas_object_size_hint_weight_get(rect, &x, &y);
printf("\tweight hints: h(%f), v(%f)\n",
x, y);
}
/* use the following commands to interact with this example - 'h' is
* the key for help */
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;
struct rect_data *r_data = NULL;
const Evas_Modifier *mods;
Evas_Object *rect = NULL;
const char *name = NULL;
mods = evas_key_modifier_get(evas);
if (evas_key_modifier_is_set(mods, "Shift"))
{
rect = d.t_rect;
r_data = &d.t_data;
name = "top";
}
else if (evas_key_modifier_is_set(mods, "Control"))
{
rect = d.b_rect;
r_data = &d.b_data;
name = "bottom";
}
else if (strcmp(ev->key, "h") == 0) /* print help */
{
printf(commands);
return;
}
else if (strcmp(ev->key, "s") == 0) /* get aspect status of the
* rectangles WRT size
* hints */
{
printf("Top rectangle:\n");
_print_rect_stats(d.t_rect);
printf("\nBottom rectangle:\n");
_print_rect_stats(d.b_rect);
return;
}
if (!rect) return;
if (strcmp(ev->key, "a") == 0) /* alignment hints */
{
(r_data->align_ptr)++;
if ((unsigned int)
(((unsigned char *)(r_data->align_ptr)) - ((unsigned char *)(r_data->align))) >=
sizeof(r_data->align))
r_data->align_ptr = r_data->align;
evas_object_size_hint_align_set(
rect, r_data->align_ptr->x, r_data->align_ptr->y);
printf("Changing align hints for %s rect. to (%f, %f)\n",
name, r_data->align_ptr->x, r_data->align_ptr->y);
return;
}
if (strcmp(ev->key, "m") == 0) /* min. size hints */
{
(r_data->min_ptr)++;
if ((unsigned int)
(((unsigned char *)(r_data->min_ptr)) - ((unsigned char *)(r_data->min))) >=
sizeof(r_data->min))
r_data->min_ptr = r_data->min;
evas_object_size_hint_min_set(
rect, r_data->min_ptr->w, r_data->min_ptr->h);
printf("Changing min. size hints for %s rect. to (%d, %d)\n",
name, r_data->min_ptr->w, r_data->min_ptr->h);
return;
}
if (strcmp(ev->key, "n") == 0) /* max. size hints */
{
(r_data->max_ptr)++;
if ((unsigned int)
(((unsigned char *)(r_data->max_ptr)) - ((unsigned char *)(r_data->max))) >=
sizeof(r_data->max))
r_data->max_ptr = r_data->max;
evas_object_size_hint_max_set(
rect, r_data->max_ptr->w, r_data->max_ptr->h);
printf("Changing max. size hints for %s rect. to (%d, %d)\n",
name, r_data->max_ptr->w, r_data->max_ptr->h);
return;
}
if (strcmp(ev->key, "p") == 0) /* padding size hints */
{
(r_data->padding_ptr)++;
if ((unsigned int)
(((unsigned char *)(r_data->padding_ptr)) - ((unsigned char *)(r_data->padding))) >=
sizeof(r_data->padding))
r_data->padding_ptr = r_data->padding;
evas_object_size_hint_padding_set(
rect, r_data->padding_ptr->l, r_data->padding_ptr->r,
r_data->padding_ptr->t, r_data->padding_ptr->b);
printf("Changing padding size hints for %s rect. to (%d, %d, %d, %d)\n",
name, r_data->padding_ptr->l, r_data->padding_ptr->r,
r_data->padding_ptr->t, r_data->padding_ptr->b);
return;
}
/* experiment with weights here. keep in mind that, for the box
* object, only if all the children have non zero weights this hint
* will have an effect */
if (strcmp(ev->key, "w") == 0) /* weight hints */
{
(r_data->weight_ptr)++;
if ((unsigned int)
(((unsigned char *)(r_data->weight_ptr)) - ((unsigned char *)(r_data->weight))) >=
sizeof(r_data->weight))
r_data->weight_ptr = r_data->weight;
evas_object_size_hint_weight_set(
rect, r_data->weight_ptr->x, r_data->weight_ptr->y);
printf("Changing weight hints for %s rect. to (%f, %f)\n",
name, r_data->weight_ptr->x, r_data->weight_ptr->y);
return;
}
}
static void
_on_destroy(Ecore_Evas *ee EINA_UNUSED)
{
ecore_main_loop_quit();
}
int
main(void)
{
if (!ecore_evas_init())
return EXIT_FAILURE;
/* init values one is going to cycle through while running this
* example */
struct rect_data init_data = \
{
.min = {{0, 0}, {30, 30}, {100, 70}, {200, 200}},
.max = {{0, 0}, {100, 100}, {100, 70}, {300, 300}},
.align = {{0.0, 0.0}, {0.5, 0.5}, {1.0, 0.5}},
.weight = {{0.0, 0.0}, {3, 6}, {10, 100}},
.padding = {{0, 0, 0, 0}, {3, 6, 9, 12}, {10, 20, 0, 30}}
};
d.t_data = init_data;
d.t_data.min_ptr = d.t_data.min + 1;
d.t_data.max_ptr = d.t_data.max + 1;
d.t_data.align_ptr = d.t_data.align;
d.t_data.weight_ptr = d.t_data.weight;
d.t_data.padding_ptr = d.t_data.padding;
d.b_data = init_data;
d.b_data.min_ptr = d.b_data.min + 1;
d.b_data.max_ptr = d.b_data.max + 1;
d.b_data.align_ptr = d.b_data.align;
d.b_data.weight_ptr = d.b_data.weight;
d.b_data.padding_ptr = d.b_data.padding;
/* this will give you a window with an Evas canvas under the first
* engine available */
d.ee = ecore_evas_new(NULL, 0, 0, WIDTH, HEIGHT, NULL);
if (!d.ee)
goto error;
ecore_evas_callback_destroy_set(d.ee, _on_destroy);
ecore_evas_callback_resize_set(d.ee, _canvas_resize_cb);
ecore_evas_show(d.ee);
/* the canvas pointer, de facto */
d.canvas = ecore_evas_get(d.ee);
d.bg = evas_object_rectangle_add(d.canvas);
evas_object_color_set(d.bg, 255, 255, 255, 255); /* white bg */
evas_object_move(d.bg, 0, 0); /* at canvas' origin */
evas_object_resize(d.bg, WIDTH, HEIGHT); /* covers full canvas */
evas_object_show(d.bg);
evas_object_focus_set(d.bg, EINA_TRUE);
evas_object_event_callback_add(
d.bg, EVAS_CALLBACK_KEY_DOWN, _on_keydown, NULL);
/* Evas box with vertical layout */
d.box = evas_object_box_add(d.canvas);
evas_object_box_layout_set(
d.box, evas_object_box_layout_vertical, NULL, NULL);
evas_object_show(d.box);
/* this is a border around the box, container of the rectangles we
* are going to experiment with (changing some size hints). this
* way you can see how the container relates to the children */
d.border = evas_object_image_filled_add(d.canvas);
evas_object_image_file_set(d.border, border_img_path, NULL);
evas_object_image_border_set(d.border, 3, 3, 3, 3);
evas_object_image_border_center_fill_set(d.border, EVAS_BORDER_FILL_NONE);
evas_object_show(d.border);
d.t_rect = evas_object_rectangle_add(d.canvas);
evas_object_color_set(d.t_rect, 0, 0, 255, 255);
evas_object_size_hint_min_set(
d.t_rect, d.t_data.min_ptr->w, d.t_data.min_ptr->h);
evas_object_show(d.t_rect);
evas_object_box_append(d.box, d.t_rect);
d.b_rect = evas_object_rectangle_add(d.canvas);
evas_object_color_set(d.b_rect, 0, 255, 0, 255);
evas_object_size_hint_min_set(
d.b_rect, d.b_data.min_ptr->w, d.b_data.min_ptr->h);
evas_object_show(d.b_rect);
evas_object_box_append(d.box, d.b_rect);
_canvas_resize_cb(d.ee);
printf(commands);
ecore_main_loop_begin();
ecore_evas_shutdown();
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.h
Evas wrapper functions.
Evas_Coord
int Evas_Coord
Type used for coordinates (in pixels, int).
Definition Evas_Common.h:116
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:608
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:1199
ecore_evas_show
EAPI void ecore_evas_show(Ecore_Evas *ee)
Shows an Ecore_Evas' window.
Definition ecore_evas.c:1494
ecore_evas_get
EAPI Evas * ecore_evas_get(const Ecore_Evas *ee)
Gets an Ecore_Evas's Evas.
Definition ecore_evas.c:1314
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:1376
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:1053
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:1154
ecore_evas_shutdown
EAPI int ecore_evas_shutdown(void)
Shuts down the Ecore_Evas system.
Definition ecore_evas.c:672
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
Eina_Size2D
struct _Eina_Size2D Eina_Size2D
A 2D size in pixel coordinates.
EINA_TRUE
#define EINA_TRUE
boolean value TRUE (numerical value 1)
Definition eina_types.h:539
EINA_UNUSED
#define EINA_UNUSED
Used to indicate that a function parameter is purposely unused.
Definition eina_types.h:339
Evas_Event_Key_Down
struct _Evas_Event_Key_Down Evas_Event_Key_Down
Event structure for EVAS_CALLBACK_KEY_DOWN event callbacks.
Definition Evas_Legacy.h:154
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
Eo Evas
An opaque handle to an Evas canvas.
Definition Evas_Common.h:163
Evas_Modifier
struct _Evas_Modifier Evas_Modifier
An opaque type containing information on which modifier keys are registered in an Evas canvas.
Definition Evas_Internal.h:36
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_box_add
EVAS_API Evas_Object * evas_object_box_add(Evas *evas)
Add a new box object on the provided canvas.
Definition evas_object_box.c:481
evas_object_box_layout_vertical
EVAS_API void evas_object_box_layout_vertical(Evas_Box *obj, Evas_Object_Box_Data *priv, void *data)
Layout function which sets the box o to a (basic) vertical box.
Definition evas_box_eo.legacy.c:39
evas_object_box_append
EVAS_API Evas_Object_Box_Option * evas_object_box_append(Evas_Box *obj, Efl_Canvas_Object *child)
Append a new child object to the given box object o.
Definition evas_box_eo.legacy.c:81
evas_object_box_layout_set
EVAS_API void evas_object_box_layout_set(Evas_Box *obj, Evas_Object_Box_Layout cb, const void *data, Eina_Free_Cb free_data)
Set a new layouting function to a given box object.
Definition evas_box_eo.legacy.c:27
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_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_size_hint_padding_set
EVAS_API void evas_object_size_hint_padding_set(Evas_Object *obj, Evas_Coord l, Evas_Coord r, Evas_Coord t, Evas_Coord b)
Sets the hints for an object's padding space.
Definition evas_object_main.c:2626
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_size_hint_align_get
EVAS_API void evas_object_size_hint_align_get(const Evas_Object *obj, double *x, double *y)
Retrieves the hints for on object's alignment.
Definition evas_object_main.c:2656
evas_object_size_hint_padding_get
EVAS_API void evas_object_size_hint_padding_get(const Evas_Object *obj, Evas_Coord *l, Evas_Coord *r, Evas_Coord *t, Evas_Coord *b)
Retrieves the hints for an object's padding space.
Definition evas_object_main.c:2632
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
evas_object_size_hint_max_set
EVAS_API void evas_object_size_hint_max_set(Evas_Object *obj, Evas_Coord w, Evas_Coord h)
Sets the hints for an object's maximum size.
Definition evas_object_main.c:2596
evas_object_size_hint_align_set
EVAS_API void evas_object_size_hint_align_set(Evas_Object *obj, double x, double y)
Sets the hints for an object's alignment.
Definition evas_object_main.c:2650
Evas_Object
Efl_Canvas_Object Evas_Object
An Evas Object handle.
Definition Evas_Common.h:185
evas_object_size_hint_weight_get
EVAS_API void evas_object_size_hint_weight_get(const Evas_Object *obj, double *x, double *y)
Retrieves the hints for an object's weight.
Definition evas_object_main.c:2644
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_max_get
EVAS_API void evas_object_size_hint_max_get(const Evas_Object *obj, Evas_Coord *w, Evas_Coord *h)
Retrieves the hints for an object's maximum size.
Definition evas_object_main.c:2602
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_image_border_set
EVAS_API void evas_object_image_border_set(Evas_Object *obj, int l, int r, int t, int b)
Dimensions of this image's border, a region that does not scale with the center area.
Definition evas_image_legacy.c:117
evas_object_image_border_center_fill_set
EVAS_API void evas_object_image_border_center_fill_set(Evas_Object *obj, Evas_Border_Fill_Mode fill)
Specifies how the center part of the object (not the borders) should be drawn when EFL is rendering i...
Definition evas_image_legacy.c:145
evas_object_image_file_set
EVAS_API void evas_object_image_file_set(Evas_Object *obj, const char *file, const char *key)
Set the source file from where an image object must fetch the real image data (it may be an Eet file,...
Definition evas_image_legacy.c:194
evas_object_image_filled_add
EVAS_API Evas_Object * evas_object_image_filled_add(Evas *eo_e)
Creates a new image object that automatically scales its bound image to the object's area,...
Definition evas_image_legacy.c:35
EVAS_BORDER_FILL_NONE
@ EVAS_BORDER_FILL_NONE
Image's center region is not to be rendered.
Definition Evas_Legacy.h:5721
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
const char * key
The logical key : (eg shift+1 == exclamation).
Definition Evas_Legacy.h:320