Evas text object example

In this example, we illustrate how to use text objects in various manners.

We place, in the canvas, a text object along with a border image to delimit its geometry. After we instantiate the text object, we set lots of properties on it to the initial ones from a preset list, which has the following declaration:

/* init values one is going to cycle through while running this
* example */
struct text_preset_data init_data =
{
.font = {"DejaVu", "Courier", "Utopia"},
.text = {BLACK, WHITE, GREY, RED, GREEN, BLUE},
.shadow = {WHITE, BLUE, GREEN, RED},
.outline = {WHITE, RED, GREEN, BLUE},
.glow = {WHITE, BLUE, GREEN, RED},
.glow2 = {WHITE, RED, BLUE, GREEN}
};

Then, we set the text string itself, on it, with evas_object_text_text_set(). We set an explicit size of 30 points for our font, as you could see, what we check back with the getter evas_object_text_font_get().

Look at how it translates to code:

d.text = evas_object_text_add(d.evas);
evas_object_text_style_set(d.text, EVAS_TEXT_STYLE_PLAIN);
/* let the pre-set things be enforced */
d.text, d.t_data.text_ptr->r, d.t_data.text_ptr->g,
d.t_data.text_ptr->b, d.t_data.text_ptr->a);
evas_object_text_glow_color_set(
d.text, d.t_data.glow_ptr->r, d.t_data.glow_ptr->g,
d.t_data.glow_ptr->b, d.t_data.glow_ptr->a);
evas_object_text_glow2_color_set(
d.text, d.t_data.glow2_ptr->r, d.t_data.glow2_ptr->g,
d.t_data.glow2_ptr->b, d.t_data.glow2_ptr->a);
evas_object_text_outline_color_set(
d.text, d.t_data.outline_ptr->r, d.t_data.outline_ptr->g,
d.t_data.outline_ptr->b, d.t_data.outline_ptr->a);
evas_object_text_shadow_color_set(
d.text, d.t_data.shadow_ptr->r, d.t_data.shadow_ptr->g,
d.t_data.shadow_ptr->b, d.t_data.shadow_ptr->a);
evas_object_text_font_set(d.text, *d.t_data.font_ptr, 30);
evas_object_text_text_set(d.text, "sample text");
evas_object_resize(d.text, (3 * WIDTH) / 4, HEIGHT / 4);
evas_object_move(d.text, WIDTH / 8, (3 * HEIGHT) / 8);
evas_object_text_font_get(d.text, &font, &size);
printf("Adding text object with font %s, size %d\n", font, size);
/* this is a border around the text object above, here just to
* emphasize its geometry */
d.border = evas_object_image_filled_add(d.evas);
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_resize(d.border, ((3 * WIDTH) / 4) + 3, (HEIGHT / 4) + 3);
evas_object_move(d.border, (WIDTH / 8) - 3, ((3 * HEIGHT) / 8) - 3);
evas_object_show(d.border);
printf("%s", commands);
return 0;
error:
fprintf(stderr, "error: Requires at least one Evas engine built and linked"

Like in other Evas examples, one interacts with it by means of key commands:

static const char *commands = \
"commands are:\n"
"\tt - change text's current style\n"
"\tz - change text's font size\n"
"\tf - change text's font family\n"
"\tb - change text's base color\n"
"\ts - change text's \'shadow\' color\n"
"\to - change text's \'outline\' color\n"
"\tw - change text's \'glow\' color\n"
"\tg - change text's \'glow 2\' color\n"
"\th - print help\n";

Use the 't' key to exercise the evas_object_text_style_set() function on the text – it will cycle through all styles on #Evas_Text_Style_Type (note we start on #EVAS_TEXT_STYLE_PLAIN, thus with no effects on it) and, with other keys, you'll be able to set properties applicable to individual styles on the text object.

The 'z' key will change the text's size, keeping the font family for it. Use 'f' to change the font, keeping the last size set. There are three font families the example will cycle through:

The 'b' command shows us that evas_object_color_set(), on a given text object, will change the text's base color. Experiment with it, which will cycle through the colors in the .text list in init_data.

The 's', 'o', 'w' and 'g' keys will make the text object to cycle to the preset values on colors for shadow, outline, glow and 'glow 2' effects, respectively. Naturally, they will only take effect on the text styles which resemble them.

The full example follows.

#ifdef HAVE_CONFIG_H
#include "config.h"
#else
#define PACKAGE_EXAMPLES_DIR "."
#endif
#include <Ecore.h>
#include <Ecore_Evas.h>
#include <stdio.h>
#include <errno.h>
#define WIDTH (320)
#define HEIGHT (240)
#define GREY {190, 190, 190, 255}
#define BLACK {0, 0, 0, 255}
#define WHITE {255, 255, 255, 255}
#define RED {255, 0, 0, 255}
#define GREEN {0, 255, 0, 255}
#define BLUE {0, 0, 255, 255}
#define POINTER_CYCLE(_ptr, _array) \
do \
{ \
if ((unsigned int)(((unsigned char *)(_ptr)) - ((unsigned char *)(_array))) >= \
sizeof(_array)) \
_ptr = _array; \
} \
while(0)
static const char *commands = \
"commands are:\n"
"\tt - change text's current style\n"
"\tz - change text's font size\n"
"\tf - change text's font family\n"
"\tb - change text's base color\n"
"\ts - change text's \'shadow\' color\n"
"\to - change text's \'outline\' color\n"
"\tw - change text's \'glow\' color\n"
"\tg - change text's \'glow 2\' color\n"
"\th - print help\n";
static const char *border_img_path = PACKAGE_EXAMPLES_DIR "/red.png";
struct color_tuple
{
int r, g, b, a;
};
struct text_preset_data
{
const char **font_ptr;
const char *font[3];
struct color_tuple *text_ptr;
struct color_tuple text[6];
struct color_tuple *shadow_ptr;
struct color_tuple shadow[4];
struct color_tuple *outline_ptr;
struct color_tuple outline[4];
struct color_tuple *glow_ptr;
struct color_tuple glow[4];
struct color_tuple *glow2_ptr;
struct color_tuple glow2[4];
};
struct test_data
{
Ecore_Evas *ee;
Evas *evas;
struct text_preset_data t_data;
Evas_Object *text, *bg, *border;
};
static struct test_data d = {0};
static void
_on_destroy(Ecore_Evas *ee EINA_UNUSED)
{
}
/* 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);
}
static const char *
_text_style_type_to_str(Evas_Text_Style_Type mode)
{
switch (mode)
{
case EVAS_TEXT_STYLE_PLAIN:
return "plain";
case EVAS_TEXT_STYLE_SHADOW:
return "shadow";
case EVAS_TEXT_STYLE_OUTLINE:
return "outline";
case EVAS_TEXT_STYLE_SOFT_OUTLINE:
return "soft outline";
case EVAS_TEXT_STYLE_GLOW:
return "glow";
case EVAS_TEXT_STYLE_OUTLINE_SHADOW:
return "outline shadow";
case EVAS_TEXT_STYLE_FAR_SHADOW:
return "far shadow";
case EVAS_TEXT_STYLE_OUTLINE_SOFT_SHADOW:
return "outline soft shadow";
case EVAS_TEXT_STYLE_SOFT_SHADOW:
return "soft shadow";
case EVAS_TEXT_STYLE_FAR_SOFT_SHADOW:
return "far soft shadow";
default:
return "invalid";
}
}
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("%s", commands);
return;
}
if (strcmp(ev->key, "t") == 0) /* change text's current style */
{
Evas_Text_Style_Type type = evas_object_text_style_get(d.text);
type = (type + 1) % 10;
evas_object_text_style_set(d.text, type);
printf("Changing text's style to \'%s\'\n",
_text_style_type_to_str(type));
return;
}
if (strcmp(ev->key, "f") == 0) /* change text's font */
{
int sz;
(d.t_data.font_ptr)++;
evas_object_text_font_get(d.text, NULL, &sz);
POINTER_CYCLE(d.t_data.font_ptr, d.t_data.font);
evas_object_text_font_set(d.text, *d.t_data.font_ptr, sz);
printf("Changing text's font to %s\n",
*d.t_data.font_ptr);
return;
}
if (strcmp(ev->key, "b") == 0) /* change text's base color */
{
(d.t_data.text_ptr)++;
POINTER_CYCLE(d.t_data.text_ptr, d.t_data.text);
d.text, d.t_data.text_ptr->r, d.t_data.text_ptr->g,
d.t_data.text_ptr->b, d.t_data.text_ptr->a);
printf("Changing base color for text to (%d, %d, %d, %d)\n",
d.t_data.text_ptr->r, d.t_data.text_ptr->g,
d.t_data.text_ptr->b, d.t_data.text_ptr->a);
return;
}
if (strcmp(ev->key, "g") == 0) /* change text's glow 2 color */
{
(d.t_data.glow2_ptr)++;
POINTER_CYCLE(d.t_data.glow2_ptr, d.t_data.glow2);
evas_object_text_glow2_color_set(
d.text, d.t_data.glow2_ptr->r, d.t_data.glow2_ptr->g,
d.t_data.glow2_ptr->b, d.t_data.glow2_ptr->a);
printf("Changing glow 2 color for text to (%d, %d, %d, %d)\n",
d.t_data.glow2_ptr->r, d.t_data.glow2_ptr->g,
d.t_data.glow2_ptr->b, d.t_data.glow2_ptr->a);
return;
}
if (strcmp(ev->key, "w") == 0) /* change text's glow color */
{
(d.t_data.glow_ptr)++;
POINTER_CYCLE(d.t_data.glow_ptr, d.t_data.glow);
evas_object_text_glow_color_set(
d.text, d.t_data.glow_ptr->r, d.t_data.glow_ptr->g,
d.t_data.glow_ptr->b, d.t_data.glow_ptr->a);
printf("Changing glow color for text to (%d, %d, %d, %d)\n",
d.t_data.glow_ptr->r, d.t_data.glow_ptr->g,
d.t_data.glow_ptr->b, d.t_data.glow_ptr->a);
return;
}
if (strcmp(ev->key, "o") == 0) /* change text's outline color */
{
(d.t_data.outline_ptr)++;
POINTER_CYCLE(d.t_data.outline_ptr, d.t_data.outline);
evas_object_text_outline_color_set(
d.text, d.t_data.outline_ptr->r, d.t_data.outline_ptr->g,
d.t_data.outline_ptr->b, d.t_data.outline_ptr->a);
printf("Changing outline color for text to (%d, %d, %d, %d)\n",
d.t_data.outline_ptr->r, d.t_data.outline_ptr->g,
d.t_data.outline_ptr->b, d.t_data.outline_ptr->a);
return;
}
if (strcmp(ev->key, "s") == 0) /* change text's shadow color */
{
(d.t_data.shadow_ptr)++;
POINTER_CYCLE(d.t_data.shadow_ptr, d.t_data.shadow);
evas_object_text_shadow_color_set(
d.text, d.t_data.shadow_ptr->r, d.t_data.shadow_ptr->g,
d.t_data.shadow_ptr->b, d.t_data.shadow_ptr->a);
printf("Changing shadow color for text to (%d, %d, %d, %d)\n",
d.t_data.shadow_ptr->r, d.t_data.shadow_ptr->g,
d.t_data.shadow_ptr->b, d.t_data.shadow_ptr->a);
return;
}
if (strcmp(ev->key, "z") == 0) /* change text's font size */
{
const char *font;
int size;
evas_object_text_font_get(d.text, &font, &size);
size = (size + 10) % 50;
if (!size) size = 10;
evas_object_text_font_set(d.text, font, size);
printf("Changing text's font size to %d\n", size);
return;
}
}
int
main(void)
{
int size;
const char *font;
return EXIT_FAILURE;
/* init values one is going to cycle through while running this
* example */
struct text_preset_data init_data =
{
.font = {"DejaVu", "Courier", "Utopia"},
.text = {BLACK, WHITE, GREY, RED, GREEN, BLUE},
.shadow = {WHITE, BLUE, GREEN, RED},
.outline = {WHITE, RED, GREEN, BLUE},
.glow = {WHITE, BLUE, GREEN, RED},
.glow2 = {WHITE, RED, BLUE, GREEN}
};
d.t_data = init_data;
d.t_data.font_ptr = d.t_data.font;
d.t_data.text_ptr = d.t_data.text;
d.t_data.glow_ptr = d.t_data.glow;
d.t_data.glow2_ptr = d.t_data.glow2;
d.t_data.outline_ptr = d.t_data.outline;
d.t_data.shadow_ptr = d.t_data.shadow;
/* this will give you a window with an Evas canvas under the first
* engine available */
d.ee = ecore_evas_new(NULL, 10, 10, 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);
/* the canvas pointer, de facto */
d.evas = ecore_evas_get(d.ee);
d.bg = evas_object_rectangle_add(d.evas);
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 */
d.bg, EVAS_CALLBACK_KEY_DOWN, _on_keydown, NULL);
d.text = evas_object_text_add(d.evas);
evas_object_text_style_set(d.text, EVAS_TEXT_STYLE_PLAIN);
/* let the pre-set things be enforced */
d.text, d.t_data.text_ptr->r, d.t_data.text_ptr->g,
d.t_data.text_ptr->b, d.t_data.text_ptr->a);
evas_object_text_glow_color_set(
d.text, d.t_data.glow_ptr->r, d.t_data.glow_ptr->g,
d.t_data.glow_ptr->b, d.t_data.glow_ptr->a);
evas_object_text_glow2_color_set(
d.text, d.t_data.glow2_ptr->r, d.t_data.glow2_ptr->g,
d.t_data.glow2_ptr->b, d.t_data.glow2_ptr->a);
evas_object_text_outline_color_set(
d.text, d.t_data.outline_ptr->r, d.t_data.outline_ptr->g,
d.t_data.outline_ptr->b, d.t_data.outline_ptr->a);
evas_object_text_shadow_color_set(
d.text, d.t_data.shadow_ptr->r, d.t_data.shadow_ptr->g,
d.t_data.shadow_ptr->b, d.t_data.shadow_ptr->a);
evas_object_text_font_set(d.text, *d.t_data.font_ptr, 30);
evas_object_text_text_set(d.text, "sample text");
evas_object_resize(d.text, (3 * WIDTH) / 4, HEIGHT / 4);
evas_object_move(d.text, WIDTH / 8, (3 * HEIGHT) / 8);
evas_object_text_font_get(d.text, &font, &size);
printf("Adding text object with font %s, size %d\n", font, size);
/* this is a border around the text object above, here just to
* emphasize its geometry */
d.border = evas_object_image_filled_add(d.evas);
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_resize(d.border, ((3 * WIDTH) / 4) + 3, (HEIGHT / 4) + 3);
evas_object_move(d.border, (WIDTH / 8) - 3, ((3 * HEIGHT) / 8) - 3);
evas_object_show(d.border);
printf("%s", 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:1059
ecore_evas_shutdown
EAPI int ecore_evas_shutdown(void)
Shuts down the Ecore_Evas system.
Definition: ecore_evas.c:668
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:1382
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:1160
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:1289
_Evas_Event_Key_Down
Key press event.
Definition: Evas_Legacy.h:313
EINA_UNUSED
#define EINA_UNUSED
Definition: eina_types.h:321
ecore_evas_free
EAPI void ecore_evas_free(Ecore_Evas *ee)
Frees an Ecore_Evas.
Definition: ecore_evas.c:1103
ecore_evas_init
EAPI int ecore_evas_init(void)
Inits the Ecore_Evas system.
Definition: ecore_evas.c:604
Evas_Object
Efl_Canvas_Object Evas_Object
Definition: Evas_Common.h:180
Ecore_Evas.h
Evas wrapper functions.
ecore_evas_get
EAPI Evas * ecore_evas_get(const Ecore_Evas *ee)
Gets an Ecore_Evas's Evas.
Definition: ecore_evas.c:1320
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:489
EVAS_CALLBACK_KEY_DOWN
Key Press Event.
Definition: Evas_Common.h:414
_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:1279
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:1853
Evas
Eo Evas
Definition: Evas_Common.h:158
EINA_TRUE
#define EINA_TRUE
Definition: eina_types.h:508
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
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_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:1205
ecore_evas_show
EAPI void ecore_evas_show(Ecore_Evas *ee)
Shows an Ecore_Evas' window.
Definition: ecore_evas.c:1500
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:2063