Color selector example

This example shows how to change the color of a rectangle using a color selector. We aren't going to explain a lot of the code since it's the usual setup code:

//Compile with:
//gcc -g colorselector_example_01.c -o colorselector_example_01 `pkg-config --cflags --libs elementary`
#include <Elementary.h>
static void _change_color(void *data, Evas_Object *obj, void *event_info);
static void _colorpalette_clicked_cb(void *data, Evas_Object *obj, void *event_info);
static void _colorpalette_longpressed_cb(void *data, Evas_Object *obj, void *event_info);
EAPI_MAIN int
elm_main(int argc EINA_UNUSED, char **argv EINA_UNUSED)
{
Evas_Object *win, *cs, *rect, *bx, *fr;
elm_policy_set(ELM_POLICY_QUIT, ELM_POLICY_QUIT_LAST_WINDOW_CLOSED);
win = elm_win_util_standard_add("color selector", "Color selector");
elm_win_autodel_set(win, EINA_TRUE);
bx = elm_box_add(win);
evas_object_size_hint_weight_set(bx, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
elm_win_resize_object_add(win, bx);
evas_object_show(bx);
fr = elm_frame_add(win);
evas_object_size_hint_weight_set(fr, 1.0, 0.5);
evas_object_size_hint_align_set(fr, EVAS_HINT_FILL, EVAS_HINT_FILL);
elm_object_text_set(fr, "Color View");
elm_box_pack_end(bx, fr);
evas_object_show(fr);
rect = evas_object_rectangle_add(evas_object_evas_get(win));
elm_object_content_set(fr, rect);
evas_object_color_set(rect, 255, 90, 18, 255);
evas_object_show(rect);
EVAS_HINT_EXPAND
#define EVAS_HINT_EXPAND
Use with evas_object_size_hint_weight_set(), evas_object_size_hint_weight_get(), evas_object_size_hin...
Definition Evas_Common.h:297
EVAS_HINT_FILL
#define EVAS_HINT_FILL
Use with evas_object_size_hint_align_set(), evas_object_size_hint_align_get(), evas_object_size_hint_...
Definition Evas_Common.h:298
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
elm_box_add
Evas_Object * elm_box_add(Evas_Object *parent)
Add a new box to the parent.
Definition elm_box.c:363
elm_box_pack_end
void elm_box_pack_end(Elm_Box *obj, Efl_Canvas_Object *subobj)
Add an object at the end of the pack list.
Definition elm_box_eo.legacy.c:57
elm_frame_add
Evas_Object * elm_frame_add(Evas_Object *parent)
Add a new frame to the parent.
Definition efl_ui_frame.c:274
elm_policy_set
Eina_Bool elm_policy_set(unsigned int policy, int value)
Set a new policy's value (for a given policy group/identifier).
Definition elm_main.c:1380
ELM_POLICY_QUIT_LAST_WINDOW_CLOSED
@ ELM_POLICY_QUIT_LAST_WINDOW_CLOSED
quit when the application's last window is closed
Definition elm_general.h:248
ELM_POLICY_QUIT
@ ELM_POLICY_QUIT
under which circumstances the application should quit automatically.
Definition elm_general.h:227
elm_win_util_standard_add
Evas_Object * elm_win_util_standard_add(const char *name, const char *title)
Adds a window object with standard setup.
Definition efl_ui_win.c:9587
elm_win_resize_object_add
void elm_win_resize_object_add(Eo *obj, Evas_Object *subobj)
Add subobj as a resize object of window obj.
Definition efl_ui_win.c:9002
elm_win_autodel_set
void elm_win_autodel_set(Eo *obj, Eina_Bool autodel)
Set the window's autodel state.
Definition efl_ui_win.c:6199
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_evas_get
EVAS_API Evas * evas_object_evas_get(const Eo *eo_obj)
Get the Evas to which this object belongs to.
Definition evas_object_main.c:2662
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_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_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

Now that we have a window with background and a rectangle we can create our color_selector

fr = elm_frame_add(win);
evas_object_size_hint_weight_set(fr, 1.0, 0.5);
evas_object_size_hint_align_set(fr, EVAS_HINT_FILL, EVAS_HINT_FILL);
elm_object_text_set(fr, "Color Selector");
elm_box_pack_end(bx, fr);
evas_object_show(fr);
cs = elm_colorselector_add(win);
elm_colorselector_add
Evas_Object * elm_colorselector_add(Evas_Object *parent)
Add a new colorselector to the parent.
Definition elm_colorselector.c:2263

Now colors can be loaded to color selector's palette by setting the palette name

elm_colorselector_palette_name_set(cs, "painting");
evas_object_size_hint_weight_set(cs, EVAS_HINT_EXPAND, 0.0);
evas_object_size_hint_align_set(cs, EVAS_HINT_FILL, 0.0);
elm_colorselector_color_set(cs, 255, 90, 18, 255);
evas_object_show(cs);

Next we ask to be notified whenever the color changes on selector:

evas_object_smart_callback_add(cs, "changed", _change_color, rect);
evas_object_smart_callback_add
EVAS_API void evas_object_smart_callback_add(Evas_Object *eo_obj, const char *event, Evas_Smart_Cb func, const void *data)
Add (register) a callback function to the smart event specified by event on the smart object obj.
Definition evas_object_smart.c:1040

Next we ask to be notified whenever the color item is selected and longpressed:

evas_object_smart_callback_add(cs, "color,item,selected", _colorpalette_clicked_cb, rect);
evas_object_smart_callback_add(cs, "color,item,longpressed", _colorpalette_longpressed_cb, rect);

We add some more code to the usual setup code:

elm_object_content_set(fr, cs);
evas_object_resize(win, 320, 480);
evas_object_show(win);
elm_run();
return 0;
}
ELM_MAIN()
ELM_MAIN
#define ELM_MAIN()
macro to be used after the elm_main() function
Definition elm_general.h:556
elm_run
void elm_run(void)
Run Elementary's main loop.
Definition elm_main.c:1357
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

now get to the "changed" callback that sets the color of the rectangle:

static void
_change_color(void *data, Evas_Object *obj, void *event_info EINA_UNUSED)
{
int r, g, b, a;
elm_colorselector_color_get(obj, &r, &g, &b, &a);
// ensure colors are pre-multiplied by alpha
evas_color_argb_premul(a, &r, &g, &b);
evas_object_color_set(data, r, g, b, a);
}
evas_color_argb_premul
EVAS_API void evas_color_argb_premul(int a, int *r, int *g, int *b)
Pre-multiplies a rgb triplet by an alpha factor.
Definition evas_main.c:1010

And now get to the "color,item,selected" callback that sets the color of the rectangle:

static void
_colorpalette_clicked_cb(void *data, Evas_Object *obj EINA_UNUSED,
void *event_info)
{
int r = 0, g = 0, b = 0 ,a = 0;
Elm_Object_Item *color_it = (Elm_Object_Item *) event_info;
elm_colorselector_palette_item_color_get(color_it, &r, &g, &b, &a);
// ensure colors are pre-multiplied by alpha
evas_color_argb_premul(a, &r, &g, &b);
evas_object_color_set(data, r, g, b, a);
}
elm_colorselector_palette_item_color_get
void elm_colorselector_palette_item_color_get(const Elm_Object_Item *it, int *r, int *g, int *b, int *a)
Get Palette item's color.
Definition elm_colorselector.c:2383
Elm_Object_Item
Eo Elm_Object_Item
An Elementary Object item handle.
Definition elm_object_item.h:6

And now get to the "color,item,longpressed" callback that gets and displays the color of the rectangle:

static void
_colorpalette_longpressed_cb(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED,
void *event_info)
{
int r = 0,g = 0,b = 0 ,a = 0;
Elm_Object_Item *color_it = (Elm_Object_Item *) event_info;
elm_colorselector_palette_item_color_get(color_it, &r, &g, &b, &a);
printf("\ncolor = %d-%d-%d-%d\n", r, g, b, a);
}

This example will look like this: