1 #include "../../lv_examples.h"
2 #if LV_USE_TINY_TTF && LV_BUILD_EXAMPLES && LV_USE_OBSERVER
3
4 static void font_size_observer_cb(lv_observer_t * observer, lv_subject_t * subject);
5
6 static lv_subject_t subject_font;
7
8 /**
9 * Change font size with Tiny_TTF
10 */
lv_example_tiny_ttf_3(void)11 void lv_example_tiny_ttf_3(void)
12 {
13 extern const uint8_t ubuntu_font[];
14 extern const int ubuntu_font_size;
15
16 lv_subject_init_int(&subject_font, 25);
17
18 /*Create style with the new font*/
19 static lv_style_t style;
20 lv_style_init(&style);
21 lv_font_t * font = lv_tiny_ttf_create_data(ubuntu_font, ubuntu_font_size, 25);
22 lv_style_set_text_font(&style, font);
23 lv_style_set_text_align(&style, LV_TEXT_ALIGN_CENTER);
24
25 lv_obj_t * slider = lv_slider_create(lv_screen_active());
26 lv_obj_center(slider);
27 lv_slider_set_range(slider, 5, 50);
28 lv_obj_align(slider, LV_ALIGN_BOTTOM_MID, 0, -50);
29 lv_slider_bind_value(slider, &subject_font);
30
31 lv_obj_t * slider_label = lv_label_create(lv_screen_active());
32 lv_obj_align_to(slider_label, slider, LV_ALIGN_OUT_BOTTOM_MID, 0, 10);
33 lv_label_bind_text(slider_label, &subject_font, "%d");
34
35 /*Create a label with the new style*/
36 lv_obj_t * label = lv_label_create(lv_screen_active());
37 lv_obj_add_style(label, &style, 0);
38 lv_obj_set_size(label, LV_SIZE_CONTENT, LV_SIZE_CONTENT);
39 lv_label_set_text(label, "Hello world!");
40 lv_obj_center(label);
41
42 lv_subject_add_observer(&subject_font, font_size_observer_cb, &style);
43 }
44
font_size_observer_cb(lv_observer_t * observer,lv_subject_t * subject)45 static void font_size_observer_cb(lv_observer_t * observer, lv_subject_t * subject)
46 {
47 lv_style_t * style = lv_observer_get_user_data(observer);
48 lv_style_value_t v;
49 lv_style_get_prop(style, LV_STYLE_TEXT_FONT, &v);
50 lv_font_t * font = (lv_font_t *) v.ptr;
51 int32_t size = lv_subject_get_int(subject);
52
53 lv_tiny_ttf_set_size(font, size);
54
55 lv_obj_report_style_change(style);
56 }
57 #endif
58
