1 #include "../../lv_examples.h"
2 #if LV_USE_ROLLER && LV_DRAW_COMPLEX && LV_BUILD_EXAMPLES
3 
mask_event_cb(lv_event_t * e)4 static void mask_event_cb(lv_event_t * e)
5 {
6     lv_event_code_t code = lv_event_get_code(e);
7     lv_obj_t * obj = lv_event_get_target(e);
8 
9     static int16_t mask_top_id = -1;
10     static int16_t mask_bottom_id = -1;
11 
12     if(code == LV_EVENT_COVER_CHECK) {
13         lv_event_set_cover_res(e, LV_COVER_RES_MASKED);
14 
15     }
16     else if(code == LV_EVENT_DRAW_MAIN_BEGIN) {
17         /* add mask */
18         const lv_font_t * font = lv_obj_get_style_text_font(obj, LV_PART_MAIN);
19         lv_coord_t line_space = lv_obj_get_style_text_line_space(obj, LV_PART_MAIN);
20         lv_coord_t font_h = lv_font_get_line_height(font);
21 
22         lv_area_t roller_coords;
23         lv_obj_get_coords(obj, &roller_coords);
24 
25         lv_area_t rect_area;
26         rect_area.x1 = roller_coords.x1;
27         rect_area.x2 = roller_coords.x2;
28         rect_area.y1 = roller_coords.y1;
29         rect_area.y2 = roller_coords.y1 + (lv_obj_get_height(obj) - font_h - line_space) / 2;
30 
31         lv_draw_mask_fade_param_t * fade_mask_top = lv_mem_buf_get(sizeof(lv_draw_mask_fade_param_t));
32         lv_draw_mask_fade_init(fade_mask_top, &rect_area, LV_OPA_TRANSP, rect_area.y1, LV_OPA_COVER, rect_area.y2);
33         mask_top_id = lv_draw_mask_add(fade_mask_top, NULL);
34 
35         rect_area.y1 = rect_area.y2 + font_h + line_space - 1;
36         rect_area.y2 = roller_coords.y2;
37 
38         lv_draw_mask_fade_param_t * fade_mask_bottom = lv_mem_buf_get(sizeof(lv_draw_mask_fade_param_t));
39         lv_draw_mask_fade_init(fade_mask_bottom, &rect_area, LV_OPA_COVER, rect_area.y1, LV_OPA_TRANSP, rect_area.y2);
40         mask_bottom_id = lv_draw_mask_add(fade_mask_bottom, NULL);
41 
42     }
43     else if(code == LV_EVENT_DRAW_POST_END) {
44         lv_draw_mask_fade_param_t * fade_mask_top = lv_draw_mask_remove_id(mask_top_id);
45         lv_draw_mask_fade_param_t * fade_mask_bottom = lv_draw_mask_remove_id(mask_bottom_id);
46         lv_draw_mask_free_param(fade_mask_top);
47         lv_draw_mask_free_param(fade_mask_bottom);
48         lv_mem_buf_release(fade_mask_top);
49         lv_mem_buf_release(fade_mask_bottom);
50         mask_top_id = -1;
51         mask_bottom_id = -1;
52     }
53 }
54 
55 /**
56  * Add a fade mask to roller.
57  */
lv_example_roller_3(void)58 void lv_example_roller_3(void)
59 {
60     static lv_style_t style;
61     lv_style_init(&style);
62     lv_style_set_bg_color(&style, lv_color_black());
63     lv_style_set_text_color(&style, lv_color_white());
64     lv_style_set_border_width(&style, 0);
65     lv_style_set_pad_all(&style, 0);
66     lv_obj_add_style(lv_scr_act(), &style, 0);
67 
68     lv_obj_t * roller1 = lv_roller_create(lv_scr_act());
69     lv_obj_add_style(roller1, &style, 0);
70     lv_obj_set_style_bg_opa(roller1, LV_OPA_TRANSP, LV_PART_SELECTED);
71 
72 #if LV_FONT_MONTSERRAT_22
73     lv_obj_set_style_text_font(roller1, &lv_font_montserrat_22, LV_PART_SELECTED);
74 #endif
75 
76     lv_roller_set_options(roller1,
77                           "January\n"
78                           "February\n"
79                           "March\n"
80                           "April\n"
81                           "May\n"
82                           "June\n"
83                           "July\n"
84                           "August\n"
85                           "September\n"
86                           "October\n"
87                           "November\n"
88                           "December",
89                           LV_ROLLER_MODE_NORMAL);
90 
91     lv_obj_center(roller1);
92     lv_roller_set_visible_row_count(roller1, 3);
93     lv_obj_add_event_cb(roller1, mask_event_cb, LV_EVENT_ALL, NULL);
94 }
95 
96 #endif
97