1 #include "../../lv_examples.h"
2 #if LV_USE_CHART && LV_BUILD_EXAMPLES
3
draw_event_cb(lv_event_t * e)4 static void draw_event_cb(lv_event_t * e)
5 {
6 lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
7 lv_draw_dsc_base_t * base_dsc = lv_draw_task_get_draw_dsc(draw_task);
8 if(base_dsc->part == LV_PART_INDICATOR) {
9 lv_obj_t * obj = lv_event_get_target(e);
10 lv_chart_series_t * ser = lv_chart_get_series_next(obj, NULL);
11 lv_draw_rect_dsc_t * rect_draw_dsc = lv_draw_task_get_draw_dsc(draw_task);
12 uint32_t cnt = lv_chart_get_point_count(obj);
13
14 /*Make older value more transparent*/
15 rect_draw_dsc->bg_opa = (LV_OPA_COVER * base_dsc->id2) / (cnt - 1);
16
17 /*Make smaller values blue, higher values red*/
18 int32_t * x_array = lv_chart_get_x_array(obj, ser);
19 int32_t * y_array = lv_chart_get_y_array(obj, ser);
20 /*dsc->id is the tells drawing order, but we need the ID of the point being drawn.*/
21 uint32_t start_point = lv_chart_get_x_start_point(obj, ser);
22 uint32_t p_act = (start_point + base_dsc->id2) % cnt; /*Consider start point to get the index of the array*/
23 lv_opa_t x_opa = (x_array[p_act] * LV_OPA_50) / 200;
24 lv_opa_t y_opa = (y_array[p_act] * LV_OPA_50) / 1000;
25
26 rect_draw_dsc->bg_color = lv_color_mix(lv_palette_main(LV_PALETTE_RED),
27 lv_palette_main(LV_PALETTE_BLUE),
28 x_opa + y_opa);
29 }
30 }
31
add_data(lv_timer_t * timer)32 static void add_data(lv_timer_t * timer)
33 {
34 lv_obj_t * chart = lv_timer_get_user_data(timer);
35 lv_chart_set_next_value2(chart, lv_chart_get_series_next(chart, NULL), lv_rand(0, 200), lv_rand(0, 1000));
36 }
37
38 /**
39 * A scatter chart
40 */
lv_example_chart_7(void)41 void lv_example_chart_7(void)
42 {
43 lv_obj_t * chart = lv_chart_create(lv_screen_active());
44 lv_obj_set_size(chart, 200, 150);
45 lv_obj_align(chart, LV_ALIGN_CENTER, 0, 0);
46 lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
47 lv_obj_add_flag(chart, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
48 lv_obj_set_style_line_width(chart, 0, LV_PART_ITEMS); /*Remove the lines*/
49
50 lv_chart_set_type(chart, LV_CHART_TYPE_SCATTER);
51
52 lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_X, 0, 200);
53 lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 1000);
54
55 lv_chart_set_point_count(chart, 50);
56
57 lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
58 uint32_t i;
59 for(i = 0; i < 50; i++) {
60 lv_chart_set_next_value2(chart, ser, lv_rand(0, 200), lv_rand(0, 1000));
61 }
62
63 lv_timer_create(add_data, 100, chart);
64 }
65
66 #endif
67
