81 lines
2.6 KiB
C
81 lines
2.6 KiB
C
#include "../lv_examples.h"
|
|
#if LV_BUILD_EXAMPLES && LV_USE_FLEX
|
|
|
|
static void scroll_event_cb(lv_event_t * e)
|
|
{
|
|
lv_obj_t * cont = lv_event_get_target(e);
|
|
|
|
lv_area_t cont_a;
|
|
lv_obj_get_coords(cont, &cont_a);
|
|
lv_coord_t cont_y_center = cont_a.y1 + lv_area_get_height(&cont_a) / 2;
|
|
|
|
lv_coord_t r = lv_obj_get_height(cont) * 7 / 10;
|
|
uint32_t i;
|
|
uint32_t child_cnt = lv_obj_get_child_cnt(cont);
|
|
for(i = 0; i < child_cnt; i++) {
|
|
lv_obj_t * child = lv_obj_get_child(cont, i);
|
|
lv_area_t child_a;
|
|
lv_obj_get_coords(child, &child_a);
|
|
|
|
lv_coord_t child_y_center = child_a.y1 + lv_area_get_height(&child_a) / 2;
|
|
|
|
lv_coord_t diff_y = child_y_center - cont_y_center;
|
|
diff_y = LV_ABS(diff_y);
|
|
|
|
/*Get the x of diff_y on a circle.*/
|
|
lv_coord_t x;
|
|
/*If diff_y is out of the circle use the last point of the circle (the radius)*/
|
|
if(diff_y >= r) {
|
|
x = r;
|
|
}
|
|
else {
|
|
/*Use Pythagoras theorem to get x from radius and y*/
|
|
uint32_t x_sqr = r * r - diff_y * diff_y;
|
|
lv_sqrt_res_t res;
|
|
lv_sqrt(x_sqr, &res, 0x8000); /*Use lvgl's built in sqrt root function*/
|
|
x = r - res.i;
|
|
}
|
|
|
|
/*Translate the item by the calculated X coordinate*/
|
|
lv_obj_set_style_translate_x(child, x, 0);
|
|
|
|
/*Use some opacity with larger translations*/
|
|
lv_opa_t opa = lv_map(x, 0, r, LV_OPA_TRANSP, LV_OPA_COVER);
|
|
lv_obj_set_style_opa(child, LV_OPA_COVER - opa, 0);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Translate the object as they scroll
|
|
*/
|
|
void lv_example_scroll_6(void)
|
|
{
|
|
lv_obj_t * cont = lv_obj_create(lv_scr_act());
|
|
lv_obj_set_size(cont, 200, 200);
|
|
lv_obj_center(cont);
|
|
lv_obj_set_flex_flow(cont, LV_FLEX_FLOW_COLUMN);
|
|
lv_obj_add_event_cb(cont, scroll_event_cb, LV_EVENT_SCROLL, NULL);
|
|
lv_obj_set_style_radius(cont, LV_RADIUS_CIRCLE, 0);
|
|
lv_obj_set_style_clip_corner(cont, true, 0);
|
|
lv_obj_set_scroll_dir(cont, LV_DIR_VER);
|
|
lv_obj_set_scroll_snap_y(cont, LV_SCROLL_SNAP_CENTER);
|
|
lv_obj_set_scrollbar_mode(cont, LV_SCROLLBAR_MODE_OFF);
|
|
|
|
uint32_t i;
|
|
for(i = 0; i < 20; i++) {
|
|
lv_obj_t * btn = lv_btn_create(cont);
|
|
lv_obj_set_width(btn, lv_pct(100));
|
|
|
|
lv_obj_t * label = lv_label_create(btn);
|
|
lv_label_set_text_fmt(label, "Button %"LV_PRIu32, i);
|
|
}
|
|
|
|
/*Update the buttons position manually for first*/
|
|
lv_event_send(cont, LV_EVENT_SCROLL, NULL);
|
|
|
|
/*Be sure the fist button is in the middle*/
|
|
lv_obj_scroll_to_view(lv_obj_get_child(cont, 0), LV_ANIM_OFF);
|
|
}
|
|
|
|
#endif
|