mirror of
https://github.com/lvgl/lvgl.git
synced 2026-05-10 04:37:55 +08:00
Mutahhar Mustafa Khan
69 lines
2.2 KiB
C
69 lines
2.2 KiB
C
#include "../lv_examples.h"
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#if LV_BUILD_EXAMPLES
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static int32_t size = 0;
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static bool size_dec = false;
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static void timer_cb(lv_timer_t * timer)
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{
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lv_obj_invalidate((lv_obj_t *) lv_timer_get_user_data(timer));
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if(size_dec) size--;
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else size++;
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if(size == 50) size_dec = true;
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else if(size == 0) size_dec = false;
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}
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static void event_cb(lv_event_t * e)
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{
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lv_obj_t * obj = lv_event_get_target_obj(e);
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lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
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lv_draw_dsc_base_t * base_dsc = (lv_draw_dsc_base_t *) lv_draw_task_get_draw_dsc(draw_task);
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if(base_dsc->part == LV_PART_MAIN) {
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lv_draw_rect_dsc_t draw_dsc;
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lv_draw_rect_dsc_init(&draw_dsc);
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draw_dsc.bg_color = lv_color_hex(0xffaaaa);
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draw_dsc.radius = LV_RADIUS_CIRCLE;
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draw_dsc.border_color = lv_color_hex(0xff5555);
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draw_dsc.border_width = 2;
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draw_dsc.outline_color = lv_color_hex(0xff0000);
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draw_dsc.outline_pad = 3;
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draw_dsc.outline_width = 2;
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lv_area_t a;
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a.x1 = 0;
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a.y1 = 0;
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a.x2 = size;
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a.y2 = size;
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lv_area_t obj_coords;
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lv_obj_get_coords(obj, &obj_coords);
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lv_area_align(&obj_coords, &a, LV_ALIGN_CENTER, 0, 0);
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lv_draw_rect(base_dsc->layer, &draw_dsc, &a);
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}
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}
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/**
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* @title Custom drawing on draw task events
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* @brief Draw a pulsing red circle on top of a container with a draw task callback.
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*
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* A 200x200 container is centered and flagged with
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* `LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS`. An `LV_EVENT_DRAW_TASK_ADDED`
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* callback inspects the draw task and, when `base_dsc->part` is
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* `LV_PART_MAIN`, calls `lv_draw_rect` to paint a pink circle with a red
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* border and outline. A 30 ms `lv_timer_t` bounces a `size` counter between
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* 0 and 50 and invalidates the container each tick to animate the circle.
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*/
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void lv_example_event_draw(void)
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{
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lv_obj_t * cont = lv_obj_create(lv_screen_active());
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lv_obj_set_size(cont, 200, 200);
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lv_obj_center(cont);
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lv_obj_add_event_cb(cont, event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
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lv_obj_add_flag(cont, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
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lv_timer_create(timer_cb, 30, cont);
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}
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#endif
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