238 lines
6.2 KiB
C
238 lines
6.2 KiB
C
/**
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* @file lv_draw_triangle.c
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*
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*/
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/*********************
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* INCLUDES
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*********************/
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#include "lv_draw_triangle.h"
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#include "../lv_misc/lv_math.h"
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#include "../lv_misc/lv_mem.h"
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/*********************
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* DEFINES
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*********************/
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/**********************
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* TYPEDEFS
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**********************/
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/**********************
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* STATIC PROTOTYPES
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**********************/
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/**********************
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* STATIC VARIABLES
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**********************/
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/**********************
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* MACROS
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**********************/
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/**********************
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* GLOBAL FUNCTIONS
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**********************/
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/**
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* Draw a triangle
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* @param points pointer to an array with 3 points
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* @param clip_area the triangle will be drawn only in this area
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* @param draw_dsc pointer to an initialized `lv_draw_rect_dsc_t` variable
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*/
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void lv_draw_triangle(const lv_point_t points[], const lv_area_t *clip_area, const lv_draw_rect_dsc_t *draw_dsc)
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{
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lv_draw_polygon(points, 3, clip_area, draw_dsc);
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}
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/**
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* Draw a polygon. Only convex polygons are supported
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* @param points an array of points
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* @param point_cnt number of points
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* @param clip_area polygon will be drawn only in this area
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* @param draw_dsc pointer to an initialized `lv_draw_rect_dsc_t` variable
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*/
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void lv_draw_polygon(const lv_point_t points[], uint16_t point_cnt, const lv_area_t *clip_area,
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const lv_draw_rect_dsc_t *draw_dsc)
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{
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if (point_cnt < 3) {
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return;
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}
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if (points == NULL) {
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return;
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}
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/*Join adjacent points if they are on the same coordinate*/
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lv_point_t *p = _lv_mem_buf_get(point_cnt * sizeof(lv_point_t));
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if (p == NULL) {
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return;
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}
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uint16_t i;
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uint16_t pcnt = 0;
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p[0] = points[0];
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for (i = 0; i < point_cnt - 1; i++) {
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if (points[i].x != points[i + 1].x || points[i].y != points[i + 1].y) {
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p[pcnt] = points[i];
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pcnt++;
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}
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}
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/*The first and the last points are also adjacent */
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if (points[0].x != points[point_cnt - 1].x || points[0].y != points[point_cnt - 1].y) {
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p[pcnt] = points[point_cnt - 1];
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pcnt++;
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}
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point_cnt = pcnt;
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if (point_cnt < 3) {
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_lv_mem_buf_release(p);
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return;
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}
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lv_area_t poly_coords = { .x1 = LV_COORD_MAX, .y1 = LV_COORD_MAX, .x2 = LV_COORD_MIN, .y2 = LV_COORD_MIN };
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for (i = 0; i < point_cnt; i++) {
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poly_coords.x1 = LV_MATH_MIN(poly_coords.x1, p[i].x);
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poly_coords.y1 = LV_MATH_MIN(poly_coords.y1, p[i].y);
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poly_coords.x2 = LV_MATH_MAX(poly_coords.x2, p[i].x);
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poly_coords.y2 = LV_MATH_MAX(poly_coords.y2, p[i].y);
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}
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bool is_common;
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lv_area_t poly_mask;
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is_common = _lv_area_intersect(&poly_mask, &poly_coords, clip_area);
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if (!is_common) {
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_lv_mem_buf_release(p);
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return;
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}
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/*Find the lowest point*/
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lv_coord_t y_min = p[0].y;
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int16_t y_min_i = 0;
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for (i = 1; i < point_cnt; i++) {
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if (p[i].y < y_min) {
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y_min = p[i].y;
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y_min_i = i;
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}
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}
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lv_draw_mask_line_param_t *mp = _lv_mem_buf_get(sizeof(lv_draw_mask_line_param_t) * point_cnt);
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lv_draw_mask_line_param_t *mp_next = mp;
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int32_t i_prev_left = y_min_i;
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int32_t i_prev_right = y_min_i;
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int32_t i_next_left;
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int32_t i_next_right;
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uint32_t mask_cnt = 0;
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/*Get the index of the left and right points*/
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i_next_left = y_min_i - 1;
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if (i_next_left < 0) {
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i_next_left = point_cnt + i_next_left;
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}
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i_next_right = y_min_i + 1;
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if (i_next_right > point_cnt - 1) {
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i_next_right = 0;
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}
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/* Check if the order of points is inverted or not.
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* The normal case is when the left point is on `y_min_i - 1`
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* Explanation:
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* if angle(p_left) < angle(p_right) -> inverted
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* dy_left/dx_left < dy_right/dx_right
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* dy_left * dx_right < dy_right * dx_left
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*/
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lv_coord_t dxl = p[i_next_left].x - p[y_min_i].x;
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lv_coord_t dxr = p[i_next_right].x - p[y_min_i].x;
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lv_coord_t dyl = p[i_next_left].y - p[y_min_i].y;
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lv_coord_t dyr = p[i_next_right].y - p[y_min_i].y;
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bool inv = false;
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if (dyl * dxr < dyr * dxl) {
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inv = true;
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}
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do {
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if (!inv) {
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i_next_left = i_prev_left - 1;
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if (i_next_left < 0) {
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i_next_left = point_cnt + i_next_left;
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}
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i_next_right = i_prev_right + 1;
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if (i_next_right > point_cnt - 1) {
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i_next_right = 0;
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}
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} else {
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i_next_left = i_prev_left + 1;
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if (i_next_left > point_cnt - 1) {
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i_next_left = 0;
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}
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i_next_right = i_prev_right - 1;
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if (i_next_right < 0) {
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i_next_right = point_cnt + i_next_right;
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}
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}
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if (p[i_next_left].y >= p[i_prev_left].y) {
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if (p[i_next_left].y != p[i_prev_left].y &&
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p[i_next_left].x != p[i_prev_left].x) {
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lv_draw_mask_line_points_init(mp_next, p[i_prev_left].x, p[i_prev_left].y,
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p[i_next_left].x, p[i_next_left].y,
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LV_DRAW_MASK_LINE_SIDE_RIGHT);
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lv_draw_mask_add(mp_next, mp);
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mp_next++;
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}
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mask_cnt++;
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i_prev_left = i_next_left;
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}
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if (mask_cnt == point_cnt) {
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break;
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}
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if (p[i_next_right].y >= p[i_prev_right].y) {
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if (p[i_next_right].y != p[i_prev_right].y &&
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p[i_next_right].x != p[i_prev_right].x) {
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lv_draw_mask_line_points_init(mp_next, p[i_prev_right].x, p[i_prev_right].y,
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p[i_next_right].x, p[i_next_right].y,
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LV_DRAW_MASK_LINE_SIDE_LEFT);
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lv_draw_mask_add(mp_next, mp);
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mp_next++;
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}
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mask_cnt++;
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i_prev_right = i_next_right;
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}
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} while (mask_cnt < point_cnt);
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lv_draw_rect(&poly_coords, clip_area, draw_dsc);
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lv_draw_mask_remove_custom(mp);
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_lv_mem_buf_release(mp);
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_lv_mem_buf_release(p);
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}
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/**********************
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* STATIC FUNCTIONS
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**********************/
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