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