1 /**
2 * @file lv_draw_sw_polygon.c
3 *
4 */
5
6 /*********************
7 * INCLUDES
8 *********************/
9 #include "lv_draw_sw.h"
10 #include "../../misc/lv_math.h"
11 #include "../../misc/lv_mem.h"
12 #include "../../misc/lv_area.h"
13 #include "../../misc/lv_color.h"
14 #include "../lv_draw_rect.h"
15
16 /*********************
17 * DEFINES
18 *********************/
19
20 /**********************
21 * TYPEDEFS
22 **********************/
23
24 /**********************
25 * STATIC PROTOTYPES
26 **********************/
27
28 /**********************
29 * STATIC VARIABLES
30 **********************/
31
32 /**********************
33 * MACROS
34 **********************/
35
36 /**********************
37 * GLOBAL FUNCTIONS
38 **********************/
39
40 /**
41 * Draw a polygon. Only convex polygons are supported
42 * @param points an array of points
43 * @param point_cnt number of points
44 * @param clip_area polygon will be drawn only in this area
45 * @param draw_dsc pointer to an initialized `lv_draw_rect_dsc_t` variable
46 */
lv_draw_sw_polygon(lv_draw_ctx_t * draw_ctx,const lv_draw_rect_dsc_t * draw_dsc,const lv_point_t * points,uint16_t point_cnt)47 void lv_draw_sw_polygon(lv_draw_ctx_t * draw_ctx, const lv_draw_rect_dsc_t * draw_dsc, const lv_point_t * points,
48 uint16_t point_cnt)
49 {
50 #if LV_DRAW_COMPLEX
51 if(point_cnt < 3) return;
52 if(points == NULL) return;
53
54 /*Join adjacent points if they are on the same coordinate*/
55 lv_point_t * p = lv_mem_buf_get(point_cnt * sizeof(lv_point_t));
56 if(p == NULL) return;
57 uint16_t i;
58 uint16_t pcnt = 0;
59 p[0] = points[0];
60 for(i = 0; i < point_cnt - 1; i++) {
61 if(points[i].x != points[i + 1].x || points[i].y != points[i + 1].y) {
62 p[pcnt] = points[i];
63 pcnt++;
64 }
65 }
66 /*The first and the last points are also adjacent*/
67 if(points[0].x != points[point_cnt - 1].x || points[0].y != points[point_cnt - 1].y) {
68 p[pcnt] = points[point_cnt - 1];
69 pcnt++;
70 }
71
72 point_cnt = pcnt;
73 if(point_cnt < 3) {
74 lv_mem_buf_release(p);
75 return;
76 }
77
78 lv_area_t poly_coords = {.x1 = LV_COORD_MAX, .y1 = LV_COORD_MAX, .x2 = LV_COORD_MIN, .y2 = LV_COORD_MIN};
79
80 for(i = 0; i < point_cnt; i++) {
81 poly_coords.x1 = LV_MIN(poly_coords.x1, p[i].x);
82 poly_coords.y1 = LV_MIN(poly_coords.y1, p[i].y);
83 poly_coords.x2 = LV_MAX(poly_coords.x2, p[i].x);
84 poly_coords.y2 = LV_MAX(poly_coords.y2, p[i].y);
85 }
86
87 bool is_common;
88 lv_area_t clip_area;
89 is_common = _lv_area_intersect(&clip_area, &poly_coords, draw_ctx->clip_area);
90 if(!is_common) {
91 lv_mem_buf_release(p);
92 return;
93 }
94
95 const lv_area_t * clip_area_ori = draw_ctx->clip_area;
96 draw_ctx->clip_area = &clip_area;
97
98 /*Find the lowest point*/
99 lv_coord_t y_min = p[0].y;
100 int16_t y_min_i = 0;
101
102 for(i = 1; i < point_cnt; i++) {
103 if(p[i].y < y_min) {
104 y_min = p[i].y;
105 y_min_i = i;
106 }
107 }
108
109 lv_draw_mask_line_param_t * mp = lv_mem_buf_get(sizeof(lv_draw_mask_line_param_t) * point_cnt);
110 lv_draw_mask_line_param_t * mp_next = mp;
111
112 int32_t i_prev_left = y_min_i;
113 int32_t i_prev_right = y_min_i;
114 int32_t i_next_left;
115 int32_t i_next_right;
116 uint32_t mask_cnt = 0;
117
118 /*Get the index of the left and right points*/
119 i_next_left = y_min_i - 1;
120 if(i_next_left < 0) i_next_left = point_cnt + i_next_left;
121
122 i_next_right = y_min_i + 1;
123 if(i_next_right > point_cnt - 1) i_next_right = 0;
124
125 /**
126 * Check if the order of points is inverted or not.
127 * The normal case is when the left point is on `y_min_i - 1`
128 * Explanation:
129 * if angle(p_left) < angle(p_right) -> inverted
130 * dy_left/dx_left < dy_right/dx_right
131 * dy_left * dx_right < dy_right * dx_left
132 */
133 lv_coord_t dxl = p[i_next_left].x - p[y_min_i].x;
134 lv_coord_t dxr = p[i_next_right].x - p[y_min_i].x;
135 lv_coord_t dyl = p[i_next_left].y - p[y_min_i].y;
136 lv_coord_t dyr = p[i_next_right].y - p[y_min_i].y;
137
138 bool inv = false;
139 if(dyl * dxr < dyr * dxl) inv = true;
140
141 do {
142 if(!inv) {
143 i_next_left = i_prev_left - 1;
144 if(i_next_left < 0) i_next_left = point_cnt + i_next_left;
145
146 i_next_right = i_prev_right + 1;
147 if(i_next_right > point_cnt - 1) i_next_right = 0;
148 }
149 else {
150 i_next_left = i_prev_left + 1;
151 if(i_next_left > point_cnt - 1) i_next_left = 0;
152
153 i_next_right = i_prev_right - 1;
154 if(i_next_right < 0) i_next_right = point_cnt + i_next_right;
155 }
156
157 if(p[i_next_left].y >= p[i_prev_left].y) {
158 if(p[i_next_left].y != p[i_prev_left].y &&
159 p[i_next_left].x != p[i_prev_left].x) {
160 lv_draw_mask_line_points_init(mp_next, p[i_prev_left].x, p[i_prev_left].y,
161 p[i_next_left].x, p[i_next_left].y,
162 LV_DRAW_MASK_LINE_SIDE_RIGHT);
163 lv_draw_mask_add(mp_next, mp);
164 mp_next++;
165 }
166 mask_cnt++;
167 i_prev_left = i_next_left;
168 }
169
170 if(mask_cnt == point_cnt) break;
171
172 if(p[i_next_right].y >= p[i_prev_right].y) {
173 if(p[i_next_right].y != p[i_prev_right].y &&
174 p[i_next_right].x != p[i_prev_right].x) {
175
176 lv_draw_mask_line_points_init(mp_next, p[i_prev_right].x, p[i_prev_right].y,
177 p[i_next_right].x, p[i_next_right].y,
178 LV_DRAW_MASK_LINE_SIDE_LEFT);
179 lv_draw_mask_add(mp_next, mp);
180 mp_next++;
181 }
182 mask_cnt++;
183 i_prev_right = i_next_right;
184 }
185
186 } while(mask_cnt < point_cnt);
187
188 lv_draw_rect(draw_ctx, draw_dsc, &poly_coords);
189
190 lv_draw_mask_remove_custom(mp);
191
192 lv_mem_buf_release(mp);
193 lv_mem_buf_release(p);
194
195 draw_ctx->clip_area = clip_area_ori;
196 #else
197 LV_UNUSED(points);
198 LV_UNUSED(point_cnt);
199 LV_UNUSED(draw_ctx);
200 LV_UNUSED(draw_dsc);
201 LV_LOG_WARN("Can't draw polygon with LV_DRAW_COMPLEX == 0");
202 #endif /*LV_DRAW_COMPLEX*/
203 }
204
205 /**********************
206 * STATIC FUNCTIONS
207 **********************/
208
