1 /**
2  * @file lv_flex.c
3  *
4  */
5 
6 /*********************
7  *      INCLUDES
8  *********************/
9 #include "../lv_layouts.h"
10 
11 #if LV_USE_FLEX
12 
13 /*********************
14  *      DEFINES
15  *********************/
16 
17 /**********************
18  *      TYPEDEFS
19  **********************/
20 typedef struct {
21     lv_flex_align_t main_place;
22     lv_flex_align_t cross_place;
23     lv_flex_align_t track_place;
24     uint8_t row : 1;
25     uint8_t wrap : 1;
26     uint8_t rev : 1;
27 } flex_t;
28 
29 typedef struct {
30     lv_obj_t * item;
31     lv_coord_t min_size;
32     lv_coord_t max_size;
33     lv_coord_t final_size;
34     uint32_t grow_value;
35     uint32_t clamped : 1;
36 } grow_dsc_t;
37 
38 typedef struct {
39     lv_coord_t track_cross_size;
40     lv_coord_t track_main_size;         /*For all items*/
41     lv_coord_t track_fix_main_size;     /*For non grow items*/
42     uint32_t item_cnt;
43     grow_dsc_t * grow_dsc;
44     uint32_t grow_item_cnt;
45     uint32_t grow_dsc_calc : 1;
46 } track_t;
47 
48 
49 /**********************
50  *  GLOBAL PROTOTYPES
51  **********************/
52 
53 /**********************
54  *  STATIC PROTOTYPES
55  **********************/
56 static void flex_update(lv_obj_t * cont, void * user_data);
57 static int32_t find_track_end(lv_obj_t * cont, flex_t * f, int32_t item_start_id, lv_coord_t max_main_size,
58                               lv_coord_t item_gap, track_t * t);
59 static void children_repos(lv_obj_t * cont, flex_t * f, int32_t item_first_id, int32_t item_last_id, lv_coord_t abs_x,
60                            lv_coord_t abs_y, lv_coord_t max_main_size, lv_coord_t item_gap, track_t * t);
61 static void place_content(lv_flex_align_t place, lv_coord_t max_size, lv_coord_t content_size, lv_coord_t item_cnt,
62                           lv_coord_t * start_pos, lv_coord_t * gap);
63 static lv_obj_t * get_next_item(lv_obj_t * cont, bool rev, int32_t * item_id);
64 
65 /**********************
66  *  GLOBAL VARIABLES
67  **********************/
68 uint16_t LV_LAYOUT_FLEX;
69 lv_style_prop_t LV_STYLE_FLEX_FLOW;
70 lv_style_prop_t LV_STYLE_FLEX_MAIN_PLACE;
71 lv_style_prop_t LV_STYLE_FLEX_CROSS_PLACE;
72 lv_style_prop_t LV_STYLE_FLEX_TRACK_PLACE;
73 lv_style_prop_t LV_STYLE_FLEX_GROW;
74 
75 
76 /**********************
77  *  STATIC VARIABLES
78  **********************/
79 
80 /**********************
81  *      MACROS
82  **********************/
83 
84 /**********************
85  *   GLOBAL FUNCTIONS
86  **********************/
87 
88 /*=====================
89  * Setter functions
90  *====================*/
91 
lv_flex_init(void)92 void lv_flex_init(void)
93 {
94     LV_LAYOUT_FLEX = lv_layout_register(flex_update, NULL);
95 
96     LV_STYLE_FLEX_FLOW = lv_style_register_prop(LV_STYLE_PROP_FLAG_NONE);
97     LV_STYLE_FLEX_MAIN_PLACE = lv_style_register_prop(LV_STYLE_PROP_LAYOUT_REFR);
98     LV_STYLE_FLEX_CROSS_PLACE = lv_style_register_prop(LV_STYLE_PROP_LAYOUT_REFR);
99     LV_STYLE_FLEX_TRACK_PLACE = lv_style_register_prop(LV_STYLE_PROP_LAYOUT_REFR);
100     LV_STYLE_FLEX_GROW = lv_style_register_prop(LV_STYLE_PROP_LAYOUT_REFR);
101 }
102 
lv_obj_set_flex_flow(lv_obj_t * obj,lv_flex_flow_t flow)103 void lv_obj_set_flex_flow(lv_obj_t * obj, lv_flex_flow_t flow)
104 {
105     lv_obj_set_style_flex_flow(obj, flow, 0);
106     lv_obj_set_style_layout(obj, LV_LAYOUT_FLEX, 0);
107 }
108 
lv_obj_set_flex_align(lv_obj_t * obj,lv_flex_align_t main_place,lv_flex_align_t cross_place,lv_flex_align_t track_place)109 void lv_obj_set_flex_align(lv_obj_t * obj, lv_flex_align_t main_place, lv_flex_align_t cross_place,
110                            lv_flex_align_t track_place)
111 {
112     lv_obj_set_style_flex_main_place(obj, main_place, 0);
113     lv_obj_set_style_flex_cross_place(obj, cross_place, 0);
114     lv_obj_set_style_flex_track_place(obj, track_place, 0);
115     lv_obj_set_style_layout(obj, LV_LAYOUT_FLEX, 0);
116 }
117 
lv_obj_set_flex_grow(lv_obj_t * obj,uint8_t grow)118 void lv_obj_set_flex_grow(lv_obj_t * obj, uint8_t grow)
119 {
120     lv_obj_set_style_flex_grow(obj, grow, 0);
121     lv_obj_mark_layout_as_dirty(lv_obj_get_parent(obj));
122 }
123 
124 
lv_style_set_flex_flow(lv_style_t * style,lv_flex_flow_t value)125 void lv_style_set_flex_flow(lv_style_t * style, lv_flex_flow_t value)
126 {
127     lv_style_value_t v = {
128         .num = (int32_t)value
129     };
130     lv_style_set_prop(style, LV_STYLE_FLEX_FLOW, v);
131 }
132 
lv_style_set_flex_main_place(lv_style_t * style,lv_flex_align_t value)133 void lv_style_set_flex_main_place(lv_style_t * style, lv_flex_align_t value)
134 {
135     lv_style_value_t v = {
136         .num = (int32_t)value
137     };
138     lv_style_set_prop(style, LV_STYLE_FLEX_MAIN_PLACE, v);
139 }
140 
lv_style_set_flex_cross_place(lv_style_t * style,lv_flex_align_t value)141 void lv_style_set_flex_cross_place(lv_style_t * style, lv_flex_align_t value)
142 {
143     lv_style_value_t v = {
144         .num = (int32_t)value
145     };
146     lv_style_set_prop(style, LV_STYLE_FLEX_CROSS_PLACE, v);
147 }
148 
lv_style_set_flex_track_place(lv_style_t * style,lv_flex_align_t value)149 void lv_style_set_flex_track_place(lv_style_t * style, lv_flex_align_t value)
150 {
151     lv_style_value_t v = {
152         .num = (int32_t)value
153     };
154     lv_style_set_prop(style, LV_STYLE_FLEX_TRACK_PLACE, v);
155 }
156 
lv_style_set_flex_grow(lv_style_t * style,uint8_t value)157 void lv_style_set_flex_grow(lv_style_t * style, uint8_t value)
158 {
159     lv_style_value_t v = {
160         .num = (int32_t)value
161     };
162     lv_style_set_prop(style, LV_STYLE_FLEX_GROW, v);
163 }
164 
165 
lv_obj_set_style_flex_flow(lv_obj_t * obj,lv_flex_flow_t value,lv_style_selector_t selector)166 void lv_obj_set_style_flex_flow(lv_obj_t * obj, lv_flex_flow_t value, lv_style_selector_t selector)
167 {
168     lv_style_value_t v = {
169         .num = (int32_t) value
170     };
171     lv_obj_set_local_style_prop(obj, LV_STYLE_FLEX_FLOW, v, selector);
172 }
173 
lv_obj_set_style_flex_main_place(lv_obj_t * obj,lv_flex_align_t value,lv_style_selector_t selector)174 void lv_obj_set_style_flex_main_place(lv_obj_t * obj, lv_flex_align_t value, lv_style_selector_t selector)
175 {
176     lv_style_value_t v = {
177         .num = (int32_t) value
178     };
179     lv_obj_set_local_style_prop(obj, LV_STYLE_FLEX_MAIN_PLACE, v, selector);
180 }
181 
lv_obj_set_style_flex_cross_place(lv_obj_t * obj,lv_flex_align_t value,lv_style_selector_t selector)182 void lv_obj_set_style_flex_cross_place(lv_obj_t * obj, lv_flex_align_t value, lv_style_selector_t selector)
183 {
184     lv_style_value_t v = {
185         .num = (int32_t) value
186     };
187     lv_obj_set_local_style_prop(obj, LV_STYLE_FLEX_CROSS_PLACE, v, selector);
188 }
189 
lv_obj_set_style_flex_track_place(lv_obj_t * obj,lv_flex_align_t value,lv_style_selector_t selector)190 void lv_obj_set_style_flex_track_place(lv_obj_t * obj, lv_flex_align_t value, lv_style_selector_t selector)
191 {
192     lv_style_value_t v = {
193         .num = (int32_t) value
194     };
195     lv_obj_set_local_style_prop(obj, LV_STYLE_FLEX_TRACK_PLACE, v, selector);
196 }
197 
lv_obj_set_style_flex_grow(lv_obj_t * obj,uint8_t value,lv_style_selector_t selector)198 void lv_obj_set_style_flex_grow(lv_obj_t * obj, uint8_t value, lv_style_selector_t selector)
199 {
200     lv_style_value_t v = {
201         .num = (int32_t) value
202     };
203     lv_obj_set_local_style_prop(obj, LV_STYLE_FLEX_GROW, v, selector);
204 }
205 
206 /**********************
207  *   STATIC FUNCTIONS
208  **********************/
209 
flex_update(lv_obj_t * cont,void * user_data)210 static void flex_update(lv_obj_t * cont, void * user_data)
211 {
212     LV_LOG_INFO("update %p container", (void *)cont);
213     LV_UNUSED(user_data);
214 
215     flex_t f;
216     lv_flex_flow_t flow = lv_obj_get_style_flex_flow(cont, LV_PART_MAIN);
217     f.row = flow & _LV_FLEX_COLUMN ? 0 : 1;
218     f.wrap = flow & _LV_FLEX_WRAP ? 1 : 0;
219     f.rev = flow & _LV_FLEX_REVERSE ? 1 : 0;
220     f.main_place = lv_obj_get_style_flex_main_place(cont, LV_PART_MAIN);
221     f.cross_place = lv_obj_get_style_flex_cross_place(cont, LV_PART_MAIN);
222     f.track_place = lv_obj_get_style_flex_track_place(cont, LV_PART_MAIN);
223 
224     bool rtl = lv_obj_get_style_base_dir(cont, LV_PART_MAIN) == LV_BASE_DIR_RTL ? true : false;
225     lv_coord_t track_gap = !f.row ? lv_obj_get_style_pad_column(cont, LV_PART_MAIN) : lv_obj_get_style_pad_row(cont,
226                                                                                                                LV_PART_MAIN);
227     lv_coord_t item_gap = f.row ? lv_obj_get_style_pad_column(cont, LV_PART_MAIN) : lv_obj_get_style_pad_row(cont,
228                                                                                                              LV_PART_MAIN);
229     lv_coord_t max_main_size = (f.row ? lv_obj_get_content_width(cont) : lv_obj_get_content_height(cont));
230     lv_coord_t border_width = lv_obj_get_style_border_width(cont, LV_PART_MAIN);
231     lv_coord_t abs_y = cont->coords.y1 + lv_obj_get_style_pad_top(cont,
232                                                                   LV_PART_MAIN) + border_width - lv_obj_get_scroll_y(cont);
233     lv_coord_t abs_x = cont->coords.x1 + lv_obj_get_style_pad_left(cont,
234                                                                    LV_PART_MAIN) + border_width - lv_obj_get_scroll_x(cont);
235 
236     lv_flex_align_t track_cross_place = f.track_place;
237     lv_coord_t * cross_pos = (f.row ? &abs_y : &abs_x);
238 
239     lv_coord_t w_set = lv_obj_get_style_width(cont, LV_PART_MAIN);
240     lv_coord_t h_set = lv_obj_get_style_height(cont, LV_PART_MAIN);
241 
242     /*Content sized objects should squeezed the gap between the children, therefore any alignment will look like `START`*/
243     if((f.row && h_set == LV_SIZE_CONTENT && cont->h_layout == 0) ||
244        (!f.row && w_set == LV_SIZE_CONTENT && cont->w_layout == 0)) {
245         track_cross_place = LV_FLEX_ALIGN_START;
246     }
247 
248     if(rtl && !f.row) {
249         if(track_cross_place == LV_FLEX_ALIGN_START) track_cross_place = LV_FLEX_ALIGN_END;
250         else if(track_cross_place == LV_FLEX_ALIGN_END) track_cross_place = LV_FLEX_ALIGN_START;
251     }
252 
253     lv_coord_t total_track_cross_size = 0;
254     lv_coord_t gap = 0;
255     uint32_t track_cnt = 0;
256     int32_t track_first_item;
257     int32_t next_track_first_item;
258 
259     if(track_cross_place != LV_FLEX_ALIGN_START) {
260         track_first_item = f.rev ? cont->spec_attr->child_cnt - 1 : 0;
261         track_t t;
262         while(track_first_item < (int32_t)cont->spec_attr->child_cnt && track_first_item >= 0) {
263             /*Search the first item of the next row*/
264             t.grow_dsc_calc = 0;
265             next_track_first_item = find_track_end(cont, &f, track_first_item, max_main_size, item_gap, &t);
266             total_track_cross_size += t.track_cross_size + track_gap;
267             track_cnt++;
268             track_first_item = next_track_first_item;
269         }
270 
271         if(track_cnt) total_track_cross_size -= track_gap;   /*No gap after the last track*/
272 
273         /*Place the tracks to get the start position*/
274         lv_coord_t max_cross_size = (f.row ? lv_obj_get_content_height(cont) : lv_obj_get_content_width(cont));
275         place_content(track_cross_place, max_cross_size, total_track_cross_size, track_cnt, cross_pos, &gap);
276     }
277 
278     track_first_item = f.rev ? cont->spec_attr->child_cnt - 1 : 0;
279 
280     if(rtl && !f.row) {
281         *cross_pos += total_track_cross_size;
282     }
283 
284     while(track_first_item < (int32_t)cont->spec_attr->child_cnt && track_first_item >= 0) {
285         track_t t;
286         t.grow_dsc_calc = 1;
287         /*Search the first item of the next row*/
288         next_track_first_item = find_track_end(cont, &f, track_first_item, max_main_size, item_gap, &t);
289 
290         if(rtl && !f.row) {
291             *cross_pos -= t.track_cross_size;
292         }
293         children_repos(cont, &f, track_first_item, next_track_first_item, abs_x, abs_y, max_main_size, item_gap, &t);
294         track_first_item = next_track_first_item;
295         lv_mem_buf_release(t.grow_dsc);
296         t.grow_dsc = NULL;
297         if(rtl && !f.row) {
298             *cross_pos -= gap + track_gap;
299         }
300         else {
301             *cross_pos += t.track_cross_size + gap + track_gap;
302         }
303     }
304     LV_ASSERT_MEM_INTEGRITY();
305 
306     if(w_set == LV_SIZE_CONTENT || h_set == LV_SIZE_CONTENT) {
307         lv_obj_refr_size(cont);
308     }
309 
310     lv_event_send(cont, LV_EVENT_LAYOUT_CHANGED, NULL);
311 
312     LV_TRACE_LAYOUT("finished");
313 }
314 
315 /**
316  * Find the last item of a track
317  */
find_track_end(lv_obj_t * cont,flex_t * f,int32_t item_start_id,lv_coord_t max_main_size,lv_coord_t item_gap,track_t * t)318 static int32_t find_track_end(lv_obj_t * cont, flex_t * f, int32_t item_start_id, lv_coord_t max_main_size,
319                               lv_coord_t item_gap, track_t * t)
320 {
321     lv_coord_t w_set = lv_obj_get_style_width(cont, LV_PART_MAIN);
322     lv_coord_t h_set = lv_obj_get_style_height(cont, LV_PART_MAIN);
323 
324     /*Can't wrap if the size if auto (i.e. the size depends on the children)*/
325     if(f->wrap && ((f->row && w_set == LV_SIZE_CONTENT) || (!f->row && h_set == LV_SIZE_CONTENT))) {
326         f->wrap = false;
327     }
328     lv_coord_t(*get_main_size)(const lv_obj_t *) = (f->row ? lv_obj_get_width : lv_obj_get_height);
329     lv_coord_t(*get_cross_size)(const lv_obj_t *) = (!f->row ? lv_obj_get_width : lv_obj_get_height);
330 
331     t->track_main_size = 0;
332     t->track_fix_main_size = 0;
333     t->grow_item_cnt = 0;
334     t->track_cross_size = 0;
335     t->item_cnt = 0;
336     t->grow_dsc = NULL;
337 
338     int32_t item_id = item_start_id;
339 
340     lv_obj_t * item = lv_obj_get_child(cont, item_id);
341     while(item) {
342         if(item_id != item_start_id && lv_obj_has_flag(item, LV_OBJ_FLAG_FLEX_IN_NEW_TRACK)) break;
343 
344         if(!lv_obj_has_flag_any(item, LV_OBJ_FLAG_IGNORE_LAYOUT | LV_OBJ_FLAG_HIDDEN | LV_OBJ_FLAG_FLOATING)) {
345             uint8_t grow_value = lv_obj_get_style_flex_grow(item, LV_PART_MAIN);
346             if(grow_value) {
347                 t->grow_item_cnt++;
348                 t->track_fix_main_size += item_gap;
349                 if(t->grow_dsc_calc) {
350                     grow_dsc_t * new_dsc = lv_mem_buf_get(sizeof(grow_dsc_t) * (t->grow_item_cnt));
351                     LV_ASSERT_MALLOC(new_dsc);
352                     if(new_dsc == NULL) return item_id;
353 
354                     if(t->grow_dsc) {
355                         lv_memcpy(new_dsc, t->grow_dsc, sizeof(grow_dsc_t) * (t->grow_item_cnt - 1));
356                         lv_mem_buf_release(t->grow_dsc);
357                     }
358                     new_dsc[t->grow_item_cnt - 1].item = item;
359                     new_dsc[t->grow_item_cnt - 1].min_size = f->row ? lv_obj_get_style_min_width(item,
360                                                                                                  LV_PART_MAIN) : lv_obj_get_style_min_height(item, LV_PART_MAIN);
361                     new_dsc[t->grow_item_cnt - 1].max_size = f->row ? lv_obj_get_style_max_width(item,
362                                                                                                  LV_PART_MAIN) : lv_obj_get_style_max_height(item, LV_PART_MAIN);
363                     new_dsc[t->grow_item_cnt - 1].grow_value = grow_value;
364                     new_dsc[t->grow_item_cnt - 1].clamped = 0;
365                     t->grow_dsc = new_dsc;
366                 }
367             }
368             else {
369                 lv_coord_t item_size = get_main_size(item);
370                 if(f->wrap && t->track_fix_main_size + item_size > max_main_size) break;
371                 t->track_fix_main_size += item_size + item_gap;
372             }
373 
374 
375             t->track_cross_size = LV_MAX(get_cross_size(item), t->track_cross_size);
376             t->item_cnt++;
377         }
378 
379         item_id += f->rev ? -1 : +1;
380         if(item_id < 0) break;
381         item = lv_obj_get_child(cont, item_id);
382     }
383 
384     if(t->track_fix_main_size > 0) t->track_fix_main_size -= item_gap; /*There is no gap after the last item*/
385 
386     /*If there is at least one "grow item" the track takes the full space*/
387     t->track_main_size = t->grow_item_cnt ? max_main_size : t->track_fix_main_size;
388 
389     /*Have at least one item in a row*/
390     if(item && item_id == item_start_id) {
391         item = cont->spec_attr->children[item_id];
392         get_next_item(cont, f->rev, &item_id);
393         if(item) {
394             t->track_cross_size = get_cross_size(item);
395             t->track_main_size = get_main_size(item);
396             t->item_cnt = 1;
397         }
398     }
399 
400     return item_id;
401 }
402 
403 /**
404  * Position the children in the same track
405  */
children_repos(lv_obj_t * cont,flex_t * f,int32_t item_first_id,int32_t item_last_id,lv_coord_t abs_x,lv_coord_t abs_y,lv_coord_t max_main_size,lv_coord_t item_gap,track_t * t)406 static void children_repos(lv_obj_t * cont, flex_t * f, int32_t item_first_id, int32_t item_last_id, lv_coord_t abs_x,
407                            lv_coord_t abs_y, lv_coord_t max_main_size, lv_coord_t item_gap, track_t * t)
408 {
409     void (*area_set_main_size)(lv_area_t *, lv_coord_t) = (f->row ? lv_area_set_width : lv_area_set_height);
410     lv_coord_t (*area_get_main_size)(const lv_area_t *) = (f->row ? lv_area_get_width : lv_area_get_height);
411     lv_coord_t (*area_get_cross_size)(const lv_area_t *) = (!f->row ? lv_area_get_width : lv_area_get_height);
412 
413     /*Calculate the size of grow items first*/
414     uint32_t i;
415     bool grow_reiterate  = true;
416     while(grow_reiterate) {
417         grow_reiterate = false;
418         lv_coord_t grow_value_sum = 0;
419         lv_coord_t grow_max_size = t->track_main_size - t->track_fix_main_size;
420         for(i = 0; i < t->grow_item_cnt; i++) {
421             if(t->grow_dsc[i].clamped == 0) {
422                 grow_value_sum += t->grow_dsc[i].grow_value;
423             }
424             else {
425                 grow_max_size -= t->grow_dsc[i].final_size;
426             }
427         }
428         lv_coord_t grow_unit;
429 
430         for(i = 0; i < t->grow_item_cnt; i++) {
431             if(t->grow_dsc[i].clamped == 0) {
432                 LV_ASSERT(grow_value_sum != 0);
433                 grow_unit = grow_max_size / grow_value_sum;
434                 lv_coord_t size = grow_unit * t->grow_dsc[i].grow_value;
435                 lv_coord_t size_clamp = LV_CLAMP(t->grow_dsc[i].min_size, size, t->grow_dsc[i].max_size);
436 
437                 if(size_clamp != size) {
438                     t->grow_dsc[i].clamped = 1;
439                     grow_reiterate = true;
440                 }
441                 t->grow_dsc[i].final_size = size_clamp;
442                 grow_value_sum -= t->grow_dsc[i].grow_value;
443                 grow_max_size  -= t->grow_dsc[i].final_size;
444             }
445         }
446     }
447 
448 
449     bool rtl = lv_obj_get_style_base_dir(cont, LV_PART_MAIN) == LV_BASE_DIR_RTL ? true : false;
450 
451     lv_coord_t main_pos = 0;
452 
453     lv_coord_t place_gap = 0;
454     place_content(f->main_place, max_main_size, t->track_main_size, t->item_cnt, &main_pos, &place_gap);
455     if(f->row && rtl) main_pos += lv_obj_get_content_width(cont);
456 
457     lv_obj_t * item = lv_obj_get_child(cont, item_first_id);
458     /*Reposition the children*/
459     while(item && item_first_id != item_last_id) {
460         if(lv_obj_has_flag_any(item, LV_OBJ_FLAG_IGNORE_LAYOUT | LV_OBJ_FLAG_HIDDEN | LV_OBJ_FLAG_FLOATING)) {
461             item = get_next_item(cont, f->rev, &item_first_id);
462             continue;
463         }
464         lv_coord_t grow_size = lv_obj_get_style_flex_grow(item, LV_PART_MAIN);
465         if(grow_size) {
466             lv_coord_t s = 0;
467             for(i = 0; i < t->grow_item_cnt; i++) {
468                 if(t->grow_dsc[i].item == item) {
469                     s = t->grow_dsc[i].final_size;
470                     break;
471                 }
472             }
473 
474             if(f->row) {
475                 item->w_layout = 1;
476                 item->h_layout = 0;
477             }
478             else {
479                 item->h_layout = 1;
480                 item->w_layout = 0;
481             }
482 
483             if(s != area_get_main_size(&item->coords)) {
484                 lv_obj_invalidate(item);
485 
486                 lv_area_t old_coords;
487                 lv_area_copy(&old_coords, &item->coords);
488                 area_set_main_size(&item->coords, s);
489                 lv_event_send(item, LV_EVENT_SIZE_CHANGED, &old_coords);
490                 lv_event_send(lv_obj_get_parent(item), LV_EVENT_CHILD_CHANGED, item);
491                 lv_obj_invalidate(item);
492             }
493         }
494         else {
495             item->w_layout = 0;
496             item->h_layout = 0;
497         }
498 
499         lv_coord_t cross_pos = 0;
500         switch(f->cross_place) {
501             case LV_FLEX_ALIGN_CENTER:
502                 /*Round up the cross size to avoid rounding error when dividing by 2
503                  *The issue comes up e,g, with column direction with center cross direction if an element's width changes*/
504                 cross_pos = (((t->track_cross_size + 1) & (~1)) - area_get_cross_size(&item->coords)) / 2;
505                 break;
506             case LV_FLEX_ALIGN_END:
507                 cross_pos = t->track_cross_size - area_get_cross_size(&item->coords);
508                 break;
509             default:
510                 break;
511         }
512 
513         if(f->row && rtl) main_pos -= area_get_main_size(&item->coords);
514 
515 
516         /*Handle percentage value of translate*/
517         lv_coord_t tr_x = lv_obj_get_style_translate_x(item, LV_PART_MAIN);
518         lv_coord_t tr_y = lv_obj_get_style_translate_y(item, LV_PART_MAIN);
519         lv_coord_t w = lv_obj_get_width(item);
520         lv_coord_t h = lv_obj_get_height(item);
521         if(LV_COORD_IS_PCT(tr_x)) tr_x = (w * LV_COORD_GET_PCT(tr_x)) / 100;
522         if(LV_COORD_IS_PCT(tr_y)) tr_y = (h * LV_COORD_GET_PCT(tr_y)) / 100;
523 
524         lv_coord_t diff_x = abs_x - item->coords.x1 + tr_x;
525         lv_coord_t diff_y = abs_y - item->coords.y1 + tr_y;
526         diff_x += f->row ? main_pos : cross_pos;
527         diff_y += f->row ? cross_pos : main_pos;
528 
529         if(diff_x || diff_y) {
530             lv_obj_invalidate(item);
531             item->coords.x1 += diff_x;
532             item->coords.x2 += diff_x;
533             item->coords.y1 += diff_y;
534             item->coords.y2 += diff_y;
535             lv_obj_invalidate(item);
536             lv_obj_move_children_by(item, diff_x, diff_y, false);
537         }
538 
539         if(!(f->row && rtl)) main_pos += area_get_main_size(&item->coords) + item_gap + place_gap;
540         else main_pos -= item_gap + place_gap;
541 
542         item = get_next_item(cont, f->rev, &item_first_id);
543     }
544 }
545 
546 /**
547  * Tell a start coordinate and gap for a placement type.
548  */
place_content(lv_flex_align_t place,lv_coord_t max_size,lv_coord_t content_size,lv_coord_t item_cnt,lv_coord_t * start_pos,lv_coord_t * gap)549 static void place_content(lv_flex_align_t place, lv_coord_t max_size, lv_coord_t content_size, lv_coord_t item_cnt,
550                           lv_coord_t * start_pos, lv_coord_t * gap)
551 {
552     if(item_cnt <= 1) {
553         switch(place) {
554             case LV_FLEX_ALIGN_SPACE_BETWEEN:
555             case LV_FLEX_ALIGN_SPACE_AROUND:
556             case LV_FLEX_ALIGN_SPACE_EVENLY:
557                 place = LV_FLEX_ALIGN_CENTER;
558                 break;
559             default:
560                 break;
561         }
562     }
563 
564     switch(place) {
565         case LV_FLEX_ALIGN_CENTER:
566             *gap = 0;
567             *start_pos += (max_size - content_size) / 2;
568             break;
569         case LV_FLEX_ALIGN_END:
570             *gap = 0;
571             *start_pos += max_size - content_size;
572             break;
573         case LV_FLEX_ALIGN_SPACE_BETWEEN:
574             *gap = (lv_coord_t)(max_size - content_size) / (lv_coord_t)(item_cnt - 1);
575             break;
576         case LV_FLEX_ALIGN_SPACE_AROUND:
577             *gap += (lv_coord_t)(max_size - content_size) / (lv_coord_t)(item_cnt);
578             *start_pos += *gap / 2;
579             break;
580         case LV_FLEX_ALIGN_SPACE_EVENLY:
581             *gap = (lv_coord_t)(max_size - content_size) / (lv_coord_t)(item_cnt + 1);
582             *start_pos += *gap;
583             break;
584         default:
585             *gap = 0;
586     }
587 }
588 
get_next_item(lv_obj_t * cont,bool rev,int32_t * item_id)589 static lv_obj_t * get_next_item(lv_obj_t * cont, bool rev, int32_t * item_id)
590 {
591     if(rev) {
592         (*item_id)--;
593         if(*item_id >= 0) return cont->spec_attr->children[*item_id];
594         else return NULL;
595     }
596     else {
597         (*item_id)++;
598         if((*item_id) < (int32_t)cont->spec_attr->child_cnt) return cont->spec_attr->children[*item_id];
599         else return NULL;
600     }
601 }
602 
603 #endif /*LV_USE_FLEX*/
604