feat(arc_label): support recolor feature

src/widgets/arc_label/lv_arc_label.c

@@ -46,7 +46,10 @@ static void lv_arc_label_constructor(const lv_obj_class_t * class_p, lv_obj_t *
 static void arc_label_draw_main(lv_event_t * e);
 static void lv_arc_label_event(const lv_obj_class_t * class_p, lv_event_t * e);
 static lv_value_precise_t calc_arc_text_total_angle(const char * text, const lv_font_t * font, uint32_t radius,
-                                                    const lv_value_precise_t angle_size, int32_t letter_space);
+                                                    const lv_value_precise_t angle_size, int32_t letter_space, bool recolor);
+static const char * recolor_cmd_get_next(const char * text_in, uint32_t len_in,
+                                         const char ** text_out, uint32_t * len_out,
+                                         lv_color_t * color_out);
 
 /**********************
  *  STATIC VARIABLES
@@ -367,6 +370,9 @@ static void arc_label_draw_main(lv_event_t * e)
     lv_obj_t * obj = lv_event_get_current_target(e);
     lv_arc_label_t * arc_label = (lv_arc_label_t *)obj;
 
+    const char * text = arc_label->text;
+    const char * text_start = text;
+
     lv_area_t coords;
     lv_obj_get_content_coords(obj, &coords);
 
@@ -407,27 +413,33 @@ static void arc_label_draw_main(lv_event_t * e)
             angle_start = angle_offset;
             break;
         case LV_ARC_LABEL_TEXT_ALIGN_CENTER:
-            angle_start = (arc_label->angle_size + angle_offset - calc_arc_text_total_angle(arc_label->text, font, arc_r,
+            angle_start = (arc_label->angle_size + angle_offset - calc_arc_text_total_angle(text_start, font, arc_r,
-                                                                                            arc_label->angle_size,
+                                                                                            arc_label->angle_size, letter_space, arc_label->recolor)) / 2;
-                                                                                            letter_space)) / 2;
             break;
         case LV_ARC_LABEL_TEXT_ALIGN_TRAILING:
-            angle_start = arc_label->angle_size - calc_arc_text_total_angle(arc_label->text, font, arc_r, arc_label->angle_size,
+            angle_start = arc_label->angle_size - calc_arc_text_total_angle(text_start, font, arc_r, arc_label->angle_size,
-                                                                            letter_space);
+                                                                            letter_space, arc_label->recolor);
             break;
         default:
             break;
     }
 
-    uint32_t word_i = 0;
     uint32_t processed_word_count = 0;
     lv_value_precise_t prev_letter_w = 0;
     lv_value_precise_t total_arc_length = arc_label->angle_size * M_PI / 180 * arc_r;
     lv_value_precise_t curr_total_arc_length = angle_start * M_PI / 180 * arc_r;
-    while(curr_total_arc_length <= total_arc_length) {
+
+    while(text) {
+        uint32_t word_i = 0;
+        uint32_t text_len = LV_TEXT_LEN_MAX;
+        lv_color_t recolor_color = color;
+        if(arc_label->recolor) text = recolor_cmd_get_next(text, LV_TEXT_LEN_MAX, &text_start, &text_len, &recolor_color);
+        else text = NULL;
+
+        while(word_i < text_len && curr_total_arc_length <= total_arc_length) {
             uint32_t letter;
             uint32_t letter_next;
-        lv_text_encoded_letter_next_2(arc_label->text, &letter, &letter_next, &word_i);
+            lv_text_encoded_letter_next_2(text_start, &letter, &letter_next, &word_i);
             const lv_value_precise_t letter_w = lv_font_get_glyph_width(font, letter, letter_next);
 
             if(processed_word_count > 0) {
@@ -457,7 +469,7 @@ static void arc_label_draw_main(lv_event_t * e)
             lv_draw_letter_dsc_t dsc;
             lv_draw_letter_dsc_init(&dsc);
             dsc.font = font;
-        dsc.color = color;
+            dsc.color = arc_label->recolor ? recolor_color : color;
             dsc.opa = opa;
             if(arc_label->dir == LV_ARC_LABEL_DIR_CLOCKWISE) dsc.rotation = (curr_angle + 90) * 10;
             else dsc.rotation = (curr_angle - 90) * 10;
@@ -490,24 +502,32 @@ static void arc_label_draw_main(lv_event_t * e)
             lv_draw_line(layer, &line_dsc);
 #endif
         }
+    }
 }
 
 static lv_value_precise_t calc_arc_text_total_angle(const char * text, const lv_font_t * font, const uint32_t radius,
-                                                    const lv_value_precise_t angle_size, const int32_t letter_space)
+                                                    const lv_value_precise_t angle_size, const int32_t letter_space, const bool recolor)
 {
-    uint32_t word_i = 0;
+    const char * text_start = text;
     uint32_t processed_letter_count = 0;
     lv_value_precise_t prev_letter_w = 0;
     const lv_value_precise_t angle_size_in_arc_length = angle_size * M_PI / 180 * radius;
     lv_value_precise_t total_arc_length = 0;
-    while(total_arc_length < angle_size_in_arc_length) {
+
+    while(text) {
+        uint32_t word_i = 0;
+        uint32_t text_len = LV_TEXT_LEN_MAX;
+        if(recolor) text = recolor_cmd_get_next(text, LV_TEXT_LEN_MAX, &text_start, &text_len, NULL);
+        else text = NULL;
+
+        while(word_i <= text_len && total_arc_length < angle_size_in_arc_length) {
             if(total_arc_length > angle_size_in_arc_length) {
                 break;
             }
 
             uint32_t letter;
             uint32_t letter_next;
-        lv_text_encoded_letter_next_2(text, &letter, &letter_next, &word_i);
+            lv_text_encoded_letter_next_2(text_start, &letter, &letter_next, &word_i);
             const lv_value_precise_t letter_w = lv_font_get_glyph_width(font, letter, letter_next);
 
             if(processed_letter_count == 0) {
@@ -525,8 +545,61 @@ static lv_value_precise_t calc_arc_text_total_angle(const char * text, const lv_
             prev_letter_w = letter_w;
             processed_letter_count++;
         }
+    }
 
     return total_arc_length * 180 / M_PI / radius;
 }
 
+static const char * recolor_cmd_get_next(const char * text_in, uint32_t len_in,
+                                         const char ** text_out, uint32_t * len_out,
+                                         lv_color_t * color_out)
+{
+    if(!text_in || len_in == 0 || *text_in == '\0') return NULL;
+
+    const char * text = text_in;
+    const char * text_end = text_in + len_in;
+    bool has_cmd = false;
+
+    if(*text == LV_TXT_COLOR_CMD[0]) {
+        if(len_in < 8) {
+            if(text_out) *text_out = text_in;
+            if(len_out) *len_out = len_in;
+            return NULL;
+        }
+        has_cmd = true;
+        text++;
+
+        int32_t index = 0;
+        uint8_t color_buf[6];
+        while(*text && index < 6) {
+            uint8_t ch = text[index];
+            if(!((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'F') || (ch >= 'a' && ch <= 'f'))) break;
+            if(ch >= 'a' && ch <= 'f')      ch -= 'a' - 10;
+            else if(ch >= 'A' && ch <= 'F') ch -= 'A' - 10;
+            else                            ch -= '0';
+            color_buf[index] = ch;
+            index++;
+        }
+
+        const bool has_valid_param = index == 6 && text[index] == ' ';
+
+        text += index;
+        if(has_valid_param && color_out)
+            *color_out = lv_color_make(color_buf[0] << 4 | color_buf[1],
+                                       color_buf[2] << 4 | color_buf[3],
+                                       color_buf[4] << 4 | color_buf[5]);
+
+        while(text < text_end && *text && *text++ != ' ') { }
+    }
+
+    const char * text_segment_start = text;
+    while(text < text_end && *text && *text != LV_TXT_COLOR_CMD[0]) text++;
+    if(text_out) *text_out = text_segment_start;
+    if(len_out)  *len_out = text - text_segment_start;
+    if(*text == '\0')  return NULL;
+    if(has_cmd && *text == LV_TXT_COLOR_CMD[0]) text++;
+
+    return text < text_end && *text ? text : NULL;
+}
+
 #endif