fix(label): do not break last line for LV_LABEL_LONG_DOT (#5606) (#6362)

src/misc/lv_text.c

@@ -164,12 +164,11 @@ void lv_text_get_size(lv_point_t * size_res, const char * text, const lv_font_t
  * @param max_width max width of the text (break the lines to fit this size). Set COORD_MAX to avoid line breaks
  * @param flags settings for the text from 'txt_flag_type' enum
  * @param[out] word_w_ptr width (in pixels) of the parsed word. May be NULL.
- * @param force Force return the fraction of the word that can fit in the provided space.
  * @return the index of the first char of the next word (in byte index not letter index. With UTF-8 they are different)
  */
 static uint32_t lv_text_get_next_word(const char * txt, const lv_font_t * font,
                                       int32_t letter_space, int32_t max_width,
-                                      lv_text_flag_t flag, uint32_t * word_w_ptr, bool force)
+                                      lv_text_flag_t flag, uint32_t * word_w_ptr)
 {
     if(txt == NULL || txt[0] == '\0') return 0;
     if(font == NULL) return 0;
@@ -239,14 +238,14 @@ static uint32_t lv_text_get_next_word(const char * txt, const lv_font_t * font,
 #if LV_TXT_LINE_BREAK_LONG_LEN > 0
     /*Word doesn't fit in provided space, but isn't "long"*/
     if(word_len < LV_TXT_LINE_BREAK_LONG_LEN) {
-        if(force) return break_index;
+        if(flag & LV_TEXT_FLAG_BREAK_ALL) return break_index;
         if(word_w_ptr != NULL) *word_w_ptr = 0; /*Return no word*/
         return 0;
     }
 
     /*Word is "long," but insufficient amounts can fit in provided space*/
     if(break_letter_count < LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN) {
-        if(force) return break_index;
+        if(flag & LV_TEXT_FLAG_BREAK_ALL) return break_index;
         if(word_w_ptr != NULL) *word_w_ptr = 0;
         return 0;
     }
@@ -266,7 +265,7 @@ static uint32_t lv_text_get_next_word(const char * txt, const lv_font_t * font,
     }
     return i;
 #else
-    if(force) return break_index;
+    if(flag & LV_TEXT_FLAG_BREAK_ALL) return break_index;
     if(word_w_ptr != NULL) *word_w_ptr = 0; /*Return no word*/
     (void) break_letter_count;
     return 0;
@@ -301,8 +300,11 @@ uint32_t lv_text_get_next_line(const char * txt, const lv_font_t * font,
     uint32_t i = 0;                                        /*Iterating index into txt*/
 
     while(txt[i] != '\0' && max_width > 0) {
+        lv_text_flag_t word_flag = flag;
+        if(i == 0) word_flag |= LV_TEXT_FLAG_BREAK_ALL;
+
         uint32_t word_w = 0;
-        uint32_t advance = lv_text_get_next_word(&txt[i], font, letter_space, max_width, flag, &word_w, i == 0);
+        uint32_t advance = lv_text_get_next_word(&txt[i], font, letter_space, max_width, word_flag, &word_w);
         max_width -= word_w;
         line_w += word_w;
 

src/misc/lv_text.h

@@ -36,9 +36,13 @@ extern "C" {
  */
 
 enum _lv_text_flag_t {
-    LV_TEXT_FLAG_NONE    = 0x00,
-    LV_TEXT_FLAG_EXPAND  = 0x01, /**< Ignore max-width to avoid automatic word wrapping*/
-    LV_TEXT_FLAG_FIT     = 0x02, /**< Max-width is already equal to the longest line. (Used to skip some calculation)*/
+    LV_TEXT_FLAG_NONE      = 0x00,
+    LV_TEXT_FLAG_EXPAND    = 0x01, /**< Ignore max-width to avoid automatic word wrapping*/
+    LV_TEXT_FLAG_FIT       = 0x02, /**< Max-width is already equal to the longest line. (Used to skip some calculation)*/
+    LV_TEXT_FLAG_BREAK_ALL = 0x04, /**< To prevent overflow, insert breaks between any two characters.
+                                        Otherwise breaks are inserted at word boundaries, as configured via LV_TXT_BREAK_CHARS
+                                        or according to LV_TXT_LINE_BREAK_LONG_LEN, LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN,
+                                        and LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN.*/
 };
 
 #ifdef DOXYGEN

src/widgets/label/lv_label.c

@@ -291,11 +291,15 @@ void lv_label_get_letter_pos(const lv_obj_t * obj, uint32_t char_id, lv_point_t
     lv_area_t txt_coords;
     lv_obj_get_content_coords(obj, &txt_coords);
     const int32_t max_w = lv_area_get_width(&txt_coords);
+    const int32_t max_h = lv_area_get_height(&txt_coords);
 
     int32_t y = 0;
     uint32_t line_start = 0;
     uint32_t new_line_start = 0;
     while(txt[new_line_start] != '\0') {
+        bool last_line = y + letter_height + line_space + letter_height > max_h;
+        if(last_line && label->long_mode == LV_LABEL_LONG_DOT) flag |= LV_TEXT_FLAG_BREAK_ALL;
+
         new_line_start += lv_text_get_next_line(&txt[line_start], font, letter_space, max_w, NULL, flag);
         if(byte_id < new_line_start || txt[new_line_start] == '\0')
             break; /*The line of 'index' letter begins at 'line_start'*/
@@ -370,7 +374,8 @@ uint32_t lv_label_get_letter_on(const lv_obj_t * obj, lv_point_t * pos_in, bool
     const char * txt         = lv_label_get_text(obj);
     uint32_t line_start      = 0;
     uint32_t new_line_start  = 0;
-    int32_t max_w         = lv_area_get_width(&txt_coords);
+    int32_t max_w = lv_area_get_width(&txt_coords);
+    int32_t max_h = lv_area_get_height(&txt_coords);
     const lv_font_t * font   = lv_obj_get_style_text_font(obj, LV_PART_MAIN);
     const int32_t line_space = lv_obj_get_style_text_line_space(obj, LV_PART_MAIN);
     const int32_t letter_space = lv_obj_get_style_text_letter_space(obj, LV_PART_MAIN);
@@ -381,6 +386,11 @@ uint32_t lv_label_get_letter_on(const lv_obj_t * obj, lv_point_t * pos_in, bool
 
     /*Search the line of the index letter*/;
     while(txt[line_start] != '\0') {
+        /*If dots will be shown, break the last visible line anywhere,
+         *not only at word boundaries.*/
+        bool last_line = y + letter_height + line_space + letter_height > max_h;
+        if(last_line && label->long_mode == LV_LABEL_LONG_DOT) flag |= LV_TEXT_FLAG_BREAK_ALL;
+
         new_line_start += lv_text_get_next_line(&txt[line_start], font, letter_space, max_w, NULL, flag);
 
         if(pos.y <= y + letter_height) {
@@ -479,7 +489,8 @@ bool lv_label_is_char_under_pos(const lv_obj_t * obj, lv_point_t * pos)
     lv_label_t * label     = (lv_label_t *)obj;
     uint32_t line_start      = 0;
     uint32_t new_line_start  = 0;
-    const int32_t max_w         = lv_area_get_width(&txt_coords);
+    const int32_t max_w = lv_area_get_width(&txt_coords);
+    const int32_t max_h = lv_area_get_height(&txt_coords);
     const lv_font_t * font   = lv_obj_get_style_text_font(obj, LV_PART_MAIN);
     const int32_t line_space = lv_obj_get_style_text_line_space(obj, LV_PART_MAIN);
     const int32_t letter_space = lv_obj_get_style_text_letter_space(obj, LV_PART_MAIN);
@@ -490,6 +501,9 @@ bool lv_label_is_char_under_pos(const lv_obj_t * obj, lv_point_t * pos)
     /*Search the line of the index letter*/
     int32_t y = 0;
     while(txt[line_start] != '\0') {
+        bool last_line = y + letter_height + line_space + letter_height > max_h;
+        if(last_line && label->long_mode == LV_LABEL_LONG_DOT) flag |= LV_TEXT_FLAG_BREAK_ALL;
+
         new_line_start += lv_text_get_next_line(&txt[line_start], font, letter_space, max_w, NULL, flag);
 
         if(pos->y <= y + letter_height) break; /*The line is found (stored in 'line_start')*/

tests/src/test_cases/widgets/test_label.c

@@ -598,6 +598,8 @@ void test_label_max_width(void)
     lv_label_set_text(test_label1, long_text);
     lv_obj_set_width(test_label1, 600);
     lv_obj_set_style_max_width(test_label1, 200, LV_PART_MAIN);
+    lv_obj_set_style_bg_color(test_label1, lv_palette_main(LV_PALETTE_GREY), LV_PART_MAIN);
+    lv_obj_set_style_bg_opa(test_label1, LV_OPA_100, LV_PART_MAIN);
 
     lv_obj_t * test_label2 = lv_label_create(lv_screen_active());
     lv_label_set_text(test_label2, long_text);
@@ -605,6 +607,8 @@ void test_label_max_width(void)
     lv_obj_set_height(test_label2, 50);
     lv_obj_set_x(test_label2, 300);
     lv_obj_set_style_max_width(test_label2, 200, LV_PART_MAIN);
+    lv_obj_set_style_bg_color(test_label2, lv_palette_main(LV_PALETTE_GREY), LV_PART_MAIN);
+    lv_obj_set_style_bg_opa(test_label2, LV_OPA_100, LV_PART_MAIN);
     lv_label_set_long_mode(test_label2, LV_LABEL_LONG_DOT);
 
     TEST_ASSERT_EQUAL_SCREENSHOT("widgets/label_max_width.png");