fix(text): do not draw letters treated as marker (#4865)

Signed-off-by: Xu Xingliang <xuxingliang@xiaomi.com>

src/draw/lv_draw_label.c

@@ -100,6 +100,8 @@ LV_ATTRIBUTE_FAST_MEM void lv_draw_letter(lv_layer_t * layer, lv_draw_label_dsc_
         return;
     }
 
+    if(_lv_text_is_marker(unicode_letter)) return;
+
     lv_font_glyph_dsc_t g;
     lv_font_get_glyph_dsc(dsc->font, &g, unicode_letter, 0);
 
@@ -362,16 +364,14 @@ static void draw_letter(lv_draw_unit_t * draw_unit, lv_draw_glyph_dsc_t * dsc,
 {
     lv_font_glyph_dsc_t g;
 
+    if(_lv_text_is_marker(letter)) /*Markers are valid letters but should not be rendered.*/
+        return;
+
     LV_PROFILER_BEGIN;
     bool g_ret = lv_font_get_glyph_dsc(font, &g, letter, '\0');
     if(g_ret == false) {
-        /*Add warning if the dsc is not found
+        /*Add warning if the dsc is not found*/
-         *but do not print warning for non printable ASCII chars (e.g. '\n')*/
+        LV_LOG_WARN("lv_draw_letter: glyph dsc. not found for U+%" LV_PRIX32, letter);
-        if(letter >= 0x20 &&
-           letter != 0xf8ff && /*LV_SYMBOL_DUMMY*/
-           letter != 0x200c) { /*ZERO WIDTH NON-JOINER*/
-            LV_LOG_WARN("lv_draw_letter: glyph dsc. not found for U+%" LV_PRIX32, letter);
-        }
     }
 
     /*Don't draw anything if the character is empty. E.g. space*/

src/font/lv_font.c

@@ -8,9 +8,11 @@
  *********************/
 
 #include "lv_font.h"
+#include "../misc/lv_text.h"
 #include "../misc/lv_utils.h"
 #include "../misc/lv_log.h"
 #include "../misc/lv_assert.h"
+#include "../stdlib/lv_string.h"
 
 /*********************
  *      DEFINES
@@ -86,21 +88,13 @@ bool lv_font_get_glyph_dsc(const lv_font_t * font_p, lv_font_glyph_dsc_t * dsc_o
     }
 #endif
 
-    if(letter < 0x20 ||
-       letter == 0xf8ff || /*LV_SYMBOL_DUMMY*/
-       letter == 0x200c) { /*ZERO WIDTH NON-JOINER*/
-        dsc_out->box_w = 0;
-        dsc_out->adv_w = 0;
-    }
-    else {
 #if LV_USE_FONT_PLACEHOLDER
-        dsc_out->box_w = font_p->line_height / 2;
+    dsc_out->box_w = font_p->line_height / 2;
-        dsc_out->adv_w = dsc_out->box_w + 2;
+    dsc_out->adv_w = dsc_out->box_w + 2;
 #else
-        dsc_out->box_w = 0;
+    dsc_out->box_w = 0;
-        dsc_out->adv_w = 0;
+    dsc_out->adv_w = 0;
 #endif
-    }
 
     dsc_out->resolved_font = NULL;
     dsc_out->box_h = font_p->line_height;
@@ -116,6 +110,10 @@ uint16_t lv_font_get_glyph_width(const lv_font_t * font, uint32_t letter, uint32
 {
     LV_ASSERT_NULL(font);
     lv_font_glyph_dsc_t g;
+
+    /*Return zero if letter is marker*/
+    if(_lv_text_is_marker(letter)) return 0;
+
     lv_font_get_glyph_dsc(font, &g, letter, letter_next);
     return g.adv_w;
 }

src/misc/lv_text.h

@@ -220,6 +220,41 @@ static inline bool _lv_text_is_a_word(uint32_t letter)
     return false;
 }
 
+/**
+ * Test if character can be treated as marker, and don't need to be rendered.
+ * Note, this is not a full list. Add your findings to the list.
+ *
+ * @param letter a letter
+ * @return true if so
+ */
+static inline bool _lv_text_is_marker(uint32_t letter)
+{
+    if(letter < 0x20) return true;
+
+    /*U+061C ARABIC LETTER MARK, see https://www.compart.com/en/unicode/block/U+0600*/
+    if(letter == 0x061C) return true;
+
+    /*U+115F HANGUL CHOSEONG FILLER, See https://www.compart.com/en/unicode/block/U+1100*/
+    if(letter == 0x115F) return true;
+    /*U+1160 HANGUL JUNGSEONG FILLER*/
+    if(letter == 0x1160) return true;
+
+    /*See https://www.compart.com/en/unicode/block/U+1800*/
+    if(letter >= 0x180B && letter <= 0x180E) return true;
+
+    /*See https://www.compart.com/en/unicode/block/U+2000*/
+    if(letter >= 0x200B && letter <= 0x200F) return true;
+    if(letter >= 0x2028 && letter <= 0x202F) return true;
+    if(letter >= 0x205F && letter <= 0x206F) return true;
+
+    /*U+FEFF ZERO WIDTH NO-BREAK SPACE, see https://www.compart.com/en/unicode/block/U+FE70*/
+    if(letter == 0xFEFF) return true;
+
+    if(letter == 0xF8FF) return true; /*LV_SYMBOL_DUMMY*/
+
+    return false;
+}
+
 /***************************************************************
  *  GLOBAL FUNCTION POINTERS FOR CHARACTER ENCODING INTERFACE
  ***************************************************************/