feat(draw/sw): added support for 3 bpp font rendering (#7350)

Co-authored-by: Gabor Kiss-Vamosi <kisvegabor@gmail.com>

docs/details/main-components/font.rst

@@ -221,7 +221,8 @@ However, there are some limitations:
 Compressed fonts
 ----------------
 
-The bitmaps of fonts can be compressed by
+The built-in font engine supports compressed bitmaps.
+Compressed fonts can be generated by
 
 - ticking the ``Compressed`` check box in the online converter
 - not passing the ``--no-compress`` flag to the offline converter (compression is applied by default)
@@ -235,6 +236,8 @@ because
 - they can be compressed better
 - and probably they are used less frequently then the medium-sized fonts, so the performance cost is smaller.
 
+Compressed fonts also support ``bpp=3``.
+
 Kerning
 -------
 

src/draw/sw/lv_draw_sw_letter.c

@@ -83,6 +83,7 @@ static void LV_ATTRIBUTE_FAST_MEM draw_letter_cb(lv_draw_unit_t * draw_unit, lv_
                 break;
             case LV_FONT_GLYPH_FORMAT_A1:
             case LV_FONT_GLYPH_FORMAT_A2:
+            case LV_FONT_GLYPH_FORMAT_A3:
             case LV_FONT_GLYPH_FORMAT_A4:
             case LV_FONT_GLYPH_FORMAT_A8:
             case LV_FONT_GLYPH_FORMAT_A1_ALIGNED:

src/draw/vg_lite/lv_draw_vg_lite_label.c

@@ -100,6 +100,7 @@ static void draw_letter_cb(lv_draw_unit_t * draw_unit, lv_draw_glyph_dsc_t * gly
         switch(glyph_draw_dsc->format) {
             case LV_FONT_GLYPH_FORMAT_A1:
             case LV_FONT_GLYPH_FORMAT_A2:
+            case LV_FONT_GLYPH_FORMAT_A3:
             case LV_FONT_GLYPH_FORMAT_A4:
             case LV_FONT_GLYPH_FORMAT_A8:
             case LV_FONT_GLYPH_FORMAT_A1_ALIGNED:

src/font/lv_font.h

@@ -39,6 +39,7 @@ typedef enum {
     /**< Legacy simple formats with no byte padding at end of the lines*/
     LV_FONT_GLYPH_FORMAT_A1     = 0x01, /**< 1 bit per pixel*/
     LV_FONT_GLYPH_FORMAT_A2     = 0x02, /**< 2 bit per pixel*/
+    LV_FONT_GLYPH_FORMAT_A3     = 0x03, /**< 3 bit per pixel*/
     LV_FONT_GLYPH_FORMAT_A4     = 0x04, /**< 4 bit per pixel*/
     LV_FONT_GLYPH_FORMAT_A8     = 0x08, /**< 8 bit per pixel*/
 

tests/CMakeLists.txt

@@ -293,7 +293,7 @@ add_library(test_common
         src/test_assets/test_font_montserrat_ascii_1bpp.c
         src/test_assets/test_font_montserrat_ascii_2bpp.c
         src/test_assets/test_font_montserrat_ascii_4bpp.c
-        src/test_assets/test_font_montserrat_ascii_4bpp_compressed.c
+        src/test_assets/test_font_montserrat_ascii_3bpp_compressed.c
         src/test_assets/test_font_1_bin.c
         src/test_assets/test_font_2_bin.c
         src/test_assets/test_font_3_bin.c

tests/src/test_cases/draw/test_draw_label.c

@@ -33,14 +33,12 @@ static void all_labels_create(const char * name, lv_style_t * style)
     LV_FONT_DECLARE(test_font_montserrat_ascii_1bpp);
     LV_FONT_DECLARE(test_font_montserrat_ascii_2bpp);
     LV_FONT_DECLARE(test_font_montserrat_ascii_4bpp);
-    LV_FONT_DECLARE(test_font_montserrat_ascii_4bpp_compressed);
-    //    LV_FONT_DECLARE(test_font_montserrat_ascii_4bpp_subpx);
+    LV_FONT_DECLARE(test_font_montserrat_ascii_3bpp_compressed);
 
     label_create(&test_font_montserrat_ascii_1bpp, style, "1bpp font");
     label_create(&test_font_montserrat_ascii_2bpp, style, "2bpp font");
     label_create(&test_font_montserrat_ascii_4bpp, style, "4bpp font");
-    label_create(&test_font_montserrat_ascii_4bpp_compressed, style, "4bpp compressed font");
-    //    label_create(&test_font_montserrat_ascii_4bpp_subpx, style, "4bpp subpx font");
+    label_create(&test_font_montserrat_ascii_3bpp_compressed, style, "3bpp compressed font");
 
     char buf[64];
     lv_snprintf(buf, sizeof(buf), "draw/label_%s.png", name);