Apparently the directives that the OFFLINE converter is placing are not compatible with LVGL 9.3.0

[rtek1000]

When trying to specify another font in the style that is not linked in the LV_FONT_DEFAULT definition, the screen gets stuck where the letter would be displayed.

I copied the instructions from the footer of the lv_monterrat_18 font file to the lv_freesans_18 font file. Now it works.

lv_monterrat_18:

/*--------------------
 *  ALL CUSTOM DATA
 *--------------------*/

#if LVGL_VERSION_MAJOR >= 8
/*Store all the custom data of the font*/

static const lv_font_fmt_txt_dsc_t font_dsc = {
#else
static lv_font_fmt_txt_dsc_t font_dsc = {
#endif
    .glyph_bitmap = glyph_bitmap,
    .glyph_dsc = glyph_dsc,
    .cmaps = cmaps,
    .kern_dsc = &kern_classes,
    .kern_scale = 16,
    .cmap_num = 2,
    .bpp = 4,
    .kern_classes = 1,
    .bitmap_format = 0,

};

/*-----------------
 *  PUBLIC FONT
 *----------------*/

/*Initialize a public general font descriptor*/
#if LVGL_VERSION_MAJOR >= 8
const lv_font_t lv_font_montserrat_18 = {
#else
lv_font_t lv_font_montserrat_18 = {
#endif
    .get_glyph_dsc = lv_font_get_glyph_dsc_fmt_txt,    /*Function pointer to get glyph's data*/
    .get_glyph_bitmap = lv_font_get_bitmap_fmt_txt,    /*Function pointer to get glyph's bitmap*/
    .line_height = 21,          /*The maximum line height required by the font*/
    .base_line = 4,             /*Baseline measured from the bottom of the line*/
#if !(LVGL_VERSION_MAJOR == 6 && LVGL_VERSION_MINOR == 0)
    .subpx = LV_FONT_SUBPX_NONE,
#endif
#if LV_VERSION_CHECK(7, 4, 0) || LVGL_VERSION_MAJOR >= 8
    .underline_position = -1,
    .underline_thickness = 1,
#endif
    .dsc = &font_dsc           /*The custom font data. Will be accessed by `get_glyph_bitmap/dsc` */
};

lv_freesans_18:

/*--------------------
 *  ALL CUSTOM DATA
 *--------------------*/

#if LVGL_VERSION_MAJOR == 8
/*Store all the custom data of the font*/
static  lv_font_fmt_txt_glyph_cache_t cache;
#endif

#if LVGL_VERSION_MAJOR >= 8
static const lv_font_fmt_txt_dsc_t font_dsc = {
#else
static lv_font_fmt_txt_dsc_t font_dsc = {
#endif
    .glyph_bitmap = glyph_bitmap,
    .glyph_dsc = glyph_dsc,
    .cmaps = cmaps,
    .kern_dsc = &kern_classes,
    .kern_scale = 16,
    .cmap_num = 2,
    .bpp = 4,
    .kern_classes = 1,
    .bitmap_format = 0,
#if LVGL_VERSION_MAJOR == 8
    .cache = &cache
#endif
};

extern const lv_font_t lv_font_freesans_18;


/*-----------------
 *  PUBLIC FONT
 *----------------*/

/*Initialize a public general font descriptor*/
#if LVGL_VERSION_MAJOR >= 8
const lv_font_t lv_font_freesans_18 = {
#else
lv_font_t lv_font_freesans_18 = {
#endif
    .get_glyph_dsc = lv_font_get_glyph_dsc_fmt_txt,    /*Function pointer to get glyph's data*/
    .get_glyph_bitmap = lv_font_get_bitmap_fmt_txt,    /*Function pointer to get glyph's bitmap*/
    .line_height = 22,          /*The maximum line height required by the font*/
    .base_line = 4,             /*Baseline measured from the bottom of the line*/
#if !(LVGL_VERSION_MAJOR == 6 && LVGL_VERSION_MINOR == 0)
    .subpx = LV_FONT_SUBPX_NONE,
#endif
#if LV_VERSION_CHECK(7, 4, 0) || LVGL_VERSION_MAJOR >= 8
    .underline_position = -3,
    .underline_thickness = 1,
#endif
    .dsc = &font_dsc,          /*The custom font data. Will be accessed by `get_glyph_bitmap/dsc` */
#if LV_VERSION_CHECK(8, 2, 0) || LVGL_VERSION_MAJOR >= 9
    .fallback = &lv_font_freesans_18,
#endif
    .user_data = NULL,
};

REF.: https://github.com/lvgl/lvgl/issues/8480#issuecomment-3005677152

[kisvegabor]

We have updated the online font converter and it should work well now.