Select a custom default font in KConfig

[ntd]

lvgl 9.5.0 on an ESP32S3 board.

Hi all,

my GUI uses custom fonts exclusively, so all montserrat fonts are disabled. In my lv_conf.h I select my custom default font in this way:

#define LV_FONT_CUSTOM_DECLARE \
    LV_FONT_DECLARE(font_geist_medium_20)

/** Always set a default font */
#define LV_FONT_DEFAULT &font_geist_medium_20

So far so good, no problems there.

Now I want to replicate this environment by using idf.py menuconfig but I did not find any way to do that, apart from setting CONFIG_LV_CONF_SKIP=n and using a custom lv_conf.h. I did not try that because it seems to me a clear declaration of defeat.

Am I missing something?

[arturv2000]

There is this in the release notes for the new v9.6

Migrating from v9.5 to v9.6 | LVGL Open

what I have done with some required “configs” was to add to the project CMakeList.txt

add_compile_definitions(CONFIG_LV_SYSMON_GET_IDLE=lv_timer_get_idle)
add_compile_definitions(CONFIG_LV_ATTRIBUTE_LARGE_RAM_ARRAY=EXT_RAM_BSS_ATTR)

for example…

[kisvegabor]

cc @AndreCostaaa

[AndreCostaaa]

Hi these work arounds are no longer required. So the whole issue is that it’s impossible to declare raw C expression in kconfig, it requires a header file or via some compiler definitions

Starting in v9.6 the following pattern was introduced:

Kconfig

that is you can directly define in your .config file:

LV_SYSMON_USE_CUSTOM_INCLUDE=y

LV_SYSMON_CUSTOM_INCLUDE=“path/to/something.h”

LVGL then includes path/to/something.h for you so you can define LV_SYSMON_GET_IDLE in that file and it will be picked up

The same pattern exists for all modules where the user can pass a custom C expression, font is also one of them

Let me know what you think

[ntd]

@AndreCostaaa

Let me know what you think

If I understood you correctly, in 9.6 I could include my own custom header file after the generated one. In my case I would need to do something like:

#undef LV_FONT_CUSTOM_DECLARE
#define LV_FONT_CUSTOM_DECLARE \
    LV_FONT_DECLARE(font_geist_medium_20)

#undef LV_FONT_DEFAULT
#define LV_FONT_DEFAULT &font_geist_medium_20

After that I would need to add font_geist_medium_20.c (or whatever C file defines that font) to the linking process in some way.

That sounds reasonable to me, although I would rename LV_SYSMON_USE_CUSTOM_INCLUDE and friends to LV_USE_CUSTOM_INCLUDE as the current name is quite misleading.

[AndreCostaaa]

Yes that is correct, although

in this case you would use

LV_FONT_USE_CUSTOM_INCLUDE and LV_FONT_CUSTOM_INCLUDE instead of SYSMON

There is one custom include per module that needs it as to avoid having one big custom include with every possibility

[ntd]

@AndreCostaaa

LV_FONT_USE_CUSTOM_INCLUDE and LV_FONT_CUSTOM_INCLUDE instead of SYSMON

Even better. Thank you for your help.

[ntd]

I can confirm it works. And this is the content of main/gui-font.h:

#define LV_FONT_CUSTOM_DECLARE \
        LV_FONT_DECLARE(font_geist_bold_24) \
        LV_FONT_DECLARE(font_geist_medium_20) \
        LV_FONT_DECLARE(font_geist_medium_40) \
        LV_FONT_DECLARE(font_geist_medium_48) \
        LV_FONT_DECLARE(font_geist_regular_20)
#undef LV_FONT_DEFAULT
#define LV_FONT_DEFAULT &font_geist_medium_20