Portions of characters are generated wrong

[rchaucha]

I've used the converter with the following dump command :
lv_font_conv --font svthin.ttf --size 40 --bpp 1 --no-compress --symbols 4 --format dump -o font_dump --full-info

Here I dump only the "4" character which has a problem, but it's not the only one ("m" also has a similar problem for instance).

The font I'm using is this one : https://fontstruct.com/fontstructions/show/1543912/svthin

Here is the difference between the original "4" font and the one dumped :

Original : Ouput :

The difference can be found directly in the generated pixels in the font_info.json file :

As I said, the problem can be found on the "m" character too, as you can see here with the middle leg being smaller than the other :

Original : Ouput :

Code :

[kisvegabor]

I'm not sure if this is the issue here, but usually pixel fonts work well only with some specific sizes. For example if a character is composed of 10 lines and you want size=11 it needs to add an extra pixel somewhere.