Unsolved License Plate Font Size

If you just modified the texture file ( MOD_license_plate.json)
"text" : { "x" : 0.5, "y" : 0.85, "scale" : 1, "color" : "white", "limit" : 12},

If you are creating a new font (platfont.json)
"char": [
{
"id": "45",
"x": "0",
"y": "0",
"width": "56",
"height": "115",
"xoffset": "0",
"yoffset": "0",
"xadvance": "56",
"page": "0",
"chnl": "15"
},

 

If you have special characters you should do a new font.
If not you should just replace the original texture

This is JSON, char is an array of objects

the object is defined by the ID which is the decimal value of the character in the ascii table (45 = '-' dash)
then all other properties are used to get where the uper-left and the size of the char is on the font texture

 

In the picture you will see that it's a modified font

I reuse the same position of letter as the default font (note : it should be repeated because the first ones are minuscules)

I have to add some special characters because french one have a logo and an area code at the end of the licence plate

If you don't have any special things needed you can use the default font with a modded texture
For a modded texture you can just change this

Code:

            "diffuse" : {
                "spriteImg" : "vehicles\common\licenseplates\MOD_license_plate\platefont_d.png",

and then tweak the scale (in the json, try to have the same letter size)

 

you can use any image editor I think (GIMP, paint.net, photoshop, Inkscape ....)
If you have your font as a windows font you just replace the letters
if all letters have the same width you can do it line by line
else you will have to place all letter by hand

I recommend using layers, this way you will know how to position the new letters