Hacking Help Needed Interpreting Hexes/UTF-8 for Acekard Theme

[WhatManual]

Though it feels like a very noob question to ask, how do I interpret the following hexes? This is found in the uisettings file in the theme and I assume these are color hexes, but it's too short to be a straight color hex. This is just a small part of the uisettings file.

(I'd just snip the damn uisettings file but I'm a newcomer and cant post images)

I've stuffed it into an online UTF-8 Tool, interpreting the numbers as a hex code print, which was the only option I've tried both within and outside of the UTF-8 that made the numbers intelligible into a hex. Even then, I'm not certain whether the outputted colors correlate correctly (it may just be the black background, but all of the outputted hexes are too light. 0x0C0F, the highlight color for the [calendar day] is interpreted as E0B08F, which seems far too light to be the right color, though my eyesight may just be bad and the black background may just be darkening an apparently transparent highlight)

How are the hexes/UTF-8/numbers 0x39CE,0x2D6B and so on to be interpreted so that I know what color I'm changing something into?
Are the hexes even then 1:1 with what appears on my DS, or will they be desaturated (I play on low brightness so that may be why colors look off)?
Is this what you guys did when you made custom themes? The tutorial I found here that recommends some software leads to some dead links, like every other theme website I've tried to go through (though I have found a github with a few working themes from a reddit post).

 

[Pk11]

They're not UTF-8, that's for encoding Unicode text not colors, what they actually are is colors in BGR15 (blue, green, red, with 5 bits. Normal hex colors are RGB24, red, green, blue, with 8 bits each).

The reason the numbers don't make much sense is that 5 bits doesn't cleanly line up with the 4 bits each digit represents so some digits are affected by both blue and green or green and red. This color format is pretty common on the DS as it matches exactly with what the DS actually uses so no conversion is necessary, if you used 24-bit colors on DS then they would need to be converted down to these 15-bit colors to actually be used which could look a bit different depending on how accurately you do the conversion.

This web page lets you convert normal 24-bit RGB colors into BGR15 and gives a nice explanation of what it's doing: http://www.conradshome.com/html2bgr15/

One minor thing to note is that the highest bit, bit 15, is used for transparency, the colors you have currently don't have it set as the Acekard menu must either force it or use rendering modes that ignore it, but that site will set it so colors might have different numbers but are actually the same, for example you have black as 0x0000 but that site will do 0x8000, these will look identical though so nothing to worry about.

For making themes, I've only made one and it was a while ago but iirc I used GIMP to edit the images and that site to get the converted colors.

 

[WhatManual]

Thanks! I've been planning on using Gimp as well for my project