> most other tools suck.

Your think they suck because they're not coloured? But black-and-white images are standard, that's how you'll be seeing them in dictionaries, textbooks and transcriptions.

Also, I think some hieratic texts use different inks, like red and black, and the transcription into hieroglyphs needs to convey this difference. If you use a coloured hieroglyphic font, it would be hard to transcribe these hieratic texts.

Please add images to the README!

Hieroglyphic systems like Ancient Egyptian work on a combination of phonetic and semantic (meaning-based) principles. To write a word like "penis" or "dog" you will write several symbols, some indicating the sound, and some indicating the meaning. This is still how it works today in languages that use Chinese characters. A Chinese character like 液 yè "liquid" has two parts: the first part to the left (the three dots) indicates that the meaning has something to do with water. The part to the right is phonetic and means that the word is pronounced similarly to the other word 夜 yè "night" (which character can itself be broken down into semantic and phonetic parts). In the Egyptian examples you linked, the phonetic parts are followed by a semantic part.

Furthermore, in ancient systems, there's some nondeterminism in how you can write: you can write a word using only the meaning element, or only the sound elements, or a combination of both, depending on how you feel, how much space you have, etc. You see the same kind of thing in Mayan hieroglyphics and in Chinese writing before it was standardized by Li Si in the Qin dynasty.

This kind of system is useful because, by complementing the phonetic writing with semantic symbols, you can disambiguate homophones and maybe make reading faster. But I don't think this functional reason is why systems like this emerged: usually writing systems start off fully semantic and then acquire phonetic parts as time goes on. Semantic writing seems to be the "default" somehow, if you have writing at all, and phonetic writing is something that people have to figure out over hundreds of years of cultural evolution.

> That sounds... vaguely inefficient to me?

All languages and writing have built-in redundancy

In Egyptian, you can probably get away with writing the determiner in question + vertical stroke below it, to mean the determined thing. I guess Egyptians would understand you (that's how they wrote some common words like 'sun', with sun disk + | stroke). The vertical stroke is somewhat like putting spaces around the symbol in our writing system.

But usually that's not desirable because then you need to be extra-careful with drawing your dog or penis. And most writing wasn't carved in stone, it was a simplified hieratic style where a length of one stroke could be very important

So, some redundancy is useful. In Egyptian it usually means adding phonetic symbols before the image (imagine drawing a pen before a penis to show how the word sounds; then, you could have also drawn a duck before penis before the penis image to mean a different word that sounds like duck).

determinatives are for disambiguiating words and clarity. everything is phonetically spelled minus some vowels (usually assumed to be 'e').

sounds can be overspecified for clarity. some of the symbols have multiple consonants.

here is something short i made whilst working toward automatic transcription, transliteration and translation

https://imgur.com/a/KjkYKZS

4 of the glyphs here are silent, despite having phonetic values (or you could look at it as different glyphs being silent...)

interesting point about the penis glyphs is that Google Noto font project has purposefully decided to leave it as tofu, so much for "no more tofu". Microsoft have done the same with their Segoe font...

Isn‘t this (𓂸) penis and just one symbol?

A million?