Amazfit activity tracker and watch face asset generation

Summary

I recently wanted to track my heart rate and sleeping patterns, but do not want an Apple Watch. So I ended up buying a cheap Amazfit Band 7 from Decathlon sports store. The one I bought was reduced because of a damaged box—I love a good bargain! It’s a cool little thing and goes for an unbelievable 18 days on a single charge with default settings. Since I bought it I’ve had to charge it once! Even more amazing is that this little thing runs apps and watch faces powered by JavaScript, has an OLED screen, senses heart rate, step count, blood oxygen, sleep patterns, and lots more features I’ll never use. And it still gets multiple weeks on a single charge! The app it comes with is fairly low-nag if you don’t want to buy into the ecosystem. Anyway, I found some nice watch faces but if anything they were all a little bit busy for me. Ideally I’d make my own but it seemed like a lot of work—I would need to create images for every digit at every size as well as any other things I want on the face—so I put it on the rainy day list. OK, Computer Today it isn’t raining but I do have some time on my hands, which is the next best thing. I didn’t want to spend time in Figma exporting images over and over again. I get cold shivers thinking about slicing images in Fireworks. So I wondered if I could create a tool that would make light work of generating the images I need from a font of my choosing. It was pretty straightforward and I ended up with what you see below, where you can customise: font, size, color, alignment, filename prefix, and required characters/phrases/symbols. And then you can download all the images in one click! NICE. I do my best to adhere to the specs required by the most common watch face building tools, and in almost all cases I’ve been able to use the images exactly as they come out of the tool. There is some extraneous padding, which means you have to use quite large negative spacing (equivalent to kerning) but it all works well in practice. There’s nothi...