digital font - transparent trick?

Hello, could anyone tell me how to make a transparent font, as it is on a digital watch, for example? Is this a font trick, or is it necessary to use a special font?

I only need to have numbers displayed this way.

Thank you for answer.

Shent-Aurkhan (SHN) over 3 years ago

hi,

the trick is (for 10:08 for exemple)

you draw 88:88 in dark blue, then 10:08 in light blue, that is it ;)

7643321 over 3 years ago in reply to Shent-Aurkhan (SHN)

And that's all? Thank you very much ;-)

jim_m_58 over 3 years ago in reply to 7643321

Yes, that's it. For other interesting font tricks, see https://developer.garmin.com/connect-iq/connect-iq-faq/how-do-i-use-custom-fonts/#howdoiusecustomfonts

flocsy🤠 over 3 years ago in reply to jim_m_58

Doesn't this "trick" have the disadvantage that everything is drawn twice, so the battery will drain faster?

Unfortunately the only idea I can think of to mitigate it is to create the "complementer" of each digit and use that to draw the "background", but that has the disadvantage of producing bigger app, so it might be not a good option if your app is getting big.

7643321 over 3 years ago in reply to flocsy🤠

That's a good note. I was still wondering if it is not possible to create it in the BM Font program? Any special Alpha channel ???

Shent-Aurkhan (SHN) over 3 years ago in reply to flocsy🤠

I guess I don't get it, it will be the same? instead of drawing "88:88" you want to draw "CC:CC"?

(where C is your complementer), another idea is to import bmp but will take too much resources...

don't think this take too much battery, for sure not a lot of resources.

flocsy🤠 over 3 years ago in reply to Shent-Aurkhan (SHN)

Make sure you only re-draw the area of the seconds if you have the seconds active, and not all the screen. Though this might only be possible on certain devices :(

Yes, my idea was to only draw the CC:CC in dark blue and then the 11:11 with the light blue. Maybe it doesn't matter much. You can always run some profiling with and without drawing the dark blue complementer and compare

jim_m_58 over 3 years ago in reply to Shent-Aurkhan (SHN)

Yes, what you said is only one extra drawText, where this watch face is doing a number for draws already, so the impact would be minor. I'd do the setColors, draw 88:88, setColors, draw HH:MM.

With this, you don't even need a separate font, as you can just use the 8.

jim_m_58 over 3 years ago in reply to flocsy🤠

You are talking onPartialUpdate()/1hz watch faces, where you define clip regions for what you want to update?That's the way to update seconds all the time so you don't exceed the power budget.

jim_m_58 over 3 years ago in reply to jim_m_58

It's actually a similar in impact as using the checkerboard trick on venu/epix devices for AOD.