Gradient color and transparency on amoleds

I think you maybe be able to do it with blendMode. https://developer.garmin.com/connect-iq/core-topics/graphics/

Might require using layers as well.

Bump anyone, how to achieve this?


I figured out how to make opacity on circles and rectangles etc, but how can you blend smoothly two colors?
I have made functions to calculate fading to colors like gradient and it works pretty well on simulator, but on the watch it's too heavy in my opinion, so I guess there have to be another simpler way todo this :)

What are you trying to paint? The background and draw on it with characters that have transparent color and black background? Or the letters? I don't think it's a good idea. If you already have a custom font, why don't you have the color in the png file for the characters as we see it on the image? All the heavy lifting is done in pre-processing, and you only copy pixels when you draw.

I think the goal is to do it dynamically and I know it's possible as I've seen it on some watchfaces with user selectable colors. But like you said, it will have a processing cost. It would be nice if Garmin gave us the SDK tools to do this more easily especially now that most new watches have an amoled display. Putting the colors in the bitmap font hasn't worked for me, dc.setColor overrides it.

What color did you use? COLOR_TRANSPARENT?

Yes, transparent. Maybe I'm missing an option in the .fnt file?

ended up with jim_m_58 and Hermo's solution to this, which I'm quite happy with

That looks nice! Any chance of sharing your code? :)