BufferedBitmap size

Hi,

Please help me understand the situation:

I am using BufferedBitmap to add support ALWAYS ON (1Hz) mode to my analog watchface.
I am testing on a emulator (Fenix 5x) and I see that my watchface has a peak memory consumption of 52KB. (I use custom anti-aliased fonts for rendering graphics).

But as soon as I add this line to the code:

var offscreenBuffer = new Toybox.Graphics.BufferedBitmap ({: width => dc.getWidth (),: height => dc.getHeight ()});

then I immediately get an "Out of Memory" error , while I see that all available emulator memory is occupied (92Kb).
Due to the use of anti-aliasing fonts, I am unable to specify a limited palette.
If I turn off all the watchface drawing code, leaving a black screen, then after creating the BufferedBitmap, the memory consumption is 89KB.
I looked at the Analog sample from SDK, but this sample uses a BufferedBitmap with a palette and therefore there is no memory problem.
Help me understand why BufferedBitmap takes up such a huge amount of memory. Does my situation mean that I am not able to create a watchface with support for ALWAYS ON mode if I use custom fonts with anti-aliasing to render graphics?

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jim_m_58 over 4 years ago

Without a palette, each pixel can have 64 possible colors, therefore more memory than if you had a palette of 2 colors. That's why the Analog Sample uses a palette -to reduce memory. Try turning off anti-aliasing for your font and setting the palette you need and see how that works.

Garry_808 over 4 years ago in reply to jim_m_58

The result is simply awful, graphics without anti-aliasing look unacceptable.
As far as I understand, the only option in my case is to use BufferedBitmap for models with a huge amount of memory (for example, Venu with 512Kb), of which BufferedBitmap takes up as much as 300Kb.

jim_m_58 over 4 years ago in reply to Garry_808

Make sure to look at things on a real device, as the sim can be a bit deceiving, with the pixels being much larger.

Look at Hermo's blog post, as you may be able to imporove the fonts with doing some hand editing of the png file.

developer.garmin.com/.../

You don't really need to worry about the venu, as it doesn't do 1hz, but you do have to do something special if you want the WF tt stay on in low power mode (requiresBurninProtection - no more than 10% of the pixels on and no pixel on for more than 3 minutes, etc)

Travis.ConnectIQ over 4 years ago

You can still use a paletted buffered bitmap and anti-aliased fonts... just don't draw your text to the to the paletted bitmap. Draw your text directly on the display.

Garry_808 over 4 years ago in reply to Travis.ConnectIQ

Thanks for the advice, to my regret, all graphics in my watchface consist only of fonts, I assemble the final picture from font characters like a puzzle from pieces.
It turns out that the choice is this - either I refuse anti-aliasing, thus losing the main advantage of the watchface, or they refuse to support the Always On mode.

Garry_808 over 4 years ago in reply to jim_m_58

Thanks for bringing my attention to requiresBurninProtection. I just didn't think about this moment.

PlayItLoud over 4 years ago

It s bit more tricky if you are taking that approach. Some logic on how to do it: https://forums.garmin.com/developer/connect-iq/f/showcase/6510/watchface-milsub

Garry_808 over 4 years ago in reply to PlayItLoud

Thank you very much for sharing the implementation details! It was such a post that I missed, clearly and easily show the details and limitations.I asked a question in your post, if possible please write an answer.
Thank you very much for showing me the way, thanks to all of you, experienced programmers in this topic, who took the time to advise.