Bitmap compression

Development
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There is an example project from team arg with experimental bitmap compression.

I would really love to see it in the next release of the arduboy lib but anyway can someone help me to generate a compressed bitmap for it?

I’ve tried the compress app in the command line but it doesn’t seem to work with png? And even if, how to i get the byte data? hexdump would by lame to copy?

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you rang my lord?

Did you try this tool to compress the images ?

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Hi all,

I’m working on a RLE image compression tool (developed in java) for 1-bit images. I have started testing it and image size is reduced between 10-20% compared to Cabi encoder. Draw performance is similar but I’m working to improve it more. Hope to release a preview beta at the end of this week.

Maybe @JO3RI could be interested in work together on an “encoder/decoder standard” :wink:

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Is the decode algorithm the same as Cabi? If not, I could add the new decoder function to my Arduboy2 library once you’ve completed it.

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The decoder is different (some parts are similar). It would be great that you add this function in your Arduboy2 library, anyway I think it would be better to release a unified drawCompressed function.

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Whatever works best if fine with me.

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I’d be interested in an early preview… It’s something I’ve also been prototyping. My approach is more tuned to the specific requirements of the Arduboy. Perhaps you could share a Google doc for feedback? Even discussing the header might be a simple start to collaboration? I think the main wins are applying simple masking (e.g. XOR) to minimise redundant information row-to-row. Are you familiar with the PNG filters?

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Thanks for the interest! I will try to release a preview version as soon as possible.
I tested some pre-filters on test images (as PNG does) and I didn’t find any filter that improves the image in order to encode it. Do you have any sample of a 1-bit image improved with prefiltering? Thanks!

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Here is a early preview of the bitmap encoder (compiled in java). You can test it before I release a stable version:

Moblynx encoder 0.2: http://www.moblynx.com/arduboy/encoder0.2.jar

Syntax: java -jar encoder.jar image [array_name_prefix] [-options]

-options:
-v View decoded image
-af Encode all frames (animated gif)

Please, write me if you have any problem running the encoder. Thanks!

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