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Comment by JoeAltmaier | Hacker News Reader

I needed this last week! Building an embedded firmware image for a dashboard display, with lots of PNG files for icons etc. 61 of them.

The original developer wrote a tool to expand the PNGs to BMPs (arrays of 32-bit pixel values) and generate a C array definition as a text file. Which is lots bigger than the original PNG (13K => 100K sort of thing). Then included that C source in the build. Used up 700K of my firmware image space which was only 1MB to begin with.

So I wrote a tool to represent the raw PNG file as a C declaration, then added parts of libpng to the boot code to decompress the images during initialization. Even with libpng, I saved over 400K. Now the images use RAM instead of ROM, but that's ok I had buttloads of RAM.

Anyway, this is a much slicker way of including binary files in an image. I may go back and change my build.

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There are even smaller png libs than libpng, try a stripped down stb_image for example. Wouldn't use that for user-supplied images, but since you control them all it should be fine.

I do this with embedded graphics in boards for a lot of reasons. Works great - and STB is pretty easy to modify if you need a funny one (eg : monochrome pbm for small displays). Animated gif, png, bunch of others all work pretty smoothly. Just include the bits you need so it can be even smaller.

Might be worth recompressing the PNGs too if you haven't already. In particular, using 8-bit PNG can size a lot on filesize if you don't need loads of colours.

Yes! And having tried a few different tools for this, I recommend pngcrush (easy to use, excellent results).

Edit to add: I settled on pngcrush 3 or 4 years ago; if there's something newer and better, I'm interested in hearing about it!

Nope. Dumb Visual Studio doesn't support embedded binary in cross-compile. That's the tool the client wanted, so I'm stuck with it.

Funny, they (VisualGDB) even have a tutorial on doing it. But the option 'Embedded Resource' doesn't exist in my (modern) Visual Studio.

Ha! And the feedback I gave VisualGDB about their outdated tutorial, they responded "Just pay HERE and we'll be glad to solve your problem!" They can go ahead and have outdated documentation, screw them.

Could you not try using the objcopy method mentioned here outside Visual Studio (or somewhere before the build process) and then just using the .o at link time, just referencing it from the outside at linkage? I expect at least a way to:

- hook custom tool calls

- link external objects into the project

Also, hello fellow automotive embedded SW eng! I know your suffering! :))

VisualGDB uses a tool-created makefile for cross-compiling and building. Not a lot of room for me to innovate. I suppose the .o trick could work. But it still requires careful hand-scripted builds. I already have that - I run a script to read a binary file and emit .c declaration, which I pipe to a C file and include in the project.

I suppose it lets me drop support of the script, which is something.

Afaik `xxd -i` is much simplier. No need to write another tool.

imagemagick and netpbm can do that. Gimp too.

I assume so. But how many tools do I want to include in my client's build dependencies?

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