New shared libraries of zlib and pnglib available

[ThorstenOtto]

Hi

I've recently put some effort to make zlib and pnglib, which are widely used, available as shared library for MiNT (*.slb) in a way that should make it really easy to switch from a static version to a shared one, i.e. all the functions are called as usual, without having to look them up first (like when using LDG), or needing to pass extra parameters like function numbers.

You can find them at http://tho-otto.de/sharedlibs.php. There is also a new snapshot tool available there that makes use of them.

Please let me know what you think of it, or if you find any problems.

[JeanMars]

Hi Thorsten,

Is there any example on how to use this lib (sorry i'm reading.this from my mobile and i may have missed it)?

Also.that would be very nice to have an aranym native feature for this just.like nfjpeg.

Then I would be able.to add png support in vision :—)

[shoggoth]

Nice initiative!!!

[ThorstenOtto]

Is there any example on how to use this lib (sorry i'm reading.this from my mobile and i may have missed it)?

Its explained in the readme. A simple example are the test programs in the source archive (example.c in zlib, and pngtest.c in pnglib).

Also.that would be very nice to have an aranym native feature for this just.like nfjpeg.

Yes, that's also planned. Just have to prepare the jpeg library first

[JeanMars]

Thanks for pointing this out, i'll have a look as soon as i have a decent device to read this sample

[ThorstenOtto]

Update: libiconv 1.15 and libjpeg (jpeg-8d) are also available now.

[JeanMars]

Hi Thorsten,

thanks for the update; just a question to help me design PNG integration into VISION: do you plan to include automatic switch to Aranym native feature into the lib or let the caller decide about this?

I'll be looking into this as soon as I can free some time on my side

Thanks,
Jean

[ThorstenOtto]

do you plan to include automatic switch to Aranym native feature into the lib or let the caller decide about this?

I thought about that too, but it's hardly possible. It would be easy to translate calls to the accelerated JPEGDecodeImage() into a series of jpeglib function calls, but not the other way around. And the DSP/ARAnyM decoder only returns the raw image data, not some other meta-information like jpeglib does. So its better to let the caller decide that, there are only a few functions in that interface, and most of the code needed to use it, is allocating buffers etc.

[JeanMars]

Ok I'll design on my side to let vision decide!
Thanks,
Jean

[JeanMars]

Hi Thorsten,

I tried to use pnglib, followed instructions from readme, added both pureC versions of PNGSLB16.LIB and ZLIBSLB.LIB to my project, compiled successfully but got the following link error with PureC:
****** Linker messages:

H:\PURE_C\LIB\PNGSLB16.LIB
Undefined symbol: '_base'
Undefined symbol: '__base'

Any clue?
Thanks,
Jean

[ThorstenOtto]

Any clue?

Oops. That is an alias of the _BasPag pointer in the startup code i usually use, so i didn't notice. As a workaround, you can define those variables in your code, and initialize them before calling any of the loading functions:

Code: Select all

#include <tos.h>
...
BASPAG *_base;
BASPAG *__base;
...

   _base = __base = _BasPag;
   ...
   slb_pnglib_open(NULL);


They are only used by the fallback functions that simulate Slbopen() for systems that lack it.

[ThorstenOtto]

Also fixed now in the download archives.

[JeanMars]

Thanks Thorsten,

I'll try this evening

[JeanMars]

Hi Thorsten,

looks good, I can load/unload library now
I had to comment out this section in png.h (line 1666-):

#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
png_user_transform_ptr read_user_transform_fn));
#endif

#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
png_user_transform_ptr write_user_transform_fn));
#endif

PureC reported an error on second macro lines. Don't know why, they look pretty similar to other compiling OK. I don't think I would need these user transforms, just to report.

Thanks,
Jean

[dhedberg]

Great work! Thanks!

[ThorstenOtto]

I had to comment out this section in png.h (line 1666-):

That's strange, especially since the same macro is also used in other places. Of course its fine to comment them out if you don't need them, but they might be really useful, and IIRC are also used by the test programs. Do you remember the error message?

[JeanMars]

Hi,

Syntax error... i thoight identifier length was too much but apparently not

[ThorstenOtto]

i thoight identifier length was too much but apparently not

Oh, but that could still be possible. I can't remember whether it was the same location, but for compiling the static library i had to increase the max. identifier length to something like 80, although none of the names is nearly that long. Maybe that fixes it.

[JeanMars]

Thanks for the hint, I'll have a look this evening

[JeanMars]

Hi Thorsten,

you're correct, I increased "Maximum identifier length" from 32 to 64 in the compiler options and it just compile OK now. The identifier length used in the macro is 24 but I guess this setting is for (data type+identifier) in this case.

Thanks!

[ThorstenOtto]

Thx for confirmation. i'll add a hint in the readme.

[JeanMars]

Hi Thorsten,

OK it looks promising, I just had my first png image successfully loaded into VISION
I noted something incompatible with LDG which VISION uses for additional modules:
if pnglib is loaded via SLB, any subsequent call to ldg_exec just freezes VISION (all other apps/system are OK).
If I call slb_pnglib_close just before ldg_exec, it works fine...

Any clue on this issue?
Thanks,
Jean

[ThorstenOtto]

Any clue on this issue?

No sorry, no real idea. They should not interfere, theoretically. Do you use Mint or Magic, where Slbopen() is available? And for LDG, do you have the resident program run from auto-folder?