Richard James Panturis Giuly <n...@spam.com> writes:
> Are there any libraries for reading and modifying bitmap files?
When I wasn't looking, I did come across some such Common Lisp file which appeared to do this, but it was not what I was looking for, and so I just moved on. I think it's out there. Does this help? no.
However, if you understand the format of the particular bitmap you are trying to read, can't you just read it in, create a data structure, and then play around with it (i.e. processing, whatever), and then spit it out? This seems pretty straightforward, esp. if your bitmap format is ASCII.
What exactly are you trying to do? Do you want a GUI interface for modifying the bitmaps? Something like the Unix `bitmap' program?
I'd check to see if Garnet or some other GUI CL thing has either what you're looking for, or libraries to simplify its creation.
>>>>> "Richard" == Richard James Panturis Giuly <n...@spam.com> writes:
Richard> I want to be able to grab a picture like a gif or jpg, convert it to xpm or Richard> bmp or whatever is convenient, and give it to lisp as an array of pixels.
I think converting the gif or jpeg image to ppm format would make accessing the image easier from lisp. ppm is basically a pure text file of small integers representing the RGB values, plus a few more integers about the image size. (Roughly from memory.)
Paul Graham's ANSI CL book has some simple code to read ppm files, I think.
Richard James Panturis Giuly <n...@spam.com> writes:
> I want to be able to grab a picture like a gif or jpg, convert it to xpm or > bmp or whatever is convenient, and give it to lisp as an array of pixels.
Since most image formats are mildly to highly complex (involving convoluted bit-diddling in the form of compression/decompression, which often involves patented algorithms, and similarly evil things), it often pays to avoid dealing with said formats. There are two basic approaches to do this:
- Use some of the ready-made libraries (like libpng, libjpeg, libimlib, etc.) via your implementations FFI. This has the advantage of higher efficiency, but will involve some coding (and debugging effort), given that FFI bindings to bit-diddling, call-back based code is not something for the faint of heart.
- Use netpbm or a similar conversion library to convert the original images on the fly (via sub-processes and pipes) to something much more palatable, like ASCII ppm, which can be parsed into your Lisp much more easily... This will likely not be a suitable solution for applications that are processing images in tight loops, but will otherwise give you easy access to your pictures...
Binary P(B|G|P)M formats are especially easy to parse, given that they're essentially just simple blocks of raw pixels plus dimensions...
Regs, Pierre.
-- Pierre Mai <p...@acm.org> PGP and GPG keys at your nearest Keyserver "One smaller motivation which, in part, stems from altruism is Microsoft- bashing." [Microsoft memo, see http://www.opensource.org/halloween1.html]
I will need the efficiency of the first solution. But what is FFI and how do I use it, I don't even know what the letters stand for. (I'm using FranzACL on Linux)
"Pierre R. Mai" wrote:
> - Use some of the ready-made libraries (like libpng, libjpeg, > libimlib, etc.) via your implementations FFI. This has the > advantage of higher efficiency, but will involve some coding (and > debugging effort), given that FFI bindings to bit-diddling, > call-back based code is not something for the faint of heart.
> - Use netpbm or a similar conversion library to convert the original > images on the fly (via sub-processes and pipes) to something much > more palatable, like ASCII ppm, which can be parsed into your Lisp > much more easily... This will likely not be a suitable solution for > applications that are processing images in tight loops, but will > otherwise give you easy access to your pictures...
> I will need the efficiency of the first solution. But what is FFI and how do I > use it, I don't even know what the letters stand for. (I'm using FranzACL on > Linux)
> "Pierre R. Mai" wrote:
> > - Use some of the ready-made libraries (like libpng, libjpeg, > > libimlib, etc.) via your implementations FFI. This has the > > advantage of higher efficiency, but will involve some coding (and > > debugging effort), given that FFI bindings to bit-diddling, > > call-back based code is not something for the faint of heart.
> > - Use netpbm or a similar conversion library to convert the original > > images on the fly (via sub-processes and pipes) to something much > > more palatable, like ASCII ppm, which can be parsed into your Lisp > > much more easily... This will likely not be a suitable solution for > > applications that are processing images in tight loops, but will > > otherwise give you easy access to your pictures...
* Richard James Panturis Giuly <n...@spam.com> | But what is FFI and how do I use it, I don't even know what the | letters stand for.
Foreign Function Interface. Basically, dealing with other/inferior languages. In C, for instance, you specify -l<library> to the linker, after having specified "extern foobar(...random junk...)" in your source files. It's slightly more work from Common Lisp, but it shouldn't have been. In your Allegro CL Trial Edition distribution, you will find the file .../doc/cl/foreign_functions.htm, which tells you the whole story on how to interface with C libraries.
#:Erik -- If this is not what you expected, please alter your expectations.
Richard James Panturis Giuly <n...@spam.com> writes:
> I will need the efficiency of the first solution. But what is FFI and how do I > use it, I don't even know what the letters stand for. (I'm using FranzACL on > Linux)
Foreign Function Interface, see Chapter 10 of you Allegro user guide. Essentially you develop functions in a foreign language (normally, but not necessarily C) which have hooks to allow them to be loaded into a running LISP image and called as if they were LISP functions.
You need have a good knowledge of both LISP and your foreign language of choice, and
- your code won't be trivially portable even between different releases of ACL - your code may not be trivially portable between platforms - your code won't be trivially portable between different CL implementations
Think carefully before doing this. The idea of piping your images through a PBM filter looks a lot easier to me.
I've got lisp code to read GIFs. i have not used it in quite a while...I don't know how well it does with color--I was using it for b&w things in 1993
somewhere hard to get at I have code that reads xbm or something like that.
but the suggestions of convert it to some standard middle format are probably best.
modifying: you're on your own there. I have a tiny little icon diddler program I wrote years ago, now it's in CLIM, just ran it last week (or was it earlier this week?). you're welcome to the code, but it only works on monochrome bitmaps. I use it to create icons.
Richard James Panturis Giuly wrote:
> Are there any libraries for reading and modifying bitmap files?
Clinton Hyde <ch...@bbn.com> writes: > I've got lisp code to read GIFs. i have not used it in quite a > while...I don't know how well it does with color--I was using it for > b&w things in 1993
> somewhere hard to get at I have code that reads xbm or something > like that.
> but the suggestions of convert it to some standard middle format are > probably best.
> modifying: you're on your own there. I have a tiny little icon > diddler program I wrote years ago, now it's in CLIM, just ran it > last week (or was it earlier this week?). you're welcome to the > code, but it only works on monochrome bitmaps. I use it to create > icons.
> Richard James Panturis Giuly wrote:
> > Are there any libraries for reading and modifying bitmap files?
In an earlier thread some suggested using existing libraries for C with the Foreign Functions Interface (FFI). Using the FFI is described in doc/cl/foreign_functions.htm in your ACL directory.
"Christian Nybø" wrote: > Clinton Hyde <ch...@bbn.com> writes:
> > I've got lisp code to read GIFs. i have not used it in quite a > > while...I don't know how well it does with color--I was using it for > > b&w things in 1993
> > Richard James Panturis Giuly wrote:
> > > Are there any libraries for reading and modifying bitmap files?
> > > (I'm using ACL on Linux)
> The hacker who later on wrote XEmacs and Xscreensaver left some CL
that hacker is Jamie Zawinski, also the author of Netscape Navigator Version 1 for X. and he does love those screensavers, has for years...
> The files ps-interpreter.lisp, read-x11-raster.lisp and > bit-array-editor.lisp may prove interesting, at least for > archeological purposes.
gad, I'd forgotten about those. Jamie also did sun-raster and andrew-raster readers, but like the x11-raster, those are pretty well useless these days (well, I thought they were useless at the time, too, but I guess he was doing something with them)...I could swear someone told me about or maybe gave me a copy of a TIFF reader a couple of years ago, but I can't find it on my machine...
must admit I did find that "bit-array-editor.lisp" code interesting--check the author's name. that's about when I remembered writing that stuff :) and I'd forgotten who helped. that's the original version of what I later rewrote into the CLIM version I now have. unfortunately, bit-array-ed isn't very useful without the custom font: what I did was replace the "1" and "0" glyphs with solid rectangle and empty rectangle. that way when you typed in a 1 or 0 you got the corresponding blob, I wasn't having to draw/manage/index rectangles...being unable to create/use custom fonts on the PC, I had to go with the rectangles method, it doesn't quite work as nicely, you have to use the mouse to change things. I suppose I could do the arrows and keystrokes again, but I don't use it as often as I did years ago...
oh, wait. bit-array-editor.ast IS the custom font, with a different name. why did that happen? oh well, it's a LispM font, not usable elsewhere...
> In an earlier thread some suggested using existing libraries for C > with the Foreign Functions Interface (FFI). Using the FFI is > described in doc/cl/foreign_functions.htm in your ACL directory.
Clinton Hyde <ch...@bbn.com> writes: > > The files ps-interpreter.lisp, read-x11-raster.lisp and > > bit-array-editor.lisp may prove interesting, at least for > > archeological purposes.
> gad, I'd forgotten about those. Jamie also did sun-raster and andrew-raster > readers, but like the x11-raster, those are pretty well useless these days > (well, I thought they were useless at the time, too, but I guess he was doing > something with them)... > I could swear someone told me about or maybe gave me a > copy of a TIFF reader a couple of years ago, but I can't find it on my > machine...
I've had a look at the CL web browser called Closure. It has code for reading PNG files <URL:http://www.libpng.org/pub/png/>, and appears to use external apps such as djpeg and gif2png for other bitmap formats. Closure is at <URL:http://www.uni-karlsruhe.de/~unk6/closure/>, and its png code resides in closure/src/renderer/png-images.lisp of the archive. Closure is written for Allegro CL version 5. -- chr
