I was asking me the same today. Actually I was researching for valid usecases. I think that Alchemy could speed up some slow algorithms like f.e. the encoder stuff you mentioned. Can anyone give some feedback on this?
However I played with Alchemy today and hope to see some tests regarding performance.

There appears to be little red ***** things hiding in my details.

Various findings so far:

- Using gluegen with functions that return a Boolean results in generated code that calls an AS3_Boolean() function. That function doesn't exist in the current release, although it's not hard to define an approximation of it as static AS3_Val AS3_Boolean(int val) { return val?AS3_True():AS3_False(); }

- You can use "import" statements in .gg file, so you don't have to patch the resulting .as file afterward simply because you like ByteArrays.

- However, gluegen-generated .as files don't seem to expose the .supplyFile() method and that does seem to require patching.

- talking about .supplyFile(), the method works great to fake file reads, but is not written to handle file writes. That's a downer as libjpeg apparently wants to write encoded JPEG data into a FILE* structure.

- minor quibble: if you're thinking of writing an AIR app with Alchemy that would read humongous files, don't. At least, not yet. The current implementation of open() reads the entire file in memory before returning a handle.

- dead code removal isn't quite as good as I'd hope. whatever your glue file doesn't use gets compiled away. But that's it. The entire code in the final .swc will be included in any project that references it. That's probably because the CLibInit class hardcodes references to every other chunk in the .swc. So to optimize for size, you'll have to cut through your glue files and rebuild SWCs that contain only what you use.


Anyway, at this point, I'm hoping I overlooked some way of using libjpeg without FILE* handles.

I'm not super familiar with GlueGen (when I started working with Alchemy it wasn't available yet) but I hope I can help a little bit.

The FILE* handles can be dealt with by using a C standare library function called funopen - this lets you create a file handle that goes and calls functions for read, write, lseek, and close.

http://www.gsp.com/cgi-bin/man.cgi?section=3&topic=funopen

Alrighty, here's a simple wrapper around the encoding part of libjpeg.
It uses a custom destination manager (some semi-obscure libjpeg feature) to avoid the whole FILE* issue.

http://hurlant.com/as3_encoder_jpeg.tgz

You'll need to get libjpeg separately. there's a README.txt in my .tgz file that glosses over the steps.

vevedh, I suspect the OpenSSH portable library would be a smoother ride.

You'd need to compile OpenSSL first (see the code sample Adobe made available for instructions on how to do that) and the zlib library.

Once you get the basic stuff compiled, you'd probably want to start hacking the C code a bit, as Alchemy's libc doesn't implement network-related commands yet. Also, calls to the zlib library should be replaced by builtin ByteArray methods where possible, to make things faster.

@matthewbmedia - You can use flyield() to release control back to Flash for processing events.
Here is an example from some code Scott wrote:

const int LoopSize = 20;

// don't let gcc inline you
void loopGuts(int loops) __attribute__((noinline));

// do the guts of the loop here -- unroll if you want
void loopGuts(int loops)
{
for(int j=0; j<loops; j++) {
// do a unit of processing
}
}

// here is your main looping routine
void bigLoop(int loops)
{
for(int i=0; i<loops; i++) {
if((loop % LoopSize) == 0)
flyield();
loopGuts(LoopSize);
}
}

The idea is that the inner "guts" routine will run synchronously and the outer routine will run asynchronously. Flash should be more responsive and you will still get most of the speed.

Guys, I am interesting in hiring a freelancer to make me this kind of flash applet. The basics required will be - resize before upload using this method (Alchemy + IJQ lib), ability to rotate and preview before upload.

How much will it cost me? And is there anyone here interested to help me with this project?

try this option
1.open cygwin

quote:

---

tar xvf jpegsrc.v6b.tar.gz

---

2.cd jpeg-6b

quote:

---

alc-on;./configure CFLAGS='-E';alc-off
alc-on;make CFLAGS='-O3';alc-off
alc-on;make clean;alc-off

---

take jpeg.l.bc in the directory - /jpeg-6b

Check compiler:
alc-on;gcc --help;alc-off
that there can be seen?

$ alc-on;gcc --help;alc-off
Usage: llvm-gcc [options] file...
Options:
-pass-exit-codes Exit with highest error code from a phase
--help Display this information
--target-help Display target specific command line options
(Use '-v --help' to display command line options of sub-processes)
-dumpspecs Display all of the built in spec strings
-dumpversion Display the version of the compiler
-dumpmachine Display the compiler's target processor
-print-search-dirs Display the directories in the compiler's search path

****

after that i try

Bog Imp@imp /cygdrive/c/alchemy/samples/as3_encoder_jpeg/jpeg-6b
$ alc-on;make clean;alc-off
MAKE Version 5.2 Copyright (c) 1987, 1998 Inprise Corp.
rm -f *.o *.lo libjpeg.a libjpeg.la
rm -f cjpeg djpeg jpegtran rdjpgcom wrjpgcom
rm -f ansi2knr core testout* config.log config.status
rm -f -r knr .libs _libs

Bog Imp@imp /cygdrive/c/alchemy/samples/as3_encoder_jpeg/jpeg-6b
$ alc-on;make;alc-off
MAKE Version 5.2 Copyright (c) 1987, 1998 Inprise Corp.
rm -f libjpeg.a
ar rc libjpeg.a jcapimin.o jcapistd.o jctrans.o jcparam.o jdatadst.o j
cinit.o jcmaster.o jcmarker.o jcmainct.o jcprepct.o jccoefct.o jccolor.o jcsam
ple.o jchuff.o jcphuff.o jcdctmgr.o jfdctfst.o jfdctflt.o jfdctint.o jdapimi
n.o jdapistd.o jdtrans.o jdatasrc.o jdmaster.o jdinput.o jdmarker.o jdhuff.o j
dphuff.o jdmainct.o jdcoefct.o jdpostct.o jddctmgr.o jidctfst.o jidctflt.o j
idctint.o jidctred.o jdsample.o jdcolor.o jquant1.o jquant2.o jdmerge.o jcomap
i.o jutils.o jerror.o jmemmgr.o jmemnobs.o
/usr/bin/ar: jcapimin.o: No such file or directory

** error 1 ** deleting libjpeg.a

hi Notnick I followed what you mentioned on post 46 and everything ran just right.
I was wondering what the next step for this to build the .swc file I need would be.
what am I suppose to do with the jpeg.l.bc in the directory - /jpeg-6b

Thanks so much for all the help.

I tried doing what Metalbot sugested but as I went through it all and was on the last step to make the .swc file. This errors comes up:

===================================================
Macintosh-2:jpeg-6b userName$ make
gcc -o cjpeg cjpeg.o rdppm.o rdgif.o rdtarga.o rdrle.o rdbmp.o rdswitch.o cdjpeg.o libjpeg.a
ld warning: in cjpeg.o, file is not of required architecture
ld warning: in rdppm.o, file is not of required architecture
ld warning: in rdgif.o, file is not of required architecture
ld warning: in rdtarga.o, file is not of required architecture
ld warning: in rdrle.o, file is not of required architecture
ld warning: in rdbmp.o, file is not of required architecture
ld warning: in rdswitch.o, file is not of required architecture
ld warning: in cdjpeg.o, file is not of required architecture
ld warning: in libjpeg.a, file is not of required architecture
Undefined symbols:
"_main", referenced from:
start in crt1.10.5.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [cjpeg] Error 1
===================================================

Step 5 when it says to run make. That is when the error comes up.

thanks in advance for any help.

I followed the following:
Download jpegsrc.v6b.tar.gz
Through terminal I ran the following lines:
tar xvf jpegsrc.v6b.tar.gz
cd jpeg-6b
alc-on;./configure CFLAGS='-E';alc-off
alc-on;make CFLAGS='-O3';alc-off
alc-on;make clean;alc-off

After this steps I followed the steps on the Metabolt link.
Make a new directory jpeg
take jpeg.l.bc in the directory - /jpeg
Go on to the directory jpeg
run the following:
cd ../jpeg-6b
make

After this I get the error that I already mentioned in the last post.
I did open the file jpeg.l.bc on a HEX Editor and got the (42, 43) which in symbol would be BC at the beginning

Any suggestions on what I am doing wrong? Any help would be greatly appreciated.

Thanks for all the help.

radScientist, Metalbot

Confirming approximately 1.5 sec on a Windows dual core 2.1 GHz.

For us here just joining the thread could we get a summary of what is working (and what is not working) on the jpeg encoder port / build with Alchemy on Windows? Perhaps an overview of what stage the port is at? Working, or not... -MB

Thanks notnick for all that, hey myMacromediaScreenName you mentioned you were able to successfully test the jpeg lib, I was wondering if you could share with us the c file you used to compile the swc. I been trying something here and there but haven't gotten any results yet. thanks a lot

great example notnick thank you very much. did you ever run into a problem with the jpeg_std_error().

Undefined sym: _jpeg_std_error
at <anonymous>()
at <anonymous>()
at com.hurlant.jpeg::as3_jpeg_wrapper$/write_jpeg_file()[/Users/user/Doc uments/Flex Builder 3/jpegTest/src/com/hurlant/jpeg/as3_jpeg_wrapper.as:8]
at jpegTest/testWrite()[/Users/user/Documents/Flex Builder 3/jpegTest/src/jpegTest.mxml:32]
at jpegTest/___jpegTest_Button1_click()[/Users/user/Documents/Flex Builder 3/jpegTest/src/jpegTest.mxml:44]

I tried this example with your swc then I went and compiled it myself to double check. When I did, I ran into this. I made sure I had my jpeg-6b library installed and on the right path and everything looks right, I dont have any error in the moment of compiling. thank you

I am not sure I understand what you are saying. Once the SWC is compiled I use it on my Flash / Flex projects. You mean you did not use the jpeg library on your project? I think you did because on the .gg file you have the line in which you include the jpeg lib (#include <jpeglib.h>) and then you are using this dealing with the ByteArray you pass into it through the write_jpeg_file method. Does that make any sense? My issue is that even though I do include this file and it seems to be working correctly, for some reason I have some limits on using it because I can't use any methods that this is supposed to bring in.
Thank you.

yes if you could, that would be awesome. What do we need to compile the jpeg.l.bc for? what's the use for it? And if you could please help me on why I can't seem to be able to use jpeg lib or any other lib that'd be great!

I did try Metabolt's sample in action. It does work, BUT at the moment I compile the C file that serves as the mediator with Alchemy to build a new SWC file, and it does not work. Metabol are you around? Can you get in here and explain me why my JPEG library is not getting compiled or something. I have a very simple example that I apply standard alchemy methods but as soon as I start writing some of the lines of Metabolts C file, it throws me an error. The error that I mentioned before,, like 2 posts ago. Here we go: jpegCompression
If you could take a look at that and tell me where I went wrong, and how will I be able to use the jpeg lib for the compression of images that would be great.
Thank you

Ok so now that you have seen what I have done. The purpose of the application is to resize images down from however big they are, bring them down to usable size. On my C file if you look from line 83 to 109 they are commented out. These are the methods I believe I will be using with the jpeg lib to make it happen. The main issue is that the library is just not working for me and I am not able to get it working. I am using what the "cjpeg" would apply to compress a image to jpeg format, only difference is I am getting a ByteArray, making it into a file so that I could inserted and used on the library. Hope that helps.

//It added the conversion from ByteArray to Bitmap
package {
import com.adobe.images.JPGEncoder;

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.Loader;
import flash.display.Sprite;
import flash.events.Event;
import flash.geom.Rectangle;
import flash.net.URLRequest;
import flash.utils.ByteArray;
import flash.utils.getTimer;

import hurlant.jpeg.as3_jpeg_wrapper;

public class JpegTest extends Sprite {
private var _loader:Loader = new Loader();
private var nJpg:Loader = new Loader();
public function JpegTest() {

trace("hello.");

testWrite();

}
private function testWrite():void {


_loader.contentLoaderInfo.addEventListener(Event.COMPLETE,onComplete) ;
_loader.load(new URLRequest("acura.jpg"));
}
public function onComplete(event:Event):void{
var image:Bitmap = Bitmap(_loader.content);
image.width = image.width/2;
image.height =image.height/2;
var b:BitmapData = image.bitmapData;
addChild(image);

// as3 way
var t1:int = getTimer();
var s:JPGEncoder = new JPGEncoder();
var jpg:ByteArray = s.encode(b);
trace("AS3 JPEG ENCODING: "+(getTimer()-t1)+"ms.");
trace("jpg.length = "+jpg.length);
trace(image.width);
trace(image.height);

// C way
var t2:int = getTimer();
var ba:ByteArray = b.getPixels(new Rectangle(0,0,image.width,image.height));
var ret:ByteArray = as3_jpeg_wrapper.write_jpeg_file(ba, image.width, image.height, 3, 2);
trace(" C JPEG ENCODING: "+(getTimer()-t2)+"ms.");


//It added the conversion from ByteArray to Bitmap
nJpg.contentLoaderInfo.addEventListener(Event.COMPLETE,addnewjpg);
nJpg.loadBytes(ret,null);

}
private function addnewjpg(event:Event):void{
var im:Bitmap = Bitmap(nJpg.content);
var bmpd:BitmapData = im.bitmapData;
trace(bmpd.width);
trace(bmpd.height);
im.x = 200;
this.addChild(im);

}

}
}

All ok! I was interested but there is the main point
I noticed that the real picture is very big difference in speed, between AS3 and Alchemy
I do not deepened in the reasons. But look at it.
AS3 JPEG ENCODING: 1199ms.
C JPEG ENCODING: 245ms.
In the original example, where used only generic BitmapData differences were much smaller.
AS3 JPEG ENCODING: 606ms.
C JPEG ENCODING: 206ms.
It seemed to me that you have a problem with C? You can not use the library? What are the causes?