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CMakeLists.txtD12-May-20243.9 KiB8979

MANIFEST.MFD12-May-202444 32

READMED12-May-20242.5 KiB5342

TJBench.javaD12-May-202439.1 KiB1,022875

TJExample.javaD12-May-202416.6 KiB406305

TJUnitTest.javaD12-May-202432.8 KiB961866

org_libjpegturbo_turbojpeg_TJ.hD12-May-20244.6 KiB13084

org_libjpegturbo_turbojpeg_TJCompressor.hD12-May-20243.4 KiB10232

org_libjpegturbo_turbojpeg_TJDecompressor.hD12-May-20243.4 KiB10232

org_libjpegturbo_turbojpeg_TJTransformer.hD12-May-2024838 3014

README

1 TurboJPEG Java Wrapper
2 ======================
3 
4 The TurboJPEG shared library can optionally be built with a Java Native
5 Interface wrapper, which allows the library to be loaded and used directly from
6 Java applications.  The Java front end for this is defined in several classes
7 located under org/libjpegturbo/turbojpeg.  The source code for these Java
8 classes is licensed under a BSD-style license, so the files can be incorporated
9 directly into both open source and proprietary projects without restriction.  A
10 Java archive (JAR) file containing these classes is also shipped with the
11 "official" distribution packages of libjpeg-turbo.
12 
13 TJExample.java, which should also be located in the same directory as this
14 README file, demonstrates how to use the TurboJPEG Java API to compress and
15 decompress JPEG images in memory.
16 
17 
18 Performance Pitfalls
19 --------------------
20 
21 The TurboJPEG Java API defines several convenience methods that can allocate
22 image buffers or instantiate classes to hold the result of compress,
23 decompress, or transform operations.  However, if you use these methods, then
24 be mindful of the amount of new data you are creating on the heap.  It may be
25 necessary to manually invoke the garbage collector to prevent heap exhaustion
26 or to prevent performance degradation.  Background garbage collection can kill
27 performance, particularly in a multi-threaded environment (Java pauses all
28 threads when the GC runs.)
29 
30 The TurboJPEG Java API always gives you the option of pre-allocating your own
31 source and destination buffers, which allows you to re-use those buffers for
32 compressing/decompressing multiple images.  If the image sequence you are
33 compressing or decompressing consists of images of the same size, then
34 pre-allocating the buffers is recommended.
35 
36 
37 Installation Directory
38 ----------------------
39 
40 The TurboJPEG Java Wrapper will look for the TurboJPEG JNI library
41 (libturbojpeg.so, libturbojpeg.jnilib, or turbojpeg.dll) in the system library
42 paths or in any paths specified in LD_LIBRARY_PATH (Un*x), DYLD_LIBRARY_PATH
43 (Mac), or PATH (Windows.)  Failing this, on Un*x and Mac systems, the wrapper
44 will look for the JNI library under the library directory configured when
45 libjpeg-turbo was built.  If that library directory is
46 /opt/libjpeg-turbo/lib32, then /opt/libjpeg-turbo/lib64 is also searched, and
47 vice versa.
48 
49 If you installed the JNI library into another directory, then you will need
50 to pass an argument of -Djava.library.path={path_to_JNI_library} to java, or
51 manipulate LD_LIBRARY_PATH, DYLD_LIBRARY_PATH, or PATH to include the directory
52 containing the JNI library.
53