-
Show log
Commit
-
Hash : f74989d8
Author :
Date : 2025-09-25T11:32:45
Clean up #include directives This is subtle, but #include <header.h> searches directories specified with -I, then system include directories. #include "header.h" searches the current source directory, then directories specified with -I, then system include directories. Using bracketed #include directives for jpeglib.h, jinclude.h, jerror.h, cdjpeg.h, and turbojpeg.h only worked because the build system explicitly passed -I{source_directory}/src/ to the compiler. Referring to 51cee0362998ec6f1eabac1e795f3b6e3ee639ea, it's better for the source code to have as few dependencies on our specific build system as possible. Since jpeglib.h, jinclude.h, jerror.h, and turbojpeg.h can be installed in system include directories, it's also better for internal references to those headers to resolve internally first, to avoid potential conflicts between the system-installed version of libjpeg-turbo and the version being built. (Such conflicts would never have occurred with our build system, but they might have occurred due to misintegration with a downstream build system.)
-
README
-
TurboJPEG Java Wrapper ====================== The TurboJPEG shared library can optionally be built with a Java Native Interface wrapper, which allows the library to be loaded and used directly from Java applications. The Java front end for this is defined in several classes located under org/libjpegturbo/turbojpeg. The source code for these Java classes is licensed under a BSD-style license, so the files can be incorporated directly into both open source and proprietary projects without restriction. A Java archive (JAR) file containing these classes is also shipped with the "official" distribution packages of libjpeg-turbo. TJComp.java, TJDecomp.java, and TJTran.java, which should be located in the same directory as this README file, demonstrate how to use the TurboJPEG Java API to compress, decompress, and transform JPEG images in memory. Performance Pitfalls -------------------- The TurboJPEG Java API defines several convenience methods that can allocate image buffers or instantiate classes to hold the result of compress, decompress, or transform operations. However, if you use these methods, then be mindful of the amount of new data you are creating on the heap. It may be necessary to manually invoke the garbage collector to prevent heap exhaustion or to prevent performance degradation. Background garbage collection can kill performance, particularly in a multi-threaded environment (Java pauses all threads when the GC runs.) The TurboJPEG Java API always gives you the option of pre-allocating your own source and destination buffers, which allows you to re-use those buffers for compressing/decompressing multiple images. If the image sequence you are compressing or decompressing consists of images of the same size, then pre-allocating the buffers is recommended. Installation Directory ---------------------- The TurboJPEG Java Wrapper will look for the TurboJPEG JNI library (libturbojpeg.so, libturbojpeg.dylib, or turbojpeg.dll) in the system library paths or in any paths specified in LD_LIBRARY_PATH (Un*x), DYLD_LIBRARY_PATH (Mac), or PATH (Windows.) Failing this, on Un*x and Mac systems, the wrapper will look for the JNI library under the library directory configured when libjpeg-turbo was built. If that library directory is /opt/libjpeg-turbo/lib32, then /opt/libjpeg-turbo/lib64 is also searched, and vice versa. If you installed the JNI library into another directory, then you will need to pass an argument of -Djava.library.path={path_to_JNI_library} to java, or manipulate LD_LIBRARY_PATH, DYLD_LIBRARY_PATH, or PATH to include the directory containing the JNI library.