Commit aa7459050d7a50e1d8a99488902d41fbc118a50f
2017-11-16T18:09:07
TurboJPEG C API: Add BMP/PPM load/save functions The main justification for this is to provide new libjpeg-turbo users with a quick & easy way of developing a complete JPEG compression/decompression program without requiring them to build libjpeg-turbo from source (which was necessary in order to use the project-private bmp API) or to use external libraries. These new functions build upon significant enhancements to rdbmp.c, wrbmp.c, rdppm.c, and wrppm.c which allow those engines to convert directly between the native pixel format of the file and a pixel format ("colorspace" in libjpeg parlance) specified by the calling program. rdbmp.c and wrbmp.c have also been modified such that the calling program can choose to read or write image rows in the native (bottom-up) order of the file format, thus eliminating the need to use an inversion array. tjLoadImage() and tjSaveImage() leverage these new underlying features in order to significantly improve upon the performance of the old bmp API. Because these new functions cannot work without the libjpeg-turbo colorspace extensions, the libjpeg-compatible code in turbojpeg.c has been removed. That code was only there to serve as an example of how to use the TurboJPEG API on top of libjpeg, but more specific, buildable examples now exist in the https://github.com/libjpeg-turbo/ijg repository.