jpegsrc.v8d.tar.gz

jpegsrc.v8d.tar.gz
ThispackagecontainsCsoftwaretoimplementJPEGimageencoding,decoding,andtranscoding.JPEG(pronounced"jay-peg")isastandardizedcompressionmethodforfull-colorandgray-scaleimages.ThissoftwareimplementsJPEGbaseline,extended-sequential,andprogressivecompressionprocesses.Provisionismadeforsupportingallvariantsoftheseprocesses,althoughsomeuncommonparametersettingsaren'timplementedyet.Wehavemadenoprovisionforsupportingthehierarchicalorlosslessprocessesdefinedinthestandard.WeprovideasetoflibraryroutinesforreadingandwritingJPEGimagefiles,plustwosampleapplications"cjpeg"and"djpeg",whichusethelibrarytoperformconversionbetweenJPEGandsomeotherpopularimagefileformats.Thelibraryisintendedtobereusedinotherapplications.Inordertosupportfileconversionandviewingsoftware,wehaveincludedconsiderablefunctionalitybeyondthebareJPEGcoding/decodingcapability;forexample,thecolorquantizationmodulesarenotstrictlypartofJPEGdecoding,buttheyareessentialforoutputtocolormappedfileformatsorcolormappeddisplays.Theseextrafunctionscanbecompiledoutofthelibraryifnotrequiredforaparticularapplication.Wehavealsoincluded"jpegtran",autilityforlosslesstranscodingbetweendifferentJPEGprocesses,and"rdjpgcom"and"wrjpgcom",twosimpleapplicationsforinsertingandextractingtextualcommentsinJFIFfiles.Theemphasisindesigningthissoftwarehasbeenonachievingportabilityandflexibility,whilealsomakingitfastenoughtobeuseful.Inparticular,thesoftwareisnotintendedtobereadasatutorialonJPEG.(SeetheREFERENCESsectionforintroductorymaterial.)Rather,itisintendedtobereliable,portable,industrial-strengthcode.Wedonotclaimtohaveachievedthatgoalineveryaspectofthesoftware,butwestriveforit.Wewelcometheuseofthissoftwareasacomponentofcommercialproducts.