A Media Computation Cookbook.ppt

AMediaComputationCookbook ManipulatingImagesandSoundsforUseinAlicePart1 ImageManipulationsPart2 ChangingcolorsinanareaPart3 ChromakeyfordigitalvideoeffectsPart4 ManipulatedimagesinAlicePart5 SoundmanipulationsPart6 ManipulatedsoundsinAlice Can tIdoeverythinginAlice WhydoprogrammingoutsideofAlice SometimesyouwantspecialimagesorsoundsinyourAlicestory Youcanmakethembyprogrammingthoseimagesandsounds thenbringingthemintoAlice SometimesyouwanttoaddinspecialmovieeffectstoyourAlicemovie Overall programmingoutsideofAliceisthespecialeffectsstudioforAlice AliceandMediaComputationIntro 3 SoundFrequencyProject CreateanAliceworldwith3frogsResizeonetobebiggerandonetobesmallerUsingcroak wavCreateahighersoundTakeeveryothersampleCreatealowersoundTakeeverysampletwiceImportthesoundfilesandhavethefrogsplaytheirsoundsandtaptheirfoot AliceandMediaComputationIntro 4 UsingChromakey CreateobjectsinAliceandpositionthemasdesiredDeletethegroundSetthecolorofthebackgroundtogreenintheworldpropertiesUseaconditionaltoreplacethegreencolorYoumayalsoneedtoscaleoneofthepictures AliceandMediaComputationIntro 5 DrawingProjects DrawsomethingonanAlicepictureLikeahat glasses orascarfFireworksCreateimagesinMediaComputationthatyouuseastexturesinAlicelikeagradientforthegroundClipanAlicepictureTolooklikeaportholeCreateaposteradvertisementforyourAlicemovie WithyournameonitCreateacomicpanelwithAlicepictures AliceandMediaComputationIntro 6 ComicStripProject CreateseveralscenesinAliceandtakepicturesofthescenesUseMediaComputationtocreateaComicPaneland orComicStripsDrawdifferenttypesoftextballoonsSpeechballoon thoughtballoon screamballoon AliceandMediaComputationIntro 7 AddYourselftoanAliceMovie AliceandMediaComputationIntro 8 AddAliceCharacterstoaRealMovie SplitoutframesfromamovieofpeopleCaptureframesfromanAlicemovieusingMovieCapturePanelUsechromakeytocopytheAliceitemstotherealmovie StartJES Double clicktheJES exe Pythonwithglasses icon UsingJEStoaccessimages TypecommandsinthebottompartofJEStogetfilenames printfilenames makepictures andviewpictures JPG JPEGfilesareimages WAVfilesaresounds JEScanreadsomeMP3 s AnexampleinteractionwithJES filename pickAFile printfilenameC mediasources barbara jpg picture makePicture filename explore picture KeycommandstouseinJES UPPERCASE lowercasematters print printsoutthevalueofwhatevervariable Something setsvariableequaltothevalueofSomething pickAFile letsyoupickafile andhasavalueofthefilenameyoupick makePicture filename takesafilenameasinput andhasavalueofaPictureobject explore picture showsyouthepicture MakinganewfunctioninJES defdecreaseRed picture forpingetPixels picture value getRed p setRed p value 0 5 Savethefunctioninafiletouseitlater First saveit maybe myfunctions py ThenhittheLoadProgrambutton Thenuseyournewfunctions Usealoop Ourfirstpicturerecipe defdecreaseRed picture forpingetPixels picture value getRed p setRed p value 0 5 Usedlikethis file pickAFile picture makePicture file explore picture decreaseRed picture explore picture SavingthepicturetouseinAlice writePictureTo picture file Yup thatworked Howwritingfunctionsworks Tomakeafunction usethecommanddefThen thenameofthefunction andthenamesoftheinputvaluesbetweenparentheses input1 Endthelinewithacolon Thebodyoftherecipeisindented Hint Usethreespaces That scalledablock Howdoesthatfunctionwork Whatarepixels Howdoescolorworkonacomputer Howdoesthatfunctionreduceredinallthepixelsofapicture Digitizingpicturesasbunchesoflittledots WedigitizepicturesintolotsoflittledotsEnoughdotsanditlookslikeacontinuouswholetooureyeOureyehaslimitedresolutionOurbackground depthacuityisparticularlylowEachpictureelementisreferredtoasapixelPixelsarepictureelementsEachpixelobjectknowsitscolorItalsoknowswhereitisinitspicture Encodingcolor EachpixelencodescoloratthatpositioninthepictureLotsofencodingsforcolorPrintersuseCMYK Cyan Magenta Yellow andblacK OthersuseHSBforHue Saturation andBrightness alsocalledHSVforHue Saturation andValue We llusethemostcommonforcomputersRGB Red Green Blue EncodingColor RGB InRGB eachcolorhasthreecomponentcolors AmountofrednessAmountofgreennessAmountofbluenessEachdoesappearasaseparatedotonmostdevices butoureyeblendsthem Inmostcomputer basedmodelsofRGB asinglebyte 8bits isusedforeachSoacompleteRGBcoloris24bits 8bitsofeach EncodingRGB Eachcomponentcolor red green andblue isencodedasasinglebyteColorsgofrom 0 0 0 to 255 255 255 Ifallthreecomponentsarethesame thecolorisingreyscale 50 50 50 at 2 2 0 0 0 atposition 1 2 inexample isblack 255 255 255 iswhite Howdoesthatwork defdecreaseRed picture forpingetPixels picture value getRed p setRed p value 0 5 Usedlikethis file pickAFile picture makePicture file explore picture decreaseRed picture explore picture Let swalkthatthroughslowly Herewetakeapictureobjectinasaparametertothefunctionandcallitpicture defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 picture Now getthepixels Wegetallthepixelsfromthepicture thenmakepbethenameofeachoneoneatatime Pixel colorr 135g 131b 105 Pixel colorr 133g 114b 46 Pixel colorr 134g 114b 45 p getPixels defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 picture Gettheredvaluefrompixel WegettheredvalueofpixelpandnameitoriginalRed value 135 defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 picture Pixel colorr 135g 131b 105 Pixel colorr 133g 114b 46 Pixel colorr 134g 114b 45 p getPixels Nowchangethepixel Settheredvalueofpixelpto0 5 50 oforiginalRed picture Pixel colorr 67g 131b 105 p value 135 defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 getPixels Pixel colorr 133g 114b 46 Pixel colorr 134g 114b 45 Thenmoveontothenextpixel Moveontothenextpixelandnameitp picture p value 135 defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 getPixels Pixel colorr 67g 131b 105 Pixel colorr 133g 114b 46 Pixel colorr 134g 114b 45 Getitsredvalue p Getitsredvalue SetoriginalRedtotheredvalueatthenewp thenchangetheredatthatnewpixel p defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 picture p value 133 getPixels Pixel colorr 67g 131b 105 Pixel colorr 133g 114b 46 Pixel colorr 134g 114b 45 Andchangethisredvalue Changetheredvalueatpixelpto50 ofvalue defdecreaseRed picture forpingetPixels picture originalRed getRed p setRed p originalRed 0 5 p p picture p value 133 getPixels Pixel colorr 67g 131b 105 Pixel colorr 66g 114b 46 Pixel colorr 134g 114b 45 Andeventually wedoallpixels Wegofromthis tothis Howdowechangeanythingelse Eachcomponentofthepixelischange able getRed setRedgetBlue setBluegetGreen setGreenWecanmul