Make Art with Python: Programming for Creative People

156 Pages·2019·7.947 MB·English

by  Kirk Kaiser

Make Art with Python
Programming for Creative People
Kirk Kaiser
Thisbookisforsaleathttp://leanpub.com/makeartwithpython
Thisversionwaspublishedon2019-04-20
ISBN978-0-578-46648-4
ThisisaLeanpubbook.LeanpubempowersauthorsandpublisherswiththeLeanPublishing
process.LeanPublishingistheactofpublishinganin-progressebookusinglightweighttoolsand
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©2016-2019KirkKaiser
ForLauretta,formakingthishappen.
Contents
Introduction-LearningtoProgramwithArtandPython . . . . . . . . . . . . . . . . . . . . . i
WhyArt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
WhyPython . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
TheCreativeProcessofProgramming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
TheJourneyofBecomingAProgrammer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
No“RightWay” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
ChapterOne:ATutorialIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
GettingPython . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
TheTerminal:A ProgramtoControlPrograms. . . . . . . . . . . . . . . . . . . . . . . . . . . 1
WritingOurFirstProgram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
HowtheDevelopmentCycleWorks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
TheEditor:APlaceforWritingPrograms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
ChapterTwo:ComputationalThinking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
TheLoop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
TheVariable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
PythonDataTypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
ControlFlow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
BringingItAllTogether . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
ChapterThree:WritingOurFirstGraphicsProgram . . . . . . . . . . . . . . . . . . . . . . . . 17
DrawingOurFirstPixel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
HowtoReadOurCode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
EditingOurCode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
TurningPixelsintoaLinewithaLoop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
ChangingOurLine’sDirection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
FlippingOurDiagonalLine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
AFinalChallenge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
ChapterFour:FunctionsAreTheBuildingBlocksofPrograms . . . . . . . . . . . . . . . . . 25
FromPixelstoLines,PuttingtheFuninFunction . . . . . . . . . . . . . . . . . . . . . . . . . 27
TheMechanicsofWritingAFunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
TestingYourFunctionsasYouGo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
CONTENTS
DrawingRandomnesswithOurNewFunction . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
CombiningOurFunctionsforNewEffects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
ChapterFive:ReadingtheUser’sMindWithInput . . . . . . . . . . . . . . . . . . . . . . . . . 34
DoWhattheHumansTellYou. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
GrabbingtheUser’sInput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
ListsAreLinesofVariables,AllinARow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
CreatingaList,AddingThingstoYourList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
ChapterSix:MorePlayingwithLoops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
DrawingwithOurNewCursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
DrawingwithOurNewCursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
LoopingaFade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
MakingOurFadeintoaWave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
FadingColorstoMakeRainbows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
MoreExperimenting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
ChapterSeven:InventingIdeaswithClasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
DrawinginNewWays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
MakingYourIdeasPartoftheLanguage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
CreatingOurLineClass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
PlanningYourClassDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
RethinkingHowWeDraw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
DrawingwiththeMouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
CleaningUpOurCodewithClass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
ChapterEight:InventingNewWaystoDrawwithShapes . . . . . . . . . . . . . . . . . . . . 66
ExploringPygame’sDrawingMethods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
GivingOurClassNewFeatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
ColorizingOurLines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
ChapterNine:PlayingwithFiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
SettingUpOurDirectories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
ReadingOptionsfromtheCommandLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
UsingIPythontoInspectNewLibraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
SavingOurDrawingswithPickle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
AddingUndotoOurProgram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
UsingTimetoAddDelaytoOurUndo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
ProtectingOurselvesfromErrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
ChapterTen:PaintingwithImages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
DissectinganImage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
ManipulatingWholeImages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
MakingMirrorImages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
CONTENTS
CreatingGeometricImages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
TurningOurImagesintoVideos. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
ChapterEleven:DrawingInfinities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
TheThreeRegularPolygonsthatTesselatethePlane . . . . . . . . . . . . . . . . . . . . . . . 105
DrawingACenteredTriangle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
CheckingtheDistanceofTriangles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
DrawingOurFlippedTrianglesintheRightPlaces . . . . . . . . . . . . . . . . . . . . . . . . 109
MakingOurTesselationsMoreInteresting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
TesselatingHexagons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
ColorizingOurHexagons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
ChapterTwelve:InventingInteractiveTesselations . . . . . . . . . . . . . . . . . . . . . . . . . 121
SurveytheProblemSpace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
DiscovertheRules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
DrawItFirst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
MakeItInteractive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
MakingaPlanofAttack(ForCode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
DrawingaSquareFromScratch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
AddingMidpointsToOurSquare’sLines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
SelectingAPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
FindingtheOppositePointintheSquare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
BringingItAllTogethertoDraw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
TesselatingOurNewShape. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
ChapterThirteen:ExportingOurTesselationsforPrint . . . . . . . . . . . . . . . . . . . . . . 135
RenderingVectorGraphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
AdjustingOurTesselation’sThickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
CreatingGlitchesinOurTessellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
ColorizingourTesselationswithInkscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
ExploringFurther. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Introduction - Learning to Program
with Art and Python
If you want to build a ship, don’t drum up the people to gather wood, divide the work,
andgiveorders.
Instead,teachthemtoyearnforthevastandendlesssea.
-AntoineDeSaint-Exupery,TheLittlePrince
Faceit,computershavetakenoverhumanity.
Everyone’s face is buried in their phone, oblivious to the world. We’ve collectively fallen in love
withtheworldsofthemachines.
Becauseofthis,theabilitytowritenewsoftwaregivesprogrammersunimaginablepoweroverthe
collectivemindsofhumanity.Throughtheirprograms,theymagnifyandmultiplyideas,whichcan
quicklyspreadtomillionsofpeopleindays,weeks,months.
Buttheprocessoflearningtoprogramcomputersistreacherous.Tothelayperson,itseemsasifonly
amathematicallymindedpeoplecaneverhopetolearntoprogram,andtrulycontrolacomputer.
And sure, everyone who learns to program must deal with broken code libraries, finding an
appropriateprogramminglanguage,decidingwhattomake,andsoon.Therearesomanydecisions
tomakealongthejourney,andsomanyfalsestarts,thatmostpeoplegiveupbeforetheyevenreally
begin.
But programming is especially rewarding for the type of people who are drawn to the humanities.
Theybringauniqueperspectiveandexperiencetotheworldofcomputersweinhabit.Theyenrich
theworldofcomputationbybringingfunandstoriesandcolortoourvirtualworlds.
And honestly, most great programmers are more like painters than technicians, beginning their
software with sketches, tiny little programs that just do one thing, that let them see their ideas
before beginning. They’ll often make mistakes, write things that don’t run properly the first time.
Eventually,throughsheerforceandtrialanderror,thingspushedthroughtoaclearidea.
And writing new programs isn’t just for obedient rule followers. Anyone motivated enough can
write their own programs, given the proper instruction and patience. Once you understand the
fundamental concepts, playing with software becomes an opportunity to play with the flow of
thoughtitself.
This book gives creative, intelligent people with ideas the mental tools to start programming
computers and getting their ideas into the world. If you’ve never thought of yourself as the sort
ofpersonwhocouldwriteaprogram,thisisthebookforyou.
Introduction-LearningtoProgramwithArtandPython ii
Almost everyone explores their ideas and shares their creativity through computers now. Why are
sofewpeopleexploringnewideaswithprogramming?
Andwhyareevenlesspeoplecreatingprogramsthatarefun?
Why Art
Inthisbook,we’llfocusonlearningtoprogramthroughartandthePythonprogramminglanguage.
To an outsider, art and programming couldn’t be more different. One seems rigid, with precise
instructionsthatarereadbyanunyieldingmachine,andtheotherisopentointerpretationbyerror
prone,emotionalhumans.
But the process of writing software is the same thing as the process of creating art. In each,
we experiment, copy, explore, and then share what we’ve made. Art and programming are both
mediumsforexploringourideas,andthensharingthoseideasforotherpeopletoplaywith.
This book, however, isn’t about art with a capital “A”. We’re not making artwork fit for prestigious
museums. Instead, this book is more like art with tiny “a”, as in arts and crafts, or better yet, finger
painting. We’re just here to enjoy ourselves, and the act of putting paint on paper. Or in this case,
codeonthecomputer.
Step by step, we’ll make tiny, understandable changes to the code we’ve written, and reshape and
mixideaslikeLegosintonewprograms.
We’llwriteprogramsfordrawing,editingphotos,andmakinginfinitelyrepeatingshapes.
By manually writing out and running each of these programs, you’ll get a feel for how to start
exploringandsolvingproblemsonyourown.
We’re just using drawing and art as a medium, because with art we’re allowing ourselves to make
mistakesandnotbeperfect.
Why Python
Tocreateourprograms,we’llusetheopen-sourcePythoninterpreter.
Open source is a software movement created by a global community of programmers around the
world.Eachcontributestheirtimeandmindtocreatesoftware,andthengivesitawayforfree.
Eachpersonmaycontributejustalittlebitofaprogram,butcollectively,theresourceofopensource
softwareiswhatpowersmostoftheweb,fromFacebooktoGoogle,toalltheserversinbetween.
Python is a programming language, but also a program that reads and runs programs. Python can
loadandrunprogramsfromfiles,oryoucanwritecodelinebyline,directlyintoit.BecausePython
readsyourprogramlinebyline,it’scalledaninterpreter.
Inthisbook,we’llusethemainPythoninterpreter,alsocalledCython.
Introduction-LearningtoProgramwithArtandPython iii
As an interpreter, Python reads our programs line by line executing each instruction in order from
the files we write. Indeed, we can also type out our programs directly into Python, and have our
programsrunaswetype.Forabeginner,thismakesstartingwithPythonlessfrustrating,andmakes
makingmistakeslesscostly.
Python has also been around for a long time, receiving decades of continuous improvements from
some of the best programmers in the world. Because of this, it’s also got over a hundred thousand
“libraries”,orprogramswhichextendthecapabilitiesofthePythonprogramitself.
Libraries can connect our Python programs to the internet, write AI, draw images, control 3D
printers, direct robots, and more. Each of them just gives us a new set of tools to incorporate to
ourprograms.
Finally,Pythonisaveryeasyprogramminglanguagetoread,comparedtomostlanguages.Atfirst,
looking at Python code might seem confusing, but there are very simple rules for Python code
relative to other languages. It uses a lot of white spaces to designate what parts of the code belong
toeachother.Thismakesreadingotherpeople’scodeeasier,andgivesplentyofother,opensource
codetolookatifwegetstuck.
The Creative Process of Programming
As you progress through this book, you may encounter some points where you might not really
understandwhat’shappening,orwhythingsmustbeacertainway.
Withsomuchtolearnasanewprogrammer,itcanbeveryintimidating.I’vetriedtoanticipateall
theplaceswhereyoumaygettrippedup,ornotunderstandfullywhat’shappening.
Maintaining the balance between understanding concepts completely and not understanding them
atallcandriveyoucrazyasabeginner.
Aswegoalong,I’llcalloutthemostimportantpartsyoushouldfullyunderstand.Mosteverything
else should be fine to skip over at first. Doing things repeatedly is the only way to really absorb all
theideasofprogramming.
Keep in mind, whenever we learn something new, our first efforts are often terrible. It can take us
hours to type out and run our very first, simple program. The errors we get when we try running
thingsmakenosense,andthetiniestthingsseemtomatterinwaystheycouldn’tpossibly.
Goeasyonyourselfifyoufeelstuck.Justtrusttheprocess,thatthingswillgetbetter.Slowly,piece
afterpiece,webegintofindourway.Soonwecansuccessfullymanipulateourmedium.
The Journey of Becoming A Programmer
Bytheendofthisbook,youwillbeaprogrammer.
Introduction-LearningtoProgramwithArtandPython iv
Thismeansyouwillbeabletocomeupwithnewideas,knowwheretobeginafterabitofresearch,
andthenmaintaintheresolvetokeeptryinguntilyourideascometolife.
Alongtheway,ifyougetlost,itpaystoreadotherpeople’scode.Thisisoneofthemostimportant
things you can do when first beginning. Focus on reading other people’s code and understanding
thewaysinwhichtheyhaveapproachedtheirownproblems.
Initially,youmaywonderwhether thecodeyou’rereadingis goodorbad. Whatifyou’relearning
the wrong ideas from “bad code”? Developing a taste for “good code” comes from reading a lot
of code, and making the judgement for yourself. Usually it also means writing a lot of bad code
yourself. Some people love filing their ideas into classes. Other people like making everything into
afunctionthatreturnsavalue.
Partofbecomingaprogrammerisdecidingwhichapproachresonateswithyou.Tryafewdifferent
approachesout,evenifotherpeoplecallit“bad”.You’vegottostartsomewhere.
No “Right Way”
Asyouprogress,youwillinevitablyworrythatyou’reprogrammingthe“wrongway”—asifevery
programyouwriteiswritteninthemostwrong,convolutedway.You’llwantsomebodytotellyou
the right way to write code, and to show you how to organize ideas. But here’s a secret: Nobody is
coming to save you. Instead, just remember that if you create solutions to your problems, you are
doingagoodjob.Ifyou’velearnedsomethingnew,you’redoingagoodjob.
You may wonder about code that you can maintain, or about code that’s fast, but for now, the
onlyimportantthingisthatyourcodeisunderstandabletoyourself.Ifyoucanwriteandreadand
understandwhateachlineofyourcodeisdoing,thenyouarealreadyagreatprogrammer.
Enoughtalk,let’sbegincoding!