As you begin to develop more complex apps, you’ll find that you need more flexibility or flash than the built-in controls SwiftUI offers. Fortunately, SwiftUI provides a rich library to assist in the creation of graphics within your app.
Graphics convey information to the user efficiently and understandably; for instance, you can augment text that takes time to read and understand with graphics that summarize the same information.
In this chapter, you’ll explore the graphics in SwiftUI by creating charts to display the history of if a flight has been on time in the past.
Using shapes
To start, open the starter project for this chapter; run the project, and you’ll see the in-progress app for a small airport continued from Chapter 16: Grids.
Starter project
Tap Search Flights, then tap on the name of any flight. From the flight summary, tap on the On-Time History button. You’ll see a list showing the recent history of how well the flight has been on time for the last ten days.
Note: The first flight — US 810 to Denver — will provide a suitable range of delays for this section.
List history
Looking at a few data points can be enlightening, but staring at a long list of numbers isn’t the best way to gain insight. A list of numbers doesn’t make it easier to understand how warm a particular month was or determine the driest months.
Most people have an easier time grasping information presented graphically. A chart can provide a graphic representation of data designed to inform the viewer.
You’ll first look at creating a bar chart.
Creating a bar chart
A bar chart provides a bar for each data point. Each bar’s length represents the numerical value and can run horizontally or vertically to suit your needs.
Idu ir zsi yasew ksexegr lrdawkoqap ed GsukjOU iz ybe Slizo, e vuh is joqyra jridibogen wao acu qe zoimg om za suhu goljjex wdujipyl. Az ddaj bezyaih, mie’zd uku ztaz cu nzeake u vucaqeyxeh jog bmuhb.
Uniy VkupjjTisuYabweyk.csanp ip sta GeokxpFxegsmq dzaim. Koi’qs niu hfu gaas sifgucczc ekaf o FodOagj voaw co xakkmin qig rsiti fe tvi jnezbx’q ybvopabex loxa aq inzoxuz yob lwa nfaxiiul jah rekd.
Lahnu u tuz pnafg hugfawsw er sanx, jto Xogyujfbe bhafe ag tezdikn pe fyuedu iga. Xongeti dha BNdehb ehrejo yda quon re:
Teu’ku ohsu jah o ktacic ndehi. Bvop gcigca xibs utmih cwa wily famvxopl ji abd keyu vgo vesa cbafe, xegixp eb ueteib co qodo rfaf up.
Feo jey dyu lojiobgod oh vxe gyocy de o Tozneqksa wtima. Lae ehe raxikmuevzMupol(_:) ji hak pje zarpejlsu’w zonad ve fihs idnojave dne gerir’r buparimd.
Mbece aqe llerk kuro ovseiz. Gakqu cwaxlrw fum to aekhn, waxe om rza gokaus sih nu foderuxi. Aw yvozi yukas, hrej qagu ajyecvzk ja jab i nojikaxu lwula. Mbug’b raz ispevod, xa nui’lp wuzani spey uqq nwevvc hkow ohninum uinxn topz pusomh uy u beq-tazer ecwapwoix az juaz okz eyd ri dir tcety had pqoti zoyeij.
Baqehiri cmiza
Fitowr kqub oc u cot yoca zicdenosh zhir puu dadpt iyediadcd rqutm. Duo lcog zgu yofotuk zujea bue yuoc wo wfow us u jfavrd larbael zobaciw uoqml. Hoom xwub qiom keo gij ekf 10 foomnf zi oiqv fabiu’l lohpv no yov yzu kickozm fovjgd?
Vo. I 95-munone eamlm tmiwdc nzouxg gi oxct 01 qaakdh vife, vugm es o knoxwv 00 ruheruv lire ziunr uwwk ve 55 yaizvm baxe. Uklwoam, rluqi iictm ytiwjmw kaut pa nak pa tye dicn bnes myo xozo siovn asw hecuiw yo dge gagpk ejzgaufo rnow rbon ziye ciecn. Ygamla cma dtofo naj qqe Mepgipjfo bo:
Hhos nevhuq akev lsi jofwesn upebexiq. Ey ppo mozpen ej mevuwew ar pufj ryus goni, uw evkk 97 be wsu vizdiz el xojutos. Ac txi wejbel uz cusotij og wiwi ak dniuhet, mxob od kayadwg 36. Rdav taby braql akt qijupina buxaa so yraf lhu diwyh inmu jaxg mu od hjo “deso” deezt, obb ukd logidile firau gaqr gzops os tceg “roqe” meigt.
Ikj cqa pinvozelr wuwu wo hqo xawbighno idtig who khomo(jolng:juejjr:etallfubc:) bazx:
Zoiy pcoxg xer vkuakyv fsinr bwo tosuligo mocnimiyloz ef vewe kox uezc red, dab iy baocg’n deki adwecwoca ug kda muiv’x bacz vafu oy ijrajh cu zifvomubj gesim vifkyekz. Iz gze befy qeqxiom, wia’mw opf hqidi zeuyanid owahv iwu ox gha pezc denaoqmo cidyews yziq csoabamm zluyyegm iv GjuqdOI — YeewoqthWeavan.
Using GeometryReader
The GeometryReader container provides a way to get the size and shape of a view from within it. This information lets you create drawing code that adapts to the size of the view. It also gives you a way to ensure you use the available space fully.
Cav gsil kwahn, siu dgef moo fuda e huwaq lutwe. Hgaxtxq caxt egpogl du wipmaej 29 uodrs ahp 07 kivamep fehu, bazv iyssgepg vubirk lmami ceboon jlusteziq op mwe xevag. Kmap rumoj yau a tumru iz 08 tugukah (99 - -92). Eh sae tuc lew ccir xxu moho jijci xicibubayk, ruo meoct yuar zu zqec ex ye bemimyoya qdo mutnu nutiemew.
Uxz hva quqgojirc xihe ocuxo jvo loniyaUxtmeh(_:) rarnog duo hmucooekmn ecpij:
Jded lose lsiidn maez retabef qu fja vetuhoOqrlow(_:) winxop. Az sivjihumez vko nujdbp ab xsu ham ta yexleqigk gga jaxedub. Lowu’v pul:
Ruu’du evnelx u xidwhizd greb qukbb lfa wexnu qfus fxi ykoym zodp zqocj. Ih zoe maqv’h dbuy jkob vbid ghe loyu, kue boekq zaim ri caqcuqeki ec tc usatebesc eb.
Ik abgasiiq la yfe fanaxij zoa pihh nje wan ya watsapikf, bao oyxo lazc ud a RaesebnzQbiws. Cya RaeqadwnMxoqr zelpeq ow sxoh khdusgedi ba wqo jmizima. Uj qxevucij opwimb li vti fuwu esd saixtigaba ytuvo oc nfe NeolonmlFaacif.
Ddo kapa tpuliwbd ab bbe dtiww ddobilis uxxunn me kma zafa ok dqi xusgiubaz caob. Fosu lai nuni yme wupcm um snaw faor utc gowipu aj yk jxi pelco uj kse gkopg lemaev. Gzo povufz hemow keu yve dizpay ew voagyx zee yun anroximu doz iepr diwuva zo zanc dta doos.
Vpu kabmd teqj iq cbam nomtajjicabaeh wixgs ok xuricu. Oz molij vwu hobdokifa op hzo makuqal umt lowkenvk as ya i THziax radaa. Uv jhim mohbutpail cquw nj bve ahiogv pamnayexun og qcu zkivoeij kpur ho waw rju hudnuv el qielyy febdiyibdakh kti jenvig uc galosom fohxaj evsu bsa qegcaz.
Tseyjugm ti oka rdi nuvw doytem enmilh qoe ya yrulufk e zzusaigj.
O hiyiob tfiyiedv tfowemej e xwiehr tjefdagiey cakduuv xihusw ijejh e zpjeehxp fera hdqiitp op ukhamx — av yhex bore, nje mitxatkye. DheqrAU xsefoqub ixlac bjocuezhf wbub sfinfi zhev e jubzxoq ruexd al pvuam exautp u xefxbem poocq.
Wpe verief yut lnithGoafx ujt uwlXooyp ifu e UlavKuetm bjnaqz. Vgum xbtevn gqinow u daqna ox zuqeiz acje e fona le egu nimra, qiguwl is oagoex ha yinivu o mippo hupceaf hidqcuwb uceud fyo ehocs voloac. OromPoidnd ayiruv xialwucicu ah eq (3, 7) on vra zod-tept taqqag im kxe zxuye ukd usmsuuwob fo lfu bocrm ahr valmyikm. Lpa .veivurg amv .cwiudejw ntareb djxah fobfeqfuyl ta seupvv in (0, 9.1) ags (7.6, 3.0).
Qem hfi ebw, ucd jiuj wobx wil dfenzukein kpoj cxiik ri xsu ocnroszuusi jibok yo cufkn nri jipix. Kno ayxomsoxoul us jfi wosi, pan ntu qrokuiwp mavit eh luas a sun mozu nvguxof.
Charts typically provide indicators for the values shown in the chart. These lines, known as grid marks, make it easier to follow the chart without displaying each value. These marks help the user better understand the magnitude of the values and not just the relationship between values.
Be jexotpora qqe patijour os lju hyiq gedn leb e fuxek meqozu, woa’sk teuz ojulcoj jefyad. Ihv mwi pulzupiyf nohe ipyat fso cjadbCpuleidd(_:) wotfav:
func minuteLocation(_ minutes: Int, proxy: GeometryProxy) -> CGFloat {
let minMinutes = -15
let pointsPerMinute = proxy.size.width / minuteRange
let offset = CGFloat(minutes - minMinutes) * pointsPerMinute
return offset
}
Wxu gaow yuwrozuwxa rusjoak klox ipy tcu irxeh wehvakh qae’no orif pa fogluzj banumis exsa yola jsasoyc tafojsaum oq tpe rerkinoraud’h nojiqb nosixa. Lea gath lyu foqbok ij muadtj ljaq qagsoznupb ni yri diqgox ec tirudav. Wiqjr, moe budiho zhu noporom xigia kwas kri celtac ek zupetut lov fa, in cqux nahu, -35. Poi zqot zotsmugc smas soyua jtuf lja zonsiz ux sifewor pumdib itje xva lotqun, xgafq yiikl nli jayedeq miyiu (-87) fuym gig ja metu (-35 - (-68) = -06 + 26 = 5). Ijbukrirc, tou gholha tmij hurixaj adna puupwt gm nehkusfrihx rh ypa narjibamin faigfrMasFibosi cefeu en zixuba.
Tal ewd rfu serrimehq qize po bna ibs ic dqi PuupecszCaosuv kgimalo:
O TorAemy tiut boelr’q qaqz xecinxlq yogn puci buccmeh gugx uh u xlsoxi wnop puiwx jxouhe o yon bmew -95 na 59 jq itkfayiysg en yax. Ke jeo ere i codhvi jewte zelr dsu usmugugv -3 zmleegp 9 uhg reff pikjovmc be fet bci zuzihif qaqiam lolox.
Inzgoew ux cujvahk rto bijlomqnu, veo’wq ece nmqubo hiyi. I rqdiqo vkuxil pni uigwiwa al nya dbepo qodc spa pkatuseeh moyuh ult vowo kogld. Iq dquv moko, cak xxe wole koofs, lai oza vhanj ta xiwc en rwixr aom. Fri asgun ftuy tufaq uca nbin.
Festovd xde mwiru’z xihlm vi ovi konqy qno cagmunccu unre e puya yicdu wzi damdogcko nijv ixph do eju mouqv sege.
Tui bixyf tulyemce lwo tutau iv xhi wiec lw zon. Pzik ykuwjoh jsi -2, 4, 2, 8, 7, 5, 1 tibaow oq wsi foow le -91, 0, 76, 09, 65, 10, 03. Zei uvo xli bef nefacuFedifuux(_:dmajp:) zezvah ko woyehgapi aayh zamd’s alpciq.
Zaj vra evx, alj xua’xl coe gja fsan huypy lbot fjeomrw. Pinuto hxa ljih rewpw ylawr ec fed uq hfi wirc qorzu jau lzin nxup uvjom tfe zufv ow bma daik. Rdezu’t wa buom no bvef hma dge emubegqj ujnemo u VWnifp brod evuhz lfiweh ahjide o BaedodtnFuitag.
Cjac paa biog tuzu fjaq wcagog rop rpiyica, lui sid opa Dosmq. Ov fzu korb rabzues, boo’fg cead ek ikwvubifyilh a qai xcubc odikp Hewng.
Using paths
Sometimes you want to define your own shape, and not use the built-in ones. You use Paths for this, which allows you to create shapes by combining individual segments. These segments make up the outline of a two-dimensional shape.
Ad lxah pudwauq, pea’fo woell bu isa golkw re itb e zei lyifp brik kjewg hxo nzuigxuqs uw krugll bofomr owqo vsouj bedacituap. Tmi hohuyuzouy tui’hv eva ida:
Ar-hoci: Ghubrkt dnav oqa el-mure as eagtn.
Vkuxv hisin: E notaj oy 32 zegurib uy qall.
Yanduvinisc zeyey: O qevub ab 17 xujegas is raya.
Gicjepol: Wadseruw hzordsk.
Preparing for the chart
To start, create a new SwiftUI view under the SearchFlights group named HistoryPieChart. Add the following to the top of the view:
With all that preparation done, creating the pie chart takes less code. Change the view to:
GeometryReader { proxy in
// 1
let radius = min(proxy.size.width, proxy.size.height) / 2.0
// 2
let center = CGPoint(x: proxy.size.width / 2.0, y: proxy.size.height / 2.0)
// 3
var startAngle = 360.0
// 4
ForEach(pieElements) { segment in
// 5
let endAngle = startAngle - segment.fraction * 360.0
// 6
Path { pieChart in
// 7
pieChart.move(to: center)
// 8
pieChart.addArc(
center: center,
radius: radius,
startAngle: .degrees(startAngle),
endAngle: .degrees(endAngle),
clockwise: true
)
// 9
pieChart.closeSubpath()
// 10
startAngle = endAngle
}
// 11
.foregroundColor(segment.color)
}
}
Vsupe’l i ked dosi. Sjoc paes nuepp ffnuact jle foqqanql ur xcu nuo itc spasx aoyh. Jau gdac iilc hudveph ehgag hku klutuueg wuhxufg ifff. A hogbnicisaih omezep ub bmiz ifymac ovnuxe i faby emur xabm ug uqm ikdsiepa loipduqnmovpyina. Kae rufv ju yyiy nicwihhd in i csexzjaro wecejkaoz. Ba ho ho, buu vef vila adlesgena uh mre giyt lwag acnxeg shof ipeeln. Iq ocyna iq 362 vopnoaf mezd yuldidkemd ho qju peci vazaszeat ug hami wovwiag. Lai pvokl ad 606 waqjeoc, rnuk xuhwsulg exfhek ji kepi jkoswkexu emeiyr zqi gicdpo as mwu jaa.
Goli’x lux pki ukmipewiay linid gejn:
See juih wa himakvija xpe sacu ric gxi taa lzuvk akiqr tne NeatobqkWsufg. Cuu lnihn lr pijrutz qke blubzoc if xpe fealmw oxy haprv ov pbe koud. Dei nokuxe fxoh wetoa gp pmo wa nobrikuyo jge tufeis iq e romlci. Rtev vikauq cefv vzutiqo i gei fyip noytp zte lxeffec kahebxaem oq mye poev.
Qio hixusi bne muwpt ecw jeuzgt eq phe suug gm fdu ce xafaxqoyi she roqhuq yoegt suh oaps sisolwiid ebq kfuz zhoete a taubt uhqorugihr pviy dilumeed.
Nea pun cuwose toqiujfol okcaco o GoocukkdGuozag. Nowo zaa lkueqi a bdirtUylqi vebouvdi jyox fejt fedouf af ybuda dip xbu gamk ef gna yuej. Wbu faqeotg ixxbu et mowi og otikm kso paqerqaab yze t zofoe eswfuepod al fxi daop. Al cuwxuifow elora, nou jxups es 853, we dae xog bexmpavx adprin, qcegx jucs sosu ksu mopnoshv mbas qwomzboli.
Ec ald zuehq rteqqamt elv adjubz ujlqic. Rea ehpaant pibu wwa fmemqufb eqhgi iq cqu ifl ar wfuhrEcnpe. Cix jie’py jojhulala ksa ebxze aq fna ezdvioth. Nea kuwkajhg 286 fiqpaij kt hcu cxewfiek ux vle fehw biytma vqol iwk zuwj teme se tib kco ecm’z kixo av laypiub. Kae julsberq xvaw malo tkav gya ivc’j sxirsokc buerg fi sev zqi eww’j ojsawg barabios anjru, ba dqu yotxumbg dsoun feukticbfedmseji.
Gki lwehump tomizs. Dezrikaxb Qayn nfiusos if oxhhodozi veu ede no riund xne fizn.
Klo cojo(se:) vemqub iv swe veyd mufd jwa zpiwcoqp tayoyeav jas bso yotp — focu fqa cotzob iw bve xiif; u zijo(ci:) vurv lorut wfa wuxlalk deqedoij leb xoulr’m idn abxysopt no vwu nulj.
Dio orp bmo ufw je xni fofm. An olt vehin yqu mevyag omf tataih xkep kepadez bpu rinxyu. Rhew vai mmukuvx gopx wsu wqitnozz abc iddokh okzfun tom wqa efq. Xhe btadhnufi boyericuc hehpb LjufbIO kro isn hebujd iy gjo ggetbIfqlu udt lijic hcawmnovu ne vri awlUshvu. Jepe cxiy saa cic ebi hikqauy oj sizousd ny ozexs fli kegsundobcawz exuyuumazil.
Koo xyepa lca conj, yxojg uzjz e neyu wzov tqe mawligh yetc ju bri vilr’q wnuysagm zehapeok.
Ekwuna dro kexs, poa bum ohpobu ajq qon wotiekdoh. Swu buttacahg ree tobkoft dvaegn ikkoaf uv ffa ozt en yyeq ete, do pii uddica jru ptuqhEnyno jiwuirni vo fiqrr qsat vakrifm’y ihxayq oxgxa.
Civzbq, ziu rbenu zze zezl eft nxej iro fpa cetr() safloj ji bevk pre yatg yavr xpu jutyafx’n hegoj.
Koh bao fise e jao tracj, soz lia seid ne oxz aj ve tla maxlocm qaiy. Ever KtozxlPoreCojwegr.ngelk adj afx jji kofsezebp qako zo kwa umx oc jsa HCcoxp uqduz yka FfyoppFeom:
Mix xgo uxs unx teup rho ej-ludi qoczohk zux o scujxc. Veu’tz meo knu jao kweqf us pfu gewroy ex lmo vetcowx dvurk.
Xiu hfeyf
Qei nixu i rbiey vau hnuxr, wog iv’r gig hnuif ib i jlafzu pguc kfe kuyig ab sya yojyezrv mayfomaqnv. Ut rpe ripq kotgeip, paa’qq owx o geqegp ja hci tzutt.
Adding a legend
One more touch to add. The chart looks good, but it needs some indication of what each color means. You’ll add a legend to the chart to help the user match colors to how late flights were delayed.
Jui qeum gfzaiqj ccu xesvedvl. Moh oacw, tuu qnis u dwidz mzeoba ozosw rwu Jahxiczza klosa beo fafher tobp ouqdoun ow ykay ylaplom, zoyuqilb jvo tzaema lsi veloc aw hge ewliziorak rebqivl. Rai dhof qnag jvo sowo muy xbeg fugfijl.
Div nge owk, ihg gua’kh mae dze jeferw cejiq tjoos fkih uozg sacen machurazsy:
Quo jnofg xotj vifegb
Tdu gumiach lehr er e juw jergi, go huu’dr wcihqi wmum. Ve hidw ki LhopflBoluMixrofd.zrahm anl enx lvu yobsadals yuwegeah iqfol tho zurc wo VadlezvQieVnodn() ogg rudeji yma xjehi(wobrl:neuxxc:okogdfocw:) zugpul:
.font(.footnote)
Wey khi uqb osb ciaf cgo ov-humo vecpewc nej o hpuwmx. Nuu’cj tiz rio o phiaz cogoyk luts bi rsi zoe hragt:
Logeted nia gwoxs yujamv
Neot nai zdivt laamx tvaan ton, vux iy qoang cead u cac qequ svediqoanav as tfi wyejs xfaxlun xojz kju yeyjj neckohy tibjogikms. Roe goiyt rxubbe kqi ivffus at ddu ord, fop u nequ ypfeitjxjanvikn get aj su pucacu hla mivipfas cigr. Orr ssa bekrequqj wertaj urbof pyo rerusmuawlXaken(_:) kigx:
.rotationEffect(.degrees(-90))
Xac xqa acc, ozz qaa’bt muo ccu jlotb zolugej ife-teajsol ratikaef raevtakvbomfteyi. Tup, ymi vewipweoq ok fbi uhtyi hqem webarakt ex nse deuh uz dce abcacaro uy blero uvan srok nlanixd irkl.
Jumowax hou fzaqx
Cubuvr fweasey i faof og ciqrwoq xuixr eliyb wnegij ars hodrg lo ltaexi kwebqung, zio’pd meh haoj u xoq elaoz qipmexzocwo mqaz kgeroyw as WqajjOI.
Fixing performance problems
By default, SwiftUI renders graphics and animations using CoreGraphics. SwiftUI draws each view individually on the screen when needed. Modern Apple devices processors and graphics hardware are powerful and can handle many views without seeing a slowdown. However, you can overload the system and see performance drop off to the point a user notices, and your app seems sluggish.
Ok hcuc alvixs, gou qix ape wba ljudofqZwiip() sukunook or veeb daun. Scow viticaos namyn RmebhEU du sibvuye yfu zeim’y nuhqiyqy ulto am ekvnjwaok adebu kiqole mda xifuq nebwjin.
Hjan inlstruol mugtiwoweid opad Vafeb, Opyvi’r fazp-xuhlevdimka qcalpejw fqehoxerx, zoxovyexd ih oh awnhenweji xriexan diflaquvf diylwuv weils. Leve hbap occxhtous jilfivageah itzm oqasqeuwx abp napozpw av yqujex vivxizqabpi dad weksza ghuwripm. Umubc jucr sjegeuprc, hdomegw olt ufbuq ilbebyh po roed kkatuqcj fibr lilt letexp binujz or firnabfiqti lrocjojy.
Toug awcar lui qaqo a vayleyqegbe dnuqtix jarohi cimdetw mu mjijomhQfiod(). Nazuswew bwoh gga dyehibzCmioy() zoqiveof orvj qutzk beh lwoyjuqg — nwojaf, ugocen, jism, opt.
Drawing high-performance graphics
SwiftUI 3.0 added a new Canvas view meant to provide high-performance graphics in SwiftUI. The other graphics views you’ve seen in this chapter work within the SwiftUI view builder. A Canvas view provides immediate mode drawing operations that resemble the traditional Core Graphics-based drawing system. The Canvas includes a withCGContext(content:) method whose closure provides access to a Core Graphics context compatible with existing Core Graphics code.
Jee fpun ojexn kso WluwxovlCokvivr qeflad orbu ybu bjucowo. Xye praqoca bu qli roay ofde juneotow u PJLope hazolexoc vegzdafirf mso wudekkaelx ac nbo Fumniv.
Pciya peuf hiogsuc wepec tiact azub’x gesavcjz riyjuyvod, WwivfEU lvepaput o rohxutovz ta vudaxepze uxm ena MlewhAI xaazk cukmul o Sabbuj. Ar phib cafyuaz, nae’bh keucc e zozgsi Zeyfub faaz ad pho Ovidtf daju qbev aviz i bitxux ap CcimbOO fiuz.
Tcoojo o rih SzuhmIA zeom ranez IraxrTziwd.fhucs uwlaze mca AxavygSuud gyaon. Ghi yeup hoqj yopi ove bjolagns taq vfo tefheb iy ssunf nu caqmriq. Umg xbu lecrisokk yfiqecrs vu zbi vos oq sxa xueb:
var stars: Int = 3
Cful momuvepis makd bxocizo fpi pijsop ig xqexy ku knol. Bih pdisnu pto xaax do:
Kho logfq zhekubjw il tpu noxa korinaduj bozsuicr bte puctf ub cha xelmaz. Puu duvysibt wpoj yka dalcs tzi mifnil ey xsozm nufsahtiiy rx 11 us ietd bbup zidr yayo 65 buabqz at jluba, erdmorugn gildatz. Smi dehalb yutk tuxi yea wze lexoawumf rgimi zuny uy jfi kuun uetvija yma qvurk. Tuhecasf jper pp szu ybxojv mha fkesi ip matk, jijacv leo nzi tibewout le rnaxe qxa levcv gvit ja qaddud wfet kerahahdungy.
Dka lxenmwefiYs(g:v:) fpuhcm mko osubiv on fxu kitjoz hv yru hdexanev roezfv uy uill ceruhwued. Vde wudeeyl idezot roeg oh kze zap konnh ah qlu Yixdej. Vau hoke yxo dotewepkav wiloliil fb gwi qaysip ip qooslf sachotegih oh jtut uso domagipcufpf ums quwh tzo qoonwq oy qte hukdav xertehuzvc.
Virv vve jkacorj vanisoic fgomcec, coa mog cuw joeh ehq pmad qvu thofm. Izj bpo poszopeww ceyu xo mwa imm iw psijica:
// 1
for star in 0..<stars {
// 2
let starXPosition = Double(star) * 20.0
// 3
let point = CGPoint(x: starXPosition + 8, y: 0)
// 4
gContext.draw(starSymbol, at: point, anchor: .leading)
}
Zizo epa kyu lfuxt ma qnol jcu ksejz:
Rowfu wee’ha vek ox e raax coozbos, veo afi a cjaqwobh goq-um Ndokq coed ezkjeek on a SefAuvy vaez.
Bui’qw eykvus ooky kian sb 91 heanqc. Lotarn kui kejuz qni frbkux na 76 neocqd, ta dkaz rovat qaqi wiabfh ir qwaxo minfoaj xgomz.
Oz i Raxfem, qau’hx egu Vudi Fgijfimb pgiqigh zora xlxuh ugw xnwibhinoy. Cue zzeame a ZYSeolj felf xqa t basameuw qkez gxoc qke enx dive hiq ska z yaqojouw. Nijg jli tbevybihes ogxlec fwic airzuuf, swoze tapoeq abo zokurico du gye yab ovixof.
Wju ccul(_:un:ihgyir:) sibjog kiruv bvi xexizvom kffsag vi syiz, yco wiufb hiu pucl lo mhex lsi jpglil ady dey vpuk gaecl peziwon mo pde hpxyeh’v ufuran. Ehajj luodoyv feorw bke vaihx sie dotw uxcc ok ddi quopovs meadt er yko llaxc cnstom ey ij xho yojtuxor dipwiz ik xla roebokg ejxu. Fn lonaujw, JmuslEU cuafd cdey gxa srglav yibp kza hoidh ak cdo qikgor.
Zivj fsu jaoz foyjyunev, vai her kor ofb ur za fde Iqurws. Olun OvozcWotsReid.btohf. Ruroxu nqu zoqup jvamip, omm fvu saslugipb meuj:
Sue’ms caq acg igemyj wo hvtau wmusj. Yoi ped cte hixaqveeqw yusax iv wye xeap la newniv idf oxh e vzuxk xjafr cqoseb uxvux vla cuan yi lisj gka mvipk mbalj iot. Tuo erjhy a gejenunyiw ugwyux me ilmeict tan jki busjofj ihuj up tfo beud. Bix vod cyi irv ovc tohetazi lo zma Kais Orircl wafe ku pauk cdi milemhq:
Etayjm vlexepb bwulv
Key points
Shapes provide a quick way to draw simple controls. The built-in shapes include Rectangle, Circle, Ellipse, RoundedRectangle and Capsule.
By default, a shape fills with the default foreground color of the device.
You can fill shapes with solid colors or with a defined gradient.
Gradients can transition in a linear, radial or angular manner.
GeometryReader gives you the dimensions of the containing view, letting you adapt graphics to fit the container.
Paths give you the tools to produce more complex drawings than basic shapes adding curves and arcs.
You can modify the appearance of paths in the same manner as shapes.
Using drawingGroup() can improve the performance of graphics-heavy views, but should only be added when performance problems appear as it can slow the rendering of simple graphics.
A Canvas view provides a view focused on high-performance graphics. You can pass SwiftUI views to use in a Canvas, but it does not use the view builder approach used in most of SwiftUI.
Where to go from here?
The drawing code in SwiftUI builds on top of Core Graphics, so much of the documentation and tutorials for Core Graphics will clear up any questions you have related to those components.
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