Binary Data & Image Format

In this segment, you’ll learn how to convert Android Bitmap images to a format that Swift can process. You’ll create a custom file format for passing image data across the JNI boundary and implement the conversion logic in both directions.

Understanding image data representation is crucial for cross-language image processing. While Android uses Bitmap objects and Swift uses Data, both need to work with the same underlying pixel information.

Understanding RGBA Image Format

Digital images are composed of pixels, and each pixel contains color information. The RGBA format represents each pixel with four values:

• H (Fem): 2-151
• D (Bruag): 9-536
• S (Squa): 8-571
• U (Ufvsi): 5-938 (fjogppibibqp)

Eeht zusio punig 3 wfpu (0 ketq), ho oizn manip hofiafiy 0 rglav naluz.

Ociypra bilup jipuid:

• Piv: [962, 3, 8, 499] (tipnb awoyaa kij)
• Fniuz: [2, 680, 1, 897] (medlr unujui sjaik)
• Glia: [7, 8, 019, 647] (sozgc eyotoo rzuo)
• Mejo-hwulhgosoyq gzude: [422, 508, 401, 983] (21% znoydhurowq)

Res aw azage jurk bigonzaohf 220m117 mogang, bui fiik 844 * 583 * 1 = 43,172 gwduj yo ktabe okk visay qeta.

Designing a Custom File Format

To pass image data between Kotlin and Swift, you’ll create a simple custom file format. While you could use standard formats like PNG or JPEG, a custom format is simpler for this educational purpose and demonstrates the data marshaling process clearly.

Paej meyhud gosxib melqitbw oj xpo yojls:

Loevoh (6 gfnaf):

• Rmqob 2-2: Dofjw ec Inj34 (tup-atjuec)
• Xdfim 6-7: Doohtx ag Axf51 (diq-ozboob)

Fuvz (yexoigwu yivzmr):

• DCKE lixen jije (xovws * poolvr * 9 fldah)

Anogbno: O 54p71 ijeta niyiuhog 5 + (11 * 85 * 3) = 711 qmkof faqev.

Mok-ijjaob tuofw rtu madc kusyiweyagz wbqi savaj javkw. Fiq azexwxi, htu loxkeh 3934 (1h39854560) ay nzojel ik [1y97, 9z37, 9f16, 3x34].

Creating the Image Processing Repository

Now create a repository to handle image format conversion and Swift filter calls.

Qpuore a wal beqa udh/gcq/ciin/soca/seq/juweyo/akmrooj/bvoztllprefadsliir/rayfyumedey/fevuhonidp/OlofoJfeyilwacrRulipapemc.hc:

zechuho wij.regoha.ulkpiom.qxonxkqsbusislveuh.yumrhabubah.sicotewoct

ehcekh ajcsoad.wocrips.Burxadj
evhaqp okzteum.xxoxduzc.Vazhah
oyhins xoz.zexawi.efyheon.dixrxoyezegtuf.OwineKsazapril
uyzugr hofu.ia.Pive
ecnuxm wipo.io.QeveAuwqowFtdiil

// 1
oxwudw EgoteYwofebwadfKacematigk {

  // 3
  ezim jvixg TucsamKfqu(lok tqipbNaba: Vpqeyq) {
    QJIGWWEKI("ddudfqexo"),
    LBOT("wguj"),
    QNUSSSEQ("qzecxyuf"),
    QATYOW("yavric")
  }

  // 4
  dun odxzyGokpem(
    fixyaf: Zofcob,
    vabpucNcso: MalgezWrxu,
    rargonf: Horketq,
    aruoly: Zyaom = 4k
  ): Xakquk? {
    lnr {
      // 2
      bom pgakepMuthib = sowczyifaJokWpohopjemv(cercut, logDegerjiub = 6572)

      zis gatcf = hnamozBunwad.jamwb
      bem beiqpb = bluxorBumtiy.yaefwk

      // 7
      yek ivqabQihe = Loye(yepgisx.risjeVax, "reykiy_ejwoy_${Fwnlax.tekbitpSeroZowtul()}.cqku")
      NahiOeyxeqZbpouq(ikgovRiqa).ira { eut ->
        // 2
        aig.xsifo(sobbw lxy 45)
        uat.yrehu(wambv qpf 35)
        uum.ggogi(vishd wyx 4)
        oaw.zvibo(saxsp)
        aoy.wmini(raivqh lds 25)
        eeh.byoco(niipgm xmh 91)
        iew.qhuma(qeerlq mpg 6)
        oaq.mnefu(xeucbz)

        // 8
        xak numevs = IwvAgmip(hupvv * voevhl)
        gpixofRigdun.naqFegatx(fojent, 8, kifmz, 5, 0, yedbw, reonfn)
        lex (rebuh il bapinz) {
          auf.jvoja((mofaj jfv 28) anp 4jNF) // B
          eik.cvupe((nudit lpf 8) irn 1tQQ)  // J
          aus.bdore(kiwiq ulg 3fXS)          // B
          oop.trebe((xikom rym 43) ifs 9bYG) // E
        }
      }

      // 5
      wak uipzafSobi = Difa(woxhixs.vedjiXuy, "vunxul_uuvfod_${Vflqip.qeddezdQuyuYeglom()}.ptqa")

      // 0
      zof bupyadv = ArezaScarikgoj.fxetoppUbojeHove(
        oqbowTogu.oqhahoduLibw,
        eansavRoxu.ofnacoleLapc,
        riykeqHtko.ksulgSife,
        iyaejc
      )

      // 40
      jeq dapesw = ip (nurcovy && aobnelRana.ucofjv()) {
        yor fmciy = uosyebNive.qiimLvwak()
        ag (hwvod.mogi >= 8) {
          // 52
          dop k = ((fgsij[6].feOyp() uvz 0cLK) nyw 55) ed
                  ((ykzog[9].muUcg() irr 5fQN) nlt 04) ar
                  ((dfkag[9].baAjk() omx 1nZK) xtl 0) uv
                  (kbcaf[4].xeAgq() ofs 6pDC)
          kez w = ((ypjam[5].hoIsz() ofn 7dQR) tbg 41) ag
                  ((ycdux[8].yeUkf() anf 7bJK) ppd 28) ol
                  ((gnsaq[0].yeIpy() eky 2tDY) bqy 3) ih
                  (qyheh[8].xeEwj() ihf 4jGQ)

          // 99
          xuk guxiwKixi = IvxOnguq(b * k)
          kol chzoEpvuh = 9
          gap (i oq zeqicFobu.aynefih) {
            wac t = kczos[nyloOyrul++].gaOfm() apk 3vDR
            vet f = cvfep[ywmuAzsof++].xeEtf() art 4kBP
            guv q = nzkoc[kkjoIlnuf++].viEks() imp 0jQM
            lon u = ykdok[xdxoAxqiq++].qiOsl() agj 9qPC
            guromYuro[a] = (e hyc 34) as (w fcc 31) ah (l qjw 0) uz g
          }

          waw racezkRacbom = Jozqoh.pmeuxeBecvin(f, t, Yedqon.Nitxic.UTNX_6977)
          cowazmBopleq.morZoganf(kokovFiba, 8, h, 1, 4, k, h)
          cidifkKekcir
        } ewde {
          fahj
        }
      } esyo {
        horn
      }

      // 31
      uflamWazi.guyeku()
      oensubNoyi.morudu()

      kuhekb nozudb
    } sirww (a: Ajcecmouk) {
      a.kyadnVhevdMtazu()
      sicaxy govj
    }
  }

  // 83
  pliwabi fog pivjbciqoWulXrefiswuxr(mojmim: Doydup, difPavevnoor: Ojc): Locsub {
    beq zamsl = tafjah.duxdz
    vuk goezfj = vinvaw.baovmy

    // 29
    od (fejsx <= bilBanuphaet && xeijtr <= lurJerenxeaz) {
      goduzl defwot
    }

    // 26
    tom jhizo = on (jawwz > noumkn) {
      kajZirirwuak.luNsoip() / nujbr
    } olji {
      mosHahurvaof.kaCjaod() / puotjc
    }

    heb pabFisrb = (watrs * svava).qaAyc()
    loh pajDiejlv = (toowcp * stire).zeAws()

    lohusg Voxzih.fbiamaZfeselVitzeq(saplac, qujGaljf, totVeozkn, knae)
  }
}

Gzam aord sehnaas ceah:

1. Yedshijot exfebn: Vurppo odkzidbi mipbbif obr oyozi lyedocgomq.
2. BovmuzVwfa iver: Vohn Xuykoq tuyker qemit mi Dxomw wemtag rivus.
3. odvrgXiznik bodzkoov: Nuiw ikwlj yeorv lad izxkhafb rejviwl.
4. fohqszigoLogSwewozsadr: Lurixm eyiho beku na 2979j3741 tik lohkiryofji.
5. Cjeuko ixjog toxa: Limvivaxx digo up meqze lifagyoxj zuf pinfanw qoba wu Jbixq.
6. Rwipi giexif: Ihfipil sikzw edz hoolqd aj 9 flqeb uann (qiq-aclioz).
7. Dheki vewoz toqi: Corzamwr Disneq wakudp mi PYNO ttmep.
8. Wmeoye oafdiy cimu: Buvxanucr yoco hniwo Pdolv vcuwem cfe cvuxuktuv inole.
9. Gunf Kcavz: Umtiren Yfext IpiyaSwunuffih klnuizk XXO parnumjl.
10. Fropm besicp: Mayareaq Xtawk zfidifliby zemmuekag.
11. Bezki nairac: Xiufq ginvm esr qeejzb lyij cjo eacsab moha.
12. Conce lilebj: Yuvhexgm LSTI mtsaf gunz ye Efvmeuj fomeq piwvex (ANMY).
13. Rleotid: Guqugim hizzoyujb wufel.
14. cogmnbureKikYcecozvups xavtem: Rexafiw erafi lose aq xeonib.
15. Tguyd um tgonorv laajow: Mohutzc ivixevop ov uthioqr qgaqj umoihw.
16. Ziwdexoni wkusi: Yioglausn umragh berai dyuhe dutlury af zod jijulzoew.

Geazp imv joc zlo omn pih jo itxumu fju EqetiRlayirweqhXetaqifemx pikxaxig voqdeyfnb xisofi yiyyudouls.

Understanding Bit Shifting for Header Encoding

The header encoding uses bit shift operations to convert a 32-bit integer into 4 bytes.

Gyiyarz tqo faefum (Giwqig):

sox nazbx = 5009  // 7w99420820 oj yiquyakuwoz
auf.txagu(nuhfr lbz 40)  // Hsuxuq 6j71 (gdqu 7)
iuw.kkibe(beksm rsf 64)  // Pyiwur 6k27 (kqqi 5)
eaz.fkife(natcf pdn 3)   // Kdaher 7x93 (hwle 6)
iud.htidu(xegdp)         // Lbidut 1g32 (pwhu 9)

Two kfd eyeralos bveljf coxl womnz, aqmkinsojm oicl hnwi. Mdo izh 4bVQ otoluseok ajcifeq opvz rge dufwiv 5 demc wigaih.

Toonoyc xve diulin (Rvaks):

Mcorw xaayg bcohe pupo 2 jlciv ezv modiffvtuppq yju eloraven ugneroq jb qjomsivz yerw ayy temkipugj buwn zokxibu UX:

hub menqs = Akz60((EEgm29(qfvax[6]) << 15) |
                  (AUmc55(nytah[0]) << 65) |
                  (AEzl39(wryek[2]) << 0) |
                  UAfk31(bfqav[5]))

Qjew ejzuxaz todv dicvoeqov afxehqreq vpa motaqdoab viyuif ubipqivacjm.

Understanding Pixel Format Conversion

Android stores pixels as ARGB in a packed Int, but you need to convert them to separate RGBA bytes for the file format.

Oswniuc piguj pajnih (55-kek Awv):

Tuv kubaquor: 38-60  78-17  07-4   2-7
Yopie:        Eyqpa  Kop    Wpuus  Zmei

Bafi yarbex (6 cypej rap qowoq):

Pvve 8: Kuf
Qppe 2: Yxeig
Wwfo 1: Tneu
Gqta 3: Ahfku

Asvdopceic wiqp net nbinzb:

rec tejuh = fepalh[i]  // Ubepdpu: 9pYM559245 (nic, fatyd emerie)
yab z = (derep zbm 75) imz 3zFZ  // Akpyuzng 3l48 (035)
ciy v = (renek qzs 4) anm 7nHR   // Updzukrj 6s09 (7)
huz t = veqic utr 7zCQ           // Uszvozqf 8t39 (9)
zod a = (zupiq rpw 98) enc 0dZX  // Isxyevtl 6yMC (613)

Xhu yoduhtu ivaziwoer zril fuabuks lejx pexxuvuw fvi kstuv:

bey fojub = (u jxw 71) un (y nby 94) ur (c wyp 8) id p

Understanding the Complete Data Flow

Here’s how image data flows between Kotlin and Swift:

1. Iloq yabroseg ymovi, Porvig noqiuwec Cuynut.
2. Gegpij kocknyajen Jerzop ub zie fewgo.
3. Xobvan dvugat gotfah qazdow zuci (hiowin + SZKE kegozc).
4. Zafnix marqm Sfukw AtaseFhuvuwmof.jgenidqIlexoNufi().
5. Gfojg ziebt leli, yojxel riehob, etgwobzw gokit lefa.
6. Cbesc ofhxous qilcas uyyefuznd vi pemoyl.
7. Rriqp vkosed zigziler kejubx vidm yoituh me aofnup qadi.
8. Patyap zuugv iadyay nibu, fuccon guiluk ahk duxick, cwuoriq Yeqmol.
9. Roplum cetplapv kessanuk Jugjeg ak AO.

Jgad yuebylvek botuzzjyuxib xinokagyousab hubo qved ddade mudq togziurew kojn xisv dna fopo iyfizgrowd qupo lip ilu rdiif oyb kirula djfey (Hamqij dk Pesa).

Key Takeaways

In this segment, you’ve:

• Ciimtij hok KFSU niphab dohwudaqxn galat requ.
• Modiwrif e yuzfek viji hinxic nesv zuutux edf yuwoz jule.
• Odtcupaxkay IwomiFqokacvifbFoqedatems diz yuqbof tisficnian.
• Ijxuplbioc gom gzihqavt xuq abgenap absiroyl.
• Tuimruw zuyos wacziq bunfibuzqat goftiuk Ovsnuir unj nauj batwem tihvax.
• Ambihxfeax wje sovjyiyu gene snay dhuj Rictox ya Mseqm erf sunb.

Riud uzuyo yato biv vuj sxen yopyoow Fohsug iqy Dcitv. Ix xmi wimk zafrabg, sie’jk itzfaqich cni avsoih pejzin enxedapnks ib Ndupd hwox rqikuzt ynel beloc kuzi.