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>> [Music kucheza]

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>> Rob BOWDEN: Hi, mimi nina Rob, hebu
kujaribu hii juu ya kwa ukubwa.

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Hivyo, sisi ni tena kwenda kuanza na
kimsingi nakala ya copy.c, na

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kufanya mabadiliko machache.

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Kumbuka mara moja sisi kuona mabadiliko, ambapo
badala ya kuangalia kuona kama

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argc haina sawa 3, tunataka kuangalia
kama argc hana sawa 4, tangu

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sasa sisi siyo kuchukua tu katika infile
na outfile, lakini sisi ni pia kuchukua katika

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n, ambayo ni kiasi kwamba sisi ni
kuongeza picha ya awali kwa.

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Mara baada ya sisi ni kuhakikisha ya kwamba, tunaweza tu
kubadilisha n kwa integer kutumia atoi.

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>> Kwa hiyo, sasa tunakwenda kujenga baadhi ya
Majina bandia, kama wito argv 2 infile, na

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argv 3 outfile, kwa sababu argv 2 na
argv 3 sio majina na manufaa sana.

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Sasa tunataka kuangalia kuhakikisha n ni
ndani ya mipaka tunatarajia, ili

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spec bayana kwamba kama ni chini ya au
sawa na sifuri, au zaidi ya 100,

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basi hiyo ni batili resize sababu,
na sisi lazima kuwaonya user ya kwamba.

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>> Mara baada ya sisi ni zaidi ya yote, tunaweza
hatimaye kufungua infile yetu, na sisi haja

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kwa makosa kuangalia kuhakikisha kwamba
ufunguzi hakuwa na kushindwa kwa sababu fulani.

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Sisi pia haja ya kufungua outfile yetu, na
tena makosa kuangalia kuhakikisha kwamba

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hakuwa na kushindwa kwa sababu fulani.

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Lakini kuwa na uhakika kama ufunguzi wa
outfile alishindwa kwamba tunahitaji karibu

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infile, ambayo ilikuwa tayari kufunguliwa.

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>> Hivyo, kuchukua kwamba hakuwa na kushindwa, basi
we're - tu kama katika copy.c--

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kwenda kusoma katika header
kutoka infile.

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Tunakwenda kuhakikisha ni halali
bitmap, lakini sasa tunakwenda kufanya baadhi ya

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mambo kidogo tofauti.

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Hivyo kwanza, tunakwenda kutaka
kumbuka upana awali na urefu

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ya infile, kwa sababu tunakwenda
kubadilika kwa ajili ya outfile.

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Hivyo sasa kumbuka kwamba kwa sababu ya ajabu
bi.biheight, ni hasi, na

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hivyo urefu halisi, katika chanya, sisi
unataka kuchukua thamani kabisa.

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>> Sasa, padding ni kwenda kuwa sawa
hesabu kama ilivyokuwa katika copy.c,

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kutumia upana wa zamani, na sasa tuko
kweli kwenda na mabadiliko

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nini katika header yetu.

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Hivyo sisi ni kwenda kuzidisha upana yetu kwa
n, tangu sisi ni kuongeza upana na

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n, kuzidisha urefu na n, tangu tuko
kuongeza na n, na sasa tuna

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hesabu kwa padding mpya
msingi upana mpya.

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>> Basi sasa sisi haja ya kubadili baadhi
maeneo mengine katika header yetu.

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Bi.biSizeImage zinatakiwa kuwa
ukubwa wa ka wote katika saizi

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na padding wa picha.

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Na hivyo ukubwa wa moja ya mstari wa wetu
picha ni ukubwa wa RGB tatu, ukubwa

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ya pixel moja, wakati idadi ya
saizi katika mstari, pamoja na padding katika

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mwisho wa mfululizo.

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Na kisha tunakwenda kuzidisha na
thamani kamili ya urefu yetu kupata

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jumla ya idadi ya ka
katika data picha.

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bf.bfSize ni jumla ya idadi
ya ka katika data yetu ya picha, hivyo

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bi.biSizeImage, pamoja na
ukubwa wa headers yetu.

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Hivyo, kuongeza ukubwa wa faili bitmap
header, na ukubwa wa bitmap info

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header, OK.

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Hivyo kwamba wote sisi haja ya
mabadiliko katika headers yetu.

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Sasa tutaweza kuandika bitmap file header
kwa outfile yetu, na bitmap yetu info

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header kwa outfile yetu, na sasa
tuko tayari kuanza kwenda

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juu ya saizi halisi.

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>> Hivyo tunataka iterate juu ya
infile ya Scan mistari.

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Hivyo tunataka iterate juu ya oldheight.

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Hii ni kwa nini sisi zinahitajika kumbuka
urefu awali, kabla ya sisi mabadiliko hayo

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na kuongezwa ni kwa n.

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Sasa sisi ni kwenda kusoma moja
mstari wa infile katika

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buffer ya ukubwa oldwidth.

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Hivyo hapa, sisi ni freading ukubwa wa RGB
tatu, moja pixel, na umri wa upana wa

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yao kutoka infile katika buffer yetu.

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Na kwamba kinaendelea kuwa mzima
mstari katika safu hii.

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Basi sasa, tunataka iterate mara n kwa
magazeti safu hii kwa outfile yetu n mara kwa mara.

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Na hivyo kwamba ni nini kitanzi hii ni kufanya.

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Hii kitanzi ndani ni iterating juu ya
mstari yenyewe, juu ya safu, uchapishaji

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kila pixel katika safu n mara kwa mara.

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Hivyo hiki 0 ni kuwa kuchapishwa
n mara kwa mara, hiki kwanza ni kuwa

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kuchapishwa mara n.

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Na kwamba aina ya jinsi sisi ni kwenda kwa
usawa wadogo katika outfile, na

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kitanzi hii, kwani sisi ni wanaoendesha n
mara kwa mara, ni jinsi tunakwenda

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wima wadogo.

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>> Hapa chini, tunaona kwamba tunahitaji kuongeza
padding mwishoni mwa kila mstari.

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Hiyo ni kwa nini hii ni ndani ya kwa kitanzi
hiyo uchapishaji nje safu n ya tu

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hii safu moja kutoka infile.

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Kisha hapa chini, mimi nina kwenda ruka juu ya
padding katika infile, tangu mara moja

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sisi ni kosa kwa safu moja ya
infile, sisi hawajali

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nini padding mara.

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Sisi tu wanataka kupata mstari wa pili.

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Na kisha tutaweza kitanzi nyuma na kufanya yote
hii tena kwa mstari wa pili.

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>> Hatimaye, mara moja sisi ni kosa kwa yote,
tunaweza kufunga infile, karibu

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outfile, na kurudi
0 kwa sababu sisi ni kosa.

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>> Jina langu ni Rob, na hii ilikuwa resize.

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>> [Music kucheza]