Základy počítačové grafiky IV

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1 Základy počítačové grafiky IV

2 Vektorový obrázek Mapuje čáry na neviditelné mřížce a uchovává je jako soustavu instrukcí, které přesně popisují tvar, velikost a pozici každého objektu

3 Základní objekty vektorové grafiky
úsečka křivka mnohoúhelník (trojúhelník, obdélník, pětiúhelník atd.) elipsa (kružnice, oblouk) text Kombinací objektů vzniká vektorový obrázek

4 Základní objekty vektorové grafiky
Hotová vizitka Objekty, ze kterých se skládá

5                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Změna velikosti Protože se kresby skládají z křivek, které je možné libovolně přepočítávat, můžeme velikost vektorových kreseb měnit téměř neomezeně. Můžeme je tedy jak zvětšovat, tak i zmenšovat. (Na rozdíl od rastrů.) Malé auto, střední i velké složené z křivek je vždy stejně hladké. 26

6 Nástroje vektorového programu
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Nástroje vektorového programu Změna polohy a velikosti objektu Vezmu výběrový nástroj, objekt uchopím a přesunu na zvolené místo, uchopím ho za rohy a změním jeho velikost 27

7                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Obrys a výplň Všechny objekty (kromě) čar mohou mít různý obrys a různou výplň Čáry mají samozřejmě pouze obrys, navíc také mohou mít zakončení (šipky…) U textu nastavujeme vlastnosti známé z textového editoru Tedy: písmo, velikost, styl, barvu (obrysu i výplně) a vlastnosti odstavce.

8 Zarovnání objektů vůči sobě
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Zarovnání objektů vůči sobě Vybereme dva objekty a necháme je vůči sobě zarovnat, jak potřebujeme 28

9                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Zařazení objektů Objekt může být v popředí nebo v pozadí

10 Seskupení objektů Několik objektů můžeme označit a nechat je seskupit
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Seskupení objektů Několik objektů můžeme označit a nechat je seskupit Od této chvíle s nimi manipulujeme jako s jedním objektem, jako celek se také zarovnávají vůči jiným objektům. Pokud chceme jeden z objektů změnit, musíme skupinu zrušit, objekty odznačit, jeden objekt vybrat a změnit.

11 Oříznutí, průnik a sloučení objektů
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Oříznutí, průnik a sloučení objektů Těmto akcím se také říká logické operace Většinou vybereme objekt, kterým chceme jiný oříznout (sloučit, udělat průnik) a zvolíme tuto volbu. Pak klepneme na druhý objekt, se kterým chceme operaci provést.  (Corel Draw, obr. vlevo.) Při sloučení a průniku je potřeba vybrat oba objekty najednou.

12                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Přizpůsobení textu Ve vektorových editorech můžeme text přizpůsobit osnově (tvaru jiného objektu) 29

13 Příklady Hrací kostka procvičí zarovnání Visačka zase řazení objektů
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Příklady Hrací kostka procvičí zarovnání Visačka zase řazení objektů Zajímavěji řešená vizitka 30

14                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Klipárty Klipárty jsou vektorové obrázky dodávané většinou s vektorovými programy Jsou vektorové, dají se proto libovolně zvětšovat, zmenšovat i měnit Bývají většinou volně využitelné, takže je můžeme bez obav používat ve svých dokumentech Mají rozdílnou úroveň a tím i využitelnost

15 Barvy a kompozice obrazu
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            Barvy a kompozice obrazu Jakou barvu vybrat a kam objekt umístit – to jsou pro vzhled naší práce zásadně důležité věci. To, jak se barvy v určitém programu vybírají a jak se v něm pracuje s objekty jsou (podružné) pomocné informace, mírně se měnící program od programu.

16 Barevná schémata je možné si vyzkoušet na Internetu:
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            Barevná schémata je možné si vyzkoušet na Internetu: Existují generátory barevných schémat (např. odkaz Barevná schémata). Vlevo vybereme základní barvu a v poli Schéma pak jedno z nabízených schémat. Vlevo dole můžeme ladit odstín, sytost a jas použité barvy 31

17 Základní pravidla kompozice
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            Základní pravidla kompozice Několik základních zásad: Spodní řádek víceřádkového nadpisu musí být nejkratší Optický střed je mírně nad středem geometrickým Používáme zlatý řez

18 Obrázky pro www stránky
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            Obrázky pro www  stránky Pro použití na webu si musíme obrázky připravit ve formátu JPG (fotografie) nebo GIF (grafické prvky) Začíná se používat nový formát PNG. Při použití na webu velmi závisí na velikosti souboru s obrázkem a tedy na stupni komprese    Protože obrázek vždy vymezí prostor přesně podle své velikosti, záleží při návrhu stránky na každém pixelu Grafické prvky můžeme vytvořit ve vektorovém programu a potom exportovat do formátu GIF 32

19                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             Animované obrázky Jednoduché animace jsou vlastně postupně vyměňované obrázky. Používá se tzv. animovaný GIF. 33

20 PDF soubory PDF je formát firmy Adobe pro elektronické publikování
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            PDF soubory PDF je formát firmy Adobe pro elektronické publikování – PDF formát umožňuje výborně zachovat přesný vzhled i složitě formátovaného dokumentu, včetně písem a grafických prvků. Umožňuje také zabezpečení dokumentu (heslo pro otevření i tisk). – Soubor v PDF formátu můžeme přečíst ve zdarma šířeném prohlížeči Adobe Acrobat Reader. – Uložit dokument v PDF formátu (tzv. exportovat) umí některé (hlavně grafické) programy přímo. Umí to i zdarma šířený kancelářský balík OpenOffice.org. – Existují (i volně šiřitelné - pdf95) tzv. PDF drivery, které se objeví jako tiskárna při tisku. Místo tiskárny pak vyberete tisk do PDF souboru, zadáte jeho název, a dokument se ve stejném vzhledu, jak by se vytiskl na tiskárně, „vytiskne“ do PDF souboru.

21                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             Čtení PDF souborů Soubor v PDF formátu můžeme přečíst ve zdarma šířeném prohlížeči Nemůžeme ho však lehce upravit (jen z něj zkopírovat text) a odeslat zpět. Hodí se na manuály, návody apod., kde se nepředpokládají jiné operace než čtení dokumentu a jeho tisk. Lehce můžeme: 1. Přecházet mezi stránkami. (Také 1b vlevo dole.) 2. Měnit zobrazení stránky. 3. Nechat si zobrazit miniatury stránek a případné tvůrcem definované záložky. 4. Označit text. 5. Prohledávat dokument. Samozřejmě můžeme dokument vytisknout na tiskárně. 34

22                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             Kam dále? Jak je napsáno již v letáku s obsahem kurzu, modul Grafika a digitální fotografie nemá konec, přesněji jeho konec je začátkem vlastní práce. A jak již bylo (asi 100x) řečeno, zvládnutí ovládání (jednoho) programu se nerovná zvládnutí grafiky. Pokud máte chuť získávat další informace, zkuste minimálně následující weby: Server o typografii, písmu a všem okolo tvorby tiskoviny: Server o grafice a zpracování obrázků: Fotografování a digitální fotografii se věnuje více serverů, např.: Přeji vytrvalost, trpělivost a hlavně radost z vlastní tvorby     