Transcript 슬라이드 1

Chap 14. XML and Multimedia
2006. 4. 11 (화)
한민규
[email protected]
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Contents
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DirectShow Overview
DirectShow Filter Type
Support various hardwares
DirectShow Function
Setup DirectShow SDK
Microsoft Component Model
정지영상 캡쳐 프로그램
Appendix A. WDM
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Overview
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Overview(1/2)
 Since HTML’s tags are not sufficient for the class of
Web pages as it has evolved, new tags are requried.
▲ why not sufficient?
 Ex) search to “chocolate mousse’s” on the web
 HTML에 Sort하기 위한 어떤 정보(new tag)를 더 넣은 것은
HTML을 더 무겁게 하고 unmanageable 하게 할 것이다.
 SGML (Standard Generalized Markup Language)
▲ 규정된 response time동안 parsing 하기 어렵다.
 SGML Subset XML
▲ Overhead 없이 SGML에서 제공하는 것을 지원하게 설계되었다.
▲ XML은 Web Doucment를 만들기 위해 웹 디자이너가 자신의 Tag Set을
define할 수 있게 한다.
▲ HTML의 제한에서 자유로워짐
 규정된 Tag의 사용으로써 Content를 표현하려 하던 Web에서 Content를 중심으로
한 Document의 개념으로 확장됨  DTD (Document Type Definition)
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Overview(2/2)
 XML 1.0 was adopted as a World Wide Web
Consortium Recommendation early in 1998.
 DTD (Document Type Definition) formal definition of
set of elements, their attributes and constraints on
usage
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XML(eXtensible Markup Language)
 Although XML itself has no direct support for
multimedia, it underlies the more specialized markup
language SMIL (Synchronized Multimedia Integration
Language) and SVG (Scalable Vector Graphics).
▲ ‘Like XHTML, except that you can make up your own tags and attribute
names’
▲ <tag> … </tag>
 <empty />
 Properly nested
▲ attribute-name = "attribute-value"
▲ &entity-reference
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Well-formed XML
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XML – Structure Model
 The structure which XML markup imposes on a document can be
represented in the form of a tree, sometimes called a structure
model
 Structure Model
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DTDs(Document Type Definition)
 Validity : If a well-formed document has a specification attached
to it and conforms to the rules in that specification, the document
is said to be valid.
 In XML, there are two ways of providing such a specification. The
older, better-established method is by means of a DTDs; a newer
method, which is gaining in popularity, is by an XML Schema.
 DTD에는 XML 문서의 구성요소(태그 및 속성)들을 어떻게 사용하는지를 정
의하고 그런 구성요소(태그 및 속성)들 사이의 관계나 데이터 타입, 출현빈도
등의 규칙들을 정의한다.
 DTD는 XML 문서내에서 작성될 수도 있고, 별도의 파일로 작성될 수도 있다.
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Referencing a DTD
 XML declaration
▲ Example of a Processing Instruction (PI)
 <?xml version = “1.0” encoding=“UTF-8”?>
 PIs beginning with “xml” are used for special purposes in XML processing.
 DOCTYPE declaration
▲ If a DTD in an external file is being used, the XML declaration should be followed by a
DOCTYPE declaration resembling the following:
 <!DOCTYPE books PUBLIC “-//DMM/BOOK Bibliographic information 1.0//EN”
http://www.digitalmultimedia/DTDs/books.dtd>
 XML 문서작성자는 XML 문서가 어떤 마크업 언어로 작성된 것인지를 XML 문서를 해석하는 측에 알려줄 목적으
로 문서 유형 선언을 하게 된다.
 DOCTYPE document element
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DOCTYPE books :
books – document root element
 PUBLIC 키워드를 사용해서 문서 유형을 선언하는 문법 :
PUBLIC 키워드는 공개적인 사용을 위해서 업체 및 국제공인 단체에서 작성된 외부 DTD 서브셋 문서를 지정할
경우 사용된다.
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“-//DMM/BOOK Bibliographic information 1.0//EN” :
[+,-]//DTD를 개발 및 유지보수 업체명//DTD명 및 버전번호//사용된 언어
+ : IS와 같은 국제적으로 공인된 단체 , - : 국제적으로 공인된 단체가 아닌 업체
http://www.digitalmultimedia/DTDs/books.dtd :
DTD문서를 다운로드할 수 있는 URL 경로를 기술
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Element Declarations in DTDs
 <!ELEMENT name content_model>
▲ <!ELEMENT price EMPTY>
 EMPTY – no content.
▲ <!ELEMENT author (#PCDATA)>
 (#PCDATA)* - obscure way of referring to textual content.
▲ <!ELEMENT books (book+)>
 Books must consist of one or more book elements.
▲ <!ELEMENT book (title, author+, price, publisher, numberinstock)>
 Where a sequence of elements must occur in order, ther are writeen on affter
another, separated by commas.
▲ <!ELEMENT book
(title, (author+ | editor+), price, publisher, numberinstock) >
 Note the use of brackets to delimit the choice.
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Attribute-list declarations in DTDs(1/2)
 In a DTD, an element’s attributes are listed in a
separate attribute-list declaration.
 <!ATTLIST price
sterling CDATA #REQUIRED
euro CDATA #IMPLED>
▲ <!ATTLIST element
attribute_name type default_behaviour>
 CDATA indicates that the attribute takes values which are character data(strings)
 #REQURIED  must be given an explicit value
 #IMPLED  attribute is optional
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Attribute-list declarations in DTDs(2/2)
 Default value – if attribute is omitted, takes on
specified value
▲ <!ATTLIST numberinstock
current CDATA #REQUIRED
ordered CDATA “0”>
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Namespaces
 In order to make it easy to generate unique names, XML
namespaces define a two-level naming system that ensures
that different names can be referred to differently, without
requiring any administrative mechanism to control the use of
names globally.
<lecturer>
<title>Dr</title>
…
</lecturer>
<paper>
<title>On the use of
brains</title>
</paper>
 Where namespaces are being used, an element or attribute
name may have a prefix, which is separated form the name
by a colon. (paper prefix bbl:title, lecturers prefix ppl:title)
<lecturer>
<ppl:title>Dr</ppl:title>
…
</lecturer>
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<paper>
<bbl:title>On the use of
brains</bbl:title>
</paper>
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Namespaces
 Prefixed name is an abbreviation for combination of
URL + name, URLs are always unique, so combination
is unique
 Assign namespace URL to an attribute
▲ Xmlns:prefix
 Usually done in start tag of the document element, so
prefix is in scope throughout document
▲ You can also assign a namespace URL to an attribute simply called
xmlns, with no colon or suffix
▲ <bbl:books xmlns:bbl=“http://www.digitalmultimedia.org/biblio”>
▲ You can’t use a namespace declaration inside a DTD, but you can use
prefixed names, so that, after the DTD has been processed, documents
that use it will be valid.
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Stylesheets
 No layout information at all in XML
▲ This must be done with an external stylesheet
▲ Use xml-stylesheet instruction
 <?xml-stylesheet href=“books.css” type=“text/css”?>
 CSS and XML(1/3)
▲ Using CSS with XML is a straightforward generalization of using CSS
with HTML
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You simply define rules for each element type in your XML document.
XML tends to be used in a slightly different way from HTML.
CSS1 Support HTML & CSS2  Support HTML & XML
In CSS2, it has a lengthy list of possible values, many of them concerned with
table elements
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CSS and XML(2/3)
 스타일 쉬트는 여러 개의 룰셋
(Rule set)으로 구성된다.
 CSS example
Selector
display attribute
Book {
display:block;
}
Title {
font-family:fantasy;
font-size:large;
color:blue;
display:block;
}
Rule set
Rule set
Block
Inline
List-item
none
앞,뒤의 element에 대해 줄바꿈 사용
앞,뒤의 element에 대해 줄바꿈 없음
Block과 동일한 기능에 목록 표시 추가
지정한 element에 대해 출력안함
Attribute name : value
author {
font-family:fantasy;
font-size:large;
color:green;
display:block;
}
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CSS and XML(3/3)
 attr(x) to insert value of X attribute
 Use element Selector
▲ Price:before { content: “\00A3” attr(sterling);}
 Use attribute Selector
▲ Price[euro]:after { content:”/\20AC” attr(euro);}
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Problems of CSS & XSL
 CSS는 출력되는 내용을 XML 문서의 원래 구조대로 출력하는
것을 원칙으로 한다. 입력 XML 문서와 전혀 다른 구조로 출력
하는 것은 불가능 하다.
 CSS는 XML문서에 없는 새로운 내용이나 계산된 결과를 출력
할 수 있는 기능을 제공하지 않는다. 폰트나 색깔, 여백주기 그
리고 불릿기호, 순번, 라벨을 엘리먼트의 앞뒤에 삽입할 수 있
는 정도의 간단한 스타일 밖에 지정할 수 없다.
 CSS는 XML문서의 모든 내용을 출력할수 없다. 예를 들어 속
성값을 출력할 수 있는 방법은 전혀 제공되지 않는다.
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XSLT and XSL-FO(1/2)
 CSS does not really incorporate a layout model
suitable for paged media, such as print
 The Extensible Stylesheet Language(XSL) was devised
to overcome these deficiencies of CSS.
▲ It is a much more complex language than CSS, having many of the
characteristics of a functional programming language with pattern
matching.
▲ Its approach to formatting uses a two-stage process.
Transformation Process
XML
DOC
XSL Processor
+
XSLD
Transformation
XSL
DOC
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Formatting Process
PDF
DOC
Formatter
XSL-FO Document
Result Tree
Acrobat
Reader
App
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XSLT and XSL-FO(2/2)
 XSLD Three Part
▲ XSLT(XSLD Transformation)
▲ XPath(XML Path Language)
▲ XSL-FO(XSL formatting Objects)
 In order to transform the nodes of a tree, it is necessary to
be able to address them using their position in the hierarchy
of the tree structure.
▲ XPath can be used to define links between XML documents.
▲ XSLD-FO comprises the formatting objects themselves. Formally, this is now
known simply as XSLD, but because of the possible confusion this may cause, it
is more often referred to as XSL-FO, where the FO stands for ‘formatting objects’
▲ XSLT and XSL-FO are themselves XML. That is, an XSLT stylesheet is an XML
document that uses a vocabulary of elements suitable for specifying tree
transformations. Essentially, an XSLT stylesheet comprises a collection of
templates, which define how to build part of a new tree out of parts of the old
one.
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Linking in XML
 Three components
▲ XPointer – language for identifying link destinations
▲ XPath – language for addressing nodes in a structure tree, used by
XPointer
▲ XLink – a set of attributes for constructing elements that serve as links
 XPath
▲ XPath does not use the syntax of XML proper. It uses its own notation,
which is more suited for the purpose of describing locations in a
document.
▲ A location or set of locations is described in XPath by a location path.
▲ Location path
 Set of instructions (location steps), separated by /s, telling you how to reach a
specific point in a document.
▲ Context node
 The node reached by following any preceding location steps.
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Location Steps
 / - root node
 A location path that begins with a / is an absolute
path
 The simplest form of location step consists of the
name of an element type.
▲ Element name[number], e.g. book[2]
 Particular child node of that element type, e.g. 2nd book child
▲ Instead of selecting a node by name from among the context node’s
children, you can select it from various other sets of nodes, which
are structurally related to the context node in various ways.
 Axes is simple method for select a node.
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XML Document Tree
Root
Attribute Node
Element
2nd Node Set
Element
Element
Attribute
Attribute
Element
Element
Element
Element Node
Element
Text Node
Text
Text
Text
Text
Location path
/root element/child element/ …/ child element
Absolute path
/root element node/ child element node/ … / child element node
Relative path
./child element node/ … /child element node
Sibling path
../sibling element node
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Axis Syntax
 Axis::NodeTest[Predicate]
 Axis
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 Axis(Con’t)
 Nodetest[Predicate]
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Axes Tree
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XPointer
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XLink
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