tailieunhanh - XML in 60 Minutes a Day phần 8

Nhưng chúng tôi sẽ cho bạn thấy những điều cơ bản bằng cách thảo luận về lý do tại sao sự biến đổi là cần thiết và giải thích các mô hình hoạt động của một sự biến đổi có nghĩa là, làm thế nào một phân tích cú pháp chuyển đổi hoạt động trên một nguồn tài liệu XML, theo hướng dẫn trong một phong cách trang cụ thể, | 474 Chapter 12 body par img src alt Space Gems Inc. region SGI_reg05 dur 20s audio src begin 2s repeat 3 end 30s text src alt Welcome to Space Gems region SGI_text_reg01 begin 1s dur 10s par body Media object Name L 1 30s 0 5 10 15 20 Seconds Figure The par element. The W3C groups media objects as follows Those with an intrinsic that is built-in duration also called continuous media. Examples are videos and audio files. Those without intrinsic duration also called discrete media. Examples are text files and still images. Each visual media object for example a video image is displayed by the SMIL player in an individual region within the root-layout region or the viewport if those two areas coincide. The regions are treated as containers. SMIL 475 The media objects are associated with them by URI references used as values for the src attribute within the start tag for the media object element. For example if we want to insert an actual visual image in this case let s say it s a GIF graphic image we can insert an img element within the body element and use code similar to the following img src alt Space Gems Rings region SGI_reg01 . Notice that the value of the region attribute in the img element start tag is identical to the value given to the id attribute inside the start tag of the respective region element inside the layout element. Thus the value is a pointer to the respective region and links the two components together. Try to ensure that the category into which a media object is placed is appropriately reflected in the element name. This facilitates readability and searchability of the SMIL document. For example it would be confusing to create a series of elements with image-related names if some actually contained audio or animation references. If there is doubt about how to categorize a media object for example some animation