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The Web Wizard’s Guide to HTML. Chapter Three Colors, Patterns, and Inline Graphics. Chapter Objectives. Demonstrate how to add colors to a Web page Explain how to add background patterns How how to add images to a Web page Explain the use of relative addresses for image files
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The Web Wizard’s Guide to HTML Chapter Three Colors, Patterns, and Inline Graphics
Chapter Objectives • Demonstrate how to add colors to a Web page • Explain how to add background patterns • How how to add images to a Web page • Explain the use of relative addresses for image files • Investigate the interplay between design decisions and bandwidth consumption
Background Colors • The bgcolor attribute inside the body tag is used to specify a Web page’s background color: <body bgcolor=“black”> • Bgcolor values can also be expressed in hexadecimal notation: <body bgcolor=“#AA33CC”>
Web-safe Colors • Different computers and computer monitors may display the same hexadecimal color very differently • 216 color codes are “safe” in the sense that they are displayed identically or almost identically on all computers
Background Patterns • The background attribute inside the body tag is used to specify a background pattern: <body background=“water.jpg”> • All background patterns are repeated like tiles to fill up a Web page’s background
Inline Images • The src attribute inside the img tag is used to add an image to a Web page: <img src=“donut.gif”> • GIF and JPG are the most commonly used file formats for inline images – browsers only recognize GIF, JPG, and PNG image formats
Image Attributes • The align attribute positions the image and enables text to flow around an image • The height and width attributes scale the image to any size you like • The alt attribute allows you to describe the image in text for browsers that can’t display the image
Flowing Text • Use the align attribute to make text flow alongside an image: <img src=“donut.gif” align=“left”> positions the image on the left side of the page and allows text to run down its right side
Relative Paths • The src attribute for an image file retrieves images from the same directory as the HTML file containing the img tag: <img src=“donut.gif”> • If you want to retrieve an image from a different directory, you can add path information to the file name: <img src=“pix/donut.gif”>
Bandwidth Limitations • Image files consume more bandwidth than text files • Users who access the Internet via telephone lines will have to wait for image files that are 100KB or larger • Whenever possible, use image files no larger than 30-40KB
Battling Bandwidth Limitations • Always specify height and width attributes for all your images so the browser can “work around” each image while it is downloading • Don’t put any large images at the top of a Web page • Use interlaced GIFs and progressive JPGs • Use the 1x1 image trick (with caution)