Custom Background And Colors Text Formatting and Font 课件.ppt

Objectives Putting Background Color on pages How to specify color Using background “tile” images Working with font styles and colors Underline, bold, italics Working with the font tag size, color and style Using special characters ($, %, @, #) Using Image Files Using Image Files Images are stored in separate files. They are essentially linked to your website. There are many different ways to create or find digital images Digital cameras - If you save the image in a standard format (E.g., gif, jpg), you can include on your web page On-line searches – E.g., search google for free clip art To save a image off the web: Put your cursor on the image. Right click then - save image as ... Save the image on your PC. (Make sure it is a gif, jpg, png suffix file.) Types of Graphical Image Files There are 2 dominate types of file formats for graphic images on the WWW GIF (Graphic Interchange Format) – the first graphic file type format uses 8 bit or 256 possible colors. are platform independent particularly good for areas of flat colors like logos, cartoons, icons. Does not good for photographic images since it reduces all images to 256 colors. ???????? JPEG (Joint photographic Experts Group) Uses a 24 bit RGB color information, (displays 8 bit colors on 8bit color systems) ideal use for photographs. Not good at compressing images with solid colors such as logos, line art and cartoons. ? On a side note, Unisys held the patent on the compression method that gif files uses. In 1994, announced will charge for sites using GIF, causing people to move towards nonproprietary format. This patent has run out in the USA. What is Digital Image? A format for encoding a way to represent a picture using RGB color format Each pixel to display needs to have a RGB value Less colors you display the smaller the image (since can compress the image more) Gif format specification allows you to discribe more than 1 image There is a delay to show each image giving an animati