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10.8. Media Types and @-rules

Don't get too excited yet. We aren't talking about media types in the sense of things like audio and video authoring. Well, not exactly, anyway. We're talking about creating rules for presentation within various kinds of media. The defined types of media thus far are:

These are all values of @media, one of several new @-rules. Some others are:

10.8.1. Paged Media

Since I just brought up paged media, I should probably mention that there are some new properties that apply to such media. Five of them apply to page breaks and where they appear:

page-break-before
page-break-after
page-break-inside
orphans
widows 

The first two are used to control whether a page break should appear before or after a given element, and the latter two are common desktop publishing terms for the minimum number of lines that can appear at the end or beginning of a page. They mean the same thing in CSS2 as they do in desktop publishing.

page-break-inside (first proposed by this author, as it happens) is used to define whether or not page breaks should be placed inside a given element. For example, you might not want unordered lists to have page breaks inside them. You would then declare UL {page-break-inside: avoid;}. The rendering agent (your printer, for example) would avoid breaking unordered lists whenever possible.

There is also size, which is simply used to define whether a page should be printed in landscape or portrait mode and the length of each axis. If you plan to print your page to a professional printing system, you might want to use marks, which can apply either cross or crop marks to your page. Thus you might declare:

@page {size: 8.5in 11in; margin: 0.5in; marks: cross;}

This will set the pages to be U.S. letter-standard, 8.5 inches wide by 11 inches tall, and place cross marks in the corners of each page.

In addition, there are the new pseudo-classes :left , :right, and :first, all of which are applied only to the @page rule. Thus, you could set different margins for left and right pages in double-sided printing:

@page:left {margin-left: 0.75in; margin-right: 1in;}
@page:right{margin-left: 1in; margin-right: 0.75in;} 

The :first selector applies only to the first page of a document, so that you could give it a larger top margin or a bigger font size:

@page:first {margin-top: 2in; font-size: 150%;}

10.8.2. The Spoken Word

To round things out, we'll cover some of the properties in the area of aural style sheets. These are properties that help define how a speaking browser will actually speak the page. This may not be important to many people, but for the visually impaired, these properties are a necessity.

First off, there is voice-family, which is much the same as font-family in its structure: the author can define both a specific voice and a generic voice family. There are several properties controlling the speed at which the page is read (speech-rate), as well as properties for the pitch , pitch-range, stress, richness, and volume of a given voice. There are also properties that let you control how acronyms, punctuation, dates, numerals, and time are spoken. There are ways to specify audio cues, which can be played before, during, or after a given element (such as a hyperlink), ways to insert pauses before or after elements, and even the ability to control the apparent position in space from which a sound comes via the properties azimuth and elevation. With these last two properties, you could define a style sheet where the text is read by a voice "in front of" the user, whereas background music comes from "behind" and audio cues come from "above" the user!



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as shown in Table 5-3.

Table 5-1. Hypothetical Weight Assignments for a Specific Font

The first three number values are assigned to the lightest weight. The Regular face gets the keywords 400 and normal, as expected. Since there is a Medium font, it's assigned to the number 500. There is nothing to assign to 600, so it's mapped to the Bold font face, which is also the variant to which 700 and bold are assigned.bottom, and left, plus anymargins, padding, and borders set for the element. Absolutelypositioned elements can have margins, but these margins do notcollapse.

fixed

The element's box is positioned as though it were set toabsolute, but its containing block is the viewport

First, let's create the two columns. Remember, we don't want to use tables or proprietary tags such as MULTICOL, so we'll have to resort to something else. In this case, since each column has a number of paragraphs, we can use a DIV tag -- or, to be more precise, two of them. All we need to do is split the article text roughly in half, and wrap a DIV around each half. (By article text, we mean the actual text of the article,makes is in where the tiling starts. Figure 6-51shows the difference between tiling from the center of theBODY, and from its top left corner.

Figure 6-51

Figure 6-51. The difference between starting a repeat from top left (left) and centering it (right)

Note the differences along the edges of the browser window. When thebackground repeats from the center, the grid is centered within theviewport, resulting in consistent "clipping" along theedges. The variations may seem subtle, but the odds are thatyou'll have reason to use both approaches at some point in your