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BYOND Environment This page contains an entry from the official DM Reference.

HTML tags, such as <FONT> may be used to directly format output text. Another approach, however, is to use HTML tags to specify purely structural information and use a style sheet to define how various elements within that structure should be treated. DM uses a subset of the Cascading Style Sheet (CSS) language, which was introduced for this purpose in HTML documents.

This section discusses the syntax of style sheets as an independent element. For information on how to include the style sheets in your DM code, see the section on client.script.

Why use style sheets?Edit

As an example of a style sheet, one might want combat and conversational messages to appear differently--perhaps using different colors. Instead of using the <FONT> tag to color the text, you could use <SPAN> to mark the beginning and ending of the text and to specify what kind of message it is. The result might be text such as the following:

"[usr] <SPAN CLASS=combat>spanks</SPAN> [targ]!"
"[usr] says, '<SPAN CLASS=chat>[msg]</SPAN>'"

CLASS attributeEdit

The CLASS attribute may be used with any tag, but SPAN and DIV are often convenient because they have no other side-effect but defining the style class. SPAN is for text within a single paragraph and DIV is for whole paragraphs. The way text belonging to a particular class is formatted may be controlled in a style sheet such as the following:

.combat {color: red}
.chat {color: green}

This says that text in the 'combat' class should be colored red and text in the 'chat' class should be colored green. These classes are not pre-defined; you can create whatever new style classes you need.

AdvantageEdit

The advantage of using style sheets instead of direct formatting tags is that you can cleanly separate structural information (such as combat and conversational messages) from formatting information (such as red and green text). By separating the two, you or the player can easily plug in different formatting schemes without changing any of the actual content.

RulesEdit

A style sheet is composed of a list of rules, such as the two rules in the preceding example. Each rule contains one or more selectors followed by a body of attribute assignments (in braces). The selector specifies the context of the rule and the body specifies the format.

Container tagEdit

A selector may specify a container tag (such as SPAN, BODY, or P) and a class. The above example could have been written with a selector of SPAN.chat. However, by leaving out the tag, it applies to any tag with CLASS=chat. It is also possible to only specify the tag and not the class. In that case, the selector applies to any matching tag, regardless of class.

NestingEdit

To specify a nested context, several simple selectors may be listed one after the other. For example, emphasized text within a combat message could be enlarged with the following rule:

.combat EM {font-size: larger}

Apply to multiple selectorsEdit

It is also possible to list several selectors separated by commas in order to make them all apply to the same body. For example, this next rule is equivalent to the two following ones:

.combat EM, .chat EM {font-size: larger}
.combat EM {font-size: larger}
.chat EM {font-size: larger}

AttributesEdit

The style rule body contains a list of attribute assignments, delimited by semicolons. Each assignment takes the form of an attribute name, followed by a colon, followed by the value of the attribute. The following table summarizes the recognized attributes and their possible values.

color #F00, #FF000, red, rgb(255,0,0), rgb(100%,0%,0%)
background
font-size 10pt, 1.5em, 150%
font-style normal or italic
font-weight normal, bold, lighter, darker, or 100 to 900
font-family monospace, sans-serif, serif, cursive, ...
font style weight size family
text-decoration none or underline
text-align right, left, or center
text-indent 0.25in, 3em, 20pt
margin-left
margin-right
width 16px, 32px, auto
height

FontsEdit

The font attribute is a special short-hand for assigning font-size, font-style, font-weight, and font-family in one statement. Any properties that are not specified in the font statement are assigned to their default values.

Font familyEdit

The font family may be a specific font name or a more general category such as monospace or sans-serif. Since not all users necessarily have the same fonts installed, it is a good idea to list alternate fonts. The desired font is placed first, followed by other possible fall-backs, each separated by a comma. Usually a general family such as monospace is listed last of all. Any font names containing a space should have quotes around them.

ExampleEdit

The following example sets the font for the <BODY> tag. Even if you don't explicitly use <BODY> in output text, it is applied implicitly.

BODY {font: 12pt 'Times New Roman', sans-serif}

This sets the font to 12 point and selects Times New Roman if it is available and otherwise falls back on a system-determined sans-serif font. This command also implicitly specifies not to use italics and to use a normal font weight (not bold).

Font sizeEdit

Font sizes may be specified in points (1pt = 1/72 of an inch), picas (1pc = 12pt), pixels (px), inches (in), centimeters (cm), and millimeters (mm). There are also various levels corresponding to the traditional 1 to 7 HTML scale. These are xx-small, x-small, small, medium, large, x-large, and xx-large. In addition to these absolute font sizes, it is possible to use a relative size, such as 150% or equivalently 1.5em. This scales the font relative to the currently active font setting.

Hyperlink pseudo-classesEdit

In addition to regular classes, there are special pseudo-classes for handling embedded hyperlinks. These are specified in the selector with the class starting with a colon rather than a dot. They are :link, :visited, and :active. These only apply to the <A> tag. The :link class applies to hyperlinks in their normal state. Once a link has been clicked, it belongs instead to the :visited class. When the user holds the mouse over a link, it temporarily belongs to the :active class. The only attribute that may change in an active or visited link is the text color.

Margins and IndentsEdit

Paragraphs can be given different margins according to your preferences. The margin-left attribute controls the left margin, and margin-right is the right margin. You can use specific sizes like inches or points, or a relative size unit like em or ex. (A percentage is interpreted so that 100% is 1em, not the width of the window.) Using the text-indent attribute will indent the first line of a paragraph from the left margin. It is possible to create a hanging indent by using a negative value for text-indent, like so:

BODY {text-indent: -0.5in; margin-left: 0.5in}


Background ColorsEdit

The background attribute is only relevant to the BODY context. It causes the entire terminal background to change color. When doing this, it is usually necessary to change the foreground colors of text or it may become unreadable. The various standard classes of output generated by DreamSeeker are in the following table.

System ColorsEdit

system notice general notices from the client
system command echo command echoing
system command expansion command-line expansion list
system pager pager messages
system irc IRC command prefix

Combined classesEdit

The value of the CLASS attribute may contain a list of classes separated by spaces. This permits client output to be in the 'system' class as well as more specific ones. That allows you to change all of these colors in one shot if you are too lazy to change them each individually. For example, if you define a style sheet that changes the background color, you might need to redefine the various foreground colors like this:

BODY {background: aqua; color: black}
.system {color: red; font-weight: bold}
.command {color: green}

In this example, the background color of the terminal will be aqua, normal text from the server will be black, and all output from the client will be bold and red, except echoed commands and expansion lists, which will be bold and green. The more specific .command rule is placed after the general .system rule so that its color takes precedence. This is how style sheets are composed--you write general rules first followed by any exceptions.

Style rule precedenceEdit

The order in which rules are specified is one of the factors that determines precedence of style sheet commands. The language is known as Cascading Style Sheets because of its ability to handle several layers of stylistic rules, intermingling the configurations of the user and the designer in an ordered fashion.

Rules are selected by first finding all matching candidates for a given attribute in the current HTML tag being processed. If there is more than one, rules from a higher level style sheet take precedence over lower level ones. That means the basic user configurable settings in DreamSeeker are the lowest priority, followed by a style sheet in the user's .dms script file, followed by a style sheet from the designer's client.script setting, because that is the order in which these are read by the style sheet manager.

Rules from the same style sheet are ordered by specificity. The selector SPAN.chat is more specific than .chat and .chat EM is more specific than EM. In general, the more classes referenced by a selector, the more specific it is. When that results in a tie, the selector with the greater number of tags takes precedence.

If two rules about the same attribute come from the same sheet and have the same specificity, the final one to be defined takes precedence.

Important rulesEdit

In the rare event that a rule needs to break out of the normal order of precedence, it can be flagged as important. In this case it will take precedence over all other "unimportant" rules. However, if more than one rule is important, the normal rules of precedence will be used to resolve the conflict.

The important flag is applied after the attribute assignment like this:

BODY {background: white ! important; font: serif}

In the above example, only the background color is important, not the font specification.

STYLE attributeEdit

Style commands may also be inserted directly in an html tag to control its appearance. This does not have the advantages of style sheets, which separate content from presentation, but it does allow you to use the style sheet syntax when formatting text.

The following example uses the style attribute to color some text:

usr << "That <SPAN STYLE='color: red'>HURT</SPAN>!"

As you can see, the STYLE attribute of any tag can be assigned to a text string containing a list of attribute assignments. Just the body of the style rule is given, since no selector is needed to match the current context.

See alsoEdit