4 Basic Data Types and Color Keywords

4.1 Basic Data Types

The common data types for SVG's properties and attributes fall into the following categories:

• <integer>: An <integer> is specified as an optional sign character ('+' or '-') followed by one or more digits "0" to "9". If the sign character is not present, the number is non-negative.
  
  In SVG Tiny 1.2 the range for a <integer> is -32,767 to 32,767.
  
  
• <number> (real number value): A real number value is specified in either decimal notation or in scientific notation. A <decimal-number> consists of either an <integer>, or an optional sign character followed by zero or more digits followed by a dot (.) followed by one or more digits. A <scientific-number> consists of a <decimal-number> immediately followed by the letter "e" or "E" immediately followed by an <integer>.
  
  In SVG Tiny 1.2 the internal storage of a <number> may only have the capacity for a fixed point number in the range '-32,767.9999 to +32,767.9999'. It is recommended that higher precision floating point storage and computation be performed on operations such as coordinate system transformations to provide the best possible precision and to prevent round-off errors.
  
  
• <length>: A length is a distance measurement. The format of a <length> is a <number> optionally followed immediately by a unit identifier. If the <length> is expressed as a value without a unit identifier (e.g., 48), then the <length> represents a distance in the current user coordinate system.
  
  SVG Tiny 1.2 only supports CSS units on the the 'width' and 'height' attributes on the outermost 'svg' element. These can specify values in any of the following CSS units: in, cm, mm, pt, pc, px and %. If one of the unit identifiers is provided (e.g., 12mm), then the <length> is processed according to the description in Units.
  
  Percentage values (e.g., 10%) on the width and height attributes of the svg element represent a percent of the viewport (refer to the section that discusses Units in general).
  
  
• <coordinate>: A <coordinate> represents a <length> in the user coordinate system that is the given distance from the origin of the user coordinate system along the relevant axis (the x-axis for X coordinates, the y-axis for Y coordinates).
  
  
• <list of xxx> (where xxx represents a value of some type): A list consists of a separated sequence of values. Unless explicitly described differently, lists can be either comma-separated, with optional white space before or after the comma, or white space-separated.
  
  White space in lists is defined as one or more of the following consecutive characters: "space" (Unicode code 32), "tab" (9), "line feed" (10), "carriage return" (13) and "form-feed" (12).
  
  Here is a description of the grammar for a <list of xxx>:

  ListOfXXX:
      XXX
      | XXX comma-wsp ListOfXXX
  comma-wsp:
      (wsp+ comma? wsp*) | (comma wsp*)
  comma:
      ","
  wsp:
      (#x20 | #x9 | #xD | #xA)
  

  where XXX represents a particular type of value.
  
  
  
  
• <color>: The basic type <color> is a CSS2-compatible specification for a color in the sRGB color space [sRGB]. <color> applies to SVG's use of the 'color' property and is a component of the definitions of properties 'fill', 'stroke' 'stop-color' and 'solid-color'.
  
  SVG supports all of the syntax alternatives for <color> defined in [ CSS2-color-types], including a list of recognized color keywords names.
  
  A <color> is either a keyword (see Recognized color keyword names) or a numerical RGB specification.
  
  In addition to these color keywords, users may specify keywords that correspond to the colors used by objects in the user's environment. The normative definition of these keywords is [CSS2 system colors].
  
  The format of an RGB value in hexadecimal notation is a '#' immediately followed by either three or six hexadecimal characters. The three-digit RGB notation (#rgb) is converted into six-digit form (#rrggbb) by replicating digits, not by adding zeros. For example, #fb0 expands to #ffbb00. This ensures that white (#ffffff) can be specified with the short notation (#fff) and removes any dependencies on the color depth of the display. The format of an RGB value in the functional notation is 'rgb(' followed by a comma-separated list of three numerical values (either three integer values or three percentage values) followed by ')'. The integer value 255 corresponds to 100%, and to F or FF in the hexadecimal notation: rgb(255,255,255) = rgb(100%,100%,100%) = #FFF. White space characters are allowed around the numerical values. All RGB colors are specified in the sRGB color space (see [SRGB]). Using sRGB provides an unambiguous and objectively measurable definition of the color, which can be related to international standards.
• <paint> : The values for properties 'fill' and 'stroke' are specifications of the type of paint to use when filling or stroking a given graphics element. The available options and syntax for <paint> are described in Specifying paint.
  
  
• <percentage>: The format of a percentage value is a <number> immediately followed by a '%'. Percentage values are always relative to another value, for example a length. SVG Tiny 1.2 does not support percentage values except for the 'width' and 'height' attributes on the outermost 'svg' element. Each attribute or property that allows percentages also defines the reference distance measurement to which the percentage refers.
  
  
• <transform-list> : The detailed description of the possible values for a <transform-list> are detailed in Modifying the User Coordinate System: the transform attribute.
  
  
• <iri> The <iri> type holds a reference to an International Resource Identifier (see [IRI] ): A IRI is the address of a resource on the Web. For the specification of IRI references in SVG, see IRI references.
  
  
• <time>: A time value is a <number> optionally followed by a time unit identifier. Time unit identifiers are:
  • ms: milliseconds
  • s: seconds
  Time values may not be negative. If a time value is specified without a time unit the time is interpreted as if seconds were specified.
  
  

4.2 Recognized color keyword names

The following sixteen color keywords can be used as a keyword value for data type <color>:

	black	rgb( 0, 0, 0)		green	rgb( 0, 128, 0)
	silver	rgb(192, 192, 192)		lime	rgb( 0, 255, 0)
	gray	rgb(128, 128, 128)		olive	rgb(128, 128, 0)
	white	rgb(255, 255, 255)		yellow	rgb(255, 255, 0)
	maroon	rgb(128, 0, 0)		navy	rgb( 0, 0, 128)
	red	rgb(255, 0, 0)		blue	rgb( 0, 0, 255)
	purple	rgb(128, 0, 128)		teal	rgb( 0, 128, 128)
	fuchsia	rgb(255, 0, 255)		aqua	rgb( 0, 255, 255)