DocBook 5: The Definitive Guide

Name

imagedata — Pointer to external image data

Synopsis

imagedata (db.imagedata) ::= info? ^{db.titleforbidden.info}

Attribute synopsis

Common attributes.

Additional attributes:

• align (enumeration) = “center” | “char” | “justify” | “left” | “right”

• contentdepth

• contentwidth

• depth

• Each of:

  • format

  • Exactly one of:

    • fileref (anyURI)

    • entityref (ENTITY)

• scale (positiveInteger)

• scalefit (enumeration) = “0” | “1”

• valign (enumeration) = “bottom” | “middle” | “top”

• width

Required attributes are shown in bold.

Description

This element points to an external entity containing graphical image data.

Processing expectations

Render the image. May be formatted inline or as a displayed block, depending on context.

There are two ways to provide content for imagedata: entityref or fileref. It is best to use only one of these methods; however, if multiple sources are provided, entityref will be used in favor of fileref.

The imagedata provides a selection of attributes that can be used to control how the image is rendered. These attributes define two rectangles, the viewport area and the content area, and how these rectangles are related to each other. The intrinsic size of the image is a third rectangle that sometimes influences the way an image is rendered.

It is important to understand the distinction between these three areas. When rendering an image, the viewport area defines the space reserved in the flow of content for the image. If a 6in × 4in viewport area is specified, that’s how much space will be reserved for the image, ...