Table of contents

Appendices

7.3 Reference Rectangle for Percentage Computations

Allowed conversions for percentages, specified on the property definition, is typically in terms of the content-rectangle of some area. That area is determined as follows:

1. For properties defined in CSS2 referring to the "containing block" the content-rectangle of the closest ancestor block-area that is not a line-area is used.

2. For properties defined by XSL, the property definition specifies which area's content-rectangle is used.

3. Exceptions to the rules above for determining which area is used are:

   1. When used on fo:root, fo:page-sequence, and fo:title and any descendant of fo:title where there is no ancestor block-area the rectangle used has the dimensions corresponding to the "auto" value of the "page-height" and "page-width" properties. The block-progression-dimension and inline-progression-dimension is then determined based on the computed value of the reference-orientation and writing-mode on the formatting object for which the percentage is computed, or on fo:title in the case of a descentdant of fo:title.

   2. When used on fo:static-content and fo:flow the content rectangle used is based on the region on the first page into which the content is directed. For region-body it is the normal-flow-reference-area and for the other regions it is the region-reference-area.

   3. When used on fo:footnote-body, and fo:float that generates an area with area-class "xsl-before-float" the rectangle used is the content rectangle of the footnote-reference-area and the before-float-reference-area respectively.

   4. When used on fo:float that generates an area with area-class "xsl-side-float" the content rectangle used is the closest ancestor block-area that is not a line-area of the area of area-type "xsl-anchor" that was generated by the fo:float.

   5. When the absolute-position is "fixed", the containing block is defined by the nearest ancestor viewport area. If there is no ancestor viewport area, the containing block is defined by the user agent.

   6. When the absolute-position is "absolute", the containing block is established by the nearest ancestor area A which has an area-class different from xsl-normal or a relative-position of "relative".

      In the case where A is a block-area, the rectangle used is the padding-rectangle of A.

      In the case where A is an inline-area, generated by some formatting object F, the rectangle used is a virtual rectangle whose before-edge and start-edge are the before-edge and start-edge of the first area generated by F, and whose after-edge and end-edge are the after-edge and end-edge of the last area generated by F. This "rectangle" may have negative extent.

4. If the formatting object generating the identified area generates a sequence of such areas the first area is used for the conversion.