Table of contents

Appendices

7.20 Layout-related Properties

The following are layout-related properties that are not common to all formatting objects.

clip[top]

CSS2 Definition: as amended by [http://www.w3.org/Style/css2-updates/REC-CSS2-19980512-errata.html#x68]

CSS2 Reference: [ "clip" property ] http://www.w3.org/TR/REC-CSS2/visufx.html#propdef-clip

The 'clip' property applies to elements that have a 'overflow' property with a value other than 'visible'. Values have the following meanings:

auto

The clipping region has the same size and location as the element's box(es).

<shape>

In CSS2, the only valid <shape> value is: rect (<top>, <right>, <bottom>, <left>) where <top>, <bottom> <right>, and <left> specify offsets from the respective sides of the box.

<top>, <right>, <bottom>, and <left> may either have a <length> value or "auto". Negative lengths are permitted. The value "auto" means that a given edge of the clipping region will be the same as the edge of the element's generated box (i.e., "auto" means the same as "0".)

When coordinates are rounded to pixel coordinates, care should be taken that no pixels remain visible when <left> + <right> is equal to the element's width (or <top> + <bottom> equals the element's height), and conversely that no pixels remain hidden when these values are 0.

The element's ancestors may also have clipping regions (in case their "overflow" property is not "visible"); what is rendered is the intersection of the various clipping regions.

If the clipping region exceeds the bounds of the UA's document window, content may be clipped to that window by the native operating environment.

overflow[top]

CSS2 Definition: as amended by [http://www.w3.org/Style/css2-updates/REC-CSS2-19980512-errata.html#x67]

CSS2 Reference: [ "overflow" property ] http://www.w3.org/TR/REC-CSS2/visufx.html#propdef-overflow

This property specifies whether the content of a block-level element is clipped when it overflows the element's box (which is acting as a containing block for the content). Values have the following meanings:

visible

This value indicates that content is not clipped, i.e., it may be rendered outside the block box.

hidden

This value indicates that the content is clipped and that no scrolling mechanism should be provided to view the content outside the clipping region; users will not have access to clipped content. The size and shape of the clipping region is specified by the "clip" property.

scroll

This value indicates that the content is clipped and that if the user agent uses a scrolling mechanism that is visible on the screen (such as a scroll bar or a panner), that mechanism should be displayed for a box whether or not any of its content is clipped. This avoids any problem with scrollbars appearing and disappearing in a dynamic environment. When this value is specified and the target medium is "print", overflowing content should be printed.

auto

The behavior of the "auto" value is user agent dependent, but should cause a scrolling mechanism to be provided for overflowing boxes.

Even if "overflow" is set to "visible", content may be clipped to a UA's document window by the native operating environment.

XSL modifications to the CSS definition:

One more value is defined as follows:

error-if-overflow

This value implies the same semantics as the value "hidden" with the additional semantic that an error shall be indicated; implementations may recover by clipping the region.

For print media, implementations must support "auto" and "visible", as defined in this Recommendation. Other values may be treated as if "auto" had been specified.

reference-orientation[top]

XSL Definition:

Values have the following meanings:

0

The reference-orientation of this reference-area has the same reference-orientation as the containing reference-area.

90

The reference-orientation of this reference-area is rotated 90 degrees counter-clockwise from the reference-orientation of the containing reference-area.

180

The reference-orientation of this reference-area is rotated 180 degrees counter-clockwise from the reference-orientation of the containing reference-area.

270

The reference-orientation of this reference-area is rotated 270 degrees counter-clockwise from the reference-orientation of the containing reference-area.

-90

The reference-orientation of this reference-area is rotated 270 degrees counter-clockwise from the reference-orientation of the containing reference-area.

NOTE: 

This is equivalent to specifying "270".

-180

The reference-orientation of this reference-area is rotated 180 degrees counter-clockwise from the reference-orientation of the containing reference-area.

NOTE: 

This is equivalent to specifying "180".

-270

The reference-orientation of this reference-area is rotated 90 degrees counter-clockwise from the reference-orientation of the containing reference-area.

NOTE: 

This is equivalent to specifying "90".

The reference-orientation specifies the direction for "top" for the content-rectangle of the "reference-area". This is used as the reference for deriving directions, such as the block-progression-direction, inline-progression-direction, etc. as specified by the "writing-mode" and "direction" properties, and the orientation, placement, and tiling of the background.

The "reference-orientation" property is applied only on formatting objects that establish a reference-area. Each value of "reference-orientation" sets the absolute direction for "top", "left", "bottom", and "right"; which is used by "writing-mode", "direction", and all positioning operations that are referenced to the reference-area or are nested within it.

The reference-orientation trait on an area is indirectly derived from the "reference-orientation" property on the formatting object that generates the area or the formatting object ancestors of that formatting object.

span[top]

XSL Definition:

Values have the following meanings:

none

This object does not span multiple columns.

all

The areas resulting from this flow object shall span all the columns of a multi-column region.

Specifies if a block-level object should be placed in the current column or should span all columns of a multi-column region.

NOTE: 

This only has effect on areas returned by a flow; e.g. block-areas generated by fo:block children of an fo:flow. Children and further descendants of these areas take on the spanning characteristic of their parent.