Table of contents

Appendices

5.10 Core Function Library

Number Functions[top]

The floor function returns the largest (closest to positive infinity) integer that is not greater than the argument. The numeric argument to this function must be of unit power zero.

NOTE: 

If it is necessary to use the floor function for a property where a unit power of one is expected, then an expression such as: "floor(1.4in div 1.0in)*1.0in" must be used. This applies to the ceiling, round, and other such functions where a unit power of zero is required.

The ceiling function returns the smallest (closest to negative infinity) integer that is not less than the argument. The numeric argument to this function must be of unit power zero.

The round function returns the integer that is closest to the argument. If there are two such numbers, then the one that is closest to positive infinity is returned. The numeric argument to this function must be of unit power zero.

The min function returns the minimum of the two numeric arguments. These arguments must have the same unit power.

The max function returns the maximum of the two numeric arguments. These arguments must have the same unit power.

The abs function returns the absolute value of the numeric argument. That is, if the numeric argument is negative, it returns the negation of the argument.

Color Functions[top]

The rgb function returns a specific color from the RGB color space. The parameters to this function must be numerics (real numbers) with a length power of zero.

The rgb-icc function returns a specific color from the ICC Color Profile. The color profile is specified by the name parameter (the fourth parameter). This color profile must have been declared in the fo:declarations formatting object using an fo:color-profile formatting object.

The first three parameters specify a fallback color from the sRGB color space. This color is used when the color profile is not available.

The color is specified by a sequence of one or more color values (real numbers) specified after the name parameter. These values are specific to the color profile.

The system-color function returns a system defined color with a given name.

Font Functions[top]

The system-font function returns a characteristic of a system font. The first argument is the name of the system font and the second argument, which is optional, names the property that specifies the characteristic. If the second argument is omitted, then the characteristic returned is the same as the name of the property to which the expression is being assigned.

For example, the expression "system-font(heading,font-size)" returns the font-size characteristic for the system font named "heading". This is equivalent to the property assignment 'font-size="system-font(heading)"'.

Property Value Functions[top]

The inherited-property-value function returns the inherited value of the property whose name matches the argument specified, or if omitted for the property for which the expression is being evaluated. It is an error if this property is not an inherited property.

The returned "inherited value" is the computed value of this property on this object's parent. In particular, given the following example:

<fo:list-block>
  ...
  <fo:list-item color="red">
    <fo:list-item-body background-color="green">
      <fo:block background-color="inherited-property-value(color)">
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
</fo:list-block>

The background-color property on the fo:block is assigned the value "red" because the (computed, after inheritance) value of the color (not background-color) property on the fo:list-item-body that is the parent of fo:block is "red".

The label-end function returns the calculated label-end value for lists. See the definition in [provisional-label-separation] .

The body-start function returns the calculated body-start value for lists. See the definition in [provisional-distance-between-starts] .

NOTE: 

When this function is used outside of a list, it still returns a calculated value as specified.

The from-parent function returns a computed value of the property whose name matches the argument specified, or if omitted for the property for which the expression is being evaluated. The value returned is that for the parent of the formatting object for which the expression is evaluated. If there is no parent, the value returned is the initial value. If the argument specifies a shorthand property and if the expression only consists of the from-parent function with an argument matching the property being computed, it is interpreted as an expansion of the shorthand with each property into which the shorthand expands, each having a value of from-parent with an argument matching the property. It is an error if arguments matching a shorthand property are used in any other way.

The from-nearest-specified-value function returns a computed value of the property whose name matches the argument specified, or if omitted for the property for which the expression is being evaluated. The value returned is that for the closest ancestor of the formatting object for which the expression is evaluated on which there is an assignment of the property in the XML result tree in the fo namespace. If there is no such ancestor, the value returned is the initial value. If the argument specifies a shorthand property and if the expression only consists of the from-nearest-specified-value function with an argument matching the property being computed, it is interpreted as an expansion of the shorthand with each property into which the shorthand expands, each having a value of from-nearest-specified-value with an argument matching the property. It is an error if arguments matching a shorthand property are used in any other way.

The from-table-column function returns the inherited value of the property whose name matches the argument specified, or if omitted for the property for which the expression is being evaluated, from the fo:table-column whose column-number matches the column for which this expression is evaluated and whose number-columns-spanned also matches any span. If there is no match for the number-columns-spanned, it is matched against a span of 1. If there is still no match, the initial value is returned. It is an error to use this function on formatting objects that are not an fo:table-cell or its descendants.

The proportional-column-width function returns N units of proportional measure where N is the argument given to this function. The column widths are first determined ignoring the proportional measures. The difference between the table-width and the sum of the column widths is the available proportional width. One unit of proportional measure is the available proportional width divided by the sum of the proportional factors. It is an error to use this function on formatting objects other than an fo:table-column. It is also an error to use this function if the fixed table layout is not used.

The merge-property-values function returns a value of the property whose name matches the argument, or if omitted for the property for which the expression is being evaluated. The value returned is the specified value on the last fo:multi-property-set, of the parent fo:multi-properties, that applies to the User Agent state. If there is no such value, the computed value of the parent fo:multi-properties is returned.

NOTE: 

The test for applicability of a User Agent state is specified using the "active-state" property.

It is an error to use this function on formatting objects other than an fo:wrapper that is the child of an fo:multi-properties.