com.nwalsh.xalan
Class Table

java.lang.Object
  extended by com.nwalsh.xalan.Table

public class Table
extends java.lang.Object

Xalan extensions supporting Tables

$Id: Table.java,v 1.5 2002/11/15 13:50:53 nwalsh Exp $

Copyright (C) 2000 Norman Walsh.

This class provides a Xalan implementation of some code to adjust CALS Tables to HTML Tables.

Column Widths

The adjustColumnWidths method takes a result tree fragment (assumed to contain the colgroup of an HTML Table) and returns the result tree fragment with the column widths adjusted to HTML terms.

Convert Lengths

The convertLength method takes a length specification of the form 9999.99xx (where "xx" is a unit) and returns that length as an integral number of pixels. For convenience, percentage lengths are returned unchanged.

The recognized units are: inches (in), centimeters (cm), millimeters (mm), picas (pc, 1pc=12pt), points (pt), and pixels (px). A number with no units is assumed to be pixels.

Change Log:

1.0

Initial release.

Version:
$Id: Table.java,v 1.5 2002/11/15 13:50:53 nwalsh Exp $
Author:
Norman Walsh ndw@nwalsh.com

Field Summary
protected static java.lang.String foURI
          The FO namespace name.
protected static java.util.Hashtable unitHash
          The hash used to associate units with a length in pixels.
 
Constructor Summary
Table()
          Constructor for Verbatim
 
Method Summary
 org.w3c.dom.DocumentFragment adjustColumnWidths(ExpressionContext context, org.w3c.dom.traversal.NodeIterator xalanNI)
          Adjust column widths in an HTML table.
static int convertLength(java.lang.String length)
          Convert a length specification to a number of pixels.
protected  java.lang.String[] correctRoundingError(java.lang.String[] widths)
          Correct rounding errors introduced in calculating the width of each column.
 int getPixelsPerInch()
          Return the current pixels-per-inch value.
protected static void initializeHash()
          Initialize the internal hash table with proper values.
static void setPixelsPerInch(int value)
          Set the pixels-per-inch value.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

unitHash

protected static java.util.Hashtable unitHash
The hash used to associate units with a length in pixels.


foURI

protected static java.lang.String foURI
The FO namespace name.

Constructor Detail

Table

public Table()

Constructor for Verbatim

All of the methods are static, so the constructor does nothing.

Method Detail

initializeHash

protected static void initializeHash()
Initialize the internal hash table with proper values.


setPixelsPerInch

public static void setPixelsPerInch(int value)
Set the pixels-per-inch value. Only positive values are legal.


getPixelsPerInch

public int getPixelsPerInch()
Return the current pixels-per-inch value.


convertLength

public static int convertLength(java.lang.String length)

Convert a length specification to a number of pixels.

The specified length should be of the form [+/-]999.99xx, where xx is a valid unit.


adjustColumnWidths

public org.w3c.dom.DocumentFragment adjustColumnWidths(ExpressionContext context,
                                                       org.w3c.dom.traversal.NodeIterator xalanNI)

Adjust column widths in an HTML table.

The specification of column widths in CALS (a relative width plus an optional absolute width) are incompatible with HTML column widths. This method adjusts CALS column width specifiers in an attempt to produce equivalent HTML specifiers.

In order for this method to work, the CALS width specifications should be placed in the "width" attribute of the <col>s within a <colgroup>. Then the colgroup result tree fragment is passed to this method.

This method makes use of two parameters from the XSL stylesheet that calls it: nominal.table.width and table.width. The value of nominal.table.width must be an absolute distance. The value of table.width can be either absolute or relative.

Presented with a mixture of relative and absolute lengths, the table width is used to calculate appropriate values. If the table.width is relative, the nominal width is used for this calculation.

There are three possible combinations of values:

  1. There are no relative widths; in this case the absolute widths are used in the HTML table.
  2. There are no absolute widths; in this case the relative widths are used in the HTML table.
  3. There are a mixture of absolute and relative widths:
    1. If the table width is absolute, all widths become absolute.
    2. If the table width is relative, make all the widths absolute relative to the nominal table width then turn them all back into relative widths.

Parameters:
context - The stylesheet context; supplied automatically by Xalan
rtf - The result tree fragment containing the colgroup.
Returns:
The result tree fragment containing the adjusted colgroup.

correctRoundingError

protected java.lang.String[] correctRoundingError(java.lang.String[] widths)
Correct rounding errors introduced in calculating the width of each column. Make sure they sum to 100% in the end.