com.nwalsh.saxon
Class Table

java.lang.Object
  com.nwalsh.saxon.Table

public class Table
extends java.lang.Object

Saxon extensions supporting Tables

$Id: Table.java 5907 2006-04-27 08:26:47Z xmldoc $

Copyright (C) 2000 Norman Walsh.

This class provides a Saxon 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.

Field Summary

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

static com.icl.saxon.expr.NodeSetValue	adjustColumnWidths(com.icl.saxon.Context context, com.icl.saxon.expr.NodeSetValue rtf_ns) Adjust column widths in an HTML table.
static int	convertLength(java.lang.String length) Convert a length specification to a number of pixels.
protected static 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 java.lang.String	getVariable(com.icl.saxon.Context context, java.lang.String varName) Find the string value of a stylesheet variable or parameter
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.

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.

getVariable

protected static java.lang.String getVariable(com.icl.saxon.Context context,
                                              java.lang.String varName)
                                       throws javax.xml.transform.TransformerException

Find the string value of a stylesheet variable or parameter

Returns the string value of varName in the current context. Returns the empty string if the variable is not defined.

Parameters:

context - The current stylesheet context

varName - The name of the variable (without the dollar sign)

Returns:

The string value of the variable

Throws:

javax.xml.transform.TransformerException

adjustColumnWidths

public static com.icl.saxon.expr.NodeSetValue adjustColumnWidths(com.icl.saxon.Context context,
                                                                 com.icl.saxon.expr.NodeSetValue rtf_ns)

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 Saxon

rtf_ns - The result tree fragment containing the colgroup.

Returns:

The result tree fragment containing the adjusted colgroup.

correctRoundingError

protected static 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.