excel_api.php

<?php
# MantisBT - A PHP based bugtracking system

# MantisBT is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# MantisBT is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with MantisBT.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Excel API
 *
 * @package CoreAPI
 * @subpackage ExcelAPI
 * @copyright Copyright 2000 - 2002  Kenzaburo Ito - kenito@300baud.org
 * @copyright Copyright 2002  MantisBT Team - mantisbt-dev@lists.sourceforge.net
 * @link http://www.mantisbt.org
 *
 * @uses authentication_api.php
 * @uses bug_api.php
 * @uses category_api.php
 * @uses columns_api.php
 * @uses config_api.php
 * @uses constant_inc.php
 * @uses custom_field_api.php
 * @uses helper_api.php
 * @uses lang_api.php
 * @uses project_api.php
 * @uses user_api.php
 */

require_api( 'authentication_api.php' );
require_api( 'bug_api.php' );
require_api( 'category_api.php' );
require_api( 'columns_api.php' );
require_api( 'config_api.php' );
require_api( 'constant_inc.php' );
require_api( 'custom_field_api.php' );
require_api( 'helper_api.php' );
require_api( 'lang_api.php' );
require_api( 'project_api.php' );
require_api( 'user_api.php' );

/**
 * A method that returns the header for an Excel Xml file.
 *
 * @param string $p_worksheet_title The worksheet title.
 * @param array  $p_styles          An optional array of ExcelStyle entries . Parent entries must be placed before child entries.
 * @return string the header Xml.
 */
function excel_get_header( $p_worksheet_title, array $p_styles = array() ) {
	$p_worksheet_title = preg_replace( '/[\/:*?"<>|]/', '', $p_worksheet_title );
	return "<?xml version=\"1.0\" encoding=\"UTF-8\"?><?mso-application progid=\"Excel.Sheet\"?>
 <Workbook xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"
 xmlns:x=\"urn:schemas-microsoft-com:office:excel\"
 xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\"
 xmlns:html=\"http://www.w3.org/TR/REC-html40\">\n ". excel_get_styles( $p_styles ). '<Worksheet ss:Name="' . urlencode( $p_worksheet_title ) . "\">\n<Table>\n<Column ss:Index=\"1\" ss:AutoFitWidth=\"0\" ss:Width=\"110\"/>\n";
}

/**
 * Returns an XML string containing the <tt>ss:Styles</tt> entry, possibly empty
 *
 * @param array $p_styles An array of ExcelStyle entries.
 * @return null|string
 */
function excel_get_styles( array $p_styles ) {
	if( count( $p_styles ) == 0 ) {
		return null;
	}

	$t_styles_string = '<ss:Styles>';

	foreach ( $p_styles as $t_style ) {
		$t_styles_string .= $t_style->asXml();
	}
	$t_styles_string .= '</ss:Styles>';

	return $t_styles_string;
}

/**
 * A method that returns the footer for an Excel Xml file.
 * @return string the footer xml.
 */
function excel_get_footer() {
	return "</Table>\n</Worksheet></Workbook>\n";
}

/**
 * Generates a cell XML for a column title.
 * @param string $p_column_title Column title.
 * @return string The cell xml.
 */
function excel_format_column_title( $p_column_title ) {
	return '<Cell><Data ss:Type="String">' . $p_column_title . '</Data></Cell>';
}

/**
 * Generates the xml for the start of an Excel row.
 *
 * @param string $p_style_id The optional style id.
 * @return string The Row tag.
 */
function excel_get_start_row( $p_style_id = '' ) {
	if( $p_style_id != '' ) {
		return '<Row ss:StyleID="' . $p_style_id . '">';
	} else {
		return '<Row>';
	}
}

/**
 * Generates the xml for the end of an Excel row.
 * @return string The Row end tag.
 */
function excel_get_end_row() {
	return '</Row>';
}

/**
 * Gets an Xml Row that contains all column titles
 * @param string $p_style_id The optional style id.
 * @return string The xml row.
 */
function excel_get_titles_row( $p_style_id = '' ) {
	$t_columns = excel_get_columns();
	$t_ret = excel_get_start_row( $p_style_id );

	foreach( $t_columns as $t_column ) {
		$t_ret .= excel_format_column_title( column_get_title( $t_column ) );
	}

	$t_ret .= '</Row>';

	return $t_ret;
}

/**
 * Gets the download file name for the Excel export.  If 'All Projects' selected, default to <username>,
 * otherwise default to <projectname>.
 * @return string file name without extension
 */
function excel_get_default_filename() {
	$t_current_project_id = helper_get_current_project();

	if( ALL_PROJECTS == $t_current_project_id ) {
		$t_filename = user_get_name( auth_get_current_user_id() );
	} else {
		$t_filename = project_get_field( $t_current_project_id, 'name' );
	}

	return $t_filename;
}

/**
 * Escapes the specified column value and includes it in a Cell Xml as a string.
 * @param string $p_value The value.
 * @return string The Cell Xml.
 */
function excel_prepare_string( $p_value ) {
	return excel_get_cell( $p_value, 'String' );
}

/**
 * Escapes the specified column value and includes it in a Cell Xml as a number.
 * @param integer $p_value The value.
 * @return string The Cell Xml.
 */
function excel_prepare_number( $p_value ) {
	return excel_get_cell( $p_value, 'Number' );
}

/**
 * Returns an <tt>Cell</tt> as an XML string
 *
 * <p>All the parameters are assumed to be valid and escaped, as this function performs no
 * escaping of its own.</p>
 *
 * @param string $p_value      Cell Value.
 * @param string $p_type       Cell Type.
 * @param array  $p_attributes An array where the keys are attribute names and values attribute
 *                             values for the <tt>Cell</tt> object.
 * @return string
 */
function excel_get_cell( $p_value, $p_type, array $p_attributes = array() ) {
	if ( !is_int( $p_value ) ) {
		$t_value = str_replace( array( '&', "\n", '<', '>' ), array( '&amp;', '&#10;', '&lt;', '&gt;' ), $p_value );
	} else {
		$t_value = $p_value;
	}

	$t_ret = '<Cell ';

	foreach ( $p_attributes as $t_attribute_name => $t_attribute_value ) {
		$t_ret .= $t_attribute_name. '="' . $t_attribute_value . '" ';
	}

	$t_ret .= '>';

	$t_ret .= '<Data ss:Type="' . $p_type . '">' . $t_value . "</Data></Cell>\n";

	return $t_ret;
}

/**
 * Gets the columns to be included in the Excel Xml export.
 * @return array column names.
 */
function excel_get_columns() {
	$t_columns = helper_get_columns_to_view( COLUMNS_TARGET_EXCEL_PAGE );
	return $t_columns;
}

#
# Formatting Functions
#
# Names for formatting functions are excel_format_*, where * corresponds to the
# field name as return get excel_get_columns() and by the filter api.
#
/**
 * Gets the formatted bug id value.
 * @param BugData $p_bug The bug object.
 * @return string The bug id prefixed with 0s.
 */
function excel_format_id( BugData $p_bug ) {
	return excel_prepare_number( bug_format_id( $p_bug->id ) );
}

/**
 * Gets the formatted project id value.
 * @param BugData $p_bug The bug object.
 * @return string The project name.
 */
function excel_format_project_id( BugData $p_bug ) {
	return excel_prepare_string( project_get_name( $p_bug->project_id ) );
}

/**
 * Gets the formatted reporter id value.
 * @param BugData $p_bug A bug object.
 * @return string The reporter user name.
 */
function excel_format_reporter_id( BugData $p_bug ) {
	return excel_prepare_string( user_get_name( $p_bug->reporter_id ) );
}

/**
 * Gets the formatted number of bug notes.
 * @param BugData $p_bug A bug object.
 * @return string The number of bug notes.
 */
function excel_format_bugnotes_count( BugData $p_bug ) {
	return excel_prepare_number( $p_bug->bugnotes_count );
}

/**
 * Gets the formatted handler id.
 * @param BugData $p_bug A bug object.
 * @return string The handler user name or empty string.
 */
function excel_format_handler_id( BugData $p_bug ) {
	if( $p_bug->handler_id > 0 ) {
		return excel_prepare_string( user_get_name( $p_bug->handler_id ) );
	} else {
		return excel_prepare_string( '' );
	}
}

/**
 * Gets the formatted priority.
 * @param BugData $p_bug A bug object.
 * @return string the priority text.
 */
function excel_format_priority( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'priority', $p_bug->priority, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the formatted severity.
 * @param BugData $p_bug A bug object.
 * @return string the severity text.
 */
function excel_format_severity( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'severity', $p_bug->severity, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the formatted reproducibility.
 * @param BugData $p_bug A bug object.
 * @return string the reproducibility text.
 */
function excel_format_reproducibility( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'reproducibility', $p_bug->reproducibility, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the formatted view state,
 * @param BugData $p_bug A bug object.
 * @return string The view state
 */
function excel_format_view_state( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'view_state', $p_bug->view_state, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the formatted projection.
 * @param BugData $p_bug A bug object.
 * @return string the projection text.
 */
function excel_format_projection( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'projection', $p_bug->projection, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the formatted eta.
 * @param BugData $p_bug A bug object.
 * @return string the eta text.
 */
function excel_format_eta( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'eta', $p_bug->eta, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the status field.
 * @param BugData $p_bug A bug object.
 * @return string the formatted status.
 */
function excel_format_status( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'status', $p_bug->status, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the resolution field.
 * @param BugData $p_bug A bug object.
 * @return string the formatted resolution.
 */
function excel_format_resolution( BugData $p_bug ) {
	return excel_prepare_string( get_enum_element( 'resolution', $p_bug->resolution, auth_get_current_user_id(), $p_bug->project_id ) );
}

/**
 * Gets the formatted version.
 * @param BugData $p_bug A bug object.
 * @return string the product version.
 */
function excel_format_version( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->version );
}

/**
 * Gets the formatted fixed in version.
 * @param BugData $p_bug A bug object.
 * @return string the fixed in version.
 */
function excel_format_fixed_in_version( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->fixed_in_version );
}

/**
 * Gets the formatted target version.
 * @param BugData $p_bug A bug object.
 * @return string the target version.
 */
function excel_format_target_version( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->target_version );
}

/**
 * Gets the formatted category.
 * @param BugData $p_bug A bug object.
 * @return string the category.
 */
function excel_format_category_id( BugData $p_bug ) {
	return excel_prepare_string( category_full_name( $p_bug->category_id, false ) );
}

/**
 * Gets the formatted operating system.
 * @param BugData $p_bug A bug object.
 * @return string the operating system.
 */
function excel_format_os( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->os );
}

/**
 * Gets the formatted operating system build (version).
 * @param BugData $p_bug A bug object.
 * @return string the operating system build (version)
 */
function excel_format_os_build( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->os_build );
}

/**
 * Gets the formatted product build,
 * @param BugData $p_bug A bug object.
 * @return string the product build.
 */
function excel_format_build( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->build );
}

/**
 * Gets the formatted platform,
 * @param BugData $p_bug A bug object.
 * @return string the platform.
 */
function excel_format_platform( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->platform );
}

/**
 * Gets the formatted date submitted.
 * @param BugData $p_bug A bug object.
 * @return string the date submitted in short date format.
 */
function excel_format_date_submitted( BugData $p_bug ) {
	return excel_prepare_string( date( config_get( 'short_date_format' ), $p_bug->date_submitted ) );
}

/**
 * Gets the formatted date last updated.
 * @param BugData $p_bug A bug object.
 * @return string the date last updated in short date format.
 */
function excel_format_last_updated( BugData $p_bug ) {
	return excel_prepare_string( date( config_get( 'short_date_format' ), $p_bug->last_updated ) );
}

/**
 * Gets the summary field.
 * @param BugData $p_bug A bug object.
 * @return string the formatted summary.
 */
function excel_format_summary( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->summary );
}

/**
 * Gets the formatted selection.
 * @param BugData $p_bug A bug object.
 * @return string an formatted empty string.
 */
function excel_format_selection( BugData $p_bug ) {
	return excel_prepare_string( '' );
}

/**
 * Gets the formatted description field.
 * @param BugData $p_bug A bug object.
 * @return string The formatted description (multi-line).
 */
function excel_format_description( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->description );
}

/**
 * Gets the formatted 'steps to reproduce' field.
 * @param BugData $p_bug A bug object.
 * @return string The formatted steps to reproduce (multi-line).
 */
function excel_format_steps_to_reproduce( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->steps_to_reproduce );
}

/**
 * Gets the formatted 'additional information' field.
 * @param BugData $p_bug A bug object.
 * @return string The formatted additional information (multi-line).
 */
function excel_format_additional_information( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->additional_information );
}

/**
 * Gets the formatted value for the specified issue id, project and custom field.
 * @param integer $p_issue_id     The issue id.
 * @param integer $p_project_id   The project id.
 * @param string  $p_custom_field The custom field name (without 'custom_' prefix).
 * @return string The custom field value.
 */
function excel_format_custom_field( $p_issue_id, $p_project_id, $p_custom_field ) {
	$t_field_id = custom_field_get_id_from_name( $p_custom_field );

	if( $t_field_id === false ) {
		return excel_prepare_string( '@' . $p_custom_field . '@' );
	}

	if( custom_field_is_linked( $t_field_id, $p_project_id ) ) {
		$t_def = custom_field_get_definition( $t_field_id );

		if ( $t_def['type'] == CUSTOM_FIELD_TYPE_NUMERIC ) {
			return excel_prepare_number( string_custom_field_value( $t_def, $t_field_id, $p_issue_id ) );
		}

		return excel_prepare_string( string_custom_field_value( $t_def, $t_field_id, $p_issue_id ) );
	}

	# field is not linked to project
	return excel_prepare_string( '' );
}

/**
 * Gets the formatted value for the specified plugin column value.
 * @param string  $p_column The plugin column name.
 * @param BugData $p_bug    A bug object to print the column for - needed for the display function of the plugin column.
 * @return string The plugin column value.
 */
function excel_format_plugin_column_value( $p_column, BugData $p_bug ) {
	$t_plugin_columns = columns_get_plugin_columns();

	if( !isset( $t_plugin_columns[$p_column] ) ) {
		return excel_prepare_string( '' );
	} else {
		$t_column_object = $t_plugin_columns[$p_column];
		ob_start();
		$t_column_object->display( $p_bug, COLUMNS_TARGET_EXCEL_PAGE );
		$t_value = ob_get_clean();
		return excel_prepare_string( $t_value );
	}
}

/**
 * Gets the formatted due date.
 * @param BugData $p_bug A bug object.
 * @return string The formatted due date.
 */
function excel_format_due_date( BugData $p_bug ) {
	return excel_prepare_string( date( config_get( 'short_date_format' ), $p_bug->due_date ) );
}

/**
 * Gets the sponsorship total for an issue
 * @param BugData $p_bug A bug object.
 * @return string
 * @access public
 */
function excel_format_sponsorship_total( BugData $p_bug ) {
	return excel_prepare_string( $p_bug->sponsorship_total );
}

/**
 * The <tt>ExcelStyle</tt> class is able to render style information
 *
 * <p>For more information regarding the values taken by the parameters of this class' methods
 * please see <a href="http://msdn.microsoft.com/en-us/library/aa140066(v=office.10).aspx#odc_xmlss_ss:style">
 * the ss:Style documentation</a>.</p>
 *
 */
class ExcelStyle {
	/**
	 * Id
	 */
	private $id;

	/**
	 * Parent id
	 */
	private $parent_id;

	/**
	 * Interior
	 */
	private $interior;

	/**
	 * Font
	 */
	private $font;

	/**
	 * Border
	 */
	private $border;

	/**
	 * Alignment
	 */
	private $alignment;

	/**
	 * Default Constructor
	 * @param string $p_id        The unique style id.
	 * @param string $p_parent_id The parent style id.
	 */
	function __construct( $p_id, $p_parent_id = '' ) {
		$this->id = $p_id;
		$this->parent_id = $p_parent_id;
	}

	/**
	 * Return ID
	 * @return integer
	 */
	function getId() {
		return $this->id;
	}

	/**
	 * Set background color
	 * @param string $p_color   The color in #rrggbb format or a named color.
	 * @param string $p_pattern Fill Pattern.
	 * @return void
	 */
	function setBackgroundColor( $p_color, $p_pattern = 'Solid' ) {
		if( ! isset ( $this->interior ) ) {
			$this->interior = new Interior();
		}

		$this->interior->color = $p_color;
		$this->interior->pattern = $p_pattern;
	}

	/**
	 * Set Font
	 * @param integer $p_bold   Either 1 for bold, 0 for not bold.
	 * @param string  $p_color  The color in #rrggbb format or a named color.
	 * @param string  $p_name   The name of the font.
	 * @param integer $p_italic Either 1 for italic, 0 for not italic.
	 * @return void
	 */
	function setFont( $p_bold, $p_color = '', $p_name = '', $p_italic = -1 ) {
		if( !isset( $this->font ) ) {
			$this->font = new Font();
		}

		if( $p_bold != -1 ) {
			$this->font->bold = $p_bold;
		}
		if( $p_color != '' ) {
			$this->font->color = $p_color;
		}
		if( $p_name != '' ) {
			$this->font->fontName = $p_name;
		}
		if( $p_italic != -1 ) {
			$this->font->italic = $p_italic;
		}
	}

	/**
	 * Sets the border values for the style
	 *
	 * <p>The values are set for the following positions: Left, Top, Right, Bottom. There is no
	 * support for setting individual values.</p>
	 *
	 * @param string  $p_color      The color in #rrggbb format or a named color.
	 * @param string  $p_line_style None, Continuous, Dash, Dot, DashDot, DashDotDot, SlantDashDot, or Double.
	 * @param integer $p_weight     Thickness in points.
	 * @return void
	 */
	function setBorder( $p_color, $p_line_style = 'Continuous', $p_weight = 1 ) {
		if( !isset( $this->border ) ) {
			$this->border = new Border();
		}

		if( $p_color != '' ) {
			$this->border->color = $p_color;
		}

		if( $p_line_style != '' ) {
			$this->border->lineStyle = $p_line_style;
		}

		if( $p_weight != -1 ) {
			$this->border->weight = $p_weight;
		}
	}

	/**
	 * Sets the alignment for the style
	 *
	 * @param integer $p_wrap_text  Either 1 to wrap, 0 to not wrap.
	 * @param string  $p_horizontal Automatic, Left, Center, Right, Fill, Justify, CenterAcrossSelection, Distributed, and JustifyDistributed.
	 * @param string  $p_vertical   Automatic, Top, Bottom, Center, Justify, Distributed, and JustifyDistributed.
	 * @return void
	 */
	function setAlignment( $p_wrap_text, $p_horizontal = '', $p_vertical = '' ) {
		if( !isset( $this->alignment ) ) {
			$this->alignment = new Alignment();
		}

		if( $p_wrap_text != '' ) {
			$this->alignment->wrapText = $p_wrap_text;
		}

		if( $p_horizontal != '' ) {
			$this->alignment->horizontal = $p_horizontal;
		}

		if( $p_vertical != '' ) {
			$this->alignment->vertical = $p_vertical;
		}
	}

	/**
	 * Return XML
	 * @return string
	 */
	function asXml() {
		$t_xml = '<ss:Style ss:ID="' . $this->id.'" ss:Name="'.$this->id.'" ';
		if( $this->parent_id != '' ) {
			$t_xml .= 'ss:Parent="' . $this->parent_id .'" ';
		}
		$t_xml .= '>';
		if( $this->interior ) {
			$t_xml .= $this->interior->asXml();
		}
		if( $this->font ) {
			$t_xml .= $this->font->asXml();
		}
		if( $this->border ) {
			$t_xml .= $this->border->asXml();
		}
		if( $this->alignment ) {
			$t_xml .= $this->alignment->asXml();
		}
		$t_xml .= '</ss:Style>'."\n";

		return $t_xml;
	}
}

/**
 * Interior
 */
class Interior {
	/**
	 * Color
	 */
	public $color;

	/**
	 * Pattern
	 */
	public $pattern;

	/**
	 * Return XML
	 * @return string
	 */
	function asXml() {
		$t_xml = '<ss:Interior ';

		if( $this->color ) {
		   $t_xml .= 'ss:Color="' . $this->color .'" ss:Pattern="'. $this->pattern . '" ';
		}

		$t_xml .= '/>';

		return $t_xml;
	}
}

/**
 * Font
 */
class Font {
	/**
	 * Bold
	 */
	public $bold;

	/**
	 * Colour
	 */
	public $color;

	/**
	 * Font Name
	 */
	public $fontName;

	/**
	 * Italic
	 */
	public $italic;

	/**
	 * Return XML
	 * @return string
	 */
	function asXml() {
		$t_xml = '<ss:Font ';

		if( $this->bold ) {
			$t_xml .= 'ss:Bold="' . $this->bold .'" ';
		}

		if( $this->color ) {
			$t_xml .= 'ss:Color="' . $this->color .'" ';
		}

		if( $this->fontName ) {
			$t_xml .= 'ss:FontName="' . $this->fontName .'" ';
		}

		if( $this->italic ) {
			$t_xml .= 'ss:Italic="' . $this->italic .'" ';
		}

		$t_xml .= '/>';

		return $t_xml;
	}
}

/**
 * Border
 */
class Border {
	/**
	 * Border Positions
	 */
	private $positions = array('Left', 'Top', 'Right', 'Bottom');

	/**
	 * Color
	 */
	public $color;

	/**
	 * Line Style
	 */
	public $lineStyle;

	/**
	 * Border Weight
	 */
	public $weight;

	/**
	 * Return XML
	 * @return string
	 */
	function asXml() {
		$t_xml = '<ss:Borders>';

		foreach ( $this->positions as $p_position ) {
			$t_xml.= '<ss:Border ss:Position="' . $p_position .'" ';

			if( $this->lineStyle ) {
				$t_xml .= 'ss:LineStyle="' . $this->lineStyle .'" ';
			}

			if( $this->color ) {
				$t_xml .= 'ss:Color="' . $this->color .'" ';
			}

			if( $this->weight ) {
				$t_xml .= 'ss:Weight="' . $this->weight .'" ';
			}

			$t_xml.= '/>';
		}

		$t_xml .= '</ss:Borders>';

		return $t_xml;
	}
}

/**
 * Alignment
 */
class Alignment {
	/**
	 * Wrap Text
	 */
	public $wrapText;

	/**
	 * Horizontal
	 */
	public $horizontal;

	/**
	 * Vertical
	 */
	public $vertical;

	/**
	 * Return XML
	 * @return string
	 */
	function asXml() {
		$t_xml = '<ss:Alignment ';

		if( $this->wrapText ) {
			$t_xml .= 'ss:WrapText="' . $this->wrapText.'" ';
		}

		if( $this->horizontal ) {
			$t_xml .= 'ss:Horizontal="' . $this->horizontal.'" ';
		}

		if( $this->vertical ) {
			$t_xml .= 'ss:Vertical="' . $this->vertical.'" ';
		}

		$t_xml .= '/>';

		return $t_xml;
	}
}