Graph/src/driver/svg_font.php - zetacomponents - Git at Google

 <?php
 /**
  * File containing the ezcGraphSVGDriver class
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  *
  * @package Graph
  * @version //autogentag//
  * @author Freddie Witherden
  * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
  */

 /**
  * Helper class, offering requrired calculation basics and font metrics to use
  * SVG fonts with the SVG driver.
  *
  * You may convert any ttf font into a SVG font using the `ttf2svg` bianry from
  * the batik package. Depending on the distribution it may only be available as
  * `batik-ttf2svg-<version>`.
  *
  * Usage:
  * <code>
  *  $font = new ezcGraphSvgFont();
  *  var_dump(
  *      $font->calculateStringWidth( '../tests/data/font.svg', 'Just a test string.' ),
  *      $font->calculateStringWidth( '../tests/data/font2.svg', 'Just a test string.' )
  *  );
  * </code>
  *
  * @version //autogentag//
  * @package Graph
  * @mainclass
  */
 class ezcGraphSvgFont
 {
     /**
      * Units per EM
      *
      * @var float
      */
     protected $unitsPerEm;

     /**
      * Used glyphs
      *
      * @var array
      */
     protected $usedGlyphs = array();

     /**
      * Cache for glyph size to save XPath lookups.
      *
      * @var array
      */
     protected $glyphCache = array();

     /**
      * Used kernings
      *
      * @var array
      */
     protected $usedKerns = array();

     /**
      * Path to font
      *
      * @var string
      */
     protected $fonts = array();

     /**
      * Initialize SVG font
      *
      * Loads the SVG font $filename. This should be the path to the file
      * generated by ttf2svg.
      *
      * Returns the (normlized) name of the initilized font.
      *
      * @param string $fontPath
      * @return string
      */
     protected function initializeFont( $fontPath )
     {
         if ( isset( $this->fonts[$fontPath] ) )
         {
             return $fontPath;
         }

         // Check for existance of font file
         if ( !is_file( $fontPath ) || !is_readable( $fontPath ) )
         {
             throw new ezcBaseFileNotFoundException( $fontPath );
         }

         $this->fonts[$fontPath] = simplexml_load_file( $fontPath )->defs->font;

         // SimpleXML requires us to register a namespace for XPath to work
         $this->fonts[$fontPath]->registerXPathNamespace( 'svg', 'http://www.w3.org/2000/svg' );

         // Extract the number of units per Em
         $this->unitsPerEm[$fontPath] = (int) $this->fonts[$fontPath]->{'font-face'}['units-per-em'];

         return $fontPath;
     }

     /**
      * Get name of font
      *
      * Get the name of the given font, by extracting its font family from the
      * SVG font file.
      *
      * @param string $fontPath
      * @return string
      */
     public static function getFontName( $fontPath )
     {
         $font = simplexml_load_file( $fontPath )->defs->font;

         // SimpleXML requires us to register a namespace for XPath to work
         $font->registerXPathNamespace( 'svg', 'http://www.w3.org/2000/svg' );

         // Extract the font family name
         return (string) $font->{'font-face'}['font-family'];
     }

     /**
      * XPath has no standard means of escaping ' and ", with the only solution
      * being to delimit your string with the opposite type of quote. ( And if
      * your string contains both concat(  ) it ).
      *
      * This method will correctly delimit $char with the appropriate quote type
      * so that it can be used in an XPath expression.
      *
      * @param string $char
      * @return string
      */
     protected static function xpathEscape( $char )
     {
         return "'" . str_replace(
             array( '\'', '\\' ),
             array( '\\\'', '\\\\' ),
             $char ) . "'";
     }

     /**
      * Returns the <glyph> associated with $char.
      *
      * @param string $fontPath
      * @param string $char
      * @return float
      */
     protected function getGlyph( $fontPath, $char )
     {
         // Check if glyphwidth has already been calculated.
         if ( isset( $this->glyphCache[$fontPath][$char] ) )
         {
             return $this->glyphCache[$fontPath][$char];
         }

         $matches = $this->fonts[$fontPath]->xpath(
             $query = "glyph[@unicode=" . self::xpathEscape( $char ) . "]"
         );

         if ( count( $matches ) === 0 )
         {
              // Just ignore missing glyphs. The client will still render them
              // using a default font. We try to estimate some width by using a
              // common other character.
             return $this->glyphCache[$fontPath][$char] =
                 ( $char === 'o' ? false : $this->getGlyph( $fontPath, 'o' ) );
         }

         $glyph = $matches[0];
         if ( !in_array( $glyph, $this->usedGlyphs ) )
         {
             $this->usedGlyphs[$fontPath][] = $glyph;
         }

         // There should only ever be one match
         return $this->glyphCache[$fontPath][$char] = $glyph;
     }

     /**
      * Returns the amount of kerning to apply for glyphs $g1 and $g2. If no
      * valid kerning pair can be found 0 is returned.
      *
      * @param string $fontPath
      * @param SimpleXMLElement $g1
      * @param SimpleXMLElement $g2
      * @return int
      */
     public function getKerning( $fontPath, SimpleXMLElement $glyph1, SimpleXMLElement $glyph2 )
     {
         // Get the glyph names
         $g1Name = self::xpathEscape( ( string ) $glyph1['glyph-name'] );
         $g2Name = self::xpathEscape( ( string ) $glyph2['glyph-name'] );

         // Get the unicode character names
         $g1Uni = self::xpathEscape( ( string ) $glyph1['unicode'] );
         $g2Uni = self::xpathEscape( ( string ) $glyph2['unicode'] );

         // Search for kerning pairs
         $pair = $this->fonts[$fontPath]->xpath(
             "svg:hkern[( @g1=$g1Name and @g2=$g2Name )
                 or
              ( @u1=$g1Uni and @g2=$g2Uni )]"
         );

         // If we found anything return it
         if ( count( $pair ) )
         {
             if ( !in_array( $pair[0], $this->usedKerns ) )
             {
                 $this->usedKerns[$fontPath][] = $pair[0];
             }

             return ( int ) $pair[0]['k'];
         }
         else
         {
             return 0;
         }
     }

     /**
      * Calculates the width of $string in the current font in Em's.
      *
      * @param string $fontPath
      * @param string $string
      * @return float
      */
     public function calculateStringWidth( $fontPath, $string )
     {
         // Ensure font is properly initilized
         $fontPath = $this->initializeFont( $fontPath );

         $strlen = strlen( $string );
         $prevCharInfo = null;
         $length = 0;
         // @TODO: Add UTF-8 support here - iterating over the bytes does not
         // really help.
         for ( $i = 0; $i < $strlen; ++$i )
         {
             // Find the font information for the character
             $charInfo = $this->getGlyph( $fontPath, $string[$i] );

             // Handle missing glyphs
             if ( $charInfo === false )
             {
                 $prevCharInfo = null;
                 $length += .5 * $this->unitsPerEm[$fontPath];
                 continue;
             }

             // Add the horizontal advance for the character to the length
             $length += (float) $charInfo['horiz-adv-x'];

             // If we are not the first character, look for kerning pairs
             if ( $prevCharInfo !== null )
             {
                 // Apply kerning (if any)
                 $length -= $this->getKerning( $fontPath, $prevCharInfo, $charInfo );
             }

             $prevCharInfo = clone $charInfo;
         }

         // Divide by _unitsPerEm to get the length in Em
         return (float) $length / $this->unitsPerEm[$fontPath];
     }

     /**
      * Add font definitions to SVG document
      *
      * Add the SVG font definition paths for all used glyphs and kernings to
      * the given SVG document.
      *
      * @param DOMDocument $document
      * @return void
      */
     public function addFontToDocument( DOMDocument $document )
     {
         $defs = $document->getElementsByTagName( 'defs' )->item( 0 );

         $fontNr = 0;
         foreach ( $this->fonts as $path => $definition )
         {
             // Just import complete font for now.
             // @TODO: Only import used characters.
             $font = dom_import_simplexml( $definition );
             $font = $document->importNode( $font, true );
             $font->setAttribute( 'id', 'Font' . ++$fontNr );

             $defs->appendChild( $font );
         }
     }
 }

 ?>
	<?php
	/**
	* File containing the ezcGraphSVGDriver class
	*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*
	* @package Graph
	* @version //autogentag//
	* @author Freddie Witherden
	* @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
	*/

	/**
	* Helper class, offering requrired calculation basics and font metrics to use
	* SVG fonts with the SVG driver.
	*
	* You may convert any ttf font into a SVG font using the `ttf2svg` bianry from
	* the batik package. Depending on the distribution it may only be available as
	* `batik-ttf2svg-<version>`.
	*
	* Usage:
	* <code>
	* $font = new ezcGraphSvgFont();
	* var_dump(
	* $font->calculateStringWidth( '../tests/data/font.svg', 'Just a test string.' ),
	* $font->calculateStringWidth( '../tests/data/font2.svg', 'Just a test string.' )
	* );
	* </code>
	*
	* @version //autogentag//
	* @package Graph
	* @mainclass
	*/
	class ezcGraphSvgFont
	{
	/**
	* Units per EM
	*
	* @var float
	*/
	protected $unitsPerEm;

	/**
	* Used glyphs
	*
	* @var array
	*/
	protected $usedGlyphs = array();

	/**
	* Cache for glyph size to save XPath lookups.
	*
	* @var array
	*/
	protected $glyphCache = array();

	/**
	* Used kernings
	*
	* @var array
	*/
	protected $usedKerns = array();

	/**
	* Path to font
	*
	* @var string
	*/
	protected $fonts = array();

	/**
	* Initialize SVG font
	*
	* Loads the SVG font $filename. This should be the path to the file
	* generated by ttf2svg.
	*
	* Returns the (normlized) name of the initilized font.
	*
	* @param string $fontPath
	* @return string
	*/
	protected function initializeFont( $fontPath )
	{
	if ( isset( $this->fonts[$fontPath] ) )
	{
	return $fontPath;
	}

	// Check for existance of font file
	if ( !is_file( $fontPath ) \|\| !is_readable( $fontPath ) )
	{
	throw new ezcBaseFileNotFoundException( $fontPath );
	}

	$this->fonts[$fontPath] = simplexml_load_file( $fontPath )->defs->font;

	// SimpleXML requires us to register a namespace for XPath to work
	$this->fonts[$fontPath]->registerXPathNamespace( 'svg', 'http://www.w3.org/2000/svg' );

	// Extract the number of units per Em
	$this->unitsPerEm[$fontPath] = (int) $this->fonts[$fontPath]->{'font-face'}['units-per-em'];

	return $fontPath;
	}

	/**
	* Get name of font
	*
	* Get the name of the given font, by extracting its font family from the
	* SVG font file.
	*
	* @param string $fontPath
	* @return string
	*/
	public static function getFontName( $fontPath )
	{
	$font = simplexml_load_file( $fontPath )->defs->font;

	// SimpleXML requires us to register a namespace for XPath to work
	$font->registerXPathNamespace( 'svg', 'http://www.w3.org/2000/svg' );

	// Extract the font family name
	return (string) $font->{'font-face'}['font-family'];
	}

	/**
	* XPath has no standard means of escaping ' and ", with the only solution
	* being to delimit your string with the opposite type of quote. ( And if
	* your string contains both concat( ) it ).
	*
	* This method will correctly delimit $char with the appropriate quote type
	* so that it can be used in an XPath expression.
	*
	* @param string $char
	* @return string
	*/
	protected static function xpathEscape( $char )
	{
	return "'" . str_replace(
	array( '\'', '\\' ),
	array( '\\\'', '\\\\' ),
	$char ) . "'";
	}

	/**
	* Returns the <glyph> associated with $char.
	*
	* @param string $fontPath
	* @param string $char
	* @return float
	*/
	protected function getGlyph( $fontPath, $char )
	{
	// Check if glyphwidth has already been calculated.
	if ( isset( $this->glyphCache[$fontPath][$char] ) )
	{
	return $this->glyphCache[$fontPath][$char];
	}

	$matches = $this->fonts[$fontPath]->xpath(
	$query = "glyph[@unicode=" . self::xpathEscape( $char ) . "]"
	);

	if ( count( $matches ) === 0 )
	{
	// Just ignore missing glyphs. The client will still render them
	// using a default font. We try to estimate some width by using a
	// common other character.
	return $this->glyphCache[$fontPath][$char] =
	( $char === 'o' ? false : $this->getGlyph( $fontPath, 'o' ) );
	}

	$glyph = $matches[0];
	if ( !in_array( $glyph, $this->usedGlyphs ) )
	{
	$this->usedGlyphs[$fontPath][] = $glyph;
	}

	// There should only ever be one match
	return $this->glyphCache[$fontPath][$char] = $glyph;
	}

	/**
	* Returns the amount of kerning to apply for glyphs $g1 and $g2. If no
	* valid kerning pair can be found 0 is returned.
	*
	* @param string $fontPath
	* @param SimpleXMLElement $g1
	* @param SimpleXMLElement $g2
	* @return int
	*/
	public function getKerning( $fontPath, SimpleXMLElement $glyph1, SimpleXMLElement $glyph2 )
	{
	// Get the glyph names
	$g1Name = self::xpathEscape( ( string ) $glyph1['glyph-name'] );
	$g2Name = self::xpathEscape( ( string ) $glyph2['glyph-name'] );

	// Get the unicode character names
	$g1Uni = self::xpathEscape( ( string ) $glyph1['unicode'] );
	$g2Uni = self::xpathEscape( ( string ) $glyph2['unicode'] );

	// Search for kerning pairs
	$pair = $this->fonts[$fontPath]->xpath(
	"svg:hkern[( @g1=$g1Name and @g2=$g2Name )
	or
	( @u1=$g1Uni and @g2=$g2Uni )]"
	);

	// If we found anything return it
	if ( count( $pair ) )
	{
	if ( !in_array( $pair[0], $this->usedKerns ) )
	{
	$this->usedKerns[$fontPath][] = $pair[0];
	}

	return ( int ) $pair[0]['k'];
	}
	else
	{
	return 0;
	}
	}

	/**
	* Calculates the width of $string in the current font in Em's.
	*
	* @param string $fontPath
	* @param string $string
	* @return float
	*/
	public function calculateStringWidth( $fontPath, $string )
	{
	// Ensure font is properly initilized
	$fontPath = $this->initializeFont( $fontPath );

	$strlen = strlen( $string );
	$prevCharInfo = null;
	$length = 0;
	// @TODO: Add UTF-8 support here - iterating over the bytes does not
	// really help.
	for ( $i = 0; $i < $strlen; ++$i )
	{
	// Find the font information for the character
	$charInfo = $this->getGlyph( $fontPath, $string[$i] );

	// Handle missing glyphs
	if ( $charInfo === false )
	{
	$prevCharInfo = null;
	$length += .5 * $this->unitsPerEm[$fontPath];
	continue;
	}

	// Add the horizontal advance for the character to the length
	$length += (float) $charInfo['horiz-adv-x'];

	// If we are not the first character, look for kerning pairs
	if ( $prevCharInfo !== null )
	{
	// Apply kerning (if any)
	$length -= $this->getKerning( $fontPath, $prevCharInfo, $charInfo );
	}

	$prevCharInfo = clone $charInfo;
	}

	// Divide by _unitsPerEm to get the length in Em
	return (float) $length / $this->unitsPerEm[$fontPath];
	}

	/**
	* Add font definitions to SVG document
	*
	* Add the SVG font definition paths for all used glyphs and kernings to
	* the given SVG document.
	*
	* @param DOMDocument $document
	* @return void
	*/
	public function addFontToDocument( DOMDocument $document )
	{
	$defs = $document->getElementsByTagName( 'defs' )->item( 0 );

	$fontNr = 0;
	foreach ( $this->fonts as $path => $definition )
	{
	// Just import complete font for now.
	// @TODO: Only import used characters.
	$font = dom_import_simplexml( $definition );
	$font = $document->importNode( $font, true );
	$font->setAttribute( 'id', 'Font' . ++$fontNr );

	$defs->appendChild( $font );
	}
	}
	}

	?>