Pdf/FileParser/Font/OpenType.php

category: Zend
copyright: Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
license: http://framework.zend.com/license/new-bsd New BSD License
package: Zend_Pdf
subpackage: FileParser
version: $Id: OpenType.php 20096 2010-01-06 02:05:09Z bkarwin $
Classes: Zend_Pdf_FileParser_Font_OpenType

Description

Zend Framework

LICENSE

This source file is subject to the new BSD license that is bundled with this package in the file LICENSE.txt. It is also available through the world-wide-web at this URL: http://framework.zend.com/license/new-bsd If you did not receive a copy of the license and are unable to obtain it through the world-wide-web, please send an email to license@zend.com so we can send you a copy immediately.

Zend_Pdf_FileParser_Font_OpenType
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Extends from: Zend_Pdf_FileParser_Font
copyright: Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
license: http://framework.zend.com/license/new-bsd New BSD License
package: Zend_Pdf
subpackage: FileParser
Properties: $_scalerType; $_tableDirectory
Methods: screen; parse; _parseTableDirectory; _parseHeadTable; _parseNameTable; _parsePostTable; _parseHheaTable; _parseMaxpTable; _parseOs2Table; _parseHmtxTable; _parseCmapTable; _readScalerType; _jumpToTable; _readTableVersion; _languageCodeForPlatform

Description

Abstract base class for OpenType font file parsers.

TrueType was originally developed by Apple and was adopted as the default font format for the Microsoft Windows platform. OpenType is an extension of TrueType, developed jointly by Microsoft and Adobe, which adds support for PostScript font data.

This abstract parser class forms the foundation for concrete subclasses which extract either TrueType or PostScript font data from the file.

All OpenType files use big-endian byte ordering.

The full TrueType and OpenType specifications can be found at:

{@link http://developer.apple.com/textfonts/TTRefMan/}
{@link http://www.microsoft.com/typography/OTSPEC/}
{@link http://partners.adobe.com/public/developer/opentype/index_spec.html}

Properties

$_scalerType
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integer $_scalerType = '0'

Stores the scaler type (font type) for the font file. See {@link _readScalerType()}.

Details

$_scalerType: integer
visibility: protected
default: 0
final: false
static: false

$_tableDirectory
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array $_tableDirectory = 'array'

Stores the byte offsets to the various information tables.

Details

$_tableDirectory: array
visibility: protected
default: array
final: false
static: false

Methods

_jumpToTable
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_jumpToTable(
          string $tableName
          )
        
        :

Validates a given table's existence, then sets the file pointer to the start of that table.

Arguments

$tableName: string

Details

visibility: protected
final: false
static: false
throws

_languageCodeForPlatform
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_languageCodeForPlatform(
          integer $platformID,  $languageID
          )
        
        :
        string

Utility method that returns ISO 639 two-letter language codes from the TrueType platform and language ID. Returns NULL for languages that are not supported.

Arguments

$platformID: integer
$languageID

Output

string: | null

Details

visibility: protected
final: false
static: false

_parseCmapTable
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_parseCmapTable(
          
          )
        
        :

Parses the OpenType cmap (Character to Glyph Mapping) table.

The cmap table provides the maps from character codes to font glyphs. There are usually at least two character maps in a font: Microsoft Unicode and Macintosh Roman. For very complex fonts, there may also be mappings for the characters in the Unicode Surrogates Area, which are UCS-4 characters.

Details

visibility: protected
final: false
static: false
throws
todo: Need to rework the selection logic for picking a subtable. We should have an explicit list of preferences, followed by a list of those that are tolerable. Most specifically, since everything above this layer deals in Unicode, we need to be sure to only accept format 0 MacRoman tables.

_parseHeadTable
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_parseHeadTable(
          
          )
        
        :

Parses the OpenType head (Font Header) table.

The head table contains global information about the font such as the revision number and global metrics.

Details

visibility: protected
final: false
static: false
throws

_parseHheaTable
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_parseHheaTable(
          
          )
        
        :

Parses the OpenType hhea (Horizontal Header) table.

The hhea table contains information used for horizontal layout. It also contains some vertical layout information for Apple systems. The vertical layout information for the PDF file is usually taken from the OS/2 table.

Details

visibility: protected
final: false
static: false
throws

_parseHmtxTable
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_parseHmtxTable(
          
          )
        
        :

Parses the OpenType hmtx (Horizontal Metrics) table.

The hmtx table contains the horizontal metrics for every glyph contained within the font. These are the critical values for horizontal layout of text.

Details

visibility: protected
final: false
static: false
throws

_parseMaxpTable
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_parseMaxpTable(
          
          )
        
        :

Parses the OpenType hhea (Horizontal Header) table.

Details

visibility: protected
final: false
static: false
throws

_parseNameTable
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_parseNameTable(
          
          )
        
        :

Parses the OpenType name (Naming) table.

The name table contains all of the identifying strings associated with the font such as its name, copyright, trademark, license, etc.

Details

visibility: protected
final: false
static: false
throws

_parseOs2Table
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_parseOs2Table(
          
          )
        
        :

Parses the OpenType OS/2 (OS/2 and Windows Metrics) table.

The OS/2 table contains additional metrics data that is required to use the font on the OS/2 or Microsoft Windows platforms. It is not required for Macintosh fonts, so may not always be present. When available, we use this table to determine most of the vertical layout and stylistic information and for the font.

Details

visibility: protected
final: false
static: false
throws

_parsePostTable
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_parsePostTable(
          
          )
        
        :

Parses the OpenType post (PostScript Information) table.

The post table contains additional information required for using the font on PostScript printers. It also contains the preferred location and thickness for an underline, which is used by our layout code.

Details

visibility: protected
final: false
static: false
throws

_parseTableDirectory
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_parseTableDirectory(
          
          )
        
        :

Parses the OpenType table directory.

The table directory contains the identifier, checksum, byte offset, and length of each of the information tables housed in the font file.

Details

visibility: protected
final: false
static: false
throws

_readScalerType
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_readScalerType(
          
          )
        
        :
        integer

Reads the scaler type from the header of the OpenType font file and returns it as an unsigned long integer.

The scaler type defines the type of font: OpenType font files may contain TrueType or PostScript outlines. Throws an exception if the scaler type is not recognized.

Output

integer

Details

visibility: protected
final: false
static: false
throws

_readTableVersion
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_readTableVersion(
          float $minVersion,  $maxVersion
          )
        
        :
        float

Reads the fixed 16.16 table version number and checks for compatibility.

If the version is incompatible, throws an exception. If it is compatible, returns the version number.

Arguments

$minVersion: float
Minimum compatible version number.
$maxVersion

Output

float: Table version number.

Details

visibility: protected
final: false
static: false
throws

parse
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Reads and parses the font data from the file on disk.

NOTE: This method should be overridden in subclasses to add type- specific parsing and set $this->isParsed.

Details

visibility: public
final: false
static: false
throws

screen
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Verifies that the font file is in the expected format.

NOTE: This method should be overridden in subclasses to check the specific format and set $this->_isScreened!

Details

visibility: public
final: false
static: false
throws

API Documentation

Pdf/FileParser/Font/OpenType.php

Description

Zend_Pdf_FileParser_Font_OpenTypejump to top

Description

Properties

$_scalerTypejump to class

Details

$_tableDirectoryjump to class

Details

Methods

_jumpToTablejump to class

Arguments

Details

_languageCodeForPlatformjump to class

Arguments

Output

Details

_parseCmapTablejump to class

Details

_parseHeadTablejump to class

Details

_parseHheaTablejump to class

Details

_parseHmtxTablejump to class

Details

_parseMaxpTablejump to class

Details

_parseNameTablejump to class

Details

_parseOs2Tablejump to class

Details

_parsePostTablejump to class

Details

_parseTableDirectoryjump to class

Details

_readScalerTypejump to class

Output

Details

_readTableVersionjump to class

Arguments

Output

Details

parsejump to class

Details

screenjump to class

Details

Zend_Pdf_FileParser_Font_OpenType
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$_scalerType
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$_tableDirectory
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_jumpToTable
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_languageCodeForPlatform
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_parseCmapTable
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_parseHeadTable
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_parseHheaTable
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_parseHmtxTable
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_parseMaxpTable
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_parseNameTable
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_parseOs2Table
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_parsePostTable
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_parseTableDirectory
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_readScalerType
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_readTableVersion
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parse
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screen
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