Pdf/FileParser/Font/OpenType.php
Zend Framework
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- Category
- Zend
- Copyright
- Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
- License
- New BSD License
- Package
- Zend_Pdf
- Subpackage
- FileParser
- Version
- $Id$
\Zend_Pdf_FileParser_Font_OpenType
Package: Zend_Pdf\FileParserAbstract 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}
- Parent(s)
- \Zend_Pdf_FileParser_Font
<
\Zend_Pdf_FileParser
- Children
- \Zend_Pdf_FileParser_Font_OpenType_TrueType
- Copyright
- Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
- License
- New BSD License
Properties
integer $_scalerType = 0
Stores the scaler type (font type) for the font file. See
{@link _readScalerType()}.
Default value0
Details- Type
- integer
array $_tableDirectory = array()
Stores the byte offsets to the various information tables.
Default valuearray()
Details- Type
- array
Methods
_jumpToTable(string $tableName) : void
Validates a given table's existence, then sets the file pointer to the
start of that table.
ParametersName | Type | Description |
---|
$tableName | string | |
---|
Throws _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.
ParametersName | Type | Description |
---|
$platformID | integer | |
---|
$languageID | | |
---|
ReturnsType | Description |
---|
string | | null |
_parseCmapTable() : void
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.
ThrowsDetails- 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() : void
Parses the OpenType head (Font Header) table.
The head table contains global information about the font such as the
revision number and global metrics.
Throws_parseHheaTable() : void
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.
Throws_parseHmtxTable() : void
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.
Throws_parseMaxpTable() : void
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.
Throws_parseNameTable() : void
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.
Throws_parseOs2Table() : void
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.
Throws_parsePostTable() : void
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.
Throws_parseTableDirectory() : void
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.
Throws_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.
ReturnsThrows_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.
ParametersName | Type | Description |
---|
$minVersion | float | Minimum compatible version number. |
---|
$maxVersion | | |
---|
ReturnsType | Description |
---|
float | Table version number. |
Throwsparse() : void
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.
Throwsscreen() : void
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!
Throws