generated from jric11/baseProject
581 lines
18 KiB
PHP
581 lines
18 KiB
PHP
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<?php
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declare(strict_types=1);
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/**
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* Subset.php
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*
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* @since 2011-05-23
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* @category Library
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* @package PdfFont
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* @author Nicola Asuni <info@tecnick.com>
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* @copyright 2011-2026 Nicola Asuni - Tecnick.com LTD
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* @license https://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE)
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* @link https://github.com/tecnickcom/tc-lib-pdf-font
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*
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* This file is part of tc-lib-pdf-font software library.
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*/
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namespace Com\Tecnick\Pdf\Font;
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use Com\Tecnick\File\Byte;
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use Com\Tecnick\File\File as ObjFile;
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use Com\Tecnick\Pdf\Font\Exception as FontException;
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use Com\Tecnick\Pdf\Font\Import\TrueType;
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/**
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* Com\Tecnick\Pdf\Font\Subset
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*
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* @since 2011-05-23
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* @category Library
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* @package PdfFont
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* @author Nicola Asuni <info@tecnick.com>
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* @copyright 2011-2026 Nicola Asuni - Tecnick.com LTD
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* @license https://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE)
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* @link https://github.com/tecnickcom/tc-lib-pdf-font
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*
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* @phpstan-import-type TFontData from Load
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*/
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class Subset
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{
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/**
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* array of table names to preserve (loca and glyf tables will be added later)
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* the cmap table is not needed and shall not be present,
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* since the mapping from character codes to glyph descriptions is provided separately
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*
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* @var array<string, bool>
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*/
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protected const TABLENAMES = [
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'head' => true,
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'hhea' => true,
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'hmtx' => true,
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'maxp' => true,
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'cvt ' => true,
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'fpgm' => true,
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'prep' => true,
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'glyf' => true,
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'loca' => true,
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];
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/**
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* Content of the input font file
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*/
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protected string $font = '';
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/**
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* Object used to read font bytes
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*/
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protected Byte $fbyte;
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/**
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* Extracted font metrics
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*
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* @var TFontData
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*/
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protected array $fdt = [
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'Ascender' => 0,
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'Ascent' => 0,
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'AvgWidth' => 0.0,
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'CapHeight' => 0,
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'CharacterSet' => '',
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'Descender' => 0,
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'Descent' => 0,
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'EncodingScheme' => '',
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'FamilyName' => '',
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'Flags' => 0,
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'FontBBox' => [],
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'FontName' => '',
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'FullName' => '',
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'IsFixedPitch' => false,
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'ItalicAngle' => 0,
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'Leading' => 0,
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'MaxWidth' => 0,
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'MissingWidth' => 0,
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'StdHW' => 0,
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'StdVW' => 0,
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'StemH' => 0,
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'StemV' => 0,
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'UnderlinePosition' => 0,
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'UnderlineThickness' => 0,
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'Version' => '',
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'Weight' => '',
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'XHeight' => 0,
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'bbox' => '',
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'cbbox' => [],
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'cidinfo' => [
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'Ordering' => '',
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'Registry' => '',
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'Supplement' => 0,
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'uni2cid' => [],
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],
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'compress' => false,
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'ctg' => '',
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'ctgdata' => [],
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'cw' => [],
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'cwu' => [],
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'datafile' => '',
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'desc' => [
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'Ascent' => 0,
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'AvgWidth' => 0,
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'CapHeight' => 0,
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'Descent' => 0,
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'Flags' => 0,
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'FontBBox' => '',
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'ItalicAngle' => 0,
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'Leading' => 0,
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'MaxWidth' => 0,
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'MissingWidth' => 0,
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'StemH' => 0,
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'StemV' => 0,
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'XHeight' => 0,
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],
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'diff' => '',
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'diff_n' => 0,
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'dir' => '',
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'dw' => 0,
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'enc' => '',
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'enc_map' => [],
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'encodingTables' => [],
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'encoding_id' => 0,
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'encrypted' => '',
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'fakestyle' => false,
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'family' => '',
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'file' => '',
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'file_n' => 0,
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'file_name' => '',
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'i' => 0,
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'ifile' => '',
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'indexToLoc' => [],
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'input_file' => '',
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'isUnicode' => false,
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'italicAngle' => 0,
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'key' => '',
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'lenIV' => 0,
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'length1' => 0,
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'length2' => 0,
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'linked' => false,
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'mode' => [
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'bold' => false,
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'italic' => false,
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'linethrough' => false,
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'overline' => false,
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'underline' => false,
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],
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'n' => 0,
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'name' => '',
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'numGlyphs' => 0,
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'numHMetrics' => 0,
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'originalsize' => 0,
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'pdfa' => false,
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'platform_id' => 0,
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'settype' => '',
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'short_offset' => false,
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'size1' => 0,
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'size2' => 0,
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'style' => '',
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'subset' => false,
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'subsetchars' => [],
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'table' => [],
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'tot_num_glyphs' => 0,
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'type' => '',
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'underlinePosition' => 0,
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'underlineThickness' => 0,
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'unicode' => false,
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'unitsPerEm' => 0,
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'up' => 0,
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'urk' => 0.0,
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'ut' => 0,
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'weight' => '',
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];
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/**
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* Array containing subset glyphs indexes of chars from cmap table
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*
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* @var array<int, bool>
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*/
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protected array $subglyphs = [];
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/**
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* Subset font
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*/
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protected string $subfont = '';
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/**
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* Pointer position on the original font data
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*/
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protected int $offset = 0;
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/**
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* File helper used to load font definition files.
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*/
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protected ObjFile $fileHelper;
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/**
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* Process TrueType font
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*
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* @param string $font Content of the input font file
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* @param TFontData $fdt Extracted font metrics
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* @param ObjFile $fileHelper Optional file helper for font loading.
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* @param array<int, bool> $subchars Array containing subset chars
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*
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* @throws FontException in case of error
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*/
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public function __construct(string $font, array $fdt, ObjFile $fileHelper, array $subchars = [])
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{
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$this->fileHelper = $fileHelper;
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$this->font = $font;
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$this->fbyte = new Byte($font);
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$trueType = new TrueType(
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font: $font,
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fdt: $fdt,
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fileHelper: $this->fileHelper,
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fbyte: $this->fbyte,
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subchars: $subchars,
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// Subsetting only needs the glyph program (loca/glyf); per-glyph bounding
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// boxes are never read here, so skip computing them.
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withCbbox: false,
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);
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$this->fdt = $trueType->getFontMetrics();
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$this->subglyphs = $trueType->getSubGlyphs();
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$this->addCompositeGlyphs();
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$this->addProcessedTables();
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$this->removeUnusedTables();
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$this->buildSubsetFont();
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}
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/**
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* Get all the extracted font metrics
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*/
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public function getSubsetFont(): string
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{
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return $this->subfont;
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}
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/**
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* Returns the checksum of a TTF table.
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*
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* @param string $table Table to check
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* @param int $length Length of table in bytes
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*
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* @return int checksum
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*
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* @throws FontException
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*/
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protected function getTableChecksum(string $table, int $length): int
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{
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$sum = 0;
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$tlen = (int) floor(($length + 3) / 4);
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$offset = 0;
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for ($idx = 0; $idx < $tlen; ++$idx) {
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$chunk = \substr($table, $offset, 4);
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if (\strlen($chunk) < 4) {
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// OpenType checksums use zero-padding for trailing partial words.
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$chunk = \str_pad($chunk, 4, "\0", STR_PAD_RIGHT);
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}
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$val = \unpack('Ni', $chunk);
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if ($val === false) {
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throw new FontException('Unable to unpack table data');
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}
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$sum += $val['i'];
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$offset += 4;
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}
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$sum = \unpack('Ni', \pack('N', $sum));
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if ($sum === false) {
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throw new FontException('Unable to unpack checksum');
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}
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return $sum['i'];
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}
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/**
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* Add composite glyphs
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*/
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protected function addCompositeGlyphs(): void
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{
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$new_sga = $this->subglyphs;
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while ($new_sga !== []) {
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$sga = \array_keys($new_sga);
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$new_sga = [];
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foreach ($sga as $key) {
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$new_sga = $this->findCompositeGlyphs($new_sga, $key);
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}
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foreach ($new_sga as $gid => $enabled) {
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if (!$enabled) {
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continue;
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}
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$this->subglyphs[$gid] = true;
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}
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}
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// sort glyphs by key
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\ksort($this->subglyphs);
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}
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/**
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* Find composite glyphs
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*
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* @param array<int, bool> $new_sga
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* @param int $key
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*
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* @return array<int, bool>
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*/
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protected function findCompositeGlyphs(array $new_sga, int $key): array
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{
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if (isset($this->fdt['indexToLoc'][$key])) {
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/**
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* Glyph Header
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* - int16 numberOfContours Normal glyph if >= 0 or composite glyph if negative (should be -1)
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* - int16 xMin Minimum x for coordinate data.
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* - int16 yMin Minimum y for coordinate data.
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* - int16 xMax Maximum x for coordinate data.
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* - int16 yMax Maximum y for coordinate data.
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*/
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$this->offset = $this->fdt['table']['glyf']['offset'] + $this->fdt['indexToLoc'][$key];
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$numberOfContours = $this->fbyte->getShort($this->offset);
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$this->offset += 2;
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if ($numberOfContours < 0) { // composite glyph
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|
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/**
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||
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* ComponentGlyph record
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* - uint16 flags Normal glyph if >= 0 or composite glyph if negative (should be -1)
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* - uint16 glyphIndex glyph index of component
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||
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* - u/int8|u/int16 argument1 x-offset for component or point number; type depends on bits 0 and 1 in component flags
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* - u/int8|u/int16 argument2 y-offset for component or point number; type depends on bits 0 and 1 in component flags
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* - [transform data] optional transform data
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||
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*/
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||
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$this->offset += 8; // skip xMin, yMin, xMax, yMax
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do {
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$flags = $this->fbyte->getUShort($this->offset);
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$this->offset += 2;
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$glyphIndex = $this->fbyte->getUShort($this->offset);
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$this->offset += 2;
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||
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if (!isset($this->subglyphs[$glyphIndex])) {
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// add missing glyphs
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||
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$new_sga[$glyphIndex] = true;
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||
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}
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||
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|
|
||
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// skip some bytes by case
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||
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// ARG_1_AND_2_ARE_WORDS (bit 0): [u]int32 if set and [u]int16 if not set
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||
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if (($flags & 1) !== 0) {
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$this->offset += 4;
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||
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} else {
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$this->offset += 2;
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||
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}
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||
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|
||
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if (($flags & 8) !== 0) {
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||
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// WE_HAVE_A_SCALE (bit 3): Adds 1 * F2DOT14 field
|
||
|
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$this->offset += 2;
|
||
|
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} elseif (($flags & 64) !== 0) {
|
||
|
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// WE_HAVE_AN_X_AND_Y_SCALE (bit 6): Adds 2 * F2DOT14 fields
|
||
|
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$this->offset += 4;
|
||
|
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} elseif (($flags & 128) !== 0) {
|
||
|
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// WE_HAVE_A_TWO_BY_TWO (bit 7): Adds 4 * F2DOT14 fields
|
||
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$this->offset += 8;
|
||
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}
|
||
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} while ($flags & 32); // MORE_COMPONENTS (bit 5)
|
||
|
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}
|
||
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}
|
||
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|
||
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return $new_sga;
|
||
|
|
}
|
||
|
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|
||
|
|
/**
|
||
|
|
* Remove unused tables
|
||
|
|
*/
|
||
|
|
protected function removeUnusedTables(): void
|
||
|
|
{
|
||
|
|
// get the tables to preserve
|
||
|
|
$this->offset = 12;
|
||
|
|
$tabname = \array_keys($this->fdt['table']);
|
||
|
|
foreach ($tabname as $tag) {
|
||
|
|
if (!isset(self::TABLENAMES[$tag])) {
|
||
|
|
// remove the table
|
||
|
|
unset($this->fdt['table'][$tag]);
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!isset($this->fdt['table'][$tag])) {
|
||
|
|
$this->fdt['table'][$tag] = [
|
||
|
|
'checkSum' => 0,
|
||
|
|
'data' => '',
|
||
|
|
'length' => 0,
|
||
|
|
'offset' => 0,
|
||
|
|
];
|
||
|
|
}
|
||
|
|
|
||
|
|
$isSubsetTable = $tag === 'loca' || $tag === 'glyf';
|
||
|
|
if (!$isSubsetTable) {
|
||
|
|
$this->fdt['table'][$tag]['data'] = \substr(
|
||
|
|
$this->font,
|
||
|
|
$this->fdt['table'][$tag]['offset'],
|
||
|
|
$this->fdt['table'][$tag]['length'],
|
||
|
|
);
|
||
|
|
if ($tag === 'head') {
|
||
|
|
// set the checkSumAdjustment to 0
|
||
|
|
$this->fdt['table'][$tag]['data'] =
|
||
|
|
\substr($this->fdt['table'][$tag]['data'], 0, 8)
|
||
|
|
. "\x0\x0\x0\x0"
|
||
|
|
. \substr($this->fdt['table'][$tag]['data'], 12);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
$pad = 4 - ((int) $this->fdt['table'][$tag]['length'] % 4);
|
||
|
|
if ($pad !== 4) {
|
||
|
|
// the length of a table must be a multiple of four bytes
|
||
|
|
$this->fdt['table'][$tag]['length'] += (int) $pad;
|
||
|
|
$this->fdt['table'][$tag]['data'] .= \str_repeat("\x0", max(0, $pad));
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->fdt['table'][$tag]['offset'] = $this->offset;
|
||
|
|
$this->offset += $this->fdt['table'][$tag]['length'];
|
||
|
|
|
||
|
|
// check sum is not changed
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Add glyf and loca tables
|
||
|
|
*
|
||
|
|
* @SuppressWarnings("PHPMD.CyclomaticComplexity")
|
||
|
|
* @SuppressWarnings("PHPMD.NPathComplexity")
|
||
|
|
*/
|
||
|
|
protected function addProcessedTables(): void
|
||
|
|
{
|
||
|
|
// build new glyf and loca tables
|
||
|
|
$glyf = '';
|
||
|
|
$loca = '';
|
||
|
|
$this->offset = 0;
|
||
|
|
$glyf_offset = $this->fdt['table']['glyf']['offset'];
|
||
|
|
for ($i = 0; $i < $this->fdt['tot_num_glyphs']; ++$i) {
|
||
|
|
$nextidx = $this->getNextLocaIndex($i + 1);
|
||
|
|
if (isset($this->subglyphs[$i], $this->fdt['indexToLoc'][$i]) && $nextidx !== null) {
|
||
|
|
$length = $this->fdt['indexToLoc'][$nextidx] - $this->fdt['indexToLoc'][$i];
|
||
|
|
$glyf .= \substr($this->font, $glyf_offset + $this->fdt['indexToLoc'][$i], $length);
|
||
|
|
} else {
|
||
|
|
$length = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
if ($this->fdt['short_offset']) {
|
||
|
|
$loca .= \pack('n', \floor($this->offset / 2));
|
||
|
|
} else {
|
||
|
|
$loca .= \pack('N', $this->offset);
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->offset += $length;
|
||
|
|
}
|
||
|
|
|
||
|
|
// add loca
|
||
|
|
if (!isset($this->fdt['table']['loca'])) {
|
||
|
|
$this->fdt['table']['loca'] = [
|
||
|
|
'checkSum' => 0,
|
||
|
|
'data' => '',
|
||
|
|
'length' => 0,
|
||
|
|
'offset' => 0,
|
||
|
|
];
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->fdt['table']['loca']['data'] = $loca;
|
||
|
|
$this->fdt['table']['loca']['length'] = \strlen($loca);
|
||
|
|
$this->fdt['table']['loca']['offset'] = $this->offset;
|
||
|
|
$pad = 4 - ($this->fdt['table']['loca']['length'] % 4);
|
||
|
|
if ($pad !== 4) {
|
||
|
|
// the length of a table must be a multiple of four bytes
|
||
|
|
$this->fdt['table']['loca']['length'] += $pad;
|
||
|
|
$this->fdt['table']['loca']['data'] .= \str_repeat("\x0", $pad);
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->fdt['table']['loca']['checkSum'] = $this->getTableChecksum(
|
||
|
|
$this->fdt['table']['loca']['data'],
|
||
|
|
$this->fdt['table']['loca']['length'],
|
||
|
|
);
|
||
|
|
|
||
|
|
$this->offset += $this->fdt['table']['loca']['length'];
|
||
|
|
|
||
|
|
// add glyf
|
||
|
|
if (!isset($this->fdt['table']['glyf'])) {
|
||
|
|
$this->fdt['table']['glyf'] = [
|
||
|
|
'checkSum' => 0,
|
||
|
|
'data' => '',
|
||
|
|
'length' => 0,
|
||
|
|
'offset' => 0,
|
||
|
|
];
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->fdt['table']['glyf']['data'] = $glyf;
|
||
|
|
$this->fdt['table']['glyf']['length'] = \strlen($glyf);
|
||
|
|
$this->fdt['table']['glyf']['offset'] = $this->offset;
|
||
|
|
$pad = 4 - ($this->fdt['table']['glyf']['length'] % 4);
|
||
|
|
if ($pad !== 4) {
|
||
|
|
// the length of a table must be a multiple of four bytes
|
||
|
|
$this->fdt['table']['glyf']['length'] += $pad;
|
||
|
|
$this->fdt['table']['glyf']['data'] .= \str_repeat("\x0", $pad);
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->fdt['table']['glyf']['checkSum'] = $this->getTableChecksum(
|
||
|
|
$this->fdt['table']['glyf']['data'],
|
||
|
|
$this->fdt['table']['glyf']['length'],
|
||
|
|
);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the first available loca index from $start, or null if none exists.
|
||
|
|
*/
|
||
|
|
protected function getNextLocaIndex(int $start): ?int
|
||
|
|
{
|
||
|
|
for ($idx = $start; $idx <= $this->fdt['tot_num_glyphs']; ++$idx) {
|
||
|
|
if (isset($this->fdt['indexToLoc'][$idx])) {
|
||
|
|
return $idx;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return null;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* build new subset font
|
||
|
|
*
|
||
|
|
* @throws FontException
|
||
|
|
*/
|
||
|
|
protected function buildSubsetFont(): void
|
||
|
|
{
|
||
|
|
$this->subfont = '';
|
||
|
|
$this->subfont .= \pack('N', 0x1_0000); // sfnt version
|
||
|
|
$numTables = \count($this->fdt['table']);
|
||
|
|
$this->subfont .= \pack('n', $numTables); // numTables
|
||
|
|
$entrySelector = \floor(\log($numTables, 2));
|
||
|
|
$searchRange = (2 ** $entrySelector) * 16;
|
||
|
|
$rangeShift = ($numTables * 16) - $searchRange;
|
||
|
|
$this->subfont .= \pack('n', $searchRange); // searchRange
|
||
|
|
$this->subfont .= \pack('n', $entrySelector); // entrySelector
|
||
|
|
$this->subfont .= \pack('n', $rangeShift); // rangeShift
|
||
|
|
// Table offsets stored in $this->fdt start after the 12-byte sfnt header.
|
||
|
|
// The full output adds the table directory immediately after that header,
|
||
|
|
// so both directory offsets and in-buffer table positions must include this base.
|
||
|
|
$tableDataBaseOffset = $numTables * 16;
|
||
|
|
$this->offset = $tableDataBaseOffset;
|
||
|
|
foreach ($this->fdt['table'] as $tag => $data) {
|
||
|
|
$this->subfont .= $tag; // tag
|
||
|
|
$this->subfont .= \pack('N', $data['checkSum']); // checkSum
|
||
|
|
$this->subfont .= \pack('N', $data['offset'] + $this->offset); // offset
|
||
|
|
$this->subfont .= \pack('N', $data['length']); // length
|
||
|
|
}
|
||
|
|
|
||
|
|
foreach ($this->fdt['table'] as $data) {
|
||
|
|
$this->subfont .= $data['data'];
|
||
|
|
}
|
||
|
|
|
||
|
|
// set checkSumAdjustment on head table
|
||
|
|
$checkSumAdjustment = 0xB1B0_AFBA - $this->getTableChecksum($this->subfont, \strlen($this->subfont));
|
||
|
|
$headAdjustmentPos = $tableDataBaseOffset + $this->fdt['table']['head']['offset'] + 8;
|
||
|
|
$this->subfont =
|
||
|
|
\substr($this->subfont, 0, $headAdjustmentPos)
|
||
|
|
. \pack('N', $checkSumAdjustment)
|
||
|
|
. \substr($this->subfont, $headAdjustmentPos + 4);
|
||
|
|
}
|
||
|
|
}
|