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Diffstat (limited to 'dviware/dvisvgm/src/TFM.cpp')
| -rw-r--r-- | dviware/dvisvgm/src/TFM.cpp | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/dviware/dvisvgm/src/TFM.cpp b/dviware/dvisvgm/src/TFM.cpp new file mode 100644 index 0000000000..005081533e --- /dev/null +++ b/dviware/dvisvgm/src/TFM.cpp @@ -0,0 +1,189 @@ +/************************************************************************* +** TFM.cpp ** +** ** +** This file is part of dvisvgm -- a fast DVI to SVG converter ** +** Copyright (C) 2005-2019 Martin Gieseking <martin.gieseking@uos.de> ** +** ** +** This program 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 3 of ** +** the License, or (at your option) any later version. ** +** ** +** This program 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 this program; if not, see <http://www.gnu.org/licenses/>. ** +*************************************************************************/ + +#include <fstream> +#include <vector> +#include "FileFinder.hpp" +#include "Length.hpp" +#include "Message.hpp" +#include "StreamReader.hpp" +#include "TFM.hpp" + +using namespace std; + + +/** Reads a sequence of n TFM words (4 Bytes each). + * @param[in] reader the TFM data is read from this object + * @param[out] v the read words + * @param[in] n number of words to be read */ +template <typename T> +static void read_words (StreamReader &reader, vector<T> &v, unsigned n) { + v.clear(); + v.resize(n); + for (unsigned i=0; i < n; i++) + v[i] = reader.readUnsigned(4); +} + + +TFM::TFM (istream &is) : _checksum(0), _firstChar(0), _lastChar(0), _designSize(0), _ascent(0), _descent(0) { + if (!is) + return; + is.seekg(0); + StreamReader reader(is); + uint16_t lf = uint16_t(reader.readUnsigned(2)); // length of entire file in 4 byte words + uint16_t lh = uint16_t(reader.readUnsigned(2)); // length of header in 4 byte words + _firstChar= uint16_t(reader.readUnsigned(2)); // smallest character code in font + _lastChar = uint16_t(reader.readUnsigned(2)); // largest character code in font + uint16_t nw = uint16_t(reader.readUnsigned(2)); // number of words in width table + uint16_t nh = uint16_t(reader.readUnsigned(2)); // number of words in height table + uint16_t nd = uint16_t(reader.readUnsigned(2)); // number of words in depth table + uint16_t ni = uint16_t(reader.readUnsigned(2)); // number of words in italic corr. table + uint16_t nl = uint16_t(reader.readUnsigned(2)); // number of words in lig/kern table + uint16_t nk = uint16_t(reader.readUnsigned(2)); // number of words in kern table + uint16_t ne = uint16_t(reader.readUnsigned(2)); // number of words in ext. char table + uint16_t np = uint16_t(reader.readUnsigned(2)); // number of font parameter words + + if (6+lh+(_lastChar-_firstChar+1)+nw+nh+nd+ni+nl+nk+ne+np != lf) + throw FontMetricException("inconsistent length values"); + if (_firstChar >= _lastChar || _lastChar > 255 || ne > 256) + throw FontMetricException("character codes out of range"); + + readHeader(reader); + is.seekg(24+lh*4); // move to char info table + readTables(reader, nw, nh, nd, ni); + is.seekg(4*(lf-np), ios::beg); // move to param section + readParameters(reader, np); +} + + +void TFM::readHeader (StreamReader &reader) { + _checksum = reader.readUnsigned(4); + _designSize = double(FixWord(reader.readUnsigned(4)))*Length::pt2bp; +} + + +void TFM::readTables (StreamReader &reader, int nw, int nh, int nd, int ni) { + read_words(reader, _charInfoTable, _lastChar-_firstChar+1); + read_words(reader, _widthTable, nw); + read_words(reader, _heightTable, nh); + read_words(reader, _depthTable, nd); + read_words(reader, _italicTable, ni); + for (FixWord h : _heightTable) + _ascent = max(_ascent, h); + for (FixWord d : _depthTable) + _descent = max(_descent, d); +} + + +/** Read the values from the param section of the TFM file. + * @param[in] reader read from this stream + * @param[in] np number of paramaters to read */ +void TFM::readParameters (StreamReader &reader, int np) { + _params.resize(7); + np = min(np, 7); + for (int i=0; i < np; i++) + _params[i] = reader.readUnsigned(4); + for (int i=np; i < 7; i++) + _params[i] = 0; +} + + +/** Returns the optimal space width between words (in PS point units). */ +double TFM::getSpace () const { + return _params.empty() ? 0 : double(_params[1])*_designSize; +} + + +/** Returns the amount of glue stretching between words (in PS point units). */ +double TFM::getSpaceStretch () const { + return _params.empty() ? 0 : double(_params[2])*_designSize; +} + + +/** Returns the amount of glue shrinking between words (in PS point units). */ +double TFM::getSpaceShrink () const { + return _params.empty() ? 0 : double(_params[3])*_designSize; +} + + +/** Returns the size of one EM unit (in PS point units). */ +double TFM::getQuad () const { + if (_params.empty() || _params[5] == 0) + return _designSize; + return double(_params[5])*_designSize; +} + + +/** Returns the index to the entry of the character info table that describes the metric of a given character. + * @param[in] c character whose index is retrieved + * @return table index for character c, or -1 if there's no entry */ +int TFM::charIndex (int c) const { + if (c < _firstChar || c > _lastChar || size_t(c-_firstChar) >= _charInfoTable.size()) + return -1; + return c-_firstChar; +} + + +// the char info word for each character consists of 4 bytes holding the following information: +// width index w, height index (h), depth index (d), italic correction index (it), +// tag (tg) and a remainder: +// +// byte 1 | byte 2 | byte 3 | byte 4 +// xxxxxxxx | xxxx xxxx | xxxxxx xx | xxxxxxxx +// w | h d | it tg | remainder + +/** Returns the width of char c in PS point units. */ +double TFM::getCharWidth (int c) const { + int index = charIndex(c); + if (index < 0) + return 0; + index = (_charInfoTable[index] >> 24) & 0xFF; + return double(_widthTable[index]) * _designSize; +} + + +/** Returns the height of char c in PS point units. */ +double TFM::getCharHeight (int c) const { + int index = charIndex(c); + if (index < 0) + return 0; + index = (_charInfoTable[index] >> 20) & 0x0F; + return double(_heightTable[index]) * _designSize; +} + + +/** Returns the depth of char c in PS point units. */ +double TFM::getCharDepth (int c) const { + int index = charIndex(c); + if (index < 0) + return 0; + index = (_charInfoTable[index] >> 16) & 0x0F; + return double(_depthTable[index]) * _designSize; +} + + +/** Returns the italic correction of char c in PS point units. */ +double TFM::getItalicCorr (int c) const { + int index = charIndex(c); + if (index < 0) + return 0; + index = (_charInfoTable[index] >> 10) & 0x3F; + return double(_italicTable[index]) * _designSize; +} |