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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
commite0c6872cf40896c7be36b11dcc744620f10adf1d (patch)
tree60335e10d2f4354b0674ec22d7b53f0f8abee672 /dviware/dvisvgm/src/TFM.cpp
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diff --git a/dviware/dvisvgm/src/TFM.cpp b/dviware/dvisvgm/src/TFM.cpp
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+/*************************************************************************
+** 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;
+}