src/preproc/eqn/sqrt.cpp

   1 // -*- C++ -*-
   2 /* Copyright (C) 1989, 1990, 1991, 1992, 2002, 2003, 2007, 2008
   3    Free Software Foundation, Inc.
   4      Written by James Clark (jjc@jclark.com)
   5
   6 This file is part of groff.
   7
   8 groff is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License along
  19 with groff; see the file COPYING.  If not, write to the Free Software
  20 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  21
  22 #include "eqn.h"
  23 #include "pbox.h"
  24
  25
  26 class sqrt_box : public pointer_box {
  27 public:
  28   sqrt_box(box *);
  29   int compute_metrics(int style);
  30   void output();
  31   void debug_print();
  32   void check_tabs(int);
  33 };
  34
  35 box *make_sqrt_box(box *pp)
  36 {
  37   return new sqrt_box(pp);
  38 }
  39
  40 sqrt_box::sqrt_box(box *pp) : pointer_box(pp)
  41 {
  42 }
  43
  44 #define SQRT_CHAR "\\[sqrt]"
  45 #define RADICAL_EXTENSION_CHAR "\\[sqrtex]"
  46
  47 #define SQRT_CHAIN "\\[sqrt\\\\n[" INDEX_REG "]]"
  48 #define BAR_CHAIN "\\[sqrtex\\\\n[" INDEX_REG "]]"
  49
  50 int sqrt_box::compute_metrics(int style)
  51 {
  52   // 11
  53   int r = p->compute_metrics(cramped_style(style));
  54   printf(".nr " TEMP_REG " \\n[" HEIGHT_FORMAT "]+\\n[" DEPTH_FORMAT
  55          "]+%dM+(%dM/4)\n",
  56          p->uid, p->uid, default_rule_thickness,
  57          (style > SCRIPT_STYLE ? x_height : default_rule_thickness));
  58   printf(".nr " SIZE_FORMAT " \\n[.ps]\n", uid);
  59   printf(".ds " SQRT_STRING_FORMAT " " SQRT_CHAR "\n", uid);
  60   printf(".ds " BAR_STRING " " RADICAL_EXTENSION_CHAR "\n");
  61   printf(".nr " SQRT_WIDTH_FORMAT
  62          " 0\\w" DELIMITER_CHAR SQRT_CHAR DELIMITER_CHAR "\n",
  63          uid);
  64   printf(".if \\n[rst]-\\n[rsb]-%dM<\\n[" TEMP_REG "] \\{",
  65          default_rule_thickness);
  66
  67   printf(".nr " INDEX_REG " 0\n"
  68          ".de " TEMP_MACRO "\n"
  69          ".ie c" SQRT_CHAIN " \\{"
  70          ".ds " SQRT_STRING_FORMAT " " SQRT_CHAIN "\n"
  71          ".ie c" BAR_CHAIN " .ds " BAR_STRING " " BAR_CHAIN "\n"
  72          ".el .ds " BAR_STRING " " RADICAL_EXTENSION_CHAR "\n"
  73          ".nr " SQRT_WIDTH_FORMAT
  74          " 0\\w" DELIMITER_CHAR SQRT_CHAIN DELIMITER_CHAR "\n"
  75          ".if \\\\n[rst]-\\\\n[rsb]-%dM<\\n[" TEMP_REG "] \\{"
  76          ".nr " INDEX_REG " +1\n"
  77          "." TEMP_MACRO "\n"
  78          ".\\}\\}\n"
  79          ".el .nr " INDEX_REG " 0-1\n"
  80          "..\n"
  81          "." TEMP_MACRO "\n",
  82          uid, uid, default_rule_thickness);
  83
  84   printf(".if \\n[" INDEX_REG "]<0 \\{");
  85
  86   // Determine the maximum point size
  87   printf(".ps 1000\n");
  88   printf(".nr " MAX_SIZE_REG " \\n[.ps]\n");
  89   printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
  90   // We define a macro that will increase the current point size
  91   // until we get a radical sign that's tall enough or we reach
  92   // the maximum point size.
  93   printf(".de " TEMP_MACRO "\n"
  94          ".nr " SQRT_WIDTH_FORMAT
  95          " 0\\w" DELIMITER_CHAR "\\*[" SQRT_STRING_FORMAT "]" DELIMITER_CHAR "\n"
  96          ".if \\\\n[rst]"
  97          "&(\\\\n[rst]-\\\\n[rsb]-%dM<\\n[" TEMP_REG "])"
  98          "&(\\\\n[.ps]<\\n[" MAX_SIZE_REG "]) \\{"
  99          ".ps +1\n"
 100          "." TEMP_MACRO "\n"
 101          ".\\}\n"
 102          "..\n"
 103          "." TEMP_MACRO "\n",
 104          uid, uid, default_rule_thickness);
 105
 106   printf(".\\}\\}\n");
 107
 108   printf(".nr " SMALL_SIZE_FORMAT " \\n[.ps]\n", uid);
 109   // set TEMP_REG to the amount by which the radical sign is too big
 110   printf(".nr " TEMP_REG " \\n[rst]-\\n[rsb]-%dM-\\n[" TEMP_REG "]\n",
 111          default_rule_thickness);
 112   // If TEMP_REG is negative, the bottom of the radical sign should
 113   // be -TEMP_REG above the bottom of p. If it's positive, the bottom
 114   // of the radical sign should be TEMP_REG/2 below the bottom of p.
 115   // This calculates the amount by which the baseline of the radical
 116   // should be raised.
 117   printf(".nr " SUP_RAISE_FORMAT " (-\\n[" TEMP_REG "]>?(-\\n[" TEMP_REG "]/2))"
 118          "-\\n[rsb]-\\n[" DEPTH_FORMAT "]\n", uid, p->uid);
 119   printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]"
 120          ">?(\\n[" SUP_RAISE_FORMAT "]+\\n[rst])\n",
 121          uid, p->uid, uid);
 122   printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]"
 123          ">?(-\\n[" SUP_RAISE_FORMAT "]-\\n[rsb])\n",
 124          uid, p->uid, uid);
 125   // Do this last, so we don't lose height and depth information on
 126   // the radical sign.
 127   // Remember that the width of the bar might be greater than the width of p.
 128
 129   printf(".nr " TEMP_REG " "
 130          "\\n[" WIDTH_FORMAT "]"
 131          ">?\\w" DELIMITER_CHAR "\\*[" BAR_STRING "]" DELIMITER_CHAR "\n",
 132          p->uid);
 133   printf(".as " SQRT_STRING_FORMAT " "
 134          "\\l'\\n[" TEMP_REG "]u\\&\\*[" BAR_STRING "]'\n",
 135          uid);
 136   printf(".nr " WIDTH_FORMAT " \\n[" TEMP_REG "]"
 137          "+\\n[" SQRT_WIDTH_FORMAT "]\n",
 138          uid, uid);
 139
 140   if (r)
 141     printf(".nr " MARK_REG " +\\n[" SQRT_WIDTH_FORMAT "]\n", uid);
 142   // the top of the bar might be higher than the top of the radical sign
 143   printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]"
 144          ">?(\\n[" SUP_RAISE_FORMAT "]+\\n[rst])\n",
 145          uid, p->uid, uid);
 146   // put a bit of extra space above the bar
 147   printf(".nr " HEIGHT_FORMAT " +%dM\n", uid, default_rule_thickness);
 148   printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
 149   return r;
 150 }
 151
 152 void sqrt_box::output()
 153 {
 154   if (output_format == troff) {
 155     printf("\\Z" DELIMITER_CHAR);
 156     printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
 157     printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
 158     printf("\\*[" SQRT_STRING_FORMAT "]", uid);
 159     printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
 160     printf(DELIMITER_CHAR);
 161
 162     printf("\\Z" DELIMITER_CHAR);
 163     printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u"
 164            "+\\n[" SQRT_WIDTH_FORMAT "]u/2u'",
 165            uid, p->uid, uid);
 166     p->output();
 167     printf(DELIMITER_CHAR);
 168
 169     printf("\\h'\\n[" WIDTH_FORMAT "]u'", uid);
 170   }
 171   else if (output_format == mathml) {
 172     printf("<msqrt>");
 173     p->output();
 174     printf("</msqrt>");
 175   }
 176 }
 177
 178 void sqrt_box::debug_print()
 179 {
 180   fprintf(stderr, "sqrt { ");
 181   p->debug_print();
 182   fprintf(stderr, " }");
 183 }
 184
 185 void sqrt_box::check_tabs(int level)
 186 {
 187   p->check_tabs(level + 1);
 188 }