src/Bidi.cpp

   1 /**
   2  * \file Bidi.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Dekel Tsur
   7  *
   8  * Full author contact details are available in file CREDITS.
   9  */
  10
  11 #include <config.h>
  12
  13 #include "Bidi.h"
  14 #include "Buffer.h"
  15 #include "BufferView.h"
  16 #include "Cursor.h"
  17 #include "Font.h"
  18 #include "Row.h"
  19 #include "LyXRC.h"
  20 #include "Paragraph.h"
  21
  22
  23 namespace lyx {
  24
  25
  26 pos_type Bidi::log2vis(pos_type pos) const
  27 {
  28         return (start_ == -1) ? pos : log2vis_list_[pos - start_];
  29 }
  30
  31
  32 pos_type Bidi::vis2log(pos_type pos) const
  33 {
  34         return (start_ == -1) ? pos : vis2log_list_[pos - start_];
  35 }
  36
  37
  38 pos_type Bidi::level(pos_type pos) const
  39 {
  40         return (start_ == -1) ? 0 : levels_[pos - start_];
  41 }
  42
  43
  44 bool Bidi::inRange(pos_type pos) const
  45 {
  46         return start_ == -1 || (start_ <= pos && pos <= end_);
  47 }
  48
  49 bool Bidi::same_direction() const
  50 {
  51         return same_direction_;
  52 }
  53
  54
  55 void Bidi::computeTables(Paragraph const & par,
  56         Buffer const & buf, Row const & row)
  57 {
  58         same_direction_ = true;
  59         if (!lyxrc.rtl_support) {
  60                 start_ = -1;
  61                 return;
  62         }
  63
  64         if (par.inInset().forceLTR()) {
  65                 start_ = -1;
  66                 return;
  67         }
  68
  69         start_ = row.pos();
  70         end_ = row.endpos() - 1;
  71
  72         if (start_ > end_) {
  73                 start_ = -1;
  74                 return;
  75         }
  76
  77         if (end_ + 2 - start_ >
  78             static_cast<pos_type>(log2vis_list_.size())) {
  79                 pos_type new_size =
  80                         (end_ + 2 - start_ < 500) ?
  81                         500 : 2 * (end_ + 2 - start_);
  82                 log2vis_list_.resize(new_size);
  83                 vis2log_list_.resize(new_size);
  84                 levels_.resize(new_size);
  85         }
  86
  87         vis2log_list_[end_ + 1 - start_] = -1;
  88         log2vis_list_[end_ + 1 - start_] = -1;
  89
  90         BufferParams const & bufparams = buf.params();
  91         pos_type stack[2];
  92         bool const rtl_par = par.isRTL(bufparams);
  93         int lev = 0;
  94         bool rtl = false;
  95         bool rtl0 = false;
  96         pos_type const body_pos = par.beginOfBody();
  97
  98         for (pos_type lpos = start_; lpos <= end_; ++lpos) {
  99                 bool is_space = false;
 100                 // We do not handle spaces around an RTL segment in a special way anymore.
 101                 // Neither do we do so when generating the LaTeX, so setting is_space
 102                 // to false makes the view in the GUI consistent with the output of LaTeX
 103                 // later. The old setting was:
 104                 //bool is_space = par.isLineSeparator(lpos);
 105                 // FIXME: once we're sure that this is what we really want, we should just
 106                 // get rid of this variable...
 107                 pos_type const pos =
 108                         (is_space && lpos + 1 <= end_ &&
 109                          !par.isLineSeparator(lpos + 1) &&
 110                          !par.isNewline(lpos + 1))
 111                         ? lpos + 1 : lpos;
 112
 113                 Font const * font = &(par.getFontSettings(bufparams, pos));
 114                 if (pos != lpos && 0 < lpos && rtl0 && font->isRightToLeft() &&
 115                     font->fontInfo().number() == FONT_ON &&
 116                     par.getFontSettings(bufparams, lpos - 1).fontInfo().number()
 117                     == FONT_ON) {
 118                         font = &(par.getFontSettings(bufparams, lpos));
 119                         is_space = false;
 120                 }
 121                 bool new_rtl = font->isVisibleRightToLeft();
 122                 bool new_rtl0 = font->isRightToLeft();
 123
 124                 int new_level;
 125
 126                 if (lpos == body_pos - 1
 127                     && row.pos() < body_pos - 1
 128                     && is_space) {
 129                         new_level = rtl_par ? 1 : 0;
 130                         new_rtl0 = rtl_par;
 131                         new_rtl = rtl_par;
 132                 } else if (new_rtl0) {
 133                         new_level = new_rtl ? 1 : 2;
 134                 } else {
 135                         new_level = rtl_par ? 2 : 0;
 136                 }
 137
 138                 if (is_space && new_level >= lev) {
 139                         new_level = lev;
 140                         new_rtl = rtl;
 141                         new_rtl0 = rtl0;
 142                 }
 143
 144                 int new_level2 = new_level;
 145
 146                 if (lev == new_level && rtl0 != new_rtl0) {
 147                         --new_level2;
 148                         log2vis_list_[lpos - start_] = rtl ? 1 : -1;
 149                 } else if (lev < new_level) {
 150                         log2vis_list_[lpos - start_] = rtl ? -1 : 1;
 151                         if (new_level > 0 && !rtl_par)
 152                                 same_direction_ = false;
 153                 } else {
 154                         log2vis_list_[lpos - start_] = new_rtl ? -1 : 1;
 155                 }
 156                 rtl = new_rtl;
 157                 rtl0 = new_rtl0;
 158                 levels_[lpos - start_] = new_level;
 159
 160                 while (lev > new_level2) {
 161                         pos_type old_lpos = stack[--lev];
 162                         int delta = lpos - old_lpos - 1;
 163                         if (lev % 2)
 164                                 delta = -delta;
 165                         log2vis_list_[lpos - start_] += delta;
 166                         log2vis_list_[old_lpos - start_] += delta;
 167                 }
 168                 while (lev < new_level)
 169                         stack[lev++] = lpos;
 170         }
 171
 172         while (lev > 0) {
 173                 pos_type const old_lpos = stack[--lev];
 174                 int delta = end_ - old_lpos;
 175                 if (lev % 2)
 176                         delta = -delta;
 177                 log2vis_list_[old_lpos - start_] += delta;
 178         }
 179
 180         pos_type vpos = start_ - 1;
 181         for (pos_type lpos = start_; lpos <= end_; ++lpos) {
 182                 vpos += log2vis_list_[lpos - start_];
 183                 vis2log_list_[vpos - start_] = lpos;
 184                 log2vis_list_[lpos - start_] = vpos;
 185         }
 186 }
 187
 188
 189 // This method requires a previous call to computeTables()
 190 bool Bidi::isBoundary(Buffer const & buf, Paragraph const & par,
 191         pos_type pos) const
 192 {
 193         if (!lyxrc.rtl_support || pos == 0)
 194                 return false;
 195
 196         if (!inRange(pos - 1)) {
 197                 // This can happen if pos is the first char of a row.
 198                 // Returning false in this case is incorrect!
 199                 return false;
 200         }
 201
 202         bool const rtl = level(pos - 1) % 2;
 203         bool const rtl2 = inRange(pos)
 204                 ? level(pos) % 2
 205                 : par.isRTL(buf.params());
 206         return rtl != rtl2;
 207 }
 208
 209
 210 bool Bidi::isBoundary(Buffer const & buf, Paragraph const & par,
 211         pos_type pos, Font const & font) const
 212 {
 213         if (!lyxrc.rtl_support)
 214                 return false;    // This is just for speedup
 215
 216         bool const rtl = font.isVisibleRightToLeft();
 217         bool const rtl2 = inRange(pos)
 218                 ? level(pos) % 2
 219                 : par.isRTL(buf.params());
 220         return rtl != rtl2;
 221 }
 222
 223
 224 bool reverseDirectionNeeded(Cursor const & cur)
 225 {
 226         /*
 227          * We determine the directions based on the direction of the
 228          * bottom() --- i.e., outermost --- paragraph, because that is
 229          * the only way to achieve consistency of the arrow's movements
 230          * within a paragraph, and thus avoid situations in which the
 231          * cursor gets stuck.
 232          */
 233         return cur.bottom().paragraph().isRTL(cur.bv().buffer().params());
 234 }
 235
 236
 237 bool isWithinRtlParagraph(Cursor const & cur)
 238 {
 239         return cur.innerParagraph().isRTL(cur.bv().buffer().params());
 240 }
 241
 242 } // namespace lyx