dlls/riched20/wrap.c

   1 /*
   2  * RichEdit - Paragraph wrapping. Don't try to understand it. You've been
   3  * warned !
   4  *
   5  * Copyright 2004 by Krzysztof Foltman
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22
  23 #include "editor.h"
  24
  25 WINE_DEFAULT_DEBUG_CHANNEL(richedit);
  26
  27 /*
  28  * Unsolved problems:
  29  *
  30  * - center and right align in WordPad omits all spaces at the start, we don't
  31  * - objects/images are not handled yet
  32  * - no tabs
  33  */
  34
  35 ME_DisplayItem *ME_MakeRow(int height, int baseline, int width)
  36 {
  37   ME_DisplayItem *item = ME_MakeDI(diStartRow);
  38
  39   item->member.row.nHeight = height;
  40   item->member.row.nBaseline = baseline;
  41   item->member.row.nWidth = width;
  42   return item;
  43 }
  44
  45 void ME_BeginRow(ME_WrapContext *wc)
  46 {
  47   wc->pRowStart = NULL;
  48   wc->bOverflown = FALSE;
  49   wc->pLastSplittableRun = NULL;
  50   wc->nAvailWidth = wc->nTotalWidth - (wc->nRow ? wc->nLeftMargin : wc->nFirstMargin) - wc->nRightMargin;
  51   wc->pt.x = 0;
  52 }
  53
  54 void ME_InsertRowStart(ME_WrapContext *wc, ME_DisplayItem *pEnd)
  55 {
  56   ME_DisplayItem *p, *row, *para;
  57   int ascent = 0, descent = 0, width=0, shift = 0, align = 0;
  58   /* wrap text */
  59   para = ME_GetParagraph(wc->pRowStart);
  60   for (p = wc->pRowStart; p!=pEnd; p = p->next)
  61   {
  62     /* ENDPARA run shouldn't affect row height, except if it's the only run in the paragraph */
  63     if (p->type==diRun && ((p==wc->pRowStart) || !(p->member.run.nFlags & MERF_ENDPARA))) { /* FIXME add more run types */
  64       if (p->member.run.nAscent>ascent)
  65         ascent = p->member.run.nAscent;
  66       if (p->member.run.nDescent>descent)
  67         descent = p->member.run.nDescent;
  68       if (!(p->member.run.nFlags & (MERF_ENDPARA|MERF_SKIPPED)))
  69         width += p->member.run.nWidth;
  70     }
  71   }
  72   row = ME_MakeRow(ascent+descent, ascent, width);
  73   row->member.row.nYPos = wc->pt.y;
  74   row->member.row.nLMargin = (!wc->nRow ? wc->nFirstMargin : wc->nLeftMargin);
  75   row->member.row.nRMargin = wc->nRightMargin;
  76   assert(para->member.para.pFmt->dwMask & PFM_ALIGNMENT);
  77   align = para->member.para.pFmt->wAlignment;
  78   if (align == PFA_CENTER)
  79     shift = (wc->nAvailWidth-width)/2;
  80   if (align == PFA_RIGHT)
  81     shift = wc->nAvailWidth-width;
  82   for (p = wc->pRowStart; p!=pEnd; p = p->next)
  83   {
  84     if (p->type==diRun) { /* FIXME add more run types */
  85       p->member.run.pt.x += row->member.row.nLMargin+shift;
  86     }
  87   }
  88   ME_InsertBefore(wc->pRowStart, row);
  89   wc->nRow++;
  90   wc->pt.y += ascent+descent;
  91   ME_BeginRow(wc);
  92 }
  93
  94 void ME_WrapEndParagraph(ME_WrapContext *wc, ME_DisplayItem *p)
  95 {
  96   if (wc->pRowStart)
  97     ME_InsertRowStart(wc, p->next);
  98
  99   /*
 100   p = p->member.para.prev_para->next;
 101   while(p) {
 102     if (p->type == diParagraph || p->type == diTextEnd)
 103       return;
 104     if (p->type == diRun)
 105     {
 106       ME_Run *run = &p->member.run;
 107       TRACE("%s - (%d, %d)\n", debugstr_w(run->strText->szData), run->pt.x, run->pt.y);
 108     }
 109     p = p->next;
 110   }
 111   */
 112 }
 113
 114 void ME_WrapSizeRun(ME_WrapContext *wc, ME_DisplayItem *p)
 115 {
 116   /* FIXME compose style (out of character and paragraph styles) here */
 117
 118   ME_UpdateRunFlags(wc->context->editor, &p->member.run);
 119
 120   ME_CalcRunExtent(wc->context, &p->member.run);
 121 }
 122
 123 ME_DisplayItem *ME_MaximizeSplit(ME_WrapContext *wc, ME_DisplayItem *p, int i)
 124 {
 125   ME_DisplayItem *pp, *piter = p;
 126   int j;
 127   if (!i)
 128     return NULL;
 129   j = ME_ReverseFindNonWhitespaceV(p->member.run.strText, i);
 130   if (j>0) {
 131     pp = ME_SplitRun(wc->context, piter, j);
 132     wc->pt.x += piter->member.run.nWidth;
 133     return pp;
 134   }
 135   else
 136   {
 137     pp = piter;
 138     /* omit all spaces before split point */
 139     while(piter != wc->pRowStart)
 140     {
 141       piter = ME_FindItemBack(piter, diRun);
 142       if (piter->member.run.nFlags & MERF_WHITESPACE)
 143       {
 144         pp = piter;
 145         continue;
 146       }
 147       if (piter->member.run.nFlags & MERF_ENDWHITE)
 148       {
 149         j = ME_ReverseFindNonWhitespaceV(piter->member.run.strText, i);
 150         pp = ME_SplitRun(wc->context, piter, i);
 151         wc->pt = pp->member.run.pt;
 152         return pp;
 153       }
 154       /* this run is the end of spaces, so the run edge is a good point to split */
 155       wc->pt = pp->member.run.pt;
 156       wc->bOverflown = TRUE;
 157       TRACE("Split point is: %s|%s\n", debugstr_w(piter->member.run.strText->szData), debugstr_w(pp->member.run.strText->szData));
 158       return pp;
 159     }
 160     wc->pt = piter->member.run.pt;
 161     return piter;
 162   }
 163 }
 164
 165 ME_DisplayItem *ME_SplitByBacktracking(ME_WrapContext *wc, ME_DisplayItem *p, int loc)
 166 {
 167   ME_DisplayItem *piter = p, *pp;
 168   int i, idesp, len;
 169   ME_Run *run = &p->member.run;
 170
 171   idesp = i = ME_CharFromPoint(wc->context->editor, loc, run);
 172   len = ME_StrVLen(run->strText);
 173   assert(len>0);
 174   assert(i<len);
 175   if (i) {
 176     /* don't split words */
 177     i = ME_ReverseFindWhitespaceV(run->strText, i);
 178     pp = ME_MaximizeSplit(wc, p, i);
 179     if (pp)
 180       return pp;
 181   }
 182   TRACE("Must backtrack to split at: %s\n", debugstr_w(p->member.run.strText->szData));
 183   if (wc->pLastSplittableRun)
 184   {
 185     if (wc->pLastSplittableRun->member.run.nFlags & MERF_GRAPHICS)
 186     {
 187       wc->pt = wc->ptLastSplittableRun;
 188       return wc->pLastSplittableRun;
 189     }
 190     else if (wc->pLastSplittableRun->member.run.nFlags & MERF_SPLITTABLE)
 191     {
 192       /* the following two lines are just to check if we forgot to call UpdateRunFlags earlier,
 193          they serve no other purpose */
 194       ME_UpdateRunFlags(wc->context->editor, run);
 195       assert((wc->pLastSplittableRun->member.run.nFlags & MERF_SPLITTABLE));
 196
 197       piter = wc->pLastSplittableRun;
 198       run = &piter->member.run;
 199       len = ME_StrVLen(run->strText);
 200       /* don't split words */
 201       i = ME_ReverseFindWhitespaceV(run->strText, len);
 202       if (i == len)
 203         i = ME_ReverseFindNonWhitespaceV(run->strText, len);
 204       if (i) {
 205         ME_DisplayItem *piter2 = ME_SplitRun(wc->context, piter, i);
 206         wc->pt = piter2->member.run.pt;
 207         return piter2;
 208       }
 209       /* splittable = must have whitespaces */
 210       assert(0 == "Splittable, but no whitespaces");
 211     }
 212     else
 213     {
 214       /* restart from the first run beginning with spaces */
 215       wc->pt = wc->ptLastSplittableRun;
 216       return wc->pLastSplittableRun;
 217     }
 218   }
 219   TRACE("Backtracking failed, trying desperate: %s\n", debugstr_w(p->member.run.strText->szData));
 220   /* OK, no better idea, so assume we MAY split words if we can split at all*/
 221   if (idesp)
 222     return ME_SplitRun(wc->context, piter, idesp);
 223   else
 224   if (wc->pRowStart && piter != wc->pRowStart)
 225   {
 226     /* don't need to break current run, because it's possible to split
 227        before this run */
 228     wc->bOverflown = TRUE;
 229     return piter;
 230   }
 231   else
 232   {
 233     /* split point inside first character - no choice but split after that char */
 234     int chars = 1;
 235     int pos2 = ME_StrRelPos(run->strText, 0, &chars);
 236     if (pos2 != len) {
 237       /* the run is more than 1 char, so we may split */
 238       return ME_SplitRun(wc->context, piter, pos2);
 239     }
 240     /* the run is one char, can't split it */
 241     return piter;
 242   }
 243 }
 244
 245 ME_DisplayItem *ME_WrapHandleRun(ME_WrapContext *wc, ME_DisplayItem *p)
 246 {
 247   ME_DisplayItem *pp;
 248   ME_Run *run;
 249   int len;
 250
 251   assert(p->type == diRun);
 252   if (!wc->pRowStart)
 253     wc->pRowStart = p;
 254   ME_WrapSizeRun(wc, p);
 255   run = &p->member.run;
 256   run->pt.x = wc->pt.x;
 257   run->pt.y = wc->pt.y;
 258   len = ME_StrVLen(run->strText);
 259
 260   if (wc->bOverflown) /* just skipping final whitespaces */
 261   {
 262     if (run->nFlags & MERF_WHITESPACE) {
 263       p->member.run.nFlags |= MERF_SKIPPED;
 264       /* wc->pt.x += run->nWidth; */
 265       /* skip runs consisting of only whitespaces */
 266       return p->next;
 267     }
 268
 269     if (run->nFlags & MERF_STARTWHITE) {
 270       /* try to split the run at the first non-white char */
 271       int black;
 272       black = ME_FindNonWhitespaceV(run->strText, 0);
 273       if (black) {
 274         wc->bOverflown = FALSE;
 275         pp = ME_SplitRun(wc->context, p, black);
 276         p->member.run.nFlags |= MERF_SKIPPED;
 277 /*
 278         run->pt = wc->pt;
 279         wc->pt.x += run->nWidth;
 280         */
 281         ME_InsertRowStart(wc, pp);
 282         return pp;
 283       }
 284     }
 285     /* black run: the row goes from pRowStart to the previous run */
 286     ME_InsertRowStart(wc, p);
 287     return p;
 288   }
 289   /* we're not at the end of the row */
 290   /* will current run fit? */
 291   if (wc->pt.x + run->nWidth > wc->nAvailWidth)
 292   {
 293     int loc = wc->nAvailWidth - wc->pt.x;
 294     /* total white run ? */
 295     if (run->nFlags & MERF_WHITESPACE) {
 296       /* let the overflow logic handle it */
 297       wc->bOverflown = TRUE;
 298       return p;
 299     }
 300     /* graphics - we can split before */
 301     if (run->nFlags & MERF_GRAPHICS) {
 302       wc->bOverflown = TRUE;
 303       return p;
 304     }
 305     /* can we separate out the last spaces ? (to use overflow logic later) */
 306     if (run->nFlags & MERF_ENDWHITE)
 307     {
 308       /* we aren't sure if it's *really* necessary, it's a good start however */
 309       int black = ME_ReverseFindNonWhitespaceV(run->strText, len);
 310       ME_SplitRun(wc->context, p, black);
 311       /* handle both parts again */
 312       return p;
 313     }
 314     /* determine the split point by backtracking */
 315     pp = ME_SplitByBacktracking(wc, p, loc);
 316     if (pp == wc->pRowStart)
 317     {
 318       /* we had only spaces so far, entire content can be omitted */
 319       wc->pt.x = 0;
 320       return p->next;
 321     }
 322     if (p != pp) /* found a suitable split point */
 323     {
 324       wc->bOverflown = TRUE;
 325       return pp;
 326     }
 327     /* we detected that it's best to split on start of this run */
 328     if (wc->bOverflown)
 329       return pp;
 330     ERR("failure!\n");
 331     /* not found anything - writing over margins is the only option left */
 332   }
 333   if ((run->nFlags & (MERF_SPLITTABLE | MERF_STARTWHITE))
 334     || ((run->nFlags & MERF_GRAPHICS) && (p != wc->pRowStart)))
 335   {
 336     wc->pLastSplittableRun = p;
 337     wc->ptLastSplittableRun = wc->pt;
 338   }
 339   wc->pt.x += run->nWidth;
 340   return p->next;
 341 }
 342
 343 void ME_WrapTextParagraph(ME_Context *c, ME_DisplayItem *tp) {
 344   ME_DisplayItem *p;
 345   ME_WrapContext wc;
 346
 347   assert(tp->type == diParagraph);
 348   if (tp->member.para.nFlags & MEPF_WRAPPED) {
 349     return;
 350   }
 351   ME_PrepareParagraphForWrapping(c, tp);
 352
 353   wc.context = c;
 354 /*   wc.para_style = tp->member.para.style; */
 355   wc.style = NULL;
 356   wc.nFirstMargin = tp->member.para.nFirstMargin;
 357   wc.nLeftMargin = tp->member.para.nLeftMargin;
 358   wc.nRightMargin = tp->member.para.nRightMargin;
 359   wc.nRow = 0;
 360   wc.pt.x = 0;
 361   wc.pt.y = 0;
 362   wc.nTotalWidth = c->rcView.right - c->rcView.left;
 363   wc.nAvailWidth = wc.nTotalWidth - wc.nFirstMargin - wc.nRightMargin;
 364   wc.pRowStart = NULL;
 365
 366   ME_BeginRow(&wc);
 367   for (p = tp->next; p!=tp->member.para.next_para; ) {
 368     assert(p->type != diStartRow);
 369     if (p->type == diRun) {
 370       ME_PrepareStyle(c, p->member.run.style);
 371       p = ME_WrapHandleRun(&wc, p);
 372       continue;
 373     }
 374     p = p->next;
 375   }
 376   ME_WrapEndParagraph(&wc, p);
 377   tp->member.para.nFlags |= MEPF_WRAPPED;
 378   tp->member.para.nHeight = wc.pt.y;
 379 }
 380
 381
 382 void ME_PrepareParagraphForWrapping(ME_Context *c, ME_DisplayItem *tp) {
 383   ME_DisplayItem *p;
 384   /* remove all items that will be reinserted by paragraph wrapper anyway */
 385   for (p = tp->next; p!=tp->member.para.next_para; p = p->next) {
 386     switch(p->type) {
 387       case diStartRow:
 388         p = p->prev;
 389         ME_Remove(p->next);
 390         break;
 391       default:
 392         break;
 393     }
 394   }
 395   /* join runs that can be joined, set up flags */
 396   for (p = tp->next; p!=tp->member.para.next_para; p = p->next) {
 397     int changed = 0;
 398     switch(p->type) {
 399       case diStartRow: assert(0); break; /* should have deleted it */
 400       case diRun:
 401         while (p->next->type == diRun) { /* FIXME */
 402           if (ME_CanJoinRuns(&p->member.run, &p->next->member.run)) {
 403             ME_JoinRuns(c->editor, p);
 404             changed = 1;
 405           }
 406           else
 407             break;
 408         }
 409         p->member.run.nFlags &= ~MERF_CALCBYWRAP;
 410         break;
 411       default:
 412         break;
 413     }
 414   }
 415 }