src/html/m_layout.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        m_layout.cpp
   3 // Purpose:     wxHtml module for basic paragraphs/layout handling
   4 // Author:      Vaclav Slavik
   5 // RCS-ID:      $Id$
   6 // Copyright:   (c) 1999 Vaclav Slavik
   7 // Licence:     wxWindows Licence
   8 /////////////////////////////////////////////////////////////////////////////
   9 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  10 #pragma implementation
  11 #endif
  12
  13 #include "wx/wxprec.h"
  14
  15
  16 #include "wx/defs.h"
  17 #if wxUSE_HTML && wxUSE_STREAMS
  18 #ifdef __BORLANDC__
  19 #pragma hdrstop
  20 #endif
  21
  22 #ifndef WXPRECOMP
  23 #endif
  24
  25
  26 #include "wx/html/forcelnk.h"
  27 #include "wx/html/m_templ.h"
  28
  29 #include "wx/html/htmlwin.h"
  30
  31 FORCE_LINK_ME(m_layout)
  32
  33
  34 #include <stdlib.h> // bsearch()
  35
  36 //-----------------------------------------------------------------------------
  37 // wxHtmlPageBreakCell
  38 //-----------------------------------------------------------------------------
  39
  40 // Since html isn't a page-layout language, it doesn't support page
  41 // page breaks directly--that requires CSS2 support. But a page-break
  42 // facility is handy, and has been requested more than once on the
  43 // mailing lists. This wxHtml tag handler implements just enough of
  44 // CSS2 to support a page break by recognizing only
  45 //   <div style="page-break-before:always">
  46 //
  47 // wxHtml maintains page breaks in wxHtmlPrintout::m_PageBreaks. The
  48 // tag handler below adds appropriate offsets to that array member.
  49 // wxHtmlDCRenderer::Render() accesses that array and makes a new page
  50 // begin after each page-break tag.
  51
  52 // The page-break handler does all its work in AdjustPagebreak(). For
  53 // all tag handlers, that function adjusts the page-break position.
  54 // For other tags, it determines whether the html element can fit on
  55 // the remainder of the page; if it cannot fit, but must not be split,
  56 // then the function moves the page break provided in the argument up,
  57 // and returns 'true' to inform the caller that the argument was
  58 // modified.
  59 //
  60 // Due to its special purpose, the page-break facility differs from
  61 // other tags. It takes up no space, but it behaves as though there is
  62 // never enough room to fit it on the remainder of the page--it always
  63 // forces a page break. Therefore, unlike other elements that trigger
  64 // a page break, it would never 'fit' on the following page either.
  65 // Therefore it's necessary to compare each pagebreak candidate to the
  66 // array wxHtmlPrintout::m_PageBreaks of pagebreaks already set, and
  67 // set a new one only if it's not in that array.
  68
  69 class wxHtmlPageBreakCell : public wxHtmlCell
  70 {
  71 public:
  72     wxHtmlPageBreakCell() {}
  73
  74     bool AdjustPagebreak(int* pagebreak,
  75                          int* known_pagebreaks = NULL,
  76                          int number_of_pages = 0) const;
  77     void Draw(wxDC& WXUNUSED(dc),
  78               int WXUNUSED(x), int WXUNUSED(y),
  79               int WXUNUSED(view_y1), int WXUNUSED(view_y2),
  80               wxHtmlRenderingInfo& WXUNUSED(info)) {}
  81
  82 private:
  83     DECLARE_NO_COPY_CLASS(wxHtmlPageBreakCell)
  84 };
  85
  86 // Comparison routine for bsearch into an int* array of pagebreaks.
  87 extern "C" int wxCMPFUNC_CONV wxInteger_compare(void const* i0, void const* i1)
  88 {
  89     return *(int*)i0 - *(int*)i1;
  90 }
  91
  92 bool wxHtmlPageBreakCell::AdjustPagebreak(int* pagebreak, int* known_pagebreaks, int number_of_pages) const
  93 {
  94     // When we are counting pages, 'known_pagebreaks' is non-NULL.
  95     // That's the only time we change 'pagebreak'. Otherwise, pages
  96     // were already counted, 'known_pagebreaks' is NULL, and we don't
  97     // do anything except return FALSE.
  98     //
  99     // We also simply return FALSE if the 'pagebreak' argument is
 100     // less than (vertically above) or the same as the current
 101     // vertical position. Otherwise we'd be setting a pagebreak above
 102     // the current cell, which is incorrect, or duplicating a
 103     // pagebreak that has already been set.
 104     if(NULL == known_pagebreaks || *pagebreak <= m_PosY)
 105         {
 106         return FALSE;
 107         }
 108
 109     // m_PosY is only the vertical offset from the parent. The pagebreak
 110     // required here is the total page offset, so m_PosY must be added
 111     // to the parent's offset and height.
 112     int total_height = m_PosY + GetParent()->GetPosY() + GetParent()->GetHeight();
 113
 114     // Search the array of pagebreaks to see whether we've already set
 115     // a pagebreak here. The standard bsearch() function is appropriate
 116     // because the array of pagebreaks through known_pagebreaks[number_of_pages]
 117     // is known to be sorted in strictly increasing order. '1 + number_of_pages'
 118     // is used as a bsearch() argument because the array contains a leading
 119     // zero plus one element for each page.
 120     int* where = (int*) bsearch(&total_height, known_pagebreaks,
 121                                 1 + number_of_pages, sizeof(int),
 122                                 wxInteger_compare);
 123     // Add a pagebreak only if there isn't one already set here.
 124     if(NULL != where)
 125         {
 126         return FALSE;
 127         }
 128     else
 129         {
 130         *pagebreak = m_PosY;
 131         return TRUE;
 132         }
 133 }
 134
 135 TAG_HANDLER_BEGIN(P, "P")
 136     TAG_HANDLER_CONSTR(P) { }
 137
 138     TAG_HANDLER_PROC(tag)
 139     {
 140         if (m_WParser->GetContainer()->GetFirstChild() != NULL)
 141         {
 142             m_WParser->CloseContainer();
 143             m_WParser->OpenContainer();
 144         }
 145         m_WParser->GetContainer()->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 146         m_WParser->GetContainer()->SetAlign(tag);
 147         return FALSE;
 148     }
 149
 150 TAG_HANDLER_END(P)
 151
 152
 153
 154 TAG_HANDLER_BEGIN(BR, "BR")
 155     TAG_HANDLER_CONSTR(BR) { }
 156
 157     TAG_HANDLER_PROC(tag)
 158     {
 159         int al = m_WParser->GetContainer()->GetAlignHor();
 160         wxHtmlContainerCell *c;
 161
 162         m_WParser->CloseContainer();
 163         c = m_WParser->OpenContainer();
 164         c->SetAlignHor(al);
 165         c->SetAlign(tag);
 166         c->SetMinHeight(m_WParser->GetCharHeight());
 167         return FALSE;
 168     }
 169
 170 TAG_HANDLER_END(BR)
 171
 172
 173
 174 TAG_HANDLER_BEGIN(CENTER, "CENTER")
 175     TAG_HANDLER_CONSTR(CENTER) { }
 176
 177     TAG_HANDLER_PROC(tag)
 178     {
 179         int old = m_WParser->GetAlign();
 180         wxHtmlContainerCell *c = m_WParser->GetContainer();
 181
 182         m_WParser->SetAlign(wxHTML_ALIGN_CENTER);
 183         if (c->GetFirstChild() != NULL)
 184         {
 185             m_WParser->CloseContainer();
 186             m_WParser->OpenContainer();
 187         }
 188         else
 189             c->SetAlignHor(wxHTML_ALIGN_CENTER);
 190
 191         if (tag.HasEnding())
 192         {
 193             ParseInner(tag);
 194
 195             m_WParser->SetAlign(old);
 196             if (c->GetFirstChild() != NULL)
 197             {
 198                 m_WParser->CloseContainer();
 199                 m_WParser->OpenContainer();
 200             }
 201             else
 202                 c->SetAlignHor(old);
 203
 204             return TRUE;
 205         }
 206         else return FALSE;
 207     }
 208
 209 TAG_HANDLER_END(CENTER)
 210
 211
 212
 213 TAG_HANDLER_BEGIN(DIV, "DIV")
 214     TAG_HANDLER_CONSTR(DIV) { }
 215
 216     TAG_HANDLER_PROC(tag)
 217     {
 218         if(tag.HasParam(wxT("STYLE")))
 219         {
 220             if(tag.GetParam(wxT("STYLE")).IsSameAs(wxT("PAGE-BREAK-BEFORE:ALWAYS"), FALSE))
 221             {
 222                 m_WParser->CloseContainer();
 223                 m_WParser->OpenContainer()->InsertCell(new wxHtmlPageBreakCell);
 224                 m_WParser->CloseContainer();
 225                 m_WParser->OpenContainer();
 226                 return FALSE;
 227             }
 228             else
 229             {
 230                 // Treat other STYLE parameters here when they're supported.
 231                 return FALSE;
 232             }
 233         }
 234         else if(tag.HasParam(wxT("ALIGN")))
 235         {
 236             int old = m_WParser->GetAlign();
 237             wxHtmlContainerCell *c = m_WParser->GetContainer();
 238             if (c->GetFirstChild() != NULL)
 239             {
 240                 m_WParser->CloseContainer();
 241                 m_WParser->OpenContainer();
 242                 c = m_WParser->GetContainer();
 243                 c->SetAlign(tag);
 244                 m_WParser->SetAlign(c->GetAlignHor());
 245             }
 246             else
 247             {
 248                 c->SetAlign(tag);
 249                 m_WParser->SetAlign(c->GetAlignHor());
 250             }
 251
 252             ParseInner(tag);
 253
 254             m_WParser->SetAlign(old);
 255             if (c->GetFirstChild() != NULL)
 256             {
 257                 m_WParser->CloseContainer();
 258                 m_WParser->OpenContainer();
 259             }
 260             else
 261                 c->SetAlignHor(old);
 262
 263             return TRUE;
 264         }
 265         else
 266         {
 267             return FALSE;
 268         }
 269     }
 270
 271 TAG_HANDLER_END(DIV)
 272
 273
 274
 275
 276 TAG_HANDLER_BEGIN(TITLE, "TITLE")
 277     TAG_HANDLER_CONSTR(TITLE) { }
 278
 279     TAG_HANDLER_PROC(tag)
 280     {
 281         if (m_WParser->GetWindow())
 282         {
 283             wxHtmlWindow *wfr = (wxHtmlWindow*)(m_WParser->GetWindow());
 284             if (wfr)
 285             {
 286                 const wxString& src = *m_WParser->GetSource();
 287                 wfr->OnSetTitle(src.Mid(tag.GetBeginPos(),
 288                                         tag.GetEndPos1()-tag.GetBeginPos()));
 289             }
 290         }
 291         return TRUE;
 292     }
 293
 294 TAG_HANDLER_END(TITLE)
 295
 296
 297
 298
 299 TAG_HANDLER_BEGIN(BODY, "BODY")
 300     TAG_HANDLER_CONSTR(BODY) { }
 301
 302     TAG_HANDLER_PROC(tag)
 303     {
 304         wxColour clr;
 305
 306         if (tag.GetParamAsColour(wxT("TEXT"), &clr))
 307         {
 308             m_WParser->SetActualColor(clr);
 309             m_WParser->GetContainer()->InsertCell(new wxHtmlColourCell(clr));
 310         }
 311
 312         if (tag.GetParamAsColour(wxT("LINK"), &clr))
 313             m_WParser->SetLinkColor(clr);
 314
 315         if (tag.GetParamAsColour(wxT("BGCOLOR"), &clr))
 316         {
 317             m_WParser->GetContainer()->InsertCell(
 318                 new wxHtmlColourCell(clr, wxHTML_CLR_BACKGROUND));
 319             if (m_WParser->GetWindow() != NULL)
 320                 m_WParser->GetWindow()->SetBackgroundColour(clr);
 321         }
 322         return FALSE;
 323     }
 324
 325 TAG_HANDLER_END(BODY)
 326
 327
 328
 329 TAG_HANDLER_BEGIN(BLOCKQUOTE, "BLOCKQUOTE")
 330     TAG_HANDLER_CONSTR(BLOCKQUOTE) { }
 331
 332     TAG_HANDLER_PROC(tag)
 333     {
 334         wxHtmlContainerCell *c;
 335
 336         m_WParser->CloseContainer();
 337         c = m_WParser->OpenContainer();
 338
 339         if (c->GetAlignHor() == wxHTML_ALIGN_RIGHT)
 340             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_RIGHT);
 341         else
 342             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_LEFT);
 343
 344         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 345         m_WParser->OpenContainer();
 346         ParseInner(tag);
 347         c = m_WParser->CloseContainer();
 348         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_BOTTOM);
 349         m_WParser->CloseContainer();
 350         m_WParser->OpenContainer();
 351         return TRUE;
 352     }
 353
 354 TAG_HANDLER_END(BLOCKQUOTE)
 355
 356
 357
 358 // Tag handler for tags that we have to ignore, otherwise non-text data
 359 // would show up as text:
 360 TAG_HANDLER_BEGIN(DoNothing, "SCRIPT")
 361     TAG_HANDLER_CONSTR(DoNothing) { }
 362
 363     TAG_HANDLER_PROC(WXUNUSED(tag))
 364     {
 365         return true;
 366     }
 367 TAG_HANDLER_END(DoNothing)
 368
 369
 370
 371 TAGS_MODULE_BEGIN(Layout)
 372
 373     TAGS_MODULE_ADD(P)
 374     TAGS_MODULE_ADD(BR)
 375     TAGS_MODULE_ADD(CENTER)
 376     TAGS_MODULE_ADD(DIV)
 377     TAGS_MODULE_ADD(TITLE)
 378     TAGS_MODULE_ADD(BODY)
 379     TAGS_MODULE_ADD(BLOCKQUOTE)
 380     TAGS_MODULE_ADD(DoNothing)
 381
 382 TAGS_MODULE_END(Layout)
 383
 384 #endif