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 #ifdef __GNUG__
  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 WXDLLEXPORT wxHtmlPageBreakCell : public wxHtmlCell
  70 {
  71   public:
  72     wxHtmlPageBreakCell() {}
  73
  74     bool AdjustPagebreak(int* pagebreak, int* known_pagebreaks = NULL, int number_of_pages = 0) const;
  75
  76   private:
  77     DECLARE_NO_COPY_CLASS(wxHtmlPageBreakCell)
  78 };
  79
  80 // Comparison routine for bsearch into an int* array of pagebreaks.
  81 static int integer_compare(void const* i0, void const* i1)
  82 {
  83     return *(int*)i0 - *(int*)i1;
  84 }
  85
  86 bool wxHtmlPageBreakCell::AdjustPagebreak(int* pagebreak, int* known_pagebreaks, int number_of_pages) const
  87 {
  88     // When we are counting pages, 'known_pagebreaks' is non-NULL.
  89     // That's the only time we change 'pagebreak'. Otherwise, pages
  90     // were already counted, 'known_pagebreaks' is NULL, and we don't
  91     // do anything except return FALSE.
  92     //
  93     // We also simply return FALSE if the 'pagebreak' argument is
  94     // less than (vertically above) or the same as the current
  95     // vertical position. Otherwise we'd be setting a pagebreak above
  96     // the current cell, which is incorrect, or duplicating a
  97     // pagebreak that has already been set.
  98     if(NULL == known_pagebreaks || *pagebreak <= m_PosY)
  99         {
 100         return FALSE;
 101         }
 102
 103     // m_PosY is only the vertical offset from the parent. The pagebreak
 104     // required here is the total page offset, so m_PosY must be added
 105     // to the parent's offset and height.
 106     int total_height = m_PosY + GetParent()->GetPosY() + GetParent()->GetHeight();
 107
 108     // Search the array of pagebreaks to see whether we've already set
 109     // a pagebreak here. The standard bsearch() function is appropriate
 110     // because the array of pagebreaks through known_pagebreaks[number_of_pages]
 111     // is known to be sorted in strictly increasing order. '1 + number_of_pages'
 112     // is used as a bsearch() argument because the array contains a leading
 113     // zero plus one element for each page.
 114     int* where = (int*) bsearch(&total_height, known_pagebreaks,
 115                                 1 + number_of_pages, sizeof(int),
 116                                 integer_compare);
 117     // Add a pagebreak only if there isn't one already set here.
 118     if(NULL != where)
 119         {
 120         return FALSE;
 121         }
 122     else
 123         {
 124         *pagebreak = m_PosY;
 125         return TRUE;
 126         }
 127 }
 128
 129 TAG_HANDLER_BEGIN(P, "P")
 130
 131     TAG_HANDLER_PROC(tag)
 132     {
 133         if (m_WParser->GetContainer()->GetFirstCell() != NULL)
 134         {
 135             m_WParser->CloseContainer();
 136             m_WParser->OpenContainer();
 137         }
 138         m_WParser->GetContainer()->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 139         m_WParser->GetContainer()->SetAlign(tag);
 140         return FALSE;
 141     }
 142
 143 TAG_HANDLER_END(P)
 144
 145
 146
 147 TAG_HANDLER_BEGIN(BR, "BR")
 148
 149     TAG_HANDLER_PROC(tag)
 150     {
 151         int al = m_WParser->GetContainer()->GetAlignHor();
 152         wxHtmlContainerCell *c;
 153
 154         m_WParser->CloseContainer();
 155         c = m_WParser->OpenContainer();
 156         c->SetAlignHor(al);
 157         c->SetAlign(tag);
 158         c->SetMinHeight(m_WParser->GetCharHeight());
 159         return FALSE;
 160     }
 161
 162 TAG_HANDLER_END(BR)
 163
 164
 165
 166 TAG_HANDLER_BEGIN(CENTER, "CENTER")
 167
 168     TAG_HANDLER_PROC(tag)
 169     {
 170         int old = m_WParser->GetAlign();
 171         wxHtmlContainerCell *c = m_WParser->GetContainer();
 172
 173         m_WParser->SetAlign(wxHTML_ALIGN_CENTER);
 174         if (c->GetFirstCell() != NULL)
 175         {
 176             m_WParser->CloseContainer();
 177             m_WParser->OpenContainer();
 178         }
 179         else
 180             c->SetAlignHor(wxHTML_ALIGN_CENTER);
 181
 182         if (tag.HasEnding())
 183         {
 184             ParseInner(tag);
 185
 186             m_WParser->SetAlign(old);
 187             if (c->GetFirstCell() != NULL)
 188             {
 189                 m_WParser->CloseContainer();
 190                 m_WParser->OpenContainer();
 191             }
 192             else
 193                 c->SetAlignHor(old);
 194
 195             return TRUE;
 196         }
 197         else return FALSE;
 198     }
 199
 200 TAG_HANDLER_END(CENTER)
 201
 202
 203
 204 TAG_HANDLER_BEGIN(DIV, "DIV")
 205
 206     TAG_HANDLER_PROC(tag)
 207     {
 208         if(tag.HasParam(wxT("STYLE")))
 209         {
 210             if(tag.GetParam(wxT("STYLE")).IsSameAs(wxT("PAGE-BREAK-BEFORE:ALWAYS"), FALSE))
 211             {
 212                 m_WParser->CloseContainer();
 213                 m_WParser->OpenContainer()->InsertCell(new wxHtmlPageBreakCell);
 214                 m_WParser->CloseContainer();
 215                 m_WParser->OpenContainer();
 216                 return FALSE;
 217             }
 218             else
 219             {
 220                 // Treat other STYLE parameters here when they're supported.
 221                 return FALSE;
 222             }
 223         }
 224         else if(tag.HasParam(wxT("ALIGN")))
 225         {
 226             int old = m_WParser->GetAlign();
 227             wxHtmlContainerCell *c = m_WParser->GetContainer();
 228             if (c->GetFirstCell() != NULL)
 229             {
 230                 m_WParser->CloseContainer();
 231                 m_WParser->OpenContainer();
 232                 c = m_WParser->GetContainer();
 233                 c->SetAlign(tag);
 234                 m_WParser->SetAlign(c->GetAlignHor());
 235             }
 236             else
 237             {
 238                 c->SetAlign(tag);
 239                 m_WParser->SetAlign(c->GetAlignHor());
 240             }
 241
 242             ParseInner(tag);
 243
 244             m_WParser->SetAlign(old);
 245             if (c->GetFirstCell() != NULL)
 246             {
 247                 m_WParser->CloseContainer();
 248                 m_WParser->OpenContainer();
 249             }
 250             else
 251                 c->SetAlignHor(old);
 252
 253             return TRUE;
 254         }
 255         else
 256         {
 257             return FALSE;
 258         }
 259     }
 260
 261 TAG_HANDLER_END(DIV)
 262
 263
 264
 265
 266 TAG_HANDLER_BEGIN(TITLE, "TITLE")
 267
 268     TAG_HANDLER_PROC(tag)
 269     {
 270         if (m_WParser->GetWindow())
 271         {
 272             wxHtmlWindow *wfr = (wxHtmlWindow*)(m_WParser->GetWindow());
 273             if (wfr)
 274             {
 275                 const wxString& src = *m_WParser->GetSource();
 276                 wfr->OnSetTitle(src.Mid(tag.GetBeginPos(),
 277                                         tag.GetEndPos1()-tag.GetBeginPos()));
 278             }
 279         }
 280         return TRUE;
 281     }
 282
 283 TAG_HANDLER_END(TITLE)
 284
 285
 286
 287
 288 TAG_HANDLER_BEGIN(BODY, "BODY")
 289
 290     TAG_HANDLER_PROC(tag)
 291     {
 292         wxColour clr;
 293
 294         if (tag.GetParamAsColour(wxT("TEXT"), &clr))
 295         {
 296             m_WParser->SetActualColor(clr);
 297             m_WParser->GetContainer()->InsertCell(new wxHtmlColourCell(clr));
 298         }
 299
 300         if (tag.GetParamAsColour(wxT("LINK"), &clr))
 301             m_WParser->SetLinkColor(clr);
 302
 303         if (tag.GetParamAsColour(wxT("BGCOLOR"), &clr))
 304         {
 305             m_WParser->GetContainer()->InsertCell(
 306                 new wxHtmlColourCell(clr, wxHTML_CLR_BACKGROUND));
 307             if (m_WParser->GetWindow() != NULL)
 308                 m_WParser->GetWindow()->SetBackgroundColour(clr);
 309         }
 310         return FALSE;
 311     }
 312
 313 TAG_HANDLER_END(BODY)
 314
 315
 316
 317 TAG_HANDLER_BEGIN(BLOCKQUOTE, "BLOCKQUOTE")
 318
 319     TAG_HANDLER_PROC(tag)
 320     {
 321         wxHtmlContainerCell *c;
 322
 323         m_WParser->CloseContainer();
 324         c = m_WParser->OpenContainer();
 325
 326         if (c->GetAlignHor() == wxHTML_ALIGN_RIGHT)
 327             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_RIGHT);
 328         else
 329             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_LEFT);
 330
 331         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 332         m_WParser->OpenContainer();
 333         ParseInner(tag);
 334         c = m_WParser->CloseContainer();
 335         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_BOTTOM);
 336         m_WParser->CloseContainer();
 337         m_WParser->OpenContainer();
 338         return TRUE;
 339     }
 340
 341 TAG_HANDLER_END(BLOCKQUOTE)
 342
 343
 344
 345 // Tag handler for tags that we have to ignore, otherwise non-text data
 346 // would show up as text:
 347 TAG_HANDLER_BEGIN(DoNothing, "SCRIPT")
 348     TAG_HANDLER_PROC(tag)
 349     {
 350         return true;
 351     }
 352 TAG_HANDLER_END(DoNothing)
 353
 354
 355
 356 TAGS_MODULE_BEGIN(Layout)
 357
 358     TAGS_MODULE_ADD(P)
 359     TAGS_MODULE_ADD(BR)
 360     TAGS_MODULE_ADD(CENTER)
 361     TAGS_MODULE_ADD(DIV)
 362     TAGS_MODULE_ADD(TITLE)
 363     TAGS_MODULE_ADD(BODY)
 364     TAGS_MODULE_ADD(BLOCKQUOTE)
 365     TAGS_MODULE_ADD(DoNothing)
 366
 367 TAGS_MODULE_END(Layout)
 368
 369 #endif