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,
  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               wxHtmlRenderingState& WXUNUSED(state)) {}
  81
  82 private:
  83     DECLARE_NO_COPY_CLASS(wxHtmlPageBreakCell)
  84 };
  85
  86 // Comparison routine for bsearch into an int* array of pagebreaks.
  87 static int integer_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                                 integer_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
 137     TAG_HANDLER_PROC(tag)
 138     {
 139         if (m_WParser->GetContainer()->GetFirstChild() != NULL)
 140         {
 141             m_WParser->CloseContainer();
 142             m_WParser->OpenContainer();
 143         }
 144         m_WParser->GetContainer()->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 145         m_WParser->GetContainer()->SetAlign(tag);
 146         return FALSE;
 147     }
 148
 149 TAG_HANDLER_END(P)
 150
 151
 152
 153 TAG_HANDLER_BEGIN(BR, "BR")
 154
 155     TAG_HANDLER_PROC(tag)
 156     {
 157         int al = m_WParser->GetContainer()->GetAlignHor();
 158         wxHtmlContainerCell *c;
 159
 160         m_WParser->CloseContainer();
 161         c = m_WParser->OpenContainer();
 162         c->SetAlignHor(al);
 163         c->SetAlign(tag);
 164         c->SetMinHeight(m_WParser->GetCharHeight());
 165         return FALSE;
 166     }
 167
 168 TAG_HANDLER_END(BR)
 169
 170
 171
 172 TAG_HANDLER_BEGIN(CENTER, "CENTER")
 173
 174     TAG_HANDLER_PROC(tag)
 175     {
 176         int old = m_WParser->GetAlign();
 177         wxHtmlContainerCell *c = m_WParser->GetContainer();
 178
 179         m_WParser->SetAlign(wxHTML_ALIGN_CENTER);
 180         if (c->GetFirstChild() != NULL)
 181         {
 182             m_WParser->CloseContainer();
 183             m_WParser->OpenContainer();
 184         }
 185         else
 186             c->SetAlignHor(wxHTML_ALIGN_CENTER);
 187
 188         if (tag.HasEnding())
 189         {
 190             ParseInner(tag);
 191
 192             m_WParser->SetAlign(old);
 193             if (c->GetFirstChild() != NULL)
 194             {
 195                 m_WParser->CloseContainer();
 196                 m_WParser->OpenContainer();
 197             }
 198             else
 199                 c->SetAlignHor(old);
 200
 201             return TRUE;
 202         }
 203         else return FALSE;
 204     }
 205
 206 TAG_HANDLER_END(CENTER)
 207
 208
 209
 210 TAG_HANDLER_BEGIN(DIV, "DIV")
 211
 212     TAG_HANDLER_PROC(tag)
 213     {
 214         if(tag.HasParam(wxT("STYLE")))
 215         {
 216             if(tag.GetParam(wxT("STYLE")).IsSameAs(wxT("PAGE-BREAK-BEFORE:ALWAYS"), FALSE))
 217             {
 218                 m_WParser->CloseContainer();
 219                 m_WParser->OpenContainer()->InsertCell(new wxHtmlPageBreakCell);
 220                 m_WParser->CloseContainer();
 221                 m_WParser->OpenContainer();
 222                 return FALSE;
 223             }
 224             else
 225             {
 226                 // Treat other STYLE parameters here when they're supported.
 227                 return FALSE;
 228             }
 229         }
 230         else if(tag.HasParam(wxT("ALIGN")))
 231         {
 232             int old = m_WParser->GetAlign();
 233             wxHtmlContainerCell *c = m_WParser->GetContainer();
 234             if (c->GetFirstChild() != NULL)
 235             {
 236                 m_WParser->CloseContainer();
 237                 m_WParser->OpenContainer();
 238                 c = m_WParser->GetContainer();
 239                 c->SetAlign(tag);
 240                 m_WParser->SetAlign(c->GetAlignHor());
 241             }
 242             else
 243             {
 244                 c->SetAlign(tag);
 245                 m_WParser->SetAlign(c->GetAlignHor());
 246             }
 247
 248             ParseInner(tag);
 249
 250             m_WParser->SetAlign(old);
 251             if (c->GetFirstChild() != NULL)
 252             {
 253                 m_WParser->CloseContainer();
 254                 m_WParser->OpenContainer();
 255             }
 256             else
 257                 c->SetAlignHor(old);
 258
 259             return TRUE;
 260         }
 261         else
 262         {
 263             return FALSE;
 264         }
 265     }
 266
 267 TAG_HANDLER_END(DIV)
 268
 269
 270
 271
 272 TAG_HANDLER_BEGIN(TITLE, "TITLE")
 273
 274     TAG_HANDLER_PROC(tag)
 275     {
 276         if (m_WParser->GetWindow())
 277         {
 278             wxHtmlWindow *wfr = (wxHtmlWindow*)(m_WParser->GetWindow());
 279             if (wfr)
 280             {
 281                 const wxString& src = *m_WParser->GetSource();
 282                 wfr->OnSetTitle(src.Mid(tag.GetBeginPos(),
 283                                         tag.GetEndPos1()-tag.GetBeginPos()));
 284             }
 285         }
 286         return TRUE;
 287     }
 288
 289 TAG_HANDLER_END(TITLE)
 290
 291
 292
 293
 294 TAG_HANDLER_BEGIN(BODY, "BODY")
 295
 296     TAG_HANDLER_PROC(tag)
 297     {
 298         wxColour clr;
 299
 300         if (tag.GetParamAsColour(wxT("TEXT"), &clr))
 301         {
 302             m_WParser->SetActualColor(clr);
 303             m_WParser->GetContainer()->InsertCell(new wxHtmlColourCell(clr));
 304         }
 305
 306         if (tag.GetParamAsColour(wxT("LINK"), &clr))
 307             m_WParser->SetLinkColor(clr);
 308
 309         if (tag.GetParamAsColour(wxT("BGCOLOR"), &clr))
 310         {
 311             m_WParser->GetContainer()->InsertCell(
 312                 new wxHtmlColourCell(clr, wxHTML_CLR_BACKGROUND));
 313             if (m_WParser->GetWindow() != NULL)
 314                 m_WParser->GetWindow()->SetBackgroundColour(clr);
 315         }
 316         return FALSE;
 317     }
 318
 319 TAG_HANDLER_END(BODY)
 320
 321
 322
 323 TAG_HANDLER_BEGIN(BLOCKQUOTE, "BLOCKQUOTE")
 324
 325     TAG_HANDLER_PROC(tag)
 326     {
 327         wxHtmlContainerCell *c;
 328
 329         m_WParser->CloseContainer();
 330         c = m_WParser->OpenContainer();
 331
 332         if (c->GetAlignHor() == wxHTML_ALIGN_RIGHT)
 333             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_RIGHT);
 334         else
 335             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_LEFT);
 336
 337         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 338         m_WParser->OpenContainer();
 339         ParseInner(tag);
 340         c = m_WParser->CloseContainer();
 341         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_BOTTOM);
 342         m_WParser->CloseContainer();
 343         m_WParser->OpenContainer();
 344         return TRUE;
 345     }
 346
 347 TAG_HANDLER_END(BLOCKQUOTE)
 348
 349
 350
 351 // Tag handler for tags that we have to ignore, otherwise non-text data
 352 // would show up as text:
 353 TAG_HANDLER_BEGIN(DoNothing, "SCRIPT")
 354     TAG_HANDLER_PROC(tag)
 355     {
 356         return true;
 357     }
 358 TAG_HANDLER_END(DoNothing)
 359
 360
 361
 362 TAGS_MODULE_BEGIN(Layout)
 363
 364     TAGS_MODULE_ADD(P)
 365     TAGS_MODULE_ADD(BR)
 366     TAGS_MODULE_ADD(CENTER)
 367     TAGS_MODULE_ADD(DIV)
 368     TAGS_MODULE_ADD(TITLE)
 369     TAGS_MODULE_ADD(BODY)
 370     TAGS_MODULE_ADD(BLOCKQUOTE)
 371     TAGS_MODULE_ADD(DoNothing)
 372
 373 TAGS_MODULE_END(Layout)
 374
 375 #endif