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 #ifdef __WXWINCE__
  34     #include "wx/msw/wince/missing.h"       // for bsearch()
  35 #else
  36     #include <stdlib.h>                     // bsearch()
  37 #endif
  38
  39 //-----------------------------------------------------------------------------
  40 // wxHtmlPageBreakCell
  41 //-----------------------------------------------------------------------------
  42
  43 // Since html isn't a page-layout language, it doesn't support page
  44 // page breaks directly--that requires CSS2 support. But a page-break
  45 // facility is handy, and has been requested more than once on the
  46 // mailing lists. This wxHtml tag handler implements just enough of
  47 // CSS2 to support a page break by recognizing only
  48 //   <div style="page-break-before:always">
  49 //
  50 // wxHtml maintains page breaks in wxHtmlPrintout::m_PageBreaks. The
  51 // tag handler below adds appropriate offsets to that array member.
  52 // wxHtmlDCRenderer::Render() accesses that array and makes a new page
  53 // begin after each page-break tag.
  54
  55 // The page-break handler does all its work in AdjustPagebreak(). For
  56 // all tag handlers, that function adjusts the page-break position.
  57 // For other tags, it determines whether the html element can fit on
  58 // the remainder of the page; if it cannot fit, but must not be split,
  59 // then the function moves the page break provided in the argument up,
  60 // and returns 'true' to inform the caller that the argument was
  61 // modified.
  62 //
  63 // Due to its special purpose, the page-break facility differs from
  64 // other tags. It takes up no space, but it behaves as though there is
  65 // never enough room to fit it on the remainder of the page--it always
  66 // forces a page break. Therefore, unlike other elements that trigger
  67 // a page break, it would never 'fit' on the following page either.
  68 // Therefore it's necessary to compare each pagebreak candidate to the
  69 // array wxHtmlPrintout::m_PageBreaks of pagebreaks already set, and
  70 // set a new one only if it's not in that array.
  71
  72 class wxHtmlPageBreakCell : public wxHtmlCell
  73 {
  74 public:
  75     wxHtmlPageBreakCell() {}
  76
  77     bool AdjustPagebreak(int* pagebreak,
  78                          int* known_pagebreaks = NULL,
  79                          int number_of_pages = 0) const;
  80     void Draw(wxDC& WXUNUSED(dc),
  81               int WXUNUSED(x), int WXUNUSED(y),
  82               int WXUNUSED(view_y1), int WXUNUSED(view_y2),
  83               wxHtmlRenderingInfo& WXUNUSED(info)) {}
  84
  85 private:
  86     DECLARE_NO_COPY_CLASS(wxHtmlPageBreakCell)
  87 };
  88
  89 // Comparison routine for bsearch into an int* array of pagebreaks.
  90 extern "C" int wxCMPFUNC_CONV wxInteger_compare(void const* i0, void const* i1)
  91 {
  92     return *(int*)i0 - *(int*)i1;
  93 }
  94
  95 bool wxHtmlPageBreakCell::AdjustPagebreak(int* pagebreak, int* known_pagebreaks, int number_of_pages) const
  96 {
  97     // When we are counting pages, 'known_pagebreaks' is non-NULL.
  98     // That's the only time we change 'pagebreak'. Otherwise, pages
  99     // were already counted, 'known_pagebreaks' is NULL, and we don't
 100     // do anything except return FALSE.
 101     //
 102     // We also simply return FALSE if the 'pagebreak' argument is
 103     // less than (vertically above) or the same as the current
 104     // vertical position. Otherwise we'd be setting a pagebreak above
 105     // the current cell, which is incorrect, or duplicating a
 106     // pagebreak that has already been set.
 107     if(NULL == known_pagebreaks || *pagebreak <= m_PosY)
 108         {
 109         return FALSE;
 110         }
 111
 112     // m_PosY is only the vertical offset from the parent. The pagebreak
 113     // required here is the total page offset, so m_PosY must be added
 114     // to the parent's offset and height.
 115     int total_height = m_PosY + GetParent()->GetPosY() + GetParent()->GetHeight();
 116
 117     // Search the array of pagebreaks to see whether we've already set
 118     // a pagebreak here. The standard bsearch() function is appropriate
 119     // because the array of pagebreaks through known_pagebreaks[number_of_pages]
 120     // is known to be sorted in strictly increasing order. '1 + number_of_pages'
 121     // is used as a bsearch() argument because the array contains a leading
 122     // zero plus one element for each page.
 123     int* where = (int*) bsearch(&total_height, known_pagebreaks,
 124                                 1 + number_of_pages, sizeof(int),
 125                                 wxInteger_compare);
 126     // Add a pagebreak only if there isn't one already set here.
 127     if(NULL != where)
 128         {
 129         return FALSE;
 130         }
 131     else
 132         {
 133         *pagebreak = m_PosY;
 134         return TRUE;
 135         }
 136 }
 137
 138 TAG_HANDLER_BEGIN(P, "P")
 139     TAG_HANDLER_CONSTR(P) { }
 140
 141     TAG_HANDLER_PROC(tag)
 142     {
 143         if (m_WParser->GetContainer()->GetFirstChild() != NULL)
 144         {
 145             m_WParser->CloseContainer();
 146             m_WParser->OpenContainer();
 147         }
 148         m_WParser->GetContainer()->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 149         m_WParser->GetContainer()->SetAlign(tag);
 150         return FALSE;
 151     }
 152
 153 TAG_HANDLER_END(P)
 154
 155
 156
 157 TAG_HANDLER_BEGIN(BR, "BR")
 158     TAG_HANDLER_CONSTR(BR) { }
 159
 160     TAG_HANDLER_PROC(tag)
 161     {
 162         int al = m_WParser->GetContainer()->GetAlignHor();
 163         wxHtmlContainerCell *c;
 164
 165         m_WParser->CloseContainer();
 166         c = m_WParser->OpenContainer();
 167         c->SetAlignHor(al);
 168         c->SetAlign(tag);
 169         c->SetMinHeight(m_WParser->GetCharHeight());
 170         return FALSE;
 171     }
 172
 173 TAG_HANDLER_END(BR)
 174
 175
 176
 177 TAG_HANDLER_BEGIN(CENTER, "CENTER")
 178     TAG_HANDLER_CONSTR(CENTER) { }
 179
 180     TAG_HANDLER_PROC(tag)
 181     {
 182         int old = m_WParser->GetAlign();
 183         wxHtmlContainerCell *c = m_WParser->GetContainer();
 184
 185         m_WParser->SetAlign(wxHTML_ALIGN_CENTER);
 186         if (c->GetFirstChild() != NULL)
 187         {
 188             m_WParser->CloseContainer();
 189             m_WParser->OpenContainer();
 190         }
 191         else
 192             c->SetAlignHor(wxHTML_ALIGN_CENTER);
 193
 194         if (tag.HasEnding())
 195         {
 196             ParseInner(tag);
 197
 198             m_WParser->SetAlign(old);
 199             if (c->GetFirstChild() != NULL)
 200             {
 201                 m_WParser->CloseContainer();
 202                 m_WParser->OpenContainer();
 203             }
 204             else
 205                 c->SetAlignHor(old);
 206
 207             return TRUE;
 208         }
 209         else return FALSE;
 210     }
 211
 212 TAG_HANDLER_END(CENTER)
 213
 214
 215
 216 TAG_HANDLER_BEGIN(DIV, "DIV")
 217     TAG_HANDLER_CONSTR(DIV) { }
 218
 219     TAG_HANDLER_PROC(tag)
 220     {
 221         if(tag.HasParam(wxT("STYLE")))
 222         {
 223             if(tag.GetParam(wxT("STYLE")).IsSameAs(wxT("PAGE-BREAK-BEFORE:ALWAYS"), FALSE))
 224             {
 225                 m_WParser->CloseContainer();
 226                 m_WParser->OpenContainer()->InsertCell(new wxHtmlPageBreakCell);
 227                 m_WParser->CloseContainer();
 228                 m_WParser->OpenContainer();
 229                 return FALSE;
 230             }
 231             else
 232             {
 233                 // Treat other STYLE parameters here when they're supported.
 234                 return FALSE;
 235             }
 236         }
 237         else if(tag.HasParam(wxT("ALIGN")))
 238         {
 239             int old = m_WParser->GetAlign();
 240             wxHtmlContainerCell *c = m_WParser->GetContainer();
 241             if (c->GetFirstChild() != NULL)
 242             {
 243                 m_WParser->CloseContainer();
 244                 m_WParser->OpenContainer();
 245                 c = m_WParser->GetContainer();
 246                 c->SetAlign(tag);
 247                 m_WParser->SetAlign(c->GetAlignHor());
 248             }
 249             else
 250             {
 251                 c->SetAlign(tag);
 252                 m_WParser->SetAlign(c->GetAlignHor());
 253             }
 254
 255             ParseInner(tag);
 256
 257             m_WParser->SetAlign(old);
 258             if (c->GetFirstChild() != NULL)
 259             {
 260                 m_WParser->CloseContainer();
 261                 m_WParser->OpenContainer();
 262             }
 263             else
 264                 c->SetAlignHor(old);
 265
 266             return true;
 267         }
 268         else
 269         {
 270             // Same as BR
 271             int al = m_WParser->GetContainer()->GetAlignHor();
 272             wxHtmlContainerCell *c;
 273
 274             m_WParser->CloseContainer();
 275             c = m_WParser->OpenContainer();
 276             c->SetAlignHor(al);
 277             c->SetAlign(tag);
 278             c->SetMinHeight(m_WParser->GetCharHeight());
 279             return false;
 280         }
 281     }
 282
 283 TAG_HANDLER_END(DIV)
 284
 285
 286
 287
 288 TAG_HANDLER_BEGIN(TITLE, "TITLE")
 289     TAG_HANDLER_CONSTR(TITLE) { }
 290
 291     TAG_HANDLER_PROC(tag)
 292     {
 293         if (m_WParser->GetWindow())
 294         {
 295             wxHtmlWindow *wfr = (wxHtmlWindow*)(m_WParser->GetWindow());
 296             if (wfr)
 297             {
 298                 const wxString& src = *m_WParser->GetSource();
 299                 wfr->OnSetTitle(src.Mid(tag.GetBeginPos(),
 300                                         tag.GetEndPos1()-tag.GetBeginPos()));
 301             }
 302         }
 303         return TRUE;
 304     }
 305
 306 TAG_HANDLER_END(TITLE)
 307
 308
 309
 310
 311 TAG_HANDLER_BEGIN(BODY, "BODY")
 312     TAG_HANDLER_CONSTR(BODY) { }
 313
 314     TAG_HANDLER_PROC(tag)
 315     {
 316         wxColour clr;
 317
 318         if (tag.GetParamAsColour(wxT("TEXT"), &clr))
 319         {
 320             m_WParser->SetActualColor(clr);
 321             m_WParser->GetContainer()->InsertCell(new wxHtmlColourCell(clr));
 322         }
 323
 324         if (tag.GetParamAsColour(wxT("LINK"), &clr))
 325             m_WParser->SetLinkColor(clr);
 326
 327         if (tag.GetParamAsColour(wxT("BGCOLOR"), &clr))
 328         {
 329             m_WParser->GetContainer()->InsertCell(
 330                 new wxHtmlColourCell(clr, wxHTML_CLR_BACKGROUND));
 331             if (m_WParser->GetWindow() != NULL)
 332                 m_WParser->GetWindow()->SetBackgroundColour(clr);
 333         }
 334         return FALSE;
 335     }
 336
 337 TAG_HANDLER_END(BODY)
 338
 339
 340
 341 TAG_HANDLER_BEGIN(BLOCKQUOTE, "BLOCKQUOTE")
 342     TAG_HANDLER_CONSTR(BLOCKQUOTE) { }
 343
 344     TAG_HANDLER_PROC(tag)
 345     {
 346         wxHtmlContainerCell *c;
 347
 348         m_WParser->CloseContainer();
 349         c = m_WParser->OpenContainer();
 350
 351         if (c->GetAlignHor() == wxHTML_ALIGN_RIGHT)
 352             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_RIGHT);
 353         else
 354             c->SetIndent(5 * m_WParser->GetCharWidth(), wxHTML_INDENT_LEFT);
 355
 356         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_TOP);
 357         m_WParser->OpenContainer();
 358         ParseInner(tag);
 359         c = m_WParser->CloseContainer();
 360         c->SetIndent(m_WParser->GetCharHeight(), wxHTML_INDENT_BOTTOM);
 361         m_WParser->CloseContainer();
 362         m_WParser->OpenContainer();
 363         return TRUE;
 364     }
 365
 366 TAG_HANDLER_END(BLOCKQUOTE)
 367
 368
 369
 370 // Tag handler for tags that we have to ignore, otherwise non-text data
 371 // would show up as text:
 372 TAG_HANDLER_BEGIN(DoNothing, "SCRIPT")
 373     TAG_HANDLER_CONSTR(DoNothing) { }
 374
 375     TAG_HANDLER_PROC(WXUNUSED(tag))
 376     {
 377         return true;
 378     }
 379 TAG_HANDLER_END(DoNothing)
 380
 381
 382
 383 TAGS_MODULE_BEGIN(Layout)
 384
 385     TAGS_MODULE_ADD(P)
 386     TAGS_MODULE_ADD(BR)
 387     TAGS_MODULE_ADD(CENTER)
 388     TAGS_MODULE_ADD(DIV)
 389     TAGS_MODULE_ADD(TITLE)
 390     TAGS_MODULE_ADD(BODY)
 391     TAGS_MODULE_ADD(BLOCKQUOTE)
 392     TAGS_MODULE_ADD(DoNothing)
 393
 394 TAGS_MODULE_END(Layout)
 395
 396 #endif