src/gtk/tbargtk.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        tbargtk.cpp
   3 // Purpose:     GTK toolbar
   4 // Author:      Robert Roebling
   5 // Modified:    13.12.99 by VZ to derive from wxToolBarBase
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) Robert Roebling
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 #ifdef __GNUG__
  20     #pragma implementation "tbargtk.h"
  21 #endif
  22
  23 #include "wx/toolbar.h"
  24
  25 #if wxUSE_TOOLBAR_NATIVE
  26
  27 #include "wx/frame.h"
  28
  29 #include <glib.h>
  30 #include "wx/gtk/private.h"
  31
  32 extern GdkFont *GtkGetDefaultGuiFont();
  33
  34 // ----------------------------------------------------------------------------
  35 // globals
  36 // ----------------------------------------------------------------------------
  37
  38 // idle system
  39 extern void wxapp_install_idle_handler();
  40 extern bool g_isIdle;
  41
  42 // data
  43 extern bool       g_blockEventsOnDrag;
  44 extern wxCursor   g_globalCursor;
  45
  46 // ----------------------------------------------------------------------------
  47 // private functions
  48 // ----------------------------------------------------------------------------
  49
  50 // translate wxWindows toolbar style flags to GTK orientation and style
  51 static void GetGtkStyle(long style,
  52                         GtkOrientation *orient, GtkToolbarStyle *gtkStyle)
  53 {
  54     *orient = style & wxTB_VERTICAL ? GTK_ORIENTATION_VERTICAL
  55                                     : GTK_ORIENTATION_HORIZONTAL;
  56
  57
  58     if ( style & wxTB_TEXT )
  59     {
  60         *gtkStyle = style & wxTB_NOICONS ? GTK_TOOLBAR_TEXT : GTK_TOOLBAR_BOTH;
  61     }
  62     else // no text, hence we must have the icons or what would we show?
  63     {
  64         *gtkStyle = GTK_TOOLBAR_ICONS;
  65     }
  66 }
  67
  68 // ----------------------------------------------------------------------------
  69 // wxToolBarTool
  70 // ----------------------------------------------------------------------------
  71
  72 class wxToolBarTool : public wxToolBarToolBase
  73 {
  74 public:
  75     wxToolBarTool(wxToolBar *tbar,
  76                   int id,
  77                   const wxString& label,
  78                   const wxBitmap& bitmap1,
  79                   const wxBitmap& bitmap2,
  80                   wxItemKind kind,
  81                   wxObject *clientData,
  82                   const wxString& shortHelpString,
  83                   const wxString& longHelpString)
  84         : wxToolBarToolBase(tbar, id, label, bitmap1, bitmap2, kind,
  85                             clientData, shortHelpString, longHelpString)
  86     {
  87         Init();
  88     }
  89
  90     wxToolBarTool(wxToolBar *tbar, wxControl *control)
  91         : wxToolBarToolBase(tbar, control)
  92     {
  93         Init();
  94     }
  95
  96     // is this a radio button?
  97     //
  98     // unlike GetKind(), can be called for any kind of tools, not just buttons
  99     bool IsRadio() const { return IsButton() && GetKind() == wxITEM_RADIO; }
 100
 101     // this is only called for the normal buttons, i.e. not separators nor
 102     // controls
 103     GtkToolbarChildType GetGtkChildType() const
 104     {
 105         switch ( GetKind() )
 106         {
 107             case wxITEM_CHECK:
 108                 return GTK_TOOLBAR_CHILD_TOGGLEBUTTON;
 109
 110             case wxITEM_RADIO:
 111                 return GTK_TOOLBAR_CHILD_RADIOBUTTON;
 112
 113             default:
 114                 wxFAIL_MSG( _T("unknown toolbar child type") );
 115                 // fall through
 116
 117             case wxITEM_NORMAL:
 118                 return GTK_TOOLBAR_CHILD_BUTTON;
 119         }
 120     }
 121
 122     GtkWidget            *m_item;
 123     GtkWidget            *m_pixmap;
 124
 125 protected:
 126     void Init();
 127 };
 128
 129 // ----------------------------------------------------------------------------
 130 // wxWin macros
 131 // ----------------------------------------------------------------------------
 132
 133 IMPLEMENT_DYNAMIC_CLASS(wxToolBar, wxToolBarBase)
 134
 135 // ============================================================================
 136 // implementation
 137 // ============================================================================
 138
 139 //-----------------------------------------------------------------------------
 140 // "clicked" (internal from gtk_toolbar)
 141 //-----------------------------------------------------------------------------
 142
 143 static void gtk_toolbar_callback( GtkWidget *WXUNUSED(widget),
 144                                   wxToolBarTool *tool )
 145 {
 146     if (g_isIdle)
 147         wxapp_install_idle_handler();
 148
 149     wxToolBar *tbar = (wxToolBar *)tool->GetToolBar();
 150
 151     if (tbar->m_blockEvent) return;
 152
 153     if (g_blockEventsOnDrag) return;
 154     if (!tool->IsEnabled()) return;
 155
 156     if (tool->CanBeToggled())
 157     {
 158         tool->Toggle();
 159
 160         wxBitmap bitmap = tool->GetBitmap();
 161         if ( bitmap.Ok() )
 162         {
 163             GtkPixmap *pixmap = GTK_PIXMAP( tool->m_pixmap );
 164
 165             GdkBitmap *mask = bitmap.GetMask() ? bitmap.GetMask()->GetBitmap()
 166                                                : (GdkBitmap *)NULL;
 167
 168             gtk_pixmap_set( pixmap, bitmap.GetPixmap(), mask );
 169         }
 170
 171         if ( tool->IsRadio() && !tool->IsToggled() )
 172         {
 173             // radio button went up, don't report this as a wxWin event
 174             return;
 175         }
 176     }
 177
 178     tbar->OnLeftClick( tool->GetId(), tool->IsToggled() );
 179 }
 180
 181 //-----------------------------------------------------------------------------
 182 // "enter_notify_event" / "leave_notify_event"
 183 //-----------------------------------------------------------------------------
 184
 185 static gint gtk_toolbar_tool_callback( GtkWidget *WXUNUSED(widget),
 186                                        GdkEventCrossing *gdk_event,
 187                                        wxToolBarTool *tool )
 188 {
 189     if (g_isIdle) wxapp_install_idle_handler();
 190
 191     if (g_blockEventsOnDrag) return TRUE;
 192
 193     wxToolBar *tb = (wxToolBar *)tool->GetToolBar();
 194
 195     // emit the event
 196     if( gdk_event->type == GDK_ENTER_NOTIFY )
 197         tb->OnMouseEnter( tool->GetId() );
 198     else
 199         tb->OnMouseEnter( -1 );
 200
 201     return FALSE;
 202 }
 203
 204 //-----------------------------------------------------------------------------
 205 // InsertChild callback for wxToolBar
 206 //-----------------------------------------------------------------------------
 207
 208 static void wxInsertChildInToolBar( wxToolBar* WXUNUSED(parent),
 209                                     wxWindow* WXUNUSED(child) )
 210 {
 211     // we don't do anything here
 212 }
 213
 214 // ----------------------------------------------------------------------------
 215 // wxToolBarTool
 216 // ----------------------------------------------------------------------------
 217
 218 void wxToolBarTool::Init()
 219 {
 220     m_item =
 221     m_pixmap = (GtkWidget *)NULL;
 222 }
 223
 224 wxToolBarToolBase *wxToolBar::CreateTool(int id,
 225                                          const wxString& text,
 226                                          const wxBitmap& bitmap1,
 227                                          const wxBitmap& bitmap2,
 228                                          wxItemKind kind,
 229                                          wxObject *clientData,
 230                                          const wxString& shortHelpString,
 231                                          const wxString& longHelpString)
 232 {
 233     return new wxToolBarTool(this, id, text, bitmap1, bitmap2, kind,
 234                              clientData, shortHelpString, longHelpString);
 235 }
 236
 237 wxToolBarToolBase *wxToolBar::CreateTool(wxControl *control)
 238 {
 239     return new wxToolBarTool(this, control);
 240 }
 241
 242 //-----------------------------------------------------------------------------
 243 // wxToolBar construction
 244 //-----------------------------------------------------------------------------
 245
 246 void wxToolBar::Init()
 247 {
 248     m_fg =
 249     m_bg = (GdkColor *)NULL;
 250     m_toolbar = (GtkToolbar *)NULL;
 251     m_blockEvent = FALSE;
 252 }
 253
 254 wxToolBar::~wxToolBar()
 255 {
 256     delete m_fg;
 257     delete m_bg;
 258 }
 259
 260 bool wxToolBar::Create( wxWindow *parent,
 261                         wxWindowID id,
 262                         const wxPoint& pos,
 263                         const wxSize& size,
 264                         long style,
 265                         const wxString& name )
 266 {
 267     m_needParent = TRUE;
 268     m_insertCallback = (wxInsertChildFunction)wxInsertChildInToolBar;
 269
 270     if ( !PreCreation( parent, pos, size ) ||
 271          !CreateBase( parent, id, pos, size, style, wxDefaultValidator, name ))
 272     {
 273         wxFAIL_MSG( wxT("wxToolBar creation failed") );
 274
 275         return FALSE;
 276     }
 277
 278 #ifdef __WXGTK20__
 279     m_toolbar = GTK_TOOLBAR( gtk_toolbar_new() );
 280     GtkSetStyle();
 281
 282     // Doesn't work this way.
 283     // GtkToolbarSpaceStyle space_style = GTK_TOOLBAR_SPACE_EMPTY;
 284     // gtk_widget_style_set (GTK_WIDGET (m_toolbar), "space_style", &space_style, NULL);
 285 #else
 286     GtkOrientation orient;
 287     GtkToolbarStyle gtkStyle;
 288     GetGtkStyle(style, &orient, &gtkStyle);
 289
 290     m_toolbar = GTK_TOOLBAR( gtk_toolbar_new(orient, gtkStyle) );
 291 #endif
 292
 293     SetToolSeparation(7);
 294
 295     if (style & wxTB_DOCKABLE)
 296     {
 297         m_widget = gtk_handle_box_new();
 298         gtk_container_add( GTK_CONTAINER(m_widget), GTK_WIDGET(m_toolbar) );
 299         gtk_widget_show( GTK_WIDGET(m_toolbar) );
 300
 301         if (style & wxTB_FLAT)
 302             gtk_handle_box_set_shadow_type( GTK_HANDLE_BOX(m_widget), GTK_SHADOW_NONE );
 303     }
 304     else
 305     {
 306         m_widget = gtk_event_box_new();
 307         gtk_container_add( GTK_CONTAINER(m_widget), GTK_WIDGET(m_toolbar) );
 308         ConnectWidget( m_widget );
 309         gtk_widget_show(GTK_WIDGET(m_toolbar));
 310     }
 311
 312     gtk_toolbar_set_tooltips( GTK_TOOLBAR(m_toolbar), TRUE );
 313
 314     // FIXME: there is no such function for toolbars in 2.0
 315 #ifndef __WXGTK20__
 316     if (style & wxTB_FLAT)
 317         gtk_toolbar_set_button_relief( GTK_TOOLBAR(m_toolbar), GTK_RELIEF_NONE );
 318 #endif
 319
 320
 321     m_fg = new GdkColor;
 322     m_fg->red = 0;
 323     m_fg->green = 0;
 324     m_fg->blue = 0;
 325     wxColour fg(0,0,0);
 326     fg.CalcPixel( gtk_widget_get_colormap( GTK_WIDGET(m_toolbar) ) );
 327     m_fg->pixel = fg.GetPixel();
 328
 329     m_bg = new GdkColor;
 330     m_bg->red = 65535;
 331     m_bg->green = 65535;
 332     m_bg->blue = 49980;
 333     wxColour bg(255,255,196);
 334     bg.CalcPixel( gtk_widget_get_colormap( GTK_WIDGET(m_toolbar) ) );
 335     m_bg->pixel = bg.GetPixel();
 336
 337     gtk_tooltips_force_window( GTK_TOOLBAR(m_toolbar)->tooltips );
 338
 339     GtkStyle *g_style =
 340         gtk_style_copy(
 341                 gtk_widget_get_style(
 342                     GTK_TOOLBAR(m_toolbar)->tooltips->tip_window ) );
 343
 344     g_style->bg[GTK_STATE_NORMAL] = *m_bg;
 345
 346     SET_STYLE_FONT(g_style, GtkGetDefaultGuiFont());
 347
 348     gtk_widget_set_style( GTK_TOOLBAR(m_toolbar)->tooltips->tip_window, g_style );
 349
 350     m_parent->DoAddChild( this );
 351
 352     PostCreation();
 353
 354     Show( TRUE );
 355
 356     return TRUE;
 357 }
 358
 359 void wxToolBar::GtkSetStyle()
 360 {
 361     GtkOrientation orient;
 362     GtkToolbarStyle style;
 363     GetGtkStyle(GetWindowStyle(), &orient, &style);
 364
 365     gtk_toolbar_set_orientation(m_toolbar, orient);
 366     gtk_toolbar_set_style(m_toolbar, style);
 367 }
 368
 369 void wxToolBar::SetWindowStyleFlag( long style )
 370 {
 371     wxToolBarBase::SetWindowStyleFlag(style);
 372
 373     if ( m_toolbar )
 374         GtkSetStyle();
 375 }
 376
 377 bool wxToolBar::DoInsertTool(size_t pos, wxToolBarToolBase *toolBase)
 378 {
 379     wxToolBarTool *tool = (wxToolBarTool *)toolBase;
 380
 381 #ifndef __WXGTK20__
 382     // if we have inserted a space before all the tools we must change the GTK
 383     // index by 1
 384     size_t posGtk = m_xMargin > 1 ? pos + 1 : pos;
 385 #else
 386     size_t posGtk = pos;
 387 #endif
 388
 389     if ( tool->IsButton() )
 390     {
 391         if ( !HasFlag(wxTB_NOICONS) )
 392         {
 393             wxBitmap bitmap = tool->GetNormalBitmap();
 394
 395             wxCHECK_MSG( bitmap.Ok(), FALSE,
 396                          wxT("invalid bitmap for wxToolBar icon") );
 397
 398             wxCHECK_MSG( bitmap.GetBitmap() == NULL, FALSE,
 399                          wxT("wxToolBar doesn't support GdkBitmap") );
 400
 401             wxCHECK_MSG( bitmap.GetPixmap() != NULL, FALSE,
 402                          wxT("wxToolBar::Add needs a wxBitmap") );
 403
 404             GtkWidget *tool_pixmap = (GtkWidget *)NULL;
 405
 406             GdkPixmap *pixmap = bitmap.GetPixmap();
 407
 408             GdkBitmap *mask = (GdkBitmap *)NULL;
 409             if ( bitmap.GetMask() )
 410               mask = bitmap.GetMask()->GetBitmap();
 411
 412             tool_pixmap = gtk_pixmap_new( pixmap, mask );
 413             gtk_pixmap_set_build_insensitive( GTK_PIXMAP(tool_pixmap), TRUE );
 414
 415             gtk_misc_set_alignment( GTK_MISC(tool_pixmap), 0.5, 0.5 );
 416
 417             tool->m_pixmap = tool_pixmap;
 418         }
 419     }
 420
 421     switch ( tool->GetStyle() )
 422     {
 423         case wxTOOL_STYLE_BUTTON:
 424             // for a radio button we need the widget which starts the radio
 425             // group it belongs to, i.e. the first radio button immediately
 426             // preceding this one
 427             {
 428                 GtkWidget *widget = NULL;
 429
 430                 if ( tool->IsRadio() )
 431                 {
 432                     wxToolBarToolsList::Node *node = pos ? m_tools.Item(pos - 1)
 433                                                          : NULL;
 434                     while ( node )
 435                     {
 436                         wxToolBarTool *tool = (wxToolBarTool *)node->GetData();
 437                         if ( !tool->IsRadio() )
 438                             break;
 439
 440                         widget = tool->m_item;
 441
 442                         node = node->GetPrevious();
 443                     }
 444
 445                     if ( !widget )
 446                     {
 447                         // this is the first button in the radio button group,
 448                         // it will be toggled automatically by GTK so bring the
 449                         // internal flag in sync
 450                         tool->Toggle(TRUE);
 451                     }
 452                 }
 453
 454                 tool->m_item = gtk_toolbar_insert_element
 455                                (
 456                                   m_toolbar,
 457                                   tool->GetGtkChildType(),
 458                                   widget,
 459                                   tool->GetLabel().empty()
 460                                     ? NULL
 461                                     : (const char*) wxGTK_CONV( tool->GetLabel() ),
 462                                   tool->GetShortHelp().empty()
 463                                     ? NULL
 464                                     : (const char*) wxGTK_CONV( tool->GetShortHelp() ),
 465                                   "", // tooltip_private_text (?)
 466                                   tool->m_pixmap,
 467                                   (GtkSignalFunc)gtk_toolbar_callback,
 468                                   (gpointer)tool,
 469                                   posGtk
 470                                );
 471
 472                 if ( !tool->m_item )
 473                 {
 474                     wxFAIL_MSG( _T("gtk_toolbar_insert_element() failed") );
 475
 476                     return FALSE;
 477                 }
 478
 479                 gtk_signal_connect( GTK_OBJECT(tool->m_item),
 480                                     "enter_notify_event",
 481                                     GTK_SIGNAL_FUNC(gtk_toolbar_tool_callback),
 482                                     (gpointer)tool );
 483                 gtk_signal_connect( GTK_OBJECT(tool->m_item),
 484                                     "leave_notify_event",
 485                                     GTK_SIGNAL_FUNC(gtk_toolbar_tool_callback),
 486                                     (gpointer)tool );
 487             }
 488             break;
 489
 490         case wxTOOL_STYLE_SEPARATOR:
 491             gtk_toolbar_insert_space( m_toolbar, posGtk );
 492
 493             // skip the rest
 494             return TRUE;
 495
 496         case wxTOOL_STYLE_CONTROL:
 497             gtk_toolbar_insert_widget(
 498                                        m_toolbar,
 499                                        tool->GetControl()->m_widget,
 500                                        (const char *) NULL,
 501                                        (const char *) NULL,
 502                                        posGtk
 503                                       );
 504             break;
 505     }
 506
 507     GtkRequisition req;
 508     (* GTK_WIDGET_CLASS( GTK_OBJECT_GET_CLASS(m_widget) )->size_request )
 509         (m_widget, &req );
 510     m_width = req.width + m_xMargin;
 511     m_height = req.height + 2*m_yMargin;
 512
 513     return TRUE;
 514 }
 515
 516 bool wxToolBar::DoDeleteTool(size_t WXUNUSED(pos), wxToolBarToolBase *toolBase)
 517 {
 518     wxToolBarTool *tool = (wxToolBarTool *)toolBase;
 519
 520     switch ( tool->GetStyle() )
 521     {
 522         case wxTOOL_STYLE_CONTROL:
 523             tool->GetControl()->Destroy();
 524             break;
 525
 526         case wxTOOL_STYLE_BUTTON:
 527             gtk_widget_destroy( tool->m_item );
 528             break;
 529
 530         //case wxTOOL_STYLE_SEPARATOR: -- nothing to do
 531     }
 532
 533     return TRUE;
 534 }
 535
 536 // ----------------------------------------------------------------------------
 537 // wxToolBar tools state
 538 // ----------------------------------------------------------------------------
 539
 540 void wxToolBar::DoEnableTool(wxToolBarToolBase *toolBase, bool enable)
 541 {
 542     wxToolBarTool *tool = (wxToolBarTool *)toolBase;
 543
 544     if (tool->m_item)
 545     {
 546         gtk_widget_set_sensitive( tool->m_item, enable );
 547     }
 548 }
 549
 550 void wxToolBar::DoToggleTool( wxToolBarToolBase *toolBase, bool toggle )
 551 {
 552     wxToolBarTool *tool = (wxToolBarTool *)toolBase;
 553
 554     GtkWidget *item = tool->m_item;
 555     if ( item && GTK_IS_TOGGLE_BUTTON(item) )
 556     {
 557         wxBitmap bitmap = tool->GetBitmap();
 558         if ( bitmap.Ok() )
 559         {
 560             GtkPixmap *pixmap = GTK_PIXMAP( tool->m_pixmap );
 561
 562             GdkBitmap *mask = bitmap.GetMask() ? bitmap.GetMask()->GetBitmap()
 563                                                : (GdkBitmap *)NULL;
 564
 565             gtk_pixmap_set( pixmap, bitmap.GetPixmap(), mask );
 566         }
 567
 568         m_blockEvent = TRUE;
 569
 570         gtk_toggle_button_set_state( GTK_TOGGLE_BUTTON(item), toggle );
 571
 572         m_blockEvent = FALSE;
 573     }
 574 }
 575
 576 void wxToolBar::DoSetToggle(wxToolBarToolBase * WXUNUSED(tool),
 577                             bool WXUNUSED(toggle))
 578 {
 579     // VZ: absolutely no idea about how to do it
 580     wxFAIL_MSG( _T("not implemented") );
 581 }
 582
 583 // ----------------------------------------------------------------------------
 584 // wxToolBar geometry
 585 // ----------------------------------------------------------------------------
 586
 587 wxToolBarToolBase *wxToolBar::FindToolForPosition(wxCoord WXUNUSED(x),
 588                                                   wxCoord WXUNUSED(y)) const
 589 {
 590     // VZ: GTK+ doesn't seem to have such thing
 591     wxFAIL_MSG( _T("wxToolBar::FindToolForPosition() not implemented") );
 592
 593     return (wxToolBarToolBase *)NULL;
 594 }
 595
 596 void wxToolBar::SetMargins( int x, int y )
 597 {
 598     wxCHECK_RET( GetToolsCount() == 0,
 599                  wxT("wxToolBar::SetMargins must be called before adding tools.") );
 600
 601 #ifndef __WXGTK20__
 602     if (x > 1)
 603         gtk_toolbar_append_space( m_toolbar );  // oh well
 604 #endif
 605
 606     m_xMargin = x;
 607     m_yMargin = y;
 608 }
 609
 610 void wxToolBar::SetToolSeparation( int separation )
 611 {
 612     // FIXME: this function disappeared
 613 #ifndef __WXGTK20__
 614     gtk_toolbar_set_space_size( m_toolbar, separation );
 615 #endif
 616
 617     m_toolSeparation = separation;
 618 }
 619
 620 void wxToolBar::SetToolShortHelp( int id, const wxString& helpString )
 621 {
 622     wxToolBarTool *tool = (wxToolBarTool *)FindById(id);
 623
 624     if ( tool )
 625     {
 626         (void)tool->SetShortHelp(helpString);
 627         gtk_tooltips_set_tip(m_toolbar->tooltips, tool->m_item,
 628                              wxGTK_CONV( helpString ), "");
 629     }
 630 }
 631
 632 // ----------------------------------------------------------------------------
 633 // wxToolBar idle handling
 634 // ----------------------------------------------------------------------------
 635
 636 void wxToolBar::OnInternalIdle()
 637 {
 638     wxCursor cursor = m_cursor;
 639     if (g_globalCursor.Ok()) cursor = g_globalCursor;
 640
 641     if (cursor.Ok())
 642     {
 643         /* I now set the cursor the anew in every OnInternalIdle call
 644            as setting the cursor in a parent window also effects the
 645            windows above so that checking for the current cursor is
 646            not possible. */
 647
 648         if (HasFlag(wxTB_DOCKABLE) && (m_widget->window))
 649         {
 650             /* if the toolbar is dockable, then m_widget stands for the
 651                GtkHandleBox widget, which uses its own window so that we
 652                can set the cursor for it. if the toolbar is not dockable,
 653                m_widget comes from m_toolbar which uses its parent's
 654                window ("windowless windows") and thus we cannot set the
 655                cursor. */
 656             gdk_window_set_cursor( m_widget->window, cursor.GetCursor() );
 657         }
 658
 659         wxToolBarToolsList::Node *node = m_tools.GetFirst();
 660         while ( node )
 661         {
 662             wxToolBarTool *tool = (wxToolBarTool *)node->GetData();
 663             node = node->GetNext();
 664
 665             GtkWidget *item = tool->m_item;
 666             if ( item )
 667             {
 668                 GdkWindow *window = item->window;
 669
 670                 if ( window )
 671                 {
 672                     gdk_window_set_cursor( window, cursor.GetCursor() );
 673                 }
 674             }
 675         }
 676     }
 677
 678     UpdateWindowUI();
 679 }
 680
 681 #endif // wxUSE_TOOLBAR_NATIVE