interface/wx/scrolwin.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        scrolwin.h
   3 // Purpose:     interface of wxScrolled template
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows licence
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     Possible values for the second argument of wxScrolled::ShowScrollbars().
  11  */
  12 enum wxScrollbarVisibility
  13 {
  14     wxSHOW_SB_NEVER = -1,   ///< Never show the scrollbar at all.
  15     wxSHOW_SB_DEFAULT,      ///< Show scrollbar only if it is needed.
  16     wxSHOW_SB_ALWAYS        ///< Always show scrollbar, even if not needed.
  17 };
  18
  19 /**
  20
  21     The wxScrolled class manages scrolling for its client area, transforming
  22     the coordinates according to the scrollbar positions, and setting the
  23     scroll positions, thumb sizes and ranges according to the area in view.
  24
  25     There are two commonly used (but not the only possible!) specializations of
  26     this class:
  27
  28     - ::wxScrolledWindow, aka wxScrolled<wxPanel>, is equivalent to
  29       ::wxScrolledWindow from earlier versions. Derived from wxPanel, it shares
  30       wxPanel's behaviour with regard to TAB traversal and focus handling. Use
  31       this if the scrolled window will have child controls.
  32
  33     - ::wxScrolledCanvas, aka wxScrolled<wxWindow>, derives from wxWindow and
  34       so doesn't handle children specially. This is suitable e.g. for
  35       implementing scrollable controls such as tree or list controls.
  36
  37     Starting from version 2.4 of wxWidgets, there are several ways to use a
  38     ::wxScrolledWindow (and now wxScrolled). In particular, there are
  39     three ways to set the size of the scrolling area:
  40
  41     One way is to set the scrollbars directly using a call to SetScrollbars().
  42     This is the way it used to be in any previous version of wxWidgets and it
  43     will be kept for backwards compatibility.
  44
  45     An additional method of manual control, which requires a little less
  46     computation of your own, is to set the total size of the scrolling area by
  47     calling either wxWindow::SetVirtualSize(), or wxWindow::FitInside(), and
  48     setting the scrolling increments for it by calling SetScrollRate().
  49     Scrolling in some orientation is enabled by setting a non-zero increment
  50     for it.
  51
  52     The most automatic and newest way is to simply let sizers determine the
  53     scrolling area. This is now the default when you set an interior sizer into
  54     a wxScrolled with wxWindow::SetSizer().  The scrolling area will be
  55     set to the size requested by the sizer and the scrollbars will be assigned
  56     for each orientation according to the need for them and the scrolling
  57     increment set by SetScrollRate().  As above, scrolling is only enabled in
  58     orientations with a non-zero increment.  You can influence the minimum size
  59     of the scrolled area controlled by a sizer by calling
  60     wxWindow::SetVirtualSizeHints(). (Calling SetScrollbars() has analogous
  61     effects in wxWidgets 2.4 -- in later versions it may not continue to
  62     override the sizer.)
  63
  64     Note that if maximum size hints are still supported by
  65     wxWindow::SetVirtualSizeHints(), use them at your own dire risk. They may
  66     or may not have been removed for 2.4, but it really only makes sense to set
  67     minimum size hints here.  We should probably replace
  68     wxWindow::SetVirtualSizeHints() with wxWindow::SetMinVirtualSize() or
  69     similar and remove it entirely in future.
  70
  71     @todo review docs for this class replacing SetVirtualSizeHints() with
  72           SetMinClientSize().
  73
  74     As with all windows, an application can draw onto a wxScrolled using a
  75     @ref overview_dc "device context".
  76
  77     You have the option of handling the OnPaint handler or overriding the
  78     wxScrolled::OnDraw() function, which is passed a pre-scrolled device
  79     context (prepared by wxScrolled::DoPrepareDC()).
  80
  81     If you don't wish to calculate your own scrolling, you must call
  82     DoPrepareDC() when not drawing from within OnDraw(), to set the device
  83     origin for the device context according to the current scroll position.
  84
  85     A wxScrolled will normally scroll itself and therefore its child windows
  86     as well. It might however be desired to scroll a different window than
  87     itself: e.g. when designing a spreadsheet, you will normally only have to
  88     scroll the (usually white) cell area, whereas the (usually grey) label area
  89     will scroll very differently. For this special purpose, you can call
  90     SetTargetWindow() which means that pressing the scrollbars will scroll a
  91     different window.
  92
  93     Note that the underlying system knows nothing about scrolling coordinates,
  94     so that all system functions (mouse events, expose events, refresh calls
  95     etc) as well as the position of subwindows are relative to the "physical"
  96     origin of the scrolled window. If the user insert a child window at
  97     position (10,10) and scrolls the window down 100 pixels (moving the child
  98     window out of the visible area), the child window will report a position
  99     of (10,-90).
 100
 101     @beginStyleTable
 102     @style{wxRETAINED}
 103            Uses a backing pixmap to speed refreshes. Motif only.
 104     @endStyleTable
 105
 106
 107     @beginEventEmissionTable{wxScrollWinEvent}
 108     @event{EVT_SCROLLWIN(func)}
 109         Process all scroll events.
 110     @event{EVT_SCROLLWIN_TOP(func)}
 111         Process @c wxEVT_SCROLLWIN_TOP scroll-to-top events.
 112     @event{EVT_SCROLLWIN_BOTTOM(func)}
 113         Process @c wxEVT_SCROLLWIN_BOTTOM scroll-to-bottom events.
 114     @event{EVT_SCROLLWIN_LINEUP(func)}
 115         Process @c wxEVT_SCROLLWIN_LINEUP line up events.
 116     @event{EVT_SCROLLWIN_LINEDOWN(func)}
 117         Process @c wxEVT_SCROLLWIN_LINEDOWN line down events.
 118     @event{EVT_SCROLLWIN_PAGEUP(func)}
 119         Process @c wxEVT_SCROLLWIN_PAGEUP page up events.
 120     @event{EVT_SCROLLWIN_PAGEDOWN(func)}
 121         Process @c wxEVT_SCROLLWIN_PAGEDOWN page down events.
 122     @event{EVT_SCROLLWIN_THUMBTRACK(func)}
 123         Process @c wxEVT_SCROLLWIN_THUMBTRACK thumbtrack events
 124         (frequent events sent as the user drags the thumbtrack).
 125     @event{EVT_SCROLLWIN_THUMBRELEASE(func)}
 126         Process @c wxEVT_SCROLLWIN_THUMBRELEASE thumb release events.
 127     @endEventTable
 128
 129     @note
 130         Don't confuse wxScrollWinEvents generated by this class with
 131         wxScrollEvent objects generated by wxScrollBar and wxSlider.
 132
 133
 134     @remarks
 135     Use wxScrolled for applications where the user scrolls by a fixed amount,
 136     and where a 'page' can be interpreted to be the current visible portion of
 137     the window. For more sophisticated applications, use the wxScrolled
 138     implementation as a guide to build your own scroll behaviour or use
 139     wxVScrolledWindow or its variants.
 140
 141     @since The wxScrolled template exists since version 2.9.0. In older versions,
 142            only ::wxScrolledWindow (equivalent of wxScrolled<wxPanel>) was
 143            available.
 144
 145     @library{wxcore}
 146     @category{miscwnd}
 147
 148     @see wxScrollBar, wxClientDC, wxPaintDC,
 149          wxVScrolledWindow, wxHScrolledWindow, wxHVScrolledWindow,
 150 */
 151 template<class T>
 152 class wxScrolled : public T
 153 {
 154 public:
 155     /// Default constructor.
 156     wxScrolled();
 157
 158     /**
 159         Constructor.
 160
 161         @param parent
 162             Parent window.
 163         @param id
 164             Window identifier. The value @c wxID_ANY indicates a default value.
 165         @param pos
 166             Window position. If a position of ::wxDefaultPosition is specified
 167             then a default position is chosen.
 168         @param size
 169             Window size. If a size of ::wxDefaultSize is specified then the
 170             window is sized appropriately.
 171         @param style
 172             Window style. See wxScrolled.
 173         @param name
 174             Window name.
 175
 176         @remarks The window is initially created without visible scrollbars.
 177                  Call SetScrollbars() to specify how big the virtual window
 178                  size should be.
 179     */
 180     wxScrolled(wxWindow* parent, wxWindowID id = -1,
 181                const wxPoint& pos = wxDefaultPosition,
 182                const wxSize& size = wxDefaultSize,
 183                long style = wxHSCROLL | wxVSCROLL,
 184                const wxString& name = "scrolledWindow");
 185
 186
 187     /**
 188         Translates the logical coordinates to the device ones. For example, if
 189         a window is scrolled 10 pixels to the bottom, the device coordinates of
 190         the origin are (0, 0) (as always), but the logical coordinates are (0,
 191         10) and so the call to CalcScrolledPosition(0, 10, xx, yy) will return
 192         0 in yy.
 193
 194         @beginWxPerlOnly
 195         In wxPerl this method takes two parameters and returns a
 196         2-element list (xx, yy).
 197         @endWxPerlOnly
 198
 199         @see CalcUnscrolledPosition()
 200     */
 201     void CalcScrolledPosition(int x, int y, int* xx, int* yy) const;
 202
 203     /**
 204         Translates the device coordinates to the logical ones. For example, if
 205         a window is scrolled 10 pixels to the bottom, the device coordinates of
 206         the origin are (0, 0) (as always), but the logical coordinates are (0,
 207         10) and so the call to CalcUnscrolledPosition(0, 0, xx, yy) will return
 208         10 in yy.
 209
 210         @beginWxPerlOnly
 211         In wxPerl this method takes two parameters and returns a
 212         2-element list (xx, yy).
 213         @endWxPerlOnly
 214
 215         @see CalcScrolledPosition()
 216     */
 217     void CalcUnscrolledPosition(int x, int y, int* xx, int* yy) const;
 218
 219     /**
 220         Creates the window for two-step construction. Derived classes
 221         should call or replace this function. See wxScrolled::wxScrolled()
 222         for details.
 223     */
 224     bool Create(wxWindow* parent, wxWindowID id = -1,
 225                 const wxPoint& pos = wxDefaultPosition,
 226                 const wxSize& size = wxDefaultSize,
 227                 long style = wxHSCROLL | wxVSCROLL,
 228                 const wxString& name = "scrolledWindow");
 229
 230     /**
 231         Disable use of keyboard keys for scrolling.
 232
 233         By default cursor movement keys (including Home, End, Page Up and Down)
 234         are used to scroll the window appropriately. If the derived class uses
 235         these keys for something else, e.g. changing the currently selected
 236         item, this function can be used to disable this behaviour as it's not
 237         only not necessary then but can actually be actively harmful if another
 238         object forwards a keyboard event corresponding to one of the above keys
 239         to us using ProcessWindowEvent() because the event will always be
 240         processed which can be undesirable.
 241
 242         @since 2.9.1
 243     */
 244     void DisableKeyboardScrolling();
 245
 246     /**
 247         Call this function to prepare the device context for drawing a scrolled
 248         image.
 249
 250         It sets the device origin according to the current scroll position.
 251         DoPrepareDC() is called automatically within the default @c wxEVT_PAINT
 252         event handler, so your OnDraw() override will be passed an already
 253         'pre-scrolled' device context. However, if you wish to draw from
 254         outside of OnDraw() (e.g. from your own @c wxEVT_PAINT handler), you
 255         must call this function yourself.
 256
 257         For example:
 258         @code
 259         void MyWindow::OnEvent(wxMouseEvent& event)
 260         {
 261           wxClientDC dc(this);
 262           DoPrepareDC(dc);
 263
 264           dc.SetPen(*wxBLACK_PEN);
 265           float x, y;
 266           event.Position(&x, &y);
 267           if (xpos > -1 && ypos > -1 && event.Dragging())
 268           {
 269             dc.DrawLine(xpos, ypos, x, y);
 270           }
 271           xpos = x;
 272           ypos = y;
 273         }
 274         @endcode
 275
 276         Notice that the function sets the origin by moving it relatively to the
 277         current origin position, so you shouldn't change the origin before
 278         calling DoPrepareDC() or, if you do, reset it to (0, 0) later. If you
 279         call DoPrepareDC() immediately after device context creation, as in the
 280         example above, this problem doesn't arise, of course, so it is
 281         customary to do it like this.
 282     */
 283     void DoPrepareDC(wxDC& dc);
 284
 285     /**
 286         Enable or disable physical scrolling in the given direction. Physical
 287         scrolling is the physical transfer of bits up or down the
 288         screen when a scroll event occurs. If the application scrolls by a
 289         variable amount (e.g. if there are different font sizes) then physical
 290         scrolling will not work, and you should switch it off. Note that you
 291         will have to reposition child windows yourself, if physical scrolling
 292         is disabled.
 293
 294         @param xScrolling
 295             If @true, enables physical scrolling in the x direction.
 296         @param yScrolling
 297             If @true, enables physical scrolling in the y direction.
 298
 299         @remarks Physical scrolling may not be available on all platforms. Where
 300                  it is available, it is enabled by default.
 301     */
 302     void EnableScrolling(bool xScrolling, bool yScrolling);
 303
 304     /**
 305         Set the scrollbar visibility.
 306
 307         By default the scrollbar in the corresponding direction is only shown
 308         if it is needed, i.e. if the virtual size of the scrolled window in
 309         this direction is greater than the current physical window size. Using
 310         this function the scrollbar visibility can be changed to be:
 311             - wxSHOW_SB_ALWAYS: To always show the scrollbar, even if it is
 312                 not needed currently (wxALWAYS_SHOW_SB style can be used during
 313                 the window creation to achieve the same effect but it applies
 314                 in both directions).
 315             - wxSHOW_SB_NEVER: To never show the scrollbar at all. In this case
 316                 the program should presumably provide some other way for the
 317                 user to scroll the window.
 318             - wxSHOW_SB_DEFAULT: To restore the default behaviour described
 319                 above.
 320
 321         @param horz
 322             The desired visibility for the horizontal scrollbar.
 323         @param vert
 324             The desired visibility for the vertical scrollbar.
 325
 326         @since 2.9.0
 327      */
 328     void ShowScrollbars(wxScrollbarVisibility horz, wxScrollbarVisibility vert);
 329
 330     /**
 331         Get the number of pixels per scroll unit (line), in each direction, as
 332         set by SetScrollbars(). A value of zero indicates no scrolling in that
 333         direction.
 334
 335         @param xUnit
 336             Receives the number of pixels per horizontal unit.
 337         @param yUnit
 338             Receives the number of pixels per vertical unit.
 339
 340         @beginWxPerlOnly
 341         In wxPerl this method takes no parameters and returns a
 342         2-element list (xUnit, yUnit).
 343         @endWxPerlOnly
 344
 345         @see SetScrollbars(), GetVirtualSize()
 346     */
 347     void GetScrollPixelsPerUnit(int* xUnit, int* yUnit) const;
 348
 349     /**
 350         Get the position at which the visible portion of the window starts.
 351
 352         @param x
 353             Receives the first visible x position in scroll units.
 354         @param y
 355             Receives the first visible y position in scroll units.
 356
 357         @remarks
 358             If either of the scrollbars is not at the home position, @a x
 359             and/or @a y will be greater than zero.
 360             Combined with wxWindow::GetClientSize(), the application can use this
 361             function to efficiently redraw only the visible portion of the window.
 362             The positions are in logical scroll units, not pixels, so to convert
 363             to pixels you will have to multiply by the number of pixels per scroll
 364             increment.
 365
 366         @beginWxPerlOnly
 367         In wxPerl this method takes no parameters and returns a
 368         2-element list (x, y).
 369         @endWxPerlOnly
 370
 371         @see SetScrollbars(), Scroll()
 372     */
 373     void GetViewStart(int* x, int* y) const;
 374
 375     /**
 376         This is a simple overload of GetViewStart(int*,int*); see that function
 377         for more info.
 378     */
 379     wxPoint GetViewStart() const;
 380
 381     /**
 382         Gets the size in device units of the scrollable window area (as
 383         opposed to the client size, which is the area of the window currently
 384         visible).
 385
 386         @param x
 387             Receives the length of the scrollable window, in pixels.
 388         @param y
 389             Receives the height of the scrollable window, in pixels.
 390
 391         @remarks Use wxDC::DeviceToLogicalX() and wxDC::DeviceToLogicalY() to
 392                  translate these units to logical units.
 393
 394         @beginWxPerlOnly
 395         In wxPerl this method takes no parameters and returns a
 396         2-element list (xUnit, yUnit).
 397         @endWxPerlOnly
 398
 399         @see SetScrollbars(), GetScrollPixelsPerUnit()
 400     */
 401     void GetVirtualSize(int* x, int* y) const;
 402
 403     /**
 404         Motif only: @true if the window has a backing bitmap.
 405     */
 406     bool IsRetained() const;
 407
 408     /**
 409         Called by the default paint event handler to allow the application to
 410         define painting behaviour without having to worry about calling
 411         DoPrepareDC().
 412
 413         Instead of overriding this function you may also just process the paint
 414         event in the derived class as usual, but then you will have to call
 415         DoPrepareDC() yourself.
 416     */
 417     virtual void OnDraw(wxDC& dc);
 418
 419     /**
 420         This function is for backwards compatibility only and simply calls
 421         DoPrepareDC() now. Notice that it is not called by the default paint
 422         event handle (DoPrepareDC() is), so overriding this method in your
 423         derived class is useless.
 424     */
 425     void PrepareDC(wxDC& dc);
 426
 427     /**
 428         Scrolls a window so the view start is at the given point.
 429
 430         @param x
 431             The x position to scroll to, in scroll units.
 432         @param y
 433             The y position to scroll to, in scroll units.
 434
 435         @remarks The positions are in scroll units, not pixels, so to convert to
 436                  pixels you will have to multiply by the number of
 437                  pixels per scroll increment. If either parameter is
 438                  ::wxDefaultCoord (-1), that position will be ignored (no change
 439                  in that direction).
 440
 441         @see SetScrollbars(), GetScrollPixelsPerUnit()
 442     */
 443     void Scroll(int x, int y);
 444
 445     /**
 446         This is an overload of Scroll(int,int); see that function for more info.
 447     */
 448     void Scroll(const wxPoint& pt);
 449
 450     /**
 451         Set the horizontal and vertical scrolling increment only. See the
 452         pixelsPerUnit parameter in SetScrollbars().
 453     */
 454     void SetScrollRate(int xstep, int ystep);
 455
 456     /**
 457         Sets up vertical and/or horizontal scrollbars.
 458
 459         The first pair of parameters give the number of pixels per 'scroll
 460         step', i.e. amount moved when the up or down scroll arrows are pressed.
 461         The second pair gives the length of scrollbar in scroll steps, which
 462         sets the size of the virtual window.
 463
 464         @a xPos and @a yPos optionally specify a position to scroll to
 465         immediately.
 466
 467         For example, the following gives a window horizontal and vertical
 468         scrollbars with 20 pixels per scroll step, and a size of 50 steps (1000
 469         pixels) in each direction:
 470         @code
 471         window->SetScrollbars(20, 20, 50, 50);
 472         @endcode
 473
 474         wxScrolled manages the page size itself, using the current client
 475         window size as the page size.
 476
 477         Note that for more sophisticated scrolling applications, for example
 478         where scroll steps may be variable according to the position in the
 479         document, it will be necessary to derive a new class from wxWindow,
 480         overriding OnSize() and adjusting the scrollbars appropriately.
 481
 482         @param pixelsPerUnitX
 483             Pixels per scroll unit in the horizontal direction.
 484         @param pixelsPerUnitY
 485             Pixels per scroll unit in the vertical direction.
 486         @param noUnitsX
 487             Number of units in the horizontal direction.
 488         @param noUnitsY
 489             Number of units in the vertical direction.
 490         @param xPos
 491             Position to initialize the scrollbars in the horizontal direction,
 492             in scroll units.
 493         @param yPos
 494             Position to initialize the scrollbars in the vertical direction, in
 495             scroll units.
 496         @param noRefresh
 497             Will not refresh window if @true.
 498
 499         @see wxWindow::SetVirtualSize()
 500     */
 501     void SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
 502                        int noUnitsX,
 503                        int noUnitsY,
 504                        int xPos = 0,
 505                        int yPos = 0,
 506                        bool noRefresh = false);
 507
 508     /**
 509         Call this function to tell wxScrolled to perform the actual scrolling
 510         on a different window (and not on itself).
 511
 512         This method is useful when only a part of the window should be
 513         scrolled. A typical example is a control consisting of a fixed header
 514         and the scrollable contents window: the scrollbars are attached to the
 515         main window itself, hence it, and not the contents window must be
 516         derived from wxScrolled, but only the contents window scrolls when the
 517         scrollbars are used. To implement such setup, you need to call this
 518         method with the contents window as argument.
 519
 520         Notice that if this method is used, GetSizeAvailableForScrollTarget()
 521         method must be overridden.
 522     */
 523     void SetTargetWindow(wxWindow *window);
 524     wxWindow *GetTargetWindow() const;
 525
 526
 527     void SetTargetRect(const wxRect& rect);
 528     wxRect GetTargetRect() const;
 529
 530     int GetScrollPageSize(int orient) const;
 531     void SetScrollPageSize(int orient, int pageSize);
 532     int GetScrollLines( int orient ) const;
 533     void SetScale(double xs, double ys);
 534     double GetScaleX() const;
 535     double GetScaleY() const;
 536
 537     virtual void AdjustScrollbars();
 538
 539     /**
 540        Are we generating the autoscroll events?
 541      */
 542     bool IsAutoScrolling() const;
 543
 544     /**
 545        Stop generating the scroll events when mouse is held outside the
 546        window.
 547      */
 548     void StopAutoScrolling();
 549
 550     /**
 551        This method can be overridden in a derived class to forbid sending the
 552        auto scroll events - note that unlike StopAutoScrolling() it doesn't
 553        stop the timer, so it will be called repeatedly and will typically
 554        return different values depending on the current mouse position
 555
 556        The base class version just returns true.
 557     */
 558     virtual bool SendAutoScrollEvents(wxScrollWinEvent& event) const;
 559
 560
 561 protected:
 562     /**
 563         Function which must be overridden to implement the size available for
 564         the scroll target for the given size of the main window.
 565
 566         This method must be overridden if SetTargetWindow() is used (it is
 567         never called otherwise). The implementation should decrease the @a size
 568         to account for the size of the non-scrollable parts of the main window
 569         and return only the size available for the scrollable window itself.
 570         E.g. in the example given in SetTargetWindow() documentation the
 571         function would subtract the height of the header window from the
 572         vertical component of @a size.
 573      */
 574     virtual wxSize GetSizeAvailableForScrollTarget(const wxSize& size);
 575 };
 576
 577
 578 /**
 579     Scrolled window derived from wxPanel.
 580
 581     See wxScrolled for a detailed description.
 582
 583     @note Note that because this class derives from wxPanel, it shares its
 584           behaviour with regard to TAB traversal and focus handling (in
 585           particular, it forwards focus to its children). If you don't want
 586           this behaviour, use ::wxScrolledCanvas instead.
 587
 588     @note ::wxScrolledWindow is an alias for wxScrolled<wxPanel> since version
 589           2.9.0. In older versions, it was a standalone class.
 590
 591     @library{wxcore}
 592     @category{miscwnd}
 593
 594     @see wxScrolled, ::wxScrolledCanvas
 595 */
 596 typedef wxScrolled<wxPanel> wxScrolledWindow;
 597
 598 /**
 599     Alias for wxScrolled<wxWindow>. Scrolled window that doesn't have children
 600     and so doesn't need or want special handling of TAB traversal.
 601
 602     @since 2.9.0
 603
 604     @library{wxcore}
 605     @category{miscwnd}
 606
 607     @see wxScrolled, ::wxScrolledWindow
 608 */
 609 typedef wxScrolled<wxWindow> wxScrolledCanvas;