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       implementating 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     @remarks
 107     Use wxScrolled for applications where the user scrolls by a fixed amount,
 108     and where a 'page' can be interpreted to be the current visible portion of
 109     the window. For more sophisticated applications, use the wxScrolled
 110     implementation as a guide to build your own scroll behaviour or use
 111     wxVScrolledWindow or its variants.
 112
 113     @since The wxScrolled template exists since version 2.9.0. In older versions,
 114            only ::wxScrolledWindow (equivalent of wxScrolled<wxPanel>) was
 115            available.
 116
 117     @library{wxcore}
 118     @category{miscwnd}
 119
 120     @see wxScrollBar, wxClientDC, wxPaintDC,
 121          wxVScrolledWindow, wxHScrolledWindow, wxHVScrolledWindow,
 122 */
 123 template<class T>
 124 class wxScrolled : public T
 125 {
 126 public:
 127     /// Default constructor.
 128     wxScrolled();
 129
 130     /**
 131         Constructor.
 132
 133         @param parent
 134             Parent window.
 135         @param id
 136             Window identifier. The value @c wxID_ANY indicates a default value.
 137         @param pos
 138             Window position. If a position of ::wxDefaultPosition is specified
 139             then a default position is chosen.
 140         @param size
 141             Window size. If a size of ::wxDefaultSize is specified then the
 142             window is sized appropriately.
 143         @param style
 144             Window style. See wxScrolled.
 145         @param name
 146             Window name.
 147
 148         @remarks The window is initially created without visible scrollbars.
 149                  Call SetScrollbars() to specify how big the virtual window
 150                  size should be.
 151     */
 152     wxScrolled(wxWindow* parent, wxWindowID id = -1,
 153                const wxPoint& pos = wxDefaultPosition,
 154                const wxSize& size = wxDefaultSize,
 155                long style = wxHSCROLL | wxVSCROLL,
 156                const wxString& name = "scrolledWindow");
 157
 158
 159     /**
 160         Translates the logical coordinates to the device ones. For example, if
 161         a window is scrolled 10 pixels to the bottom, the device coordinates of
 162         the origin are (0, 0) (as always), but the logical coordinates are (0,
 163         10) and so the call to CalcScrolledPosition(0, 10, xx, yy) will return
 164         0 in yy.
 165
 166         @beginWxPerlOnly
 167         In wxPerl this method takes two parameters and returns a
 168         2-element list (xx, yy).
 169         @endWxPerlOnly
 170
 171         @see CalcUnscrolledPosition()
 172     */
 173     void CalcScrolledPosition(int x, int y, int* xx, int* yy) const;
 174
 175     /**
 176         Translates the device coordinates to the logical ones. For example, if
 177         a window is scrolled 10 pixels to the bottom, the device coordinates of
 178         the origin are (0, 0) (as always), but the logical coordinates are (0,
 179         10) and so the call to CalcUnscrolledPosition(0, 0, xx, yy) will return
 180         10 in yy.
 181
 182         @beginWxPerlOnly
 183         In wxPerl this method takes two parameters and returns a
 184         2-element list (xx, yy).
 185         @endWxPerlOnly
 186
 187         @see CalcScrolledPosition()
 188     */
 189     void CalcUnscrolledPosition(int x, int y, int* xx, int* yy) const;
 190
 191     /**
 192         Creates the window for two-step construction. Derived classes
 193         should call or replace this function. See wxScrolled::wxScrolled()
 194         for details.
 195     */
 196     bool Create(wxWindow* parent, wxWindowID id = -1,
 197                 const wxPoint& pos = wxDefaultPosition,
 198                 const wxSize& size = wxDefaultSize,
 199                 long style = wxHSCROLL | wxVSCROLL,
 200                 const wxString& name = "scrolledWindow");
 201
 202     /**
 203         Disable use of keyboard keys for scrolling.
 204
 205         By default cursor movement keys (including Home, End, Page Up and Down)
 206         are used to scroll the window appropriately. If the derived class uses
 207         these keys for something else, e.g. changing the currently selected
 208         item, this function can be used to disable this behaviour as it's not
 209         only not necessary then but can actually be actively harmful if another
 210         object forwards a keyboard event corresponding to one of the above keys
 211         to us using ProcessWindowEvent() because the event will always be
 212         processed which can be undesirable.
 213
 214         @since 2.9.1
 215     */
 216     void DisableKeyboardScrolling();
 217
 218     /**
 219         Call this function to prepare the device context for drawing a scrolled
 220         image.
 221
 222         It sets the device origin according to the current scroll position.
 223         DoPrepareDC() is called automatically within the default @c wxEVT_PAINT
 224         event handler, so your OnDraw() override will be passed an already
 225         'pre-scrolled' device context. However, if you wish to draw from
 226         outside of OnDraw() (e.g. from your own @c wxEVT_PAINT handler), you
 227         must call this function yourself.
 228
 229         For example:
 230         @code
 231         void MyWindow::OnEvent(wxMouseEvent& event)
 232         {
 233           wxClientDC dc(this);
 234           DoPrepareDC(dc);
 235
 236           dc.SetPen(*wxBLACK_PEN);
 237           float x, y;
 238           event.Position(&x, &y);
 239           if (xpos > -1 && ypos > -1 && event.Dragging())
 240           {
 241             dc.DrawLine(xpos, ypos, x, y);
 242           }
 243           xpos = x;
 244           ypos = y;
 245         }
 246         @endcode
 247
 248         Notice that the function sets the origin by moving it relatively to the
 249         current origin position, so you shouldn't change the origin before
 250         calling DoPrepareDC() or, if you do, reset it to (0, 0) later. If you
 251         call DoPrepareDC() immediately after device context creation, as in the
 252         example above, this problem doesn't arise, of course, so it is
 253         customary to do it like this.
 254     */
 255     void DoPrepareDC(wxDC& dc);
 256
 257     /**
 258         Enable or disable physical scrolling in the given direction. Physical
 259         scrolling is the physical transfer of bits up or down the
 260         screen when a scroll event occurs. If the application scrolls by a
 261         variable amount (e.g. if there are different font sizes) then physical
 262         scrolling will not work, and you should switch it off. Note that you
 263         will have to reposition child windows yourself, if physical scrolling
 264         is disabled.
 265
 266         @param xScrolling
 267             If @true, enables physical scrolling in the x direction.
 268         @param yScrolling
 269             If @true, enables physical scrolling in the y direction.
 270
 271         @remarks Physical scrolling may not be available on all platforms. Where
 272                  it is available, it is enabled by default.
 273     */
 274     void EnableScrolling(bool xScrolling, bool yScrolling);
 275
 276     /**
 277         Set the scrollbar visibility.
 278
 279         By default the scrollbar in the corresponding direction is only shown
 280         if it is needed, i.e. if the virtual size of the scrolled window in
 281         this direction is greater than the current physical window size. Using
 282         this function the scrollbar visibility can be changed to be:
 283             - wxSHOW_SB_ALWAYS: To always show the scrollbar, even if it is
 284                 not needed currently (wxALWAYS_SHOW_SB style can be used during
 285                 the window creation to achieve the same effect but it applies
 286                 in both directions).
 287             - wxSHOW_SB_NEVER: To never show the scrollbar at all. In this case
 288                 the program should presumably provide some other way for the
 289                 user to scroll the window.
 290             - wxSHOW_SB_DEFAULT: To restore the default behaviour described
 291                 above.
 292
 293         @param horz
 294             The desired visibility for the horizontal scrollbar.
 295         @param vert
 296             The desired visibility for the vertical scrollbar.
 297
 298         @since 2.9.0
 299      */
 300     void ShowScrollbars(wxScrollbarVisibility horz, wxScrollbarVisibility vert);
 301
 302     /**
 303         Get the number of pixels per scroll unit (line), in each direction, as
 304         set by SetScrollbars(). A value of zero indicates no scrolling in that
 305         direction.
 306
 307         @param xUnit
 308             Receives the number of pixels per horizontal unit.
 309         @param yUnit
 310             Receives the number of pixels per vertical unit.
 311
 312         @beginWxPerlOnly
 313         In wxPerl this method takes no parameters and returns a
 314         2-element list (xUnit, yUnit).
 315         @endWxPerlOnly
 316
 317         @see SetScrollbars(), GetVirtualSize()
 318     */
 319     void GetScrollPixelsPerUnit(int* xUnit, int* yUnit) const;
 320
 321     /**
 322         Get the position at which the visible portion of the window starts.
 323
 324         @param x
 325             Receives the first visible x position in scroll units.
 326         @param y
 327             Receives the first visible y position in scroll units.
 328
 329         @remarks
 330             If either of the scrollbars is not at the home position, @a x
 331             and/or @a y will be greater than zero.
 332             Combined with wxWindow::GetClientSize(), the application can use this
 333             function to efficiently redraw only the visible portion of the window.
 334             The positions are in logical scroll units, not pixels, so to convert
 335             to pixels you will have to multiply by the number of pixels per scroll
 336             increment.
 337
 338         @beginWxPerlOnly
 339         In wxPerl this method takes no parameters and returns a
 340         2-element list (x, y).
 341         @endWxPerlOnly
 342
 343         @see SetScrollbars(), Scroll()
 344     */
 345     void GetViewStart(int* x, int* y) const;
 346
 347     /**
 348         This is a simple overload of GetViewStart(int*,int*); see that function
 349         for more info.
 350     */
 351     wxPoint GetViewStart() const;
 352
 353     /**
 354         Gets the size in device units of the scrollable window area (as
 355         opposed to the client size, which is the area of the window currently
 356         visible).
 357
 358         @param x
 359             Receives the length of the scrollable window, in pixels.
 360         @param y
 361             Receives the height of the scrollable window, in pixels.
 362
 363         @remarks Use wxDC::DeviceToLogicalX() and wxDC::DeviceToLogicalY() to
 364                  translate these units to logical units.
 365
 366         @beginWxPerlOnly
 367         In wxPerl this method takes no parameters and returns a
 368         2-element list (xUnit, yUnit).
 369         @endWxPerlOnly
 370
 371         @see SetScrollbars(), GetScrollPixelsPerUnit()
 372     */
 373     void GetVirtualSize(int* x, int* y) const;
 374
 375     /**
 376         Motif only: @true if the window has a backing bitmap.
 377     */
 378     bool IsRetained() const;
 379
 380     /**
 381         Called by the default paint event handler to allow the application to
 382         define painting behaviour without having to worry about calling
 383         DoPrepareDC().
 384
 385         Instead of overriding this function you may also just process the paint
 386         event in the derived class as usual, but then you will have to call
 387         DoPrepareDC() yourself.
 388     */
 389     virtual void OnDraw(wxDC& dc);
 390
 391     /**
 392         This function is for backwards compatibility only and simply calls
 393         DoPrepareDC() now. Notice that it is not called by the default paint
 394         event handle (DoPrepareDC() is), so overriding this method in your
 395         derived class is useless.
 396     */
 397     void PrepareDC(wxDC& dc);
 398
 399     /**
 400         Scrolls a window so the view start is at the given point.
 401
 402         @param x
 403             The x position to scroll to, in scroll units.
 404         @param y
 405             The y position to scroll to, in scroll units.
 406
 407         @remarks The positions are in scroll units, not pixels, so to convert to
 408                  pixels you will have to multiply by the number of
 409                  pixels per scroll increment. If either parameter is
 410                  ::wxDefaultCoord (-1), that position will be ignored (no change
 411                  in that direction).
 412
 413         @see SetScrollbars(), GetScrollPixelsPerUnit()
 414     */
 415     void Scroll(int x, int y);
 416
 417     /**
 418         This is an overload of Scroll(int,int); see that function for more info.
 419     */
 420     void Scroll(const wxPoint& pt);
 421
 422     /**
 423         Set the horizontal and vertical scrolling increment only. See the
 424         pixelsPerUnit parameter in SetScrollbars().
 425     */
 426     void SetScrollRate(int xstep, int ystep);
 427
 428     /**
 429         Sets up vertical and/or horizontal scrollbars.
 430
 431         The first pair of parameters give the number of pixels per 'scroll
 432         step', i.e. amount moved when the up or down scroll arrows are pressed.
 433         The second pair gives the length of scrollbar in scroll steps, which
 434         sets the size of the virtual window.
 435
 436         @a xPos and @a yPos optionally specify a position to scroll to
 437         immediately.
 438
 439         For example, the following gives a window horizontal and vertical
 440         scrollbars with 20 pixels per scroll step, and a size of 50 steps (1000
 441         pixels) in each direction:
 442         @code
 443         window->SetScrollbars(20, 20, 50, 50);
 444         @endcode
 445
 446         wxScrolled manages the page size itself, using the current client
 447         window size as the page size.
 448
 449         Note that for more sophisticated scrolling applications, for example
 450         where scroll steps may be variable according to the position in the
 451         document, it will be necessary to derive a new class from wxWindow,
 452         overriding OnSize() and adjusting the scrollbars appropriately.
 453
 454         @param pixelsPerUnitX
 455             Pixels per scroll unit in the horizontal direction.
 456         @param pixelsPerUnitY
 457             Pixels per scroll unit in the vertical direction.
 458         @param noUnitsX
 459             Number of units in the horizontal direction.
 460         @param noUnitsY
 461             Number of units in the vertical direction.
 462         @param xPos
 463             Position to initialize the scrollbars in the horizontal direction,
 464             in scroll units.
 465         @param yPos
 466             Position to initialize the scrollbars in the vertical direction, in
 467             scroll units.
 468         @param noRefresh
 469             Will not refresh window if @true.
 470
 471         @see wxWindow::SetVirtualSize()
 472     */
 473     void SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
 474                        int noUnitsX,
 475                        int noUnitsY,
 476                        int xPos = 0,
 477                        int yPos = 0,
 478                        bool noRefresh = false);
 479
 480     /**
 481         Call this function to tell wxScrolled to perform the actual scrolling
 482         on a different window (and not on itself).
 483
 484         This method is useful when only a part of the window should be
 485         scrolled. A typical example is a control consisting of a fixed header
 486         and the scrollable contents window: the scrollbars are attached to the
 487         main window itself, hence it, and not the contents window must be
 488         derived from wxScrolled, but only the contents window scrolls when the
 489         scrollbars are used. To implement such setup, you need to call this
 490         method with the contents window as argument.
 491
 492         Notice that if this method is used, GetSizeAvailableForScrollTarget()
 493         method must be overridden.
 494     */
 495     void SetTargetWindow(wxWindow *window);
 496
 497 protected:
 498     /**
 499         Function which must be overridden to implement the size available for
 500         the scroll target for the given size of the main window.
 501
 502         This method must be overridden if SetTargetWindow() is used (it is
 503         never called otherwise). The implementation should decrease the @a size
 504         to account for the size of the non-scrollable parts of the main window
 505         and return only the size available for the scrollable window itself.
 506         E.g. in the example given in SetTargetWindow() documentation the
 507         function would subtract the height of the header window from the
 508         vertical component of @a size.
 509      */
 510     virtual wxSize GetSizeAvailableForScrollTarget(const wxSize& size);
 511 };
 512
 513
 514 /**
 515     Scrolled window derived from wxPanel.
 516
 517     See wxScrolled for detailed description.
 518
 519     @note Note that because this class derives from wxPanel, it shares its
 520           behavior with regard to TAB traversal and focus handling (in
 521           particular, it forwards focus to its children). If you don't want
 522           this behaviour, use ::wxScrolledCanvas instead.
 523
 524     @note ::wxScrolledWindow is an alias for wxScrolled<wxPanel> since version
 525           2.9.0. In older versions, it was a standalone class.
 526
 527     @library{wxcore}
 528     @category{miscwnd}
 529
 530     @see wxScrolled, ::wxScrolledCanvas
 531 */
 532 typedef wxScrolled<wxPanel> wxScrolledWindow;
 533
 534 /**
 535     Alias for wxScrolled<wxWindow>. Scrolled window that doesn't have children
 536     and so doesn't need or want special handling of TAB traversal.
 537
 538     @since 2.9.0
 539
 540     @library{wxcore}
 541     @category{miscwnd}
 542
 543     @see wxScrolled, ::wxScrolledWindow
 544 */
 545 typedef wxScrolled<wxWindow> wxScrolledCanvas;