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 license
   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         Call this function to prepare the device context for drawing a scrolled
 204         image.
 205
 206         It sets the device origin according to the current scroll position.
 207         DoPrepareDC() is called automatically within the default @c wxEVT_PAINT
 208         event handler, so your OnDraw() override will be passed an already
 209         'pre-scrolled' device context. However, if you wish to draw from
 210         outside of OnDraw() (e.g. from your own @c wxEVT_PAINT handler), you
 211         must call this function yourself.
 212
 213         For example:
 214         @code
 215         void MyWindow::OnEvent(wxMouseEvent& event)
 216         {
 217           wxClientDC dc(this);
 218           DoPrepareDC(dc);
 219
 220           dc.SetPen(*wxBLACK_PEN);
 221           float x, y;
 222           event.Position(&x, &y);
 223           if (xpos > -1 && ypos > -1 && event.Dragging())
 224           {
 225             dc.DrawLine(xpos, ypos, x, y);
 226           }
 227           xpos = x;
 228           ypos = y;
 229         }
 230         @endcode
 231
 232         Notice that the function sets the origin by moving it relatively to the
 233         current origin position, so you shouldn't change the origin before
 234         calling DoPrepareDC() or, if you do, reset it to (0, 0) later. If you
 235         call DoPrepareDC() immediately after device context creation, as in the
 236         example above, this problem doesn't arise, of course, so it is
 237         customary to do it like this.
 238     */
 239     void DoPrepareDC(wxDC& dc);
 240
 241     /**
 242         Enable or disable physical scrolling in the given direction. Physical
 243         scrolling is the physical transfer of bits up or down the
 244         screen when a scroll event occurs. If the application scrolls by a
 245         variable amount (e.g. if there are different font sizes) then physical
 246         scrolling will not work, and you should switch it off. Note that you
 247         will have to reposition child windows yourself, if physical scrolling
 248         is disabled.
 249
 250         @param xScrolling
 251             If @true, enables physical scrolling in the x direction.
 252         @param yScrolling
 253             If @true, enables physical scrolling in the y direction.
 254
 255         @remarks Physical scrolling may not be available on all platforms. Where
 256                  it is available, it is enabled by default.
 257     */
 258     void EnableScrolling(bool xScrolling, bool yScrolling);
 259
 260     /**
 261         Set the scrollbar visibility.
 262
 263         By default the scrollbar in the corresponding direction is only shown
 264         if it is needed, i.e. if the virtual size of the scrolled window in
 265         this direction is greater than the current physical window size. Using
 266         this function the scrollbar visibility can be changed to be:
 267             - wxSHOW_SB_ALWAYS: To always show the scrollbar, even if it is
 268                 not needed currently (wxALWAYS_SHOW_SB style can be used during
 269                 the window creation to achieve the same effect but it applies
 270                 in both directions).
 271             - wxSHOW_SB_NEVER: To never show the scrollbar at all. In this case
 272                 the program should presumably provide some other way for the
 273                 user to scroll the window.
 274             - wxSHOW_SB_DEFAULT: To restore the default behaviour described
 275                 above.
 276
 277         @param horz
 278             The desired visibility for the horizontal scrollbar.
 279         @param vert
 280             The desired visibility for the vertical scrollbar.
 281
 282         @since 2.9.0
 283      */
 284     void ShowScrollbars(wxScrollbarVisibility horz, wxScrollbarVisibility vert);
 285
 286     /**
 287         Get the number of pixels per scroll unit (line), in each direction, as
 288         set by SetScrollbars(). A value of zero indicates no scrolling in that
 289         direction.
 290
 291         @param xUnit
 292             Receives the number of pixels per horizontal unit.
 293         @param yUnit
 294             Receives the number of pixels per vertical unit.
 295
 296         @beginWxPerlOnly
 297         In wxPerl this method takes no parameters and returns a
 298         2-element list (xUnit, yUnit).
 299         @endWxPerlOnly
 300
 301         @see SetScrollbars(), GetVirtualSize()
 302     */
 303     void GetScrollPixelsPerUnit(int* xUnit, int* yUnit) const;
 304
 305     /**
 306         Get the position at which the visible portion of the window starts.
 307
 308         @param x
 309             Receives the first visible x position in scroll units.
 310         @param y
 311             Receives the first visible y position in scroll units.
 312
 313         @remarks
 314             If either of the scrollbars is not at the home position, @a x
 315             and/or @a y will be greater than zero.
 316             Combined with wxWindow::GetClientSize(), the application can use this
 317             function to efficiently redraw only the visible portion of the window.
 318             The positions are in logical scroll units, not pixels, so to convert
 319             to pixels you will have to multiply by the number of pixels per scroll
 320             increment.
 321
 322         @beginWxPerlOnly
 323         In wxPerl this method takes no parameters and returns a
 324         2-element list (x, y).
 325         @endWxPerlOnly
 326
 327         @see SetScrollbars(), Scroll()
 328     */
 329     void GetViewStart(int* x, int* y) const;
 330
 331     /**
 332         This is a simple overload of GetViewStart(int*,int*); see that function
 333         for more info.
 334     */
 335     wxPoint GetViewStart() const;
 336
 337     /**
 338         Gets the size in device units of the scrollable window area (as
 339         opposed to the client size, which is the area of the window currently
 340         visible).
 341
 342         @param x
 343             Receives the length of the scrollable window, in pixels.
 344         @param y
 345             Receives the height of the scrollable window, in pixels.
 346
 347         @remarks Use wxDC::DeviceToLogicalX() and wxDC::DeviceToLogicalY() to
 348                  translate these units to logical units.
 349
 350         @beginWxPerlOnly
 351         In wxPerl this method takes no parameters and returns a
 352         2-element list (xUnit, yUnit).
 353         @endWxPerlOnly
 354
 355         @see SetScrollbars(), GetScrollPixelsPerUnit()
 356     */
 357     void GetVirtualSize(int* x, int* y) const;
 358
 359     /**
 360         Motif only: @true if the window has a backing bitmap.
 361     */
 362     bool IsRetained() const;
 363
 364     /**
 365         Called by the default paint event handler to allow the application to
 366         define painting behaviour without having to worry about calling
 367         DoPrepareDC().
 368
 369         Instead of overriding this function you may also just process the paint
 370         event in the derived class as usual, but then you will have to call
 371         DoPrepareDC() yourself.
 372     */
 373     virtual void OnDraw(wxDC& dc);
 374
 375     /**
 376         This function is for backwards compatibility only and simply calls
 377         DoPrepareDC() now. Notice that it is not called by the default paint
 378         event handle (DoPrepareDC() is), so overriding this method in your
 379         derived class is useless.
 380     */
 381     void PrepareDC(wxDC& dc);
 382
 383     /**
 384         Scrolls a window so the view start is at the given point.
 385
 386         @param x
 387             The x position to scroll to, in scroll units.
 388         @param y
 389             The y position to scroll to, in scroll units.
 390
 391         @remarks The positions are in scroll units, not pixels, so to convert to
 392                  pixels you will have to multiply by the number of
 393                  pixels per scroll increment. If either parameter is
 394                  ::wxDefaultCoord (-1), that position will be ignored (no change
 395                  in that direction).
 396
 397         @see SetScrollbars(), GetScrollPixelsPerUnit()
 398     */
 399     void Scroll(int x, int y);
 400
 401     /**
 402         This is an overload of Scroll(int,int); see that function for more info.
 403     */
 404     void Scroll(const wxPoint& pt);
 405
 406     /**
 407         Set the horizontal and vertical scrolling increment only. See the
 408         pixelsPerUnit parameter in SetScrollbars().
 409     */
 410     void SetScrollRate(int xstep, int ystep);
 411
 412     /**
 413         Sets up vertical and/or horizontal scrollbars.
 414
 415         The first pair of parameters give the number of pixels per 'scroll
 416         step', i.e. amount moved when the up or down scroll arrows are pressed.
 417         The second pair gives the length of scrollbar in scroll steps, which
 418         sets the size of the virtual window.
 419
 420         @a xPos and @a yPos optionally specify a position to scroll to
 421         immediately.
 422
 423         For example, the following gives a window horizontal and vertical
 424         scrollbars with 20 pixels per scroll step, and a size of 50 steps (1000
 425         pixels) in each direction:
 426         @code
 427         window->SetScrollbars(20, 20, 50, 50);
 428         @endcode
 429
 430         wxScrolled manages the page size itself, using the current client
 431         window size as the page size.
 432
 433         Note that for more sophisticated scrolling applications, for example
 434         where scroll steps may be variable according to the position in the
 435         document, it will be necessary to derive a new class from wxWindow,
 436         overriding OnSize() and adjusting the scrollbars appropriately.
 437
 438         @param pixelsPerUnitX
 439             Pixels per scroll unit in the horizontal direction.
 440         @param pixelsPerUnitY
 441             Pixels per scroll unit in the vertical direction.
 442         @param noUnitsX
 443             Number of units in the horizontal direction.
 444         @param noUnitsY
 445             Number of units in the vertical direction.
 446         @param xPos
 447             Position to initialize the scrollbars in the horizontal direction,
 448             in scroll units.
 449         @param yPos
 450             Position to initialize the scrollbars in the vertical direction, in
 451             scroll units.
 452         @param noRefresh
 453             Will not refresh window if @true.
 454
 455         @see wxWindow::SetVirtualSize()
 456     */
 457     void SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
 458                        int noUnitsX,
 459                        int noUnitsY,
 460                        int xPos = 0,
 461                        int yPos = 0,
 462                        bool noRefresh = false);
 463
 464     /**
 465         Call this function to tell wxScrolled to perform the actual scrolling
 466         on a different window (and not on itself).
 467
 468         This method is useful when only a part of the window should be
 469         scrolled. A typical example is a control consisting of a fixed header
 470         and the scrollable contents window: the scrollbars are attached to the
 471         main window itself, hence it, and not the contents window must be
 472         derived from wxScrolled, but only the contents window scrolls when the
 473         scrollbars are used. To implement such setup, you need to call this
 474         method with the contents window as argument.
 475
 476         Notice that if this method is used, GetSizeAvailableForScrollTarget()
 477         method must be overridden.
 478     */
 479     void SetTargetWindow(wxWindow *window);
 480
 481 protected:
 482     /**
 483         Function which must be overridden to implement the size available for
 484         the scroll target for the given size of the main window.
 485
 486         This method must be overridden if SetTargetWindow() is used (it is
 487         never called otherwise). The implementation should decrease the @a size
 488         to account for the size of the non-scrollable parts of the main window
 489         and return only the size available for the scrollable window itself.
 490         E.g. in the example given in SetTargetWindow() documentation the
 491         function would subtract the height of the header window from the
 492         vertical component of @a size.
 493      */
 494     virtual wxSize GetSizeAvailableForScrollTarget(const wxSize& size);
 495 };
 496
 497
 498 /**
 499     Scrolled window derived from wxPanel.
 500
 501     See wxScrolled for detailed description.
 502
 503     @note Note that because this class derives from wxPanel, it shares its
 504           behavior with regard to TAB traversal and focus handling (in
 505           particular, it forwards focus to its children). If you don't want
 506           this behaviour, use ::wxScrolledCanvas instead.
 507
 508     @note ::wxScrolledWindow is an alias for wxScrolled<wxPanel> since version
 509           2.9.0. In older versions, it was a standalone class.
 510
 511     @library{wxcore}
 512     @category{miscwnd}
 513
 514     @see wxScrolled, ::wxScrolledCanvas
 515 */
 516 typedef wxScrolled<wxPanel> wxScrolledWindow;
 517
 518 /**
 519     Alias for wxScrolled<wxWindow>. Scrolled window that doesn't have children
 520     and so doesn't need or want special handling of TAB traversal.
 521
 522     @since 2.9.0
 523
 524     @library{wxcore}
 525     @category{miscwnd}
 526
 527     @see wxScrolled, ::wxScrolledWindow
 528 */
 529 typedef wxScrolled<wxWindow> wxScrolledCanvas;