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