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         Get the position at which the visible portion of the window starts.
 292
 293         @param x
 294             Receives the first visible x position in scroll units.
 295         @param y
 296             Receives the first visible y position in scroll units.
 297
 298         @remarks
 299             If either of the scrollbars is not at the home position, @a x
 300             and/or @a y will be greater than zero.
 301             Combined with wxWindow::GetClientSize(), the application can use this
 302             function to efficiently redraw only the visible portion of the window.
 303             The positions are in logical scroll units, not pixels, so to convert
 304             to pixels you will have to multiply by the number of pixels per scroll
 305             increment.
 306
 307         @see SetScrollbars(), Scroll()
 308     */
 309     void GetViewStart(int* x, int* y) const;
 310
 311     /**
 312         This is a simple overload of GetViewStart(int*,int*); see that function
 313         for more info.
 314     */
 315     wxPoint GetViewStart() const;
 316
 317     /**
 318         Gets the size in device units of the scrollable window area (as
 319         opposed to the client size, which is the area of the window currently
 320         visible).
 321
 322         @param x
 323             Receives the length of the scrollable window, in pixels.
 324         @param y
 325             Receives the height of the scrollable window, in pixels.
 326
 327         @remarks Use wxDC::DeviceToLogicalX() and wxDC::DeviceToLogicalY() to
 328                  translate these units to logical units.
 329
 330         @see SetScrollbars(), GetScrollPixelsPerUnit()
 331     */
 332     void GetVirtualSize(int* x, int* y) const;
 333
 334     /**
 335         Motif only: @true if the window has a backing bitmap.
 336     */
 337     bool IsRetained() const;
 338
 339     /**
 340         Called by the default paint event handler to allow the application to
 341         define painting behaviour without having to worry about calling
 342         DoPrepareDC().
 343
 344         Instead of overriding this function you may also just process the paint
 345         event in the derived class as usual, but then you will have to call
 346         DoPrepareDC() yourself.
 347     */
 348     virtual void OnDraw(wxDC& dc);
 349
 350     /**
 351         This function is for backwards compatibility only and simply calls
 352         DoPrepareDC() now. Notice that it is not called by the default paint
 353         event handle (DoPrepareDC() is), so overriding this method in your
 354         derived class is useless.
 355     */
 356     void PrepareDC(wxDC& dc);
 357
 358     /**
 359         Scrolls a window so the view start is at the given point.
 360
 361         @param x
 362             The x position to scroll to, in scroll units.
 363         @param y
 364             The y position to scroll to, in scroll units.
 365
 366         @remarks The positions are in scroll units, not pixels, so to convert to
 367                  pixels you will have to multiply by the number of
 368                  pixels per scroll increment. If either parameter is
 369                  ::wxDefaultCoord (-1), that position will be ignored (no change
 370                  in that direction).
 371
 372         @see SetScrollbars(), GetScrollPixelsPerUnit()
 373     */
 374     void Scroll(int x, int y);
 375
 376     /**
 377         This is an overload of Scroll(int,int); see that function for more info.
 378     */
 379     void Scroll(const wxPoint& pt);
 380
 381     /**
 382         Set the horizontal and vertical scrolling increment only. See the
 383         pixelsPerUnit parameter in SetScrollbars().
 384     */
 385     void SetScrollRate(int xstep, int ystep);
 386
 387     /**
 388         Sets up vertical and/or horizontal scrollbars.
 389
 390         The first pair of parameters give the number of pixels per 'scroll
 391         step', i.e. amount moved when the up or down scroll arrows are pressed.
 392         The second pair gives the length of scrollbar in scroll steps, which
 393         sets the size of the virtual window.
 394
 395         @a xPos and @a yPos optionally specify a position to scroll to
 396         immediately.
 397
 398         For example, the following gives a window horizontal and vertical
 399         scrollbars with 20 pixels per scroll step, and a size of 50 steps (1000
 400         pixels) in each direction:
 401         @code
 402         window->SetScrollbars(20, 20, 50, 50);
 403         @endcode
 404
 405         wxScrolled manages the page size itself, using the current client
 406         window size as the page size.
 407
 408         Note that for more sophisticated scrolling applications, for example
 409         where scroll steps may be variable according to the position in the
 410         document, it will be necessary to derive a new class from wxWindow,
 411         overriding OnSize() and adjusting the scrollbars appropriately.
 412
 413         @param pixelsPerUnitX
 414             Pixels per scroll unit in the horizontal direction.
 415         @param pixelsPerUnitY
 416             Pixels per scroll unit in the vertical direction.
 417         @param noUnitsX
 418             Number of units in the horizontal direction.
 419         @param noUnitsY
 420             Number of units in the vertical direction.
 421         @param xPos
 422             Position to initialize the scrollbars in the horizontal direction,
 423             in scroll units.
 424         @param yPos
 425             Position to initialize the scrollbars in the vertical direction, in
 426             scroll units.
 427         @param noRefresh
 428             Will not refresh window if @true.
 429
 430         @see wxWindow::SetVirtualSize()
 431     */
 432     void SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
 433                        int noUnitsX,
 434                        int noUnitsY,
 435                        int xPos = 0,
 436                        int yPos = 0,
 437                        bool noRefresh = false);
 438
 439     /**
 440         Call this function to tell wxScrolled to perform the actual scrolling
 441         on a different window (and not on itself).
 442
 443         This method is useful when only a part of the window should be
 444         scrolled. A typical example is a control consisting of a fixed header
 445         and the scrollable contents window: the scrollbars are attached to the
 446         main window itself, hence it, and not the contents window must be
 447         derived from wxScrolled, but only the contents window scrolls when the
 448         scrollbars are used. To implement such setup, you need to call this
 449         method with the contents window as argument.
 450
 451         Notice that if this method is used, GetSizeAvailableForScrollTarget()
 452         method must be overridden.
 453     */
 454     void SetTargetWindow(wxWindow *window);
 455
 456 protected:
 457     /**
 458         Function which must be overridden to implement the size available for
 459         the scroll target for the given size of the main window.
 460
 461         This method must be overridden if SetTargetWindow() is used (it is
 462         never called otherwise). The implementation should decrease the @a size
 463         to account for the size of the non-scrollable parts of the main window
 464         and return only the size available for the scrollable window itself.
 465         E.g. in the example given in SetTargetWindow() documentation the
 466         function would subtract the height of the header window from the
 467         vertical component of @a size.
 468      */
 469     virtual wxSize GetSizeAvailableForScrollTarget(const wxSize& size);
 470 };
 471
 472
 473 /**
 474     Scrolled window derived from wxPanel.
 475
 476     See wxScrolled for detailed description.
 477
 478     @note Note that because this class derives from wxPanel, it shares its
 479           behavior with regard to TAB traversal and focus handling (in
 480           particular, it forwards focus to its children). If you don't want
 481           this behaviour, use ::wxScrolledCanvas instead.
 482
 483     @note ::wxScrolledWindow is an alias for wxScrolled<wxPanel> since version
 484           2.9.0. In older versions, it was a standalone class.
 485
 486     @library{wxcore}
 487     @category{miscwnd}
 488
 489     @see wxScrolled, ::wxScrolledCanvas
 490 */
 491 typedef wxScrolled<wxPanel> wxScrolledWindow;
 492
 493 /**
 494     Alias for wxScrolled<wxWindow>. Scrolled window that doesn't have children
 495     and so doesn't need or want special handling of TAB traversal.
 496
 497     @since 2.9.0
 498
 499     @library{wxcore}
 500     @category{miscwnd}
 501
 502     @see wxScrolled, ::wxScrolledWindow
 503 */
 504 typedef wxScrolled<wxWindow> wxScrolledCanvas;