docs/latex/wx/scrolbar.tex

   1 \section{\class{wxScrollBar}}\label{wxscrollbar}
   2
   3 A wxScrollBar is a control that represents a horizontal or
   4 vertical scrollbar. It is distinct from the two scrollbars that some windows
   5 provide automatically, but the two types of scrollbar share the way
   6 events are received.
   7
   8 \wxheading{Derived from}
   9
  10 \helpref{wxControl}{wxcontrol}\\
  11 \helpref{wxWindow}{wxwindow}\\
  12 \helpref{wxEvtHandler}{wxevthandler}\\
  13 \helpref{wxObject}{wxobject}
  14
  15 \wxheading{Include files}
  16
  17 <wx/scrolbar.h>
  18
  19 \wxheading{Remarks}
  20
  21 A scrollbar has the following main attributes: {\it range}, {\it thumb size}, {\it page size}, and {\it position}.
  22
  23 The range is the total number of units associated with the view represented by the scrollbar.
  24 For a table with 15 columns, the range would be 15.
  25
  26 The thumb size is the number of units that are currently visible. For the table example, the window
  27 might be sized so that only 5 columns are currently visible, in which case the application would
  28 set the thumb size to 5. When the thumb size becomes the same as or greater than the range,
  29 the scrollbar will be automatically hidden on most platforms.
  30
  31 The page size is the number of units that the scrollbar should scroll by, when `paging' through
  32 the data. This value is normally the same as the thumb size length, because
  33 it is natural to assume that the visible window size defines a page.
  34
  35 The scrollbar position is the current thumb position.
  36
  37 Most applications will find it convenient to provide a function called {\bf AdjustScrollbars} which can
  38 be called initially, from an {\bf OnSize} event handler, and whenever the application data
  39 changes in size. It will adjust the view, object and page size according
  40 to the size of the window and the size of the data.
  41
  42 \wxheading{Window styles}
  43
  44 \twocolwidtha{5cm}
  45 \begin{twocollist}\itemsep=0pt
  46 \twocolitem{\windowstyle{wxSB\_HORIZONTAL}}{Specifies a horizontal scrollbar.}
  47 \twocolitem{\windowstyle{wxSB\_VERTICAL}}{Specifies a vertical scrollbar.}
  48 \end{twocollist}
  49
  50 See also \helpref{window styles overview}{windowstyles}.
  51
  52 \input scrolevt.inc
  53
  54 \wxheading{See also}
  55
  56 \helpref{Scrolling overview}{scrollingoverview},\rtfsp
  57 \helpref{Event handling overview}{eventhandlingoverview},\rtfsp
  58 \helpref{wxScrolledWindow}{wxscrolledwindow}
  59
  60 \latexignore{\rtfignore{\wxheading{Members}}}
  61
  62
  63 \membersection{wxScrollBar::wxScrollBar}\label{wxscrollbarconstr}
  64
  65 \func{}{wxScrollBar}{\void}
  66
  67 Default constructor.
  68
  69 \func{}{wxScrollBar}{\param{wxWindow*}{ parent}, \param{wxWindowID }{id},\rtfsp
  70 \param{const wxPoint\& }{pos = wxDefaultPosition}, \param{const wxSize\& }{size = wxDefaultSize},\rtfsp
  71 \param{long}{ style = wxSB\_HORIZONTAL}, \param{const wxValidator\& }{validator = wxDefaultValidator},\rtfsp
  72 \param{const wxString\& }{name = ``scrollBar"}}
  73
  74 Constructor, creating and showing a scrollbar.
  75
  76 \wxheading{Parameters}
  77
  78 \docparam{parent}{Parent window. Must not be NULL.}
  79
  80 \docparam{id}{Window identifier. A value of -1 indicates a default value.}
  81
  82 \docparam{pos}{Window position. If the position (-1, -1) is specified then a default position is chosen.}
  83
  84 \docparam{size}{Window size. If the default size (-1, -1) is specified then a default size is chosen.}
  85
  86 \docparam{style}{Window style. See \helpref{wxScrollBar}{wxscrollbar}.}
  87
  88 \docparam{validator}{Window validator.}
  89
  90 \docparam{name}{Window name.}
  91
  92 \wxheading{See also}
  93
  94 \helpref{wxScrollBar::Create}{wxscrollbarcreate}, \helpref{wxValidator}{wxvalidator}
  95
  96
  97 \membersection{wxScrollBar::\destruct{wxScrollBar}}
  98
  99 \func{void}{\destruct{wxScrollBar}}{\void}
 100
 101 Destructor, destroying the scrollbar.
 102
 103
 104 \membersection{wxScrollBar::Create}\label{wxscrollbarcreate}
 105
 106 \func{bool}{Create}{\param{wxWindow*}{ parent}, \param{wxWindowID }{id},\rtfsp
 107 \param{const wxPoint\& }{pos = wxDefaultPosition}, \param{const wxSize\& }{size = wxDefaultSize},\rtfsp
 108 \param{long}{ style = wxSB\_HORIZONTAL}, \param{const wxValidator\& }{validator = wxDefaultValidator},\rtfsp
 109 \param{const wxString\& }{name = ``scrollBar"}}
 110
 111 Scrollbar creation function called by the scrollbar constructor.
 112 See \helpref{wxScrollBar::wxScrollBar}{wxscrollbarconstr} for details.
 113
 114
 115 \membersection{wxScrollBar::GetRange}\label{wxscrollbargetrange}
 116
 117 \constfunc{int}{GetRange}{\void}
 118
 119 Returns the length of the scrollbar.
 120
 121 \wxheading{See also}
 122
 123 \helpref{wxScrollBar::SetScrollbar}{wxscrollbarsetscrollbar}
 124
 125
 126 \membersection{wxScrollBar::GetPageSize}\label{wxscrollbargetpagesize}
 127
 128 \constfunc{int}{GetPageSize}{\void}
 129
 130 Returns the page size of the scrollbar. This is the number of scroll units
 131 that will be scrolled when the user pages up or down. Often it is the
 132 same as the thumb size.
 133
 134 \wxheading{See also}
 135
 136 \helpref{wxScrollBar::SetScrollbar}{wxscrollbarsetscrollbar}
 137
 138
 139 \membersection{wxScrollBar::GetThumbPosition}\label{wxscrollbargetthumbposition}
 140
 141 \constfunc{int}{GetThumbPosition}{\void}
 142
 143 Returns the current position of the scrollbar thumb.
 144
 145 \wxheading{See also}
 146
 147 \helpref{wxScrollBar::SetThumbPosition}{wxscrollbarsetthumbposition}
 148
 149
 150 \membersection{wxScrollBar::GetThumbSize}\label{wxscrollbargetthumbsize}
 151
 152 \constfunc{int}{GetThumbSize}{\void}
 153
 154 Returns the thumb or `view' size.
 155
 156 \wxheading{See also}
 157
 158 \helpref{wxScrollBar::SetScrollbar}{wxscrollbarsetscrollbar}
 159
 160 \begin{comment}
 161
 162 \membersection{wxScrollBar::SetObjectLength}\label{wxscrollbarsetobjectlength}
 163
 164 \func{void}{SetObjectLength}{\param{int}{ objectLength}}
 165
 166 Sets the object length for the scrollbar. This is the total object size (virtual size). You must
 167 call \helpref{SetViewLength}{wxscrollbarsetviewlength} {\it before} calling SetObjectLength.
 168
 169 \wxheading{Parameters}
 170
 171 \docparam{objectLength}{The object length of the scrollbar.}
 172
 173 \wxheading{Remarks}
 174
 175 Example: you are implementing scrollbars on a text window, where text lines have a maximum width
 176 of 100 characters. Your text window has a current width of 60 characters. So the view length is 60,
 177 and the object length is 100. The scrollbar will then enable you to scroll to see the other 40 characters.
 178
 179 You will need to call {\bf SetViewLength} and {\bf SetObjectLength} whenever there
 180 is a change in the size of the window (the view size) or the size of the
 181 contents (the object length).
 182
 183 \wxheading{See also}
 184
 185 \helpref{wxScrollBar::GetObjectLength}{wxscrollbargetobjectlength}
 186
 187
 188 \membersection{wxScrollBar::SetPageSize}\label{wxscrollbarsetpagesize}
 189
 190 \func{void}{SetPageSize}{\param{int}{ pageSize}}
 191
 192 Sets the page size for the scrollbar. This is the number of scroll units which are scrolled when the
 193 user pages down (clicks on the scrollbar outside the thumbtrack area).
 194
 195 \wxheading{Parameters}
 196
 197 \docparam{pageSize}{The page size in scroll units.}
 198
 199 \wxheading{Remarks}
 200
 201 At present, this needs to be called {\it before} other set functions.
 202
 203 \wxheading{See also}
 204
 205 \helpref{wxScrollBar::GetPageSize}{wxscrollbargetpagesize}
 206 \end{comment}
 207
 208
 209 \membersection{wxScrollBar::SetThumbPosition}\label{wxscrollbarsetthumbposition}
 210
 211 \func{void}{SetThumbPosition}{\param{int}{ viewStart}}
 212
 213 Sets the position of the scrollbar.
 214
 215 \wxheading{Parameters}
 216
 217 \docparam{viewStart}{The position of the scrollbar thumb.}
 218
 219 \wxheading{See also}
 220
 221 \helpref{wxScrollBar::GetThumbPosition}{wxscrollbargetthumbposition}
 222
 223
 224 \membersection{wxScrollBar::SetScrollbar}\label{wxscrollbarsetscrollbar}
 225
 226 \func{virtual void}{SetScrollbar}{\param{int }{position},\rtfsp
 227 \param{int }{thumbSize}, \param{int }{range},\rtfsp
 228 \param{int }{pageSize},\rtfsp
 229 \param{const bool }{refresh = true}}
 230
 231 Sets the scrollbar properties.
 232
 233 \wxheading{Parameters}
 234
 235 \docparam{position}{The position of the scrollbar in scroll units.}
 236
 237 \docparam{thumbSize}{The size of the thumb, or visible portion of the scrollbar, in scroll units.}
 238
 239 \docparam{range}{The maximum position of the scrollbar.}
 240
 241 \docparam{pageSize}{The size of the page size in scroll units. This is the number of units
 242 the scrollbar will scroll when it is paged up or down. Often it is the same as
 243 the thumb size.}
 244
 245 \docparam{refresh}{true to redraw the scrollbar, false otherwise.}
 246
 247 \wxheading{Remarks}
 248
 249 Let's say you wish to display 50 lines of text, using the same font.
 250 The window is sized so that you can only see 16 lines at a time.
 251
 252 You would use:
 253
 254 {\small%
 255 \begin{verbatim}
 256   scrollbar->SetScrollbar(0, 16, 50, 15);
 257 \end{verbatim}
 258 }
 259
 260 The page size is 1 less than the thumb size so that the last line of the previous
 261 page will be visible on the next page, to help orient the user.
 262
 263 Note that with the window at this size, the thumb position can never go
 264 above 50 minus 16, or 34.
 265
 266 You can determine how many lines are currently visible by dividing the current view
 267 size by the character height in pixels.
 268
 269 When defining your own scrollbar behaviour, you will always need to recalculate
 270 the scrollbar settings when the window size changes. You could therefore put your
 271 scrollbar calculations and SetScrollbar
 272 call into a function named AdjustScrollbars, which can be called initially and also
 273 from a \helpref{wxSizeEvent}{wxsizeevent} event handler function.
 274
 275 \wxheading{See also}
 276
 277 \helpref{Scrolling overview}{scrollingoverview},\rtfsp
 278 \helpref{wxWindow::SetScrollbar}{wxwindowsetscrollbar}, \helpref{wxScrolledWindow}{wxscrolledwindow}
 279
 280
 281 \begin{comment}
 282
 283 \membersection{wxScrollBar::SetViewLength}\label{wxscrollbarsetviewlength}
 284
 285 \func{void}{SetViewLength}{\param{int}{ viewLength}}
 286
 287 Sets the view length for the scrollbar.
 288
 289 \wxheading{Parameters}
 290
 291 \docparam{viewLength}{View length.}
 292
 293 \wxheading{See also}
 294
 295 \helpref{wxScrollBar::GetViewLength}{wxscrollbargetviewlength}
 296 \end{comment}
 297