docs/latex/wx/brush.tex

   1 \section{\class{wxBrush}}\label{wxbrush}
   2
   3 A brush is a drawing tool for filling in areas. It is used for painting
   4 the background of rectangles, ellipses, etc. It has a colour and a
   5 style.
   6
   7 \wxheading{Derived from}
   8
   9 \helpref{wxGDIObject}{wxgdiobject}\\
  10 \helpref{wxObject}{wxobject}
  11
  12 \wxheading{Remarks}
  13
  14 On a monochrome display, wxWindows shows
  15 all brushes as white unless the colour is really black.
  16
  17 Do not initialize objects on the stack before the program commences,
  18 since other required structures may not have been set up yet. Instead,
  19 define global pointers to objects and create them in \helpref{wxApp::OnInit}{wxapponinit} or
  20 when required.
  21
  22 An application may wish to create brushes with different
  23 characteristics dynamically, and there is the consequent danger that a
  24 large number of duplicate brushes will be created. Therefore an
  25 application may wish to get a pointer to a brush by using the global
  26 list of brushes {\bf wxTheBrushList}, and calling the member function
  27 \rtfsp{\bf FindOrCreateBrush}.
  28
  29 wxBrush uses a reference counting system, so assignments between brushes are very
  30 cheap. You can therefore use actual wxBrush objects instead of pointers without
  31 efficiency problems. Bear in mind, though, that changing a brush's properties may
  32 affect another brush which has been involved in an assignment with the first brush,
  33 because of the way internal brush data is shared.
  34
  35 TODO: an overview for wxBrush.
  36
  37 \wxheading{See also}
  38
  39 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxDC}{wxdc}, \helpref{wxDC::SetBrush}{wxdcsetbrush}
  40
  41 \latexignore{\rtfignore{\wxheading{Members}}}
  42
  43 \membersection{wxBrush::wxBrush}
  44
  45 \func{}{wxBrush}{\void}
  46
  47 Default constructor. The brush will be uninitialised, and \helpref{wxBrush::Ok}{wxbrushok} will
  48 return FALSE.
  49
  50 \func{}{wxBrush}{\param{const wxColour\&}{ colour}, \param{int}{ style}}
  51
  52 Constructs a brush from a colour object and style.
  53
  54 \func{}{wxBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
  55
  56 Constructs a brush from a colour name and style.
  57
  58 \func{}{wxBrush}{\param{const wxBitmap\& }{stippleBitmap}}
  59
  60 Constructs a stippled brush using a bitmap.
  61
  62 \func{}{wxBrush}{\param{const wxBrush\&}{ brush}}
  63
  64 Copy constructor. This uses reference counting so is a cheap operation.
  65
  66 \func{}{wxBrush}{\param{const wxBrush*}{ brush}}
  67
  68 Copy constructor. This uses reference counting so is a cheap operation.
  69
  70 \wxheading{Parameters}
  71
  72 \docparam{colour}{Colour object.}
  73
  74 \docparam{colourName}{Colour name. The name will be looked up in the colour database.}
  75
  76 \docparam{style}{One of:
  77
  78 \begin{twocollist}\itemsep=0pt
  79 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
  80 \twocolitem{{\bf wxSOLID}}{Solid.}
  81 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
  82 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
  83 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
  84 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
  85 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
  86 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
  87 \end{twocollist}}
  88
  89 \docparam{brush}{Pointer or reference to a brush to copy.}
  90
  91 \docparam{stippleBitmap}{A bitmap to use for stippling.}
  92
  93 \wxheading{Remarks}
  94
  95 If a stipple brush is created, the brush style will be set to wxSTIPPLE.
  96
  97 \wxheading{See also}
  98
  99 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxColour}{wxcolour}, \helpref{wxColourDatabase}{wxcolourdatabase}
 100
 101 \membersection{wxBrush::\destruct{wxBrush}}
 102
 103 \func{void}{\destruct{wxBrush}}{\void}
 104
 105 Destructor.
 106
 107 \wxheading{Remarks}
 108
 109 The destructor may not delete the underlying brush object of the native windowing
 110 system, since wxBrush uses a reference counting system for efficiency.
 111
 112 Although all remaining brushes are deleted when the application exits,
 113 the application should try to clean up all brushes itself. This is because
 114 wxWindows cannot know if a pointer to the brush object is stored in an
 115 application data structure, and there is a risk of double deletion.
 116
 117 \membersection{wxBrush::GetColour}\label{wxbrushgetcolour}
 118
 119 \constfunc{wxColour\&}{GetColour}{\void}
 120
 121 Returns a reference to the brush colour.
 122
 123 \wxheading{See also}
 124
 125 \helpref{wxBrush::SetColour}{wxbrushsetcolour}
 126
 127 \membersection{wxBrush::GetStipple}\label{wxbrushgetstipple}
 128
 129 \constfunc{wxBitmap *}{GetStipple}{\void}
 130
 131 Gets a pointer to the stipple bitmap. If the brush does not have a wxSTIPPLE style,
 132 this bitmap may be non-NULL but uninitialised (\helpref{wxBitmap::Ok}{wxbitmapok} returns FALSE).
 133
 134 \wxheading{See also}
 135
 136 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 137
 138 \membersection{wxBrush::GetStyle}\label{wxbrushgetstyle}
 139
 140 \constfunc{int}{GetStyle}{\void}
 141
 142 Returns the brush style, one of:
 143
 144 \begin{twocollist}\itemsep=0pt
 145 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 146 \twocolitem{{\bf wxSOLID}}{Solid.}
 147 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 148 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 149 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 150 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 151 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 152 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 153 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 154 \end{twocollist}
 155
 156 \wxheading{See also}
 157
 158 \helpref{wxBrush::SetStyle}{wxbrushsetstyle}, \helpref{wxBrush::SetColour}{wxbrushsetcolour},\rtfsp
 159 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 160
 161 \membersection{wxBrush::Ok}\label{wxbrushok}
 162
 163 \constfunc{bool}{Ok}{\void}
 164
 165 Returns TRUE if the brush is initialised. It will return FALSE if the default
 166 constructor has been used (for example, the brush is a member of a class, or
 167 NULL has been assigned to it).
 168
 169 \membersection{wxBrush::SetColour}\label{wxbrushsetcolour}
 170
 171 \func{void}{SetColour}{\param{wxColour\& }{colour}}
 172
 173 Sets the brush colour using a reference to a colour object.
 174
 175 \func{void}{SetColour}{\param{const wxString\& }{colourName}}
 176
 177 Sets the brush colour using a colour name from the colour database.
 178
 179 \func{void}{SetColour}{\param{const unsigned char}{ red}, \param{const unsigned char}{ green}, \param{const unsigned char}{ blue}}
 180
 181 Sets the brush colour using red, green and blue values.
 182
 183 \wxheading{See also}
 184
 185 \helpref{wxBrush::GetColour}{wxbrushgetcolour}
 186
 187 \membersection{wxBrush::SetStipple}\label{wxbrushsetstipple}
 188
 189 \func{void}{SetStipple}{\param{const wxBitmap\&}{ bitmap}}
 190
 191 Sets the stipple bitmap.
 192
 193 \wxheading{Parameters}
 194
 195 \docparam{bitmap}{The bitmap to use for stippling.}
 196
 197 \wxheading{Remarks}
 198
 199 The style will be set to wxSTIPPLE.
 200
 201 Note that there is a big difference between stippling in X and Windows.
 202 On X, the stipple is a mask between the wxBitmap and current colour.
 203 On Windows, the current colour is ignored, and the bitmap colour is used.
 204 However, for pre-defined modes like wxCROSS\_HATCH, the behaviour is the
 205 same for both platforms.
 206
 207 \wxheading{See also}
 208
 209 \helpref{wxBitmap}{wxbitmap}
 210
 211 \membersection{wxBrush::SetStyle}\label{wxbrushsetstyle}
 212
 213 \func{void}{SetStyle}{\param{int}{ style}}
 214
 215 Sets the brush style.
 216
 217 \docparam{style}{One of:
 218
 219 \begin{twocollist}\itemsep=0pt
 220 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 221 \twocolitem{{\bf wxSOLID}}{Solid.}
 222 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 223 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 224 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 225 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 226 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 227 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 228 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 229 \end{twocollist}}
 230
 231 \wxheading{See also}
 232
 233 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 234
 235 \membersection{wxBrush::operator $=$}\label{wxbrushassignment}
 236
 237 \func{wxBrush\&}{operator $=$}{\param{const wxBrush\& }{brush}}
 238
 239 Assignment operator, using reference counting. Returns a reference
 240 to `this'.
 241
 242 \membersection{wxBrush::operator $==$}\label{wxbrushequals}
 243
 244 \func{bool}{operator $==$}{\param{const wxBrush\& }{brush}}
 245
 246 Equality operator. Two brushes are equal if they contain pointers
 247 to the same underlying brush data. It does not compare each attribute,
 248 so two independently-created brushes using the same parameters will
 249 fail the test.
 250
 251 \membersection{wxBrush::operator $!=$}\label{wxbrushnotequals}
 252
 253 \func{bool}{operator $!=$}{\param{const wxBrush\& }{brush}}
 254
 255 Inequality operator. Two brushes are not equal if they contain pointers
 256 to different underlying brush data. It does not compare each attribute.
 257
 258 \section{\class{wxBrushList}}\label{wxbrushlist}
 259
 260 A brush list is a list containing all brushes which have been created.
 261
 262 \wxheading{Derived from}
 263
 264 \helpref{wxList}{wxlist}\\
 265 \helpref{wxObject}{wxobject}
 266
 267 \wxheading{Remarks}
 268
 269 There is only one instance of this class: {\bf wxTheBrushList}.  Use
 270 this object to search for a previously created brush of the desired
 271 type and create it if not already found. In some windowing systems,
 272 the brush may be a scarce resource, so it can pay to reuse old
 273 resources if possible. When an application finishes, all brushes will
 274 be deleted and their resources freed, eliminating the possibility of
 275 `memory leaks'. However, it is best not to rely on this automatic
 276 cleanup because it can lead to double deletion in some circumstances.
 277
 278 There are two mechanisms in recent versions of wxWindows which make the
 279 brush list less useful than it once was. Under Windows, scarce resources
 280 are cleaned up internally if they are not being used. Also, a referencing
 281 counting mechanism applied to all GDI objects means that some sharing
 282 of underlying resources is possible. You don't have to keep track of pointers,
 283 working out when it is safe delete a brush, because the referencing counting does
 284 it for you. For example, you can set a brush in a device context, and then
 285 immediately delete the brush you passed, because the brush is `copied'.
 286
 287 So you may find it easier to ignore the brush list, and instead create
 288 and copy brushes as you see fit. If your Windows resource meter suggests
 289 your application is using too many resources, you can resort to using
 290 GDI lists to share objects explicitly.
 291
 292 The only compelling use for the brush list is for wxWindows to keep
 293 track of brushes in order to clean them up on exit. It is also kept for
 294 backward compatibility with earlier versions of wxWindows.
 295
 296 \wxheading{See also}
 297
 298 \helpref{wxBrush}{wxbrush}
 299
 300 \latexignore{\rtfignore{\wxheading{Members}}}
 301
 302 \membersection{wxBrushList::wxBrushList}\label{wxbrushlistconstr}
 303
 304 \func{void}{wxBrushList}{\void}
 305
 306 Constructor. The application should not construct its own brush list:
 307 use the object pointer {\bf wxTheBrushList}.
 308
 309 \membersection{wxBrushList::AddBrush}\label{wxbrushlistaddbrush}
 310
 311 \func{void}{AddBrush}{\param{wxBrush *}{brush}}
 312
 313 Used internally by wxWindows to add a brush to the list.
 314
 315 \membersection{wxBrushList::FindOrCreateBrush}\label{wxbrushlistfindorcreatebrush}
 316
 317 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxColour\& }{colour}, \param{int}{ style}}
 318
 319 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 320 to the brush list, and returns it.
 321
 322 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
 323
 324 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 325 to the brush list, and returns it.
 326
 327 Finds a brush of the given specification, or creates one and adds it to the list.
 328
 329 \wxheading{Parameters}
 330
 331 \docparam{colour}{Colour object.}
 332
 333 \docparam{colourName}{Colour name, which should be in the colour database.}
 334
 335 \docparam{style}{Brush style. See \helpref{wxBrush::SetStyle}{wxbrushsetstyle} for a list of styles.}
 336
 337 \membersection{wxBrushList::RemoveBrush}\label{wxbrushlistremovebrush}
 338
 339 \func{void}{RemoveBrush}{\param{wxBrush *}{brush}}
 340
 341 Used by wxWindows to remove a brush from the list.
 342
 343