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{Include files}
  13
  14 <wx/brush.h>
  15
  16 \wxheading{Predefined objects}
  17
  18 Objects:
  19
  20 {\bf wxNullBrush}
  21
  22 Pointers:
  23
  24 {\bf wxBLUE\_BRUSH\\
  25 wxGREEN\_BRUSH\\
  26 wxWHITE\_BRUSH\\
  27 wxBLACK\_BRUSH\\
  28 wxGREY\_BRUSH\\
  29 wxMEDIUM\_GREY\_BRUSH\\
  30 wxLIGHT\_GREY\_BRUSH\\
  31 wxTRANSPARENT\_BRUSH\\
  32 wxCYAN\_BRUSH\\
  33 wxRED\_BRUSH}
  34
  35 \wxheading{Remarks}
  36
  37 On a monochrome display, wxWidgets shows
  38 all brushes as white unless the colour is really black.
  39
  40 Do not initialize objects on the stack before the program commences,
  41 since other required structures may not have been set up yet. Instead,
  42 define global pointers to objects and create them in \helpref{wxApp::OnInit}{wxapponinit} or
  43 when required.
  44
  45 An application may wish to create brushes with different
  46 characteristics dynamically, and there is the consequent danger that a
  47 large number of duplicate brushes will be created. Therefore an
  48 application may wish to get a pointer to a brush by using the global
  49 list of brushes {\bf wxTheBrushList}, and calling the member function
  50 \rtfsp{\bf FindOrCreateBrush}.
  51
  52 wxBrush uses a reference counting system, so assignments between brushes are very
  53 cheap. You can therefore use actual wxBrush objects instead of pointers without
  54 efficiency problems. Once one wxBrush object changes its data it will create its
  55 own brush data internally so that other brushes, which previously shared the
  56 data using the reference counting, are not affected.
  57
  58 %TODO: an overview for wxBrush.
  59 \wxheading{See also}
  60
  61 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxDC}{wxdc}, \helpref{wxDC::SetBrush}{wxdcsetbrush}
  62
  63 \latexignore{\rtfignore{\wxheading{Members}}}
  64
  65
  66 \membersection{wxBrush::wxBrush}\label{wxbrushctor}
  67
  68 \func{}{wxBrush}{\void}
  69
  70 Default constructor. The brush will be uninitialised, and \helpref{wxBrush::Ok}{wxbrushok} will
  71 return false.
  72
  73 \func{}{wxBrush}{\param{const wxColour\&}{ colour}, \param{int}{ style = {\tt wxSOLID}}}
  74
  75 Constructs a brush from a colour object and style.
  76
  77 \func{}{wxBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
  78
  79 Constructs a brush from a colour name and style.
  80
  81 \func{}{wxBrush}{\param{const wxBitmap\& }{stippleBitmap}}
  82
  83 Constructs a stippled brush using a bitmap.
  84
  85 \func{}{wxBrush}{\param{const wxBrush\&}{ brush}}
  86
  87 Copy constructor. This uses reference counting so is a cheap operation.
  88
  89 \wxheading{Parameters}
  90
  91 \docparam{colour}{Colour object.}
  92
  93 \docparam{colourName}{Colour name. The name will be looked up in the colour database.}
  94
  95 \docparam{style}{One of:
  96
  97 \begin{twocollist}\itemsep=0pt
  98 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
  99 \twocolitem{{\bf wxSOLID}}{Solid.}
 100 \twocolitem{{\bf wxSTIPPLE}}{Uses a bitmap as a stipple.}
 101 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 102 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 103 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 104 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 105 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 106 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 107 \end{twocollist}}
 108
 109 \docparam{brush}{Pointer or reference to a brush to copy.}
 110
 111 \docparam{stippleBitmap}{A bitmap to use for stippling.}
 112
 113 \wxheading{Remarks}
 114
 115 If a stipple brush is created, the brush style will be set to wxSTIPPLE.
 116
 117 \wxheading{See also}
 118
 119 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxColour}{wxcolour}, \helpref{wxColourDatabase}{wxcolourdatabase}
 120
 121
 122 \membersection{wxBrush::\destruct{wxBrush}}\label{wxbrushdtor}
 123
 124 \func{}{\destruct{wxBrush}}{\void}
 125
 126 Destructor.
 127
 128 \wxheading{Remarks}
 129
 130 The destructor may not delete the underlying brush object of the native windowing
 131 system, since wxBrush uses a reference counting system for efficiency.
 132
 133 Although all remaining brushes are deleted when the application exits,
 134 the application should try to clean up all brushes itself. This is because
 135 wxWidgets cannot know if a pointer to the brush object is stored in an
 136 application data structure, and there is a risk of double deletion.
 137
 138
 139 \membersection{wxBrush::GetColour}\label{wxbrushgetcolour}
 140
 141 \constfunc{wxColour\&}{GetColour}{\void}
 142
 143 Returns a reference to the brush colour.
 144
 145 \wxheading{See also}
 146
 147 \helpref{wxBrush::SetColour}{wxbrushsetcolour}
 148
 149
 150 \membersection{wxBrush::GetStipple}\label{wxbrushgetstipple}
 151
 152 \constfunc{wxBitmap *}{GetStipple}{\void}
 153
 154 Gets a pointer to the stipple bitmap. If the brush does not have a wxSTIPPLE style,
 155 this bitmap may be non-NULL but uninitialised (\helpref{wxBitmap::Ok}{wxbitmapok} returns false).
 156
 157 \wxheading{See also}
 158
 159 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 160
 161
 162 \membersection{wxBrush::GetStyle}\label{wxbrushgetstyle}
 163
 164 \constfunc{int}{GetStyle}{\void}
 165
 166 Returns the brush style, one of:
 167
 168 \begin{twocollist}\itemsep=0pt
 169 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 170 \twocolitem{{\bf wxSOLID}}{Solid.}
 171 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 172 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 173 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 174 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 175 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 176 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 177 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 178 \twocolitem{{\bf wxSTIPPLE\_MASK\_OPAQUE}}{Stippled using a bitmap's mask.}
 179 \end{twocollist}
 180
 181 \wxheading{See also}
 182
 183 \helpref{wxBrush::SetStyle}{wxbrushsetstyle}, \helpref{wxBrush::SetColour}{wxbrushsetcolour},\rtfsp
 184 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 185
 186
 187 \membersection{wxBrush::IsHatch}\label{wxbrushishatch}
 188
 189 \constfunc{bool}{IsHatch}{\void}
 190
 191 Returns true if the style of the brush is any of hatched fills.
 192
 193 \wxheading{See also}
 194
 195 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 196
 197
 198 \membersection{wxBrush::Ok}\label{wxbrushok}
 199
 200 \constfunc{bool}{Ok}{\void}
 201
 202 Returns true if the brush is initialised. It will return false if the default
 203 constructor has been used (for example, the brush is a member of a class, or
 204 NULL has been assigned to it).
 205
 206
 207 \membersection{wxBrush::SetColour}\label{wxbrushsetcolour}
 208
 209 \func{void}{SetColour}{\param{wxColour\& }{colour}}
 210
 211 Sets the brush colour using a reference to a colour object.
 212
 213 \func{void}{SetColour}{\param{const wxString\& }{colourName}}
 214
 215 Sets the brush colour using a colour name from the colour database.
 216
 217 \func{void}{SetColour}{\param{const unsigned char}{ red}, \param{const unsigned char}{ green}, \param{const unsigned char}{ blue}}
 218
 219 Sets the brush colour using red, green and blue values.
 220
 221 \wxheading{See also}
 222
 223 \helpref{wxBrush::GetColour}{wxbrushgetcolour}
 224
 225
 226 \membersection{wxBrush::SetStipple}\label{wxbrushsetstipple}
 227
 228 \func{void}{SetStipple}{\param{const wxBitmap\&}{ bitmap}}
 229
 230 Sets the stipple bitmap.
 231
 232 \wxheading{Parameters}
 233
 234 \docparam{bitmap}{The bitmap to use for stippling.}
 235
 236 \wxheading{Remarks}
 237
 238 The style will be set to wxSTIPPLE, unless the bitmap has a mask associated
 239 to it, in which case the style will be set to wxSTIPPLE\_MASK\_OPAQUE.
 240
 241 If the wxSTIPPLE variant is used, the bitmap will be used to fill out the
 242 area to be drawn. If the wxSTIPPLE\_MASK\_OPAQUE is used, the current
 243 text foreground and text background determine what colours are used for
 244 displaying and the bits in the mask (which is a mono-bitmap actually)
 245 determine where to draw what.
 246
 247 Note that under Windows 95, only 8x8 pixel large stipple bitmaps are
 248 supported, Windows 98 and NT as well as GTK support arbitrary bitmaps.
 249
 250 \wxheading{See also}
 251
 252 \helpref{wxBitmap}{wxbitmap}
 253
 254
 255 \membersection{wxBrush::SetStyle}\label{wxbrushsetstyle}
 256
 257 \func{void}{SetStyle}{\param{int}{ style}}
 258
 259 Sets the brush style.
 260
 261 \docparam{style}{One of:
 262
 263 \begin{twocollist}\itemsep=0pt
 264 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 265 \twocolitem{{\bf wxSOLID}}{Solid.}
 266 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 267 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 268 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 269 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 270 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 271 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 272 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 273 \twocolitem{{\bf wxSTIPPLE\_MASK\_OPAQUE}}{Stippled using a bitmap's mask.}
 274 \end{twocollist}}
 275
 276 \wxheading{See also}
 277
 278 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 279
 280
 281 \membersection{wxBrush::operator $=$}\label{wxbrushassignment}
 282
 283 \func{wxBrush\&}{operator $=$}{\param{const wxBrush\& }{brush}}
 284
 285 Assignment operator, using reference counting. Returns a reference
 286 to `this'.
 287
 288
 289 \membersection{wxBrush::operator $==$}\label{wxbrushequals}
 290
 291 \func{bool}{operator $==$}{\param{const wxBrush\& }{brush}}
 292
 293 Equality operator. Two brushes are equal if they contain pointers
 294 to the same underlying brush data. It does not compare each attribute,
 295 so two independently-created brushes using the same parameters will
 296 fail the test.
 297
 298
 299 \membersection{wxBrush::operator $!=$}\label{wxbrushnotequals}
 300
 301 \func{bool}{operator $!=$}{\param{const wxBrush\& }{brush}}
 302
 303 Inequality operator. Two brushes are not equal if they contain pointers
 304 to different underlying brush data. It does not compare each attribute.
 305
 306 \section{\class{wxBrushList}}\label{wxbrushlist}
 307
 308 A brush list is a list containing all brushes which have been created.
 309
 310 \wxheading{Derived from}
 311
 312 \helpref{wxList}{wxlist}\\
 313 \helpref{wxObject}{wxobject}
 314
 315 \wxheading{Include files}
 316
 317 <wx/gdicmn.h>
 318
 319 \wxheading{Remarks}
 320
 321 There is only one instance of this class: {\bf wxTheBrushList}.  Use
 322 this object to search for a previously created brush of the desired
 323 type and create it if not already found. In some windowing systems,
 324 the brush may be a scarce resource, so it can pay to reuse old
 325 resources if possible. When an application finishes, all brushes will
 326 be deleted and their resources freed, eliminating the possibility of
 327 `memory leaks'. However, it is best not to rely on this automatic
 328 cleanup because it can lead to double deletion in some circumstances.
 329
 330 There are two mechanisms in recent versions of wxWidgets which make the
 331 brush list less useful than it once was. Under Windows, scarce resources
 332 are cleaned up internally if they are not being used. Also, a referencing
 333 counting mechanism applied to all GDI objects means that some sharing
 334 of underlying resources is possible. You don't have to keep track of pointers,
 335 working out when it is safe delete a brush, because the referencing counting does
 336 it for you. For example, you can set a brush in a device context, and then
 337 immediately delete the brush you passed, because the brush is `copied'.
 338
 339 So you may find it easier to ignore the brush list, and instead create
 340 and copy brushes as you see fit. If your Windows resource meter suggests
 341 your application is using too many resources, you can resort to using
 342 GDI lists to share objects explicitly.
 343
 344 The only compelling use for the brush list is for wxWidgets to keep
 345 track of brushes in order to clean them up on exit. It is also kept for
 346 backward compatibility with earlier versions of wxWidgets.
 347
 348 \wxheading{See also}
 349
 350 \helpref{wxBrush}{wxbrush}
 351
 352 \latexignore{\rtfignore{\wxheading{Members}}}
 353
 354
 355 \membersection{wxBrushList::wxBrushList}\label{wxbrushlistconstr}
 356
 357 \func{void}{wxBrushList}{\void}
 358
 359 Constructor. The application should not construct its own brush list:
 360 use the object pointer {\bf wxTheBrushList}.
 361
 362
 363 \membersection{wxBrushList::AddBrush}\label{wxbrushlistaddbrush}
 364
 365 \func{void}{AddBrush}{\param{wxBrush *}{brush}}
 366
 367 Used internally by wxWidgets to add a brush to the list.
 368
 369
 370 \membersection{wxBrushList::FindOrCreateBrush}\label{wxbrushlistfindorcreatebrush}
 371
 372 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxColour\& }{colour}, \param{int}{ style = wxSOLID}}
 373
 374 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 375 to the brush list, and returns it.
 376
 377 \wxheading{Parameters}
 378
 379 \docparam{colour}{Colour object.}
 380
 381 \docparam{style}{Brush style. See \helpref{wxBrush::SetStyle}{wxbrushsetstyle} for a list of styles.}
 382
 383
 384 \membersection{wxBrushList::RemoveBrush}\label{wxbrushlistremovebrush}
 385
 386 \func{void}{RemoveBrush}{\param{wxBrush *}{brush}}
 387
 388 Used by wxWidgets to remove a brush from the list.
 389
 390