docs/latex/wx/brush.tex

   1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2 %% Name:        brush.tex
   3 %% Purpose:     wxPen docs
   4 %% Author:
   5 %% Modified by:
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   7 %% RCS-ID:      $Id$
   8 %% Copyright:   (c) wxWidgets
   9 %% License:     wxWindows license
  10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  11
  12 \section{\class{wxBrush}}\label{wxbrush}
  13
  14 A brush is a drawing tool for filling in areas. It is used for painting
  15 the background of rectangles, ellipses, etc. It has a colour and a
  16 style.
  17
  18 \wxheading{Derived from}
  19
  20 \helpref{wxGDIObject}{wxgdiobject}\\
  21 \helpref{wxObject}{wxobject}
  22
  23 \wxheading{Include files}
  24
  25 <wx/brush.h>
  26
  27 \wxheading{Predefined objects}
  28
  29 Objects:
  30
  31 {\bf wxNullBrush}
  32
  33 Pointers:
  34
  35 {\bf wxBLUE\_BRUSH\\
  36 wxGREEN\_BRUSH\\
  37 wxWHITE\_BRUSH\\
  38 wxBLACK\_BRUSH\\
  39 wxGREY\_BRUSH\\
  40 wxMEDIUM\_GREY\_BRUSH\\
  41 wxLIGHT\_GREY\_BRUSH\\
  42 wxTRANSPARENT\_BRUSH\\
  43 wxCYAN\_BRUSH\\
  44 wxRED\_BRUSH}
  45
  46 \wxheading{Remarks}
  47
  48 On a monochrome display, wxWidgets shows
  49 all brushes as white unless the colour is really black.
  50
  51 Do not initialize objects on the stack before the program commences,
  52 since other required structures may not have been set up yet. Instead,
  53 define global pointers to objects and create them in \helpref{wxApp::OnInit}{wxapponinit} or
  54 when required.
  55
  56 An application may wish to create brushes with different
  57 characteristics dynamically, and there is the consequent danger that a
  58 large number of duplicate brushes will be created. Therefore an
  59 application may wish to get a pointer to a brush by using the global
  60 list of brushes {\bf wxTheBrushList}, and calling the member function
  61 \rtfsp{\bf FindOrCreateBrush}.
  62
  63 wxBrush uses a reference counting system, so assignments between brushes are very
  64 cheap. You can therefore use actual wxBrush objects instead of pointers without
  65 efficiency problems. Once one wxBrush object changes its data it will create its
  66 own brush data internally so that other brushes, which previously shared the
  67 data using the reference counting, are not affected.
  68
  69 %TODO: an overview for wxBrush.
  70 \wxheading{See also}
  71
  72 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxDC}{wxdc}, \helpref{wxDC::SetBrush}{wxdcsetbrush}
  73
  74 \latexignore{\rtfignore{\wxheading{Members}}}
  75
  76
  77 \membersection{wxBrush::wxBrush}\label{wxbrushctor}
  78
  79 \func{}{wxBrush}{\void}
  80
  81 Default constructor. The brush will be uninitialised, and \helpref{wxBrush::Ok}{wxbrushok} will
  82 return false.
  83
  84 \func{}{wxBrush}{\param{const wxColour\&}{ colour}, \param{int}{ style = {\tt wxSOLID}}}
  85
  86 Constructs a brush from a colour object and style.
  87
  88 \func{}{wxBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
  89
  90 Constructs a brush from a colour name and style.
  91
  92 \func{}{wxBrush}{\param{const wxBitmap\& }{stippleBitmap}}
  93
  94 Constructs a stippled brush using a bitmap.
  95
  96 \func{}{wxBrush}{\param{const wxBrush\&}{ brush}}
  97
  98 Copy constructor. This uses reference counting so is a cheap operation.
  99
 100 \wxheading{Parameters}
 101
 102 \docparam{colour}{Colour object.}
 103
 104 \docparam{colourName}{Colour name. The name will be looked up in the colour database.}
 105
 106 \docparam{style}{One of:
 107
 108 \begin{twocollist}\itemsep=0pt
 109 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 110 \twocolitem{{\bf wxSOLID}}{Solid.}
 111 \twocolitem{{\bf wxSTIPPLE}}{Uses a bitmap as a stipple.}
 112 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 113 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 114 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 115 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 116 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 117 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 118 \end{twocollist}}
 119
 120 \docparam{brush}{Pointer or reference to a brush to copy.}
 121
 122 \docparam{stippleBitmap}{A bitmap to use for stippling.}
 123
 124 \wxheading{Remarks}
 125
 126 If a stipple brush is created, the brush style will be set to wxSTIPPLE.
 127
 128 \wxheading{See also}
 129
 130 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxColour}{wxcolour}, \helpref{wxColourDatabase}{wxcolourdatabase}
 131
 132
 133 \membersection{wxBrush::\destruct{wxBrush}}\label{wxbrushdtor}
 134
 135 \func{}{\destruct{wxBrush}}{\void}
 136
 137 Destructor.
 138
 139 \wxheading{Remarks}
 140
 141 The destructor may not delete the underlying brush object of the native windowing
 142 system, since wxBrush uses a reference counting system for efficiency.
 143
 144 Although all remaining brushes are deleted when the application exits,
 145 the application should try to clean up all brushes itself. This is because
 146 wxWidgets cannot know if a pointer to the brush object is stored in an
 147 application data structure, and there is a risk of double deletion.
 148
 149
 150 \membersection{wxBrush::GetColour}\label{wxbrushgetcolour}
 151
 152 \constfunc{wxColour\&}{GetColour}{\void}
 153
 154 Returns a reference to the brush colour.
 155
 156 \wxheading{See also}
 157
 158 \helpref{wxBrush::SetColour}{wxbrushsetcolour}
 159
 160
 161 \membersection{wxBrush::GetStipple}\label{wxbrushgetstipple}
 162
 163 \constfunc{wxBitmap *}{GetStipple}{\void}
 164
 165 Gets a pointer to the stipple bitmap. If the brush does not have a wxSTIPPLE style,
 166 this bitmap may be non-NULL but uninitialised (\helpref{wxBitmap::Ok}{wxbitmapok} returns false).
 167
 168 \wxheading{See also}
 169
 170 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 171
 172
 173 \membersection{wxBrush::GetStyle}\label{wxbrushgetstyle}
 174
 175 \constfunc{int}{GetStyle}{\void}
 176
 177 Returns the brush style, one of:
 178
 179 \begin{twocollist}\itemsep=0pt
 180 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 181 \twocolitem{{\bf wxSOLID}}{Solid.}
 182 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 183 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 184 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 185 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 186 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 187 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 188 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 189 \twocolitem{{\bf wxSTIPPLE\_MASK\_OPAQUE}}{Stippled using a bitmap's mask.}
 190 \end{twocollist}
 191
 192 \wxheading{See also}
 193
 194 \helpref{wxBrush::SetStyle}{wxbrushsetstyle}, \helpref{wxBrush::SetColour}{wxbrushsetcolour},\rtfsp
 195 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 196
 197
 198 \membersection{wxBrush::IsHatch}\label{wxbrushishatch}
 199
 200 \constfunc{bool}{IsHatch}{\void}
 201
 202 Returns true if the style of the brush is any of hatched fills.
 203
 204 \wxheading{See also}
 205
 206 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 207
 208
 209 \membersection{wxBrush::Ok}\label{wxbrushok}
 210
 211 \constfunc{bool}{Ok}{\void}
 212
 213 Returns true if the brush is initialised. It will return false if the default
 214 constructor has been used (for example, the brush is a member of a class, or
 215 NULL has been assigned to it).
 216
 217
 218 \membersection{wxBrush::SetColour}\label{wxbrushsetcolour}
 219
 220 \func{void}{SetColour}{\param{wxColour\& }{colour}}
 221
 222 Sets the brush colour using a reference to a colour object.
 223
 224 \func{void}{SetColour}{\param{const wxString\& }{colourName}}
 225
 226 Sets the brush colour using a colour name from the colour database.
 227
 228 \func{void}{SetColour}{\param{unsigned char}{ red}, \param{unsigned char}{ green}, \param{unsigned char}{ blue}}
 229
 230 Sets the brush colour using red, green and blue values.
 231
 232 \wxheading{See also}
 233
 234 \helpref{wxBrush::GetColour}{wxbrushgetcolour}
 235
 236
 237 \membersection{wxBrush::SetStipple}\label{wxbrushsetstipple}
 238
 239 \func{void}{SetStipple}{\param{const wxBitmap\&}{ bitmap}}
 240
 241 Sets the stipple bitmap.
 242
 243 \wxheading{Parameters}
 244
 245 \docparam{bitmap}{The bitmap to use for stippling.}
 246
 247 \wxheading{Remarks}
 248
 249 The style will be set to wxSTIPPLE, unless the bitmap has a mask associated
 250 to it, in which case the style will be set to wxSTIPPLE\_MASK\_OPAQUE.
 251
 252 If the wxSTIPPLE variant is used, the bitmap will be used to fill out the
 253 area to be drawn. If the wxSTIPPLE\_MASK\_OPAQUE is used, the current
 254 text foreground and text background determine what colours are used for
 255 displaying and the bits in the mask (which is a mono-bitmap actually)
 256 determine where to draw what.
 257
 258 Note that under Windows 95, only 8x8 pixel large stipple bitmaps are
 259 supported, Windows 98 and NT as well as GTK support arbitrary bitmaps.
 260
 261 \wxheading{See also}
 262
 263 \helpref{wxBitmap}{wxbitmap}
 264
 265
 266 \membersection{wxBrush::SetStyle}\label{wxbrushsetstyle}
 267
 268 \func{void}{SetStyle}{\param{int}{ style}}
 269
 270 Sets the brush style.
 271
 272 \docparam{style}{One of:
 273
 274 \begin{twocollist}\itemsep=0pt
 275 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 276 \twocolitem{{\bf wxSOLID}}{Solid.}
 277 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 278 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 279 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 280 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 281 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 282 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 283 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 284 \twocolitem{{\bf wxSTIPPLE\_MASK\_OPAQUE}}{Stippled using a bitmap's mask.}
 285 \end{twocollist}}
 286
 287 \wxheading{See also}
 288
 289 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 290
 291
 292 \membersection{wxBrush::operator $=$}\label{wxbrushassignment}
 293
 294 \func{wxBrush\&}{operator $=$}{\param{const wxBrush\& }{brush}}
 295
 296 Assignment operator, using reference counting. Returns a reference
 297 to `this'.
 298
 299
 300 \membersection{wxBrush::operator $==$}\label{wxbrushequals}
 301
 302 \func{bool}{operator $==$}{\param{const wxBrush\& }{brush}}
 303
 304 Equality operator. Two brushes are equal if they contain pointers
 305 to the same underlying brush data. It does not compare each attribute,
 306 so two independently-created brushes using the same parameters will
 307 fail the test.
 308
 309
 310 \membersection{wxBrush::operator $!=$}\label{wxbrushnotequals}
 311
 312 \func{bool}{operator $!=$}{\param{const wxBrush\& }{brush}}
 313
 314 Inequality operator. Two brushes are not equal if they contain pointers
 315 to different underlying brush data. It does not compare each attribute.
 316
 317 \section{\class{wxBrushList}}\label{wxbrushlist}
 318
 319 A brush list is a list containing all brushes which have been created.
 320
 321 \wxheading{Derived from}
 322
 323 \helpref{wxList}{wxlist}\\
 324 \helpref{wxObject}{wxobject}
 325
 326 \wxheading{Include files}
 327
 328 <wx/gdicmn.h>
 329
 330 \wxheading{Remarks}
 331
 332 There is only one instance of this class: {\bf wxTheBrushList}.  Use
 333 this object to search for a previously created brush of the desired
 334 type and create it if not already found. In some windowing systems,
 335 the brush may be a scarce resource, so it can pay to reuse old
 336 resources if possible. When an application finishes, all brushes will
 337 be deleted and their resources freed, eliminating the possibility of
 338 `memory leaks'. However, it is best not to rely on this automatic
 339 cleanup because it can lead to double deletion in some circumstances.
 340
 341 There are two mechanisms in recent versions of wxWidgets which make the
 342 brush list less useful than it once was. Under Windows, scarce resources
 343 are cleaned up internally if they are not being used. Also, a reference
 344 counting mechanism applied to all GDI objects means that some sharing
 345 of underlying resources is possible. You don't have to keep track of pointers,
 346 working out when it is safe delete a brush, because the reference counting does
 347 it for you. For example, you can set a brush in a device context, and then
 348 immediately delete the brush you passed, because the brush is `copied'.
 349
 350 So you may find it easier to ignore the brush list, and instead create
 351 and copy brushes as you see fit. If your Windows resource meter suggests
 352 your application is using too many resources, you can resort to using
 353 GDI lists to share objects explicitly.
 354
 355 The only compelling use for the brush list is for wxWidgets to keep
 356 track of brushes in order to clean them up on exit. It is also kept for
 357 backward compatibility with earlier versions of wxWidgets.
 358
 359 \wxheading{See also}
 360
 361 \helpref{wxBrush}{wxbrush}
 362
 363 \latexignore{\rtfignore{\wxheading{Members}}}
 364
 365
 366 \membersection{wxBrushList::wxBrushList}\label{wxbrushlistconstr}
 367
 368 \func{void}{wxBrushList}{\void}
 369
 370 Constructor. The application should not construct its own brush list:
 371 use the object pointer {\bf wxTheBrushList}.
 372
 373
 374 \membersection{wxBrushList::AddBrush}\label{wxbrushlistaddbrush}
 375
 376 \func{void}{AddBrush}{\param{wxBrush *}{brush}}
 377
 378 Used internally by wxWidgets to add a brush to the list.
 379
 380
 381 \membersection{wxBrushList::FindOrCreateBrush}\label{wxbrushlistfindorcreatebrush}
 382
 383 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxColour\& }{colour}, \param{int}{ style = wxSOLID}}
 384
 385 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 386 to the brush list, and returns it.
 387
 388 \wxheading{Parameters}
 389
 390 \docparam{colour}{Colour object.}
 391
 392 \docparam{style}{Brush style. See \helpref{wxBrush::SetStyle}{wxbrushsetstyle} for a list of styles.}
 393
 394
 395 \membersection{wxBrushList::RemoveBrush}\label{wxbrushlistremovebrush}
 396
 397 \func{void}{RemoveBrush}{\param{wxBrush *}{brush}}
 398
 399 Used by wxWidgets to remove a brush from the list.
 400
 401