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, wxWindows 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 \membersection{wxBrush::wxBrush}
  66
  67 \func{}{wxBrush}{\void}
  68
  69 Default constructor. The brush will be uninitialised, and \helpref{wxBrush::Ok}{wxbrushok} will
  70 return FALSE.
  71
  72 \func{}{wxBrush}{\param{const wxColour\&}{ colour}, \param{int}{ style}}
  73
  74 Constructs a brush from a colour object and style.
  75
  76 \func{}{wxBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
  77
  78 Constructs a brush from a colour name and style.
  79
  80 \func{}{wxBrush}{\param{const wxBitmap\& }{stippleBitmap}}
  81
  82 Constructs a stippled brush using a bitmap.
  83
  84 \func{}{wxBrush}{\param{const wxBrush\&}{ brush}}
  85
  86 Copy constructor. This uses reference counting so is a cheap operation.
  87
  88 \wxheading{Parameters}
  89
  90 \docparam{colour}{Colour object.}
  91
  92 \docparam{colourName}{Colour name. The name will be looked up in the colour database.}
  93
  94 \docparam{style}{One of:
  95
  96 \begin{twocollist}\itemsep=0pt
  97 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
  98 \twocolitem{{\bf wxSOLID}}{Solid.}
  99 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 100 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 101 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 102 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 103 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 104 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 105 \end{twocollist}}
 106
 107 \docparam{brush}{Pointer or reference to a brush to copy.}
 108
 109 \docparam{stippleBitmap}{A bitmap to use for stippling.}
 110
 111 \wxheading{Remarks}
 112
 113 If a stipple brush is created, the brush style will be set to wxSTIPPLE.
 114
 115 \wxheading{See also}
 116
 117 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxColour}{wxcolour}, \helpref{wxColourDatabase}{wxcolourdatabase}
 118
 119 \membersection{wxBrush::\destruct{wxBrush}}
 120
 121 \func{void}{\destruct{wxBrush}}{\void}
 122
 123 Destructor.
 124
 125 \wxheading{Remarks}
 126
 127 The destructor may not delete the underlying brush object of the native windowing
 128 system, since wxBrush uses a reference counting system for efficiency.
 129
 130 Although all remaining brushes are deleted when the application exits,
 131 the application should try to clean up all brushes itself. This is because
 132 wxWindows cannot know if a pointer to the brush object is stored in an
 133 application data structure, and there is a risk of double deletion.
 134
 135 \membersection{wxBrush::GetColour}\label{wxbrushgetcolour}
 136
 137 \constfunc{wxColour\&}{GetColour}{\void}
 138
 139 Returns a reference to the brush colour.
 140
 141 \wxheading{See also}
 142
 143 \helpref{wxBrush::SetColour}{wxbrushsetcolour}
 144
 145 \membersection{wxBrush::GetStipple}\label{wxbrushgetstipple}
 146
 147 \constfunc{wxBitmap *}{GetStipple}{\void}
 148
 149 Gets a pointer to the stipple bitmap. If the brush does not have a wxSTIPPLE style,
 150 this bitmap may be non-NULL but uninitialised (\helpref{wxBitmap::Ok}{wxbitmapok} returns FALSE).
 151
 152 \wxheading{See also}
 153
 154 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 155
 156 \membersection{wxBrush::GetStyle}\label{wxbrushgetstyle}
 157
 158 \constfunc{int}{GetStyle}{\void}
 159
 160 Returns the brush style, one of:
 161
 162 \begin{twocollist}\itemsep=0pt
 163 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 164 \twocolitem{{\bf wxSOLID}}{Solid.}
 165 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 166 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 167 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 168 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 169 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 170 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 171 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 172 \end{twocollist}
 173
 174 \wxheading{See also}
 175
 176 \helpref{wxBrush::SetStyle}{wxbrushsetstyle}, \helpref{wxBrush::SetColour}{wxbrushsetcolour},\rtfsp
 177 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 178
 179 \membersection{wxBrush::Ok}\label{wxbrushok}
 180
 181 \constfunc{bool}{Ok}{\void}
 182
 183 Returns TRUE if the brush is initialised. It will return FALSE if the default
 184 constructor has been used (for example, the brush is a member of a class, or
 185 NULL has been assigned to it).
 186
 187 \membersection{wxBrush::SetColour}\label{wxbrushsetcolour}
 188
 189 \func{void}{SetColour}{\param{wxColour\& }{colour}}
 190
 191 Sets the brush colour using a reference to a colour object.
 192
 193 \func{void}{SetColour}{\param{const wxString\& }{colourName}}
 194
 195 Sets the brush colour using a colour name from the colour database.
 196
 197 \func{void}{SetColour}{\param{const unsigned char}{ red}, \param{const unsigned char}{ green}, \param{const unsigned char}{ blue}}
 198
 199 Sets the brush colour using red, green and blue values.
 200
 201 \wxheading{See also}
 202
 203 \helpref{wxBrush::GetColour}{wxbrushgetcolour}
 204
 205 \membersection{wxBrush::SetStipple}\label{wxbrushsetstipple}
 206
 207 \func{void}{SetStipple}{\param{const wxBitmap\&}{ bitmap}}
 208
 209 Sets the stipple bitmap.
 210
 211 \wxheading{Parameters}
 212
 213 \docparam{bitmap}{The bitmap to use for stippling.}
 214
 215 \wxheading{Remarks}
 216
 217 The style will be set to wxSTIPPLE.
 218
 219 Note that there is a big difference between stippling in X and Windows.
 220 On X, the stipple is a mask between the wxBitmap and current colour.
 221 On Windows, the current colour is ignored, and the bitmap colour is used.
 222 However, for pre-defined modes like wxCROSS\_HATCH, the behaviour is the
 223 same for both platforms.
 224
 225 \wxheading{See also}
 226
 227 \helpref{wxBitmap}{wxbitmap}
 228
 229 \membersection{wxBrush::SetStyle}\label{wxbrushsetstyle}
 230
 231 \func{void}{SetStyle}{\param{int}{ style}}
 232
 233 Sets the brush style.
 234
 235 \docparam{style}{One of:
 236
 237 \begin{twocollist}\itemsep=0pt
 238 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 239 \twocolitem{{\bf wxSOLID}}{Solid.}
 240 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 241 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 242 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 243 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 244 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 245 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 246 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 247 \end{twocollist}}
 248
 249 \wxheading{See also}
 250
 251 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 252
 253 \membersection{wxBrush::operator $=$}\label{wxbrushassignment}
 254
 255 \func{wxBrush\&}{operator $=$}{\param{const wxBrush\& }{brush}}
 256
 257 Assignment operator, using reference counting. Returns a reference
 258 to `this'.
 259
 260 \membersection{wxBrush::operator $==$}\label{wxbrushequals}
 261
 262 \func{bool}{operator $==$}{\param{const wxBrush\& }{brush}}
 263
 264 Equality operator. Two brushes are equal if they contain pointers
 265 to the same underlying brush data. It does not compare each attribute,
 266 so two independently-created brushes using the same parameters will
 267 fail the test.
 268
 269 \membersection{wxBrush::operator $!=$}\label{wxbrushnotequals}
 270
 271 \func{bool}{operator $!=$}{\param{const wxBrush\& }{brush}}
 272
 273 Inequality operator. Two brushes are not equal if they contain pointers
 274 to different underlying brush data. It does not compare each attribute.
 275
 276 \section{\class{wxBrushList}}\label{wxbrushlist}
 277
 278 A brush list is a list containing all brushes which have been created.
 279
 280 \wxheading{Derived from}
 281
 282 \helpref{wxList}{wxlist}\\
 283 \helpref{wxObject}{wxobject}
 284
 285 \wxheading{Include files}
 286
 287 <wx/gdicmn.h>
 288
 289 \wxheading{Remarks}
 290
 291 There is only one instance of this class: {\bf wxTheBrushList}.  Use
 292 this object to search for a previously created brush of the desired
 293 type and create it if not already found. In some windowing systems,
 294 the brush may be a scarce resource, so it can pay to reuse old
 295 resources if possible. When an application finishes, all brushes will
 296 be deleted and their resources freed, eliminating the possibility of
 297 `memory leaks'. However, it is best not to rely on this automatic
 298 cleanup because it can lead to double deletion in some circumstances.
 299
 300 There are two mechanisms in recent versions of wxWindows which make the
 301 brush list less useful than it once was. Under Windows, scarce resources
 302 are cleaned up internally if they are not being used. Also, a referencing
 303 counting mechanism applied to all GDI objects means that some sharing
 304 of underlying resources is possible. You don't have to keep track of pointers,
 305 working out when it is safe delete a brush, because the referencing counting does
 306 it for you. For example, you can set a brush in a device context, and then
 307 immediately delete the brush you passed, because the brush is `copied'.
 308
 309 So you may find it easier to ignore the brush list, and instead create
 310 and copy brushes as you see fit. If your Windows resource meter suggests
 311 your application is using too many resources, you can resort to using
 312 GDI lists to share objects explicitly.
 313
 314 The only compelling use for the brush list is for wxWindows to keep
 315 track of brushes in order to clean them up on exit. It is also kept for
 316 backward compatibility with earlier versions of wxWindows.
 317
 318 \wxheading{See also}
 319
 320 \helpref{wxBrush}{wxbrush}
 321
 322 \latexignore{\rtfignore{\wxheading{Members}}}
 323
 324 \membersection{wxBrushList::wxBrushList}\label{wxbrushlistconstr}
 325
 326 \func{void}{wxBrushList}{\void}
 327
 328 Constructor. The application should not construct its own brush list:
 329 use the object pointer {\bf wxTheBrushList}.
 330
 331 \membersection{wxBrushList::AddBrush}\label{wxbrushlistaddbrush}
 332
 333 \func{void}{AddBrush}{\param{wxBrush *}{brush}}
 334
 335 Used internally by wxWindows to add a brush to the list.
 336
 337 \membersection{wxBrushList::FindOrCreateBrush}\label{wxbrushlistfindorcreatebrush}
 338
 339 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxColour\& }{colour}, \param{int}{ style}}
 340
 341 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 342 to the brush list, and returns it.
 343
 344 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
 345
 346 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 347 to the brush list, and returns it.
 348
 349 Finds a brush of the given specification, or creates one and adds it to the list.
 350
 351 \wxheading{Parameters}
 352
 353 \docparam{colour}{Colour object.}
 354
 355 \docparam{colourName}{Colour name, which should be in the colour database.}
 356
 357 \docparam{style}{Brush style. See \helpref{wxBrush::SetStyle}{wxbrushsetstyle} for a list of styles.}
 358
 359 \membersection{wxBrushList::RemoveBrush}\label{wxbrushlistremovebrush}
 360
 361 \func{void}{RemoveBrush}{\param{wxBrush *}{brush}}
 362
 363 Used by wxWindows to remove a brush from the list.
 364
 365