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