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 \membersection{wxBrush::wxBrush}\label{wxbrushctor}
  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 = {\tt wxSOLID}}}
  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 wxSTIPPLE}}{Uses a bitmap as a stipple.}
 100 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 101 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 102 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 103 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 104 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 105 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 106 \end{twocollist}}
 107
 108 \docparam{brush}{Pointer or reference to a brush to copy.}
 109
 110 \docparam{stippleBitmap}{A bitmap to use for stippling.}
 111
 112 \wxheading{Remarks}
 113
 114 If a stipple brush is created, the brush style will be set to wxSTIPPLE.
 115
 116 \wxheading{See also}
 117
 118 \helpref{wxBrushList}{wxbrushlist}, \helpref{wxColour}{wxcolour}, \helpref{wxColourDatabase}{wxcolourdatabase}
 119
 120 \membersection{wxBrush::\destruct{wxBrush}}\label{wxbrushdtor}
 121
 122 \func{void}{\destruct{wxBrush}}{\void}
 123
 124 Destructor.
 125
 126 \wxheading{Remarks}
 127
 128 The destructor may not delete the underlying brush object of the native windowing
 129 system, since wxBrush uses a reference counting system for efficiency.
 130
 131 Although all remaining brushes are deleted when the application exits,
 132 the application should try to clean up all brushes itself. This is because
 133 wxWidgets cannot know if a pointer to the brush object is stored in an
 134 application data structure, and there is a risk of double deletion.
 135
 136 \membersection{wxBrush::GetColour}\label{wxbrushgetcolour}
 137
 138 \constfunc{wxColour\&}{GetColour}{\void}
 139
 140 Returns a reference to the brush colour.
 141
 142 \wxheading{See also}
 143
 144 \helpref{wxBrush::SetColour}{wxbrushsetcolour}
 145
 146 \membersection{wxBrush::GetStipple}\label{wxbrushgetstipple}
 147
 148 \constfunc{wxBitmap *}{GetStipple}{\void}
 149
 150 Gets a pointer to the stipple bitmap. If the brush does not have a wxSTIPPLE style,
 151 this bitmap may be non-NULL but uninitialised (\helpref{wxBitmap::Ok}{wxbitmapok} returns false).
 152
 153 \wxheading{See also}
 154
 155 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 156
 157 \membersection{wxBrush::GetStyle}\label{wxbrushgetstyle}
 158
 159 \constfunc{int}{GetStyle}{\void}
 160
 161 Returns the brush style, one of:
 162
 163 \begin{twocollist}\itemsep=0pt
 164 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 165 \twocolitem{{\bf wxSOLID}}{Solid.}
 166 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 167 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 168 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 169 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 170 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 171 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 172 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 173 \twocolitem{{\bf wxSTIPPLE\_MASK\_OPAQUE}}{Stippled using a bitmap's mask.}
 174 \end{twocollist}
 175
 176 \wxheading{See also}
 177
 178 \helpref{wxBrush::SetStyle}{wxbrushsetstyle}, \helpref{wxBrush::SetColour}{wxbrushsetcolour},\rtfsp
 179 \helpref{wxBrush::SetStipple}{wxbrushsetstipple}
 180
 181 \membersection{wxBrush::Ok}\label{wxbrushok}
 182
 183 \constfunc{bool}{Ok}{\void}
 184
 185 Returns true if the brush is initialised. It will return false if the default
 186 constructor has been used (for example, the brush is a member of a class, or
 187 NULL has been assigned to it).
 188
 189 \membersection{wxBrush::SetColour}\label{wxbrushsetcolour}
 190
 191 \func{void}{SetColour}{\param{wxColour\& }{colour}}
 192
 193 Sets the brush colour using a reference to a colour object.
 194
 195 \func{void}{SetColour}{\param{const wxString\& }{colourName}}
 196
 197 Sets the brush colour using a colour name from the colour database.
 198
 199 \func{void}{SetColour}{\param{const unsigned char}{ red}, \param{const unsigned char}{ green}, \param{const unsigned char}{ blue}}
 200
 201 Sets the brush colour using red, green and blue values.
 202
 203 \wxheading{See also}
 204
 205 \helpref{wxBrush::GetColour}{wxbrushgetcolour}
 206
 207 \membersection{wxBrush::SetStipple}\label{wxbrushsetstipple}
 208
 209 \func{void}{SetStipple}{\param{const wxBitmap\&}{ bitmap}}
 210
 211 Sets the stipple bitmap.
 212
 213 \wxheading{Parameters}
 214
 215 \docparam{bitmap}{The bitmap to use for stippling.}
 216
 217 \wxheading{Remarks}
 218
 219 The style will be set to wxSTIPPLE, unless the bitmap has a mask associated
 220 to it, in which case the style will be set to wxSTIPPLE\_MASK\_OPAQUE.
 221
 222 If the wxSTIPPLE variant is used, the bitmap will be used to fill out the
 223 area to be drawn. If the wxSTIPPLE\_MASK\_OPAQUE is used, the current
 224 text foreground and text background determine what colours are used for
 225 displaying and the bits in the mask (which is a mono-bitmap actually)
 226 determine where to draw what.
 227
 228 Note that under Windows 95, only 8x8 pixel large stipple bitmaps are
 229 supported, Windows 98 and NT as well as GTK support arbitrary bitmaps.
 230
 231 \wxheading{See also}
 232
 233 \helpref{wxBitmap}{wxbitmap}
 234
 235 \membersection{wxBrush::SetStyle}\label{wxbrushsetstyle}
 236
 237 \func{void}{SetStyle}{\param{int}{ style}}
 238
 239 Sets the brush style.
 240
 241 \docparam{style}{One of:
 242
 243 \begin{twocollist}\itemsep=0pt
 244 \twocolitem{{\bf wxTRANSPARENT}}{Transparent (no fill).}
 245 \twocolitem{{\bf wxSOLID}}{Solid.}
 246 \twocolitem{{\bf wxBDIAGONAL\_HATCH}}{Backward diagonal hatch.}
 247 \twocolitem{{\bf wxCROSSDIAG\_HATCH}}{Cross-diagonal hatch.}
 248 \twocolitem{{\bf wxFDIAGONAL\_HATCH}}{Forward diagonal hatch.}
 249 \twocolitem{{\bf wxCROSS\_HATCH}}{Cross hatch.}
 250 \twocolitem{{\bf wxHORIZONTAL\_HATCH}}{Horizontal hatch.}
 251 \twocolitem{{\bf wxVERTICAL\_HATCH}}{Vertical hatch.}
 252 \twocolitem{{\bf wxSTIPPLE}}{Stippled using a bitmap.}
 253 \twocolitem{{\bf wxSTIPPLE\_MASK\_OPAQUE}}{Stippled using a bitmap's mask.}
 254 \end{twocollist}}
 255
 256 \wxheading{See also}
 257
 258 \helpref{wxBrush::GetStyle}{wxbrushgetstyle}
 259
 260 \membersection{wxBrush::operator $=$}\label{wxbrushassignment}
 261
 262 \func{wxBrush\&}{operator $=$}{\param{const wxBrush\& }{brush}}
 263
 264 Assignment operator, using reference counting. Returns a reference
 265 to `this'.
 266
 267 \membersection{wxBrush::operator $==$}\label{wxbrushequals}
 268
 269 \func{bool}{operator $==$}{\param{const wxBrush\& }{brush}}
 270
 271 Equality operator. Two brushes are equal if they contain pointers
 272 to the same underlying brush data. It does not compare each attribute,
 273 so two independently-created brushes using the same parameters will
 274 fail the test.
 275
 276 \membersection{wxBrush::operator $!=$}\label{wxbrushnotequals}
 277
 278 \func{bool}{operator $!=$}{\param{const wxBrush\& }{brush}}
 279
 280 Inequality operator. Two brushes are not equal if they contain pointers
 281 to different underlying brush data. It does not compare each attribute.
 282
 283 \section{\class{wxBrushList}}\label{wxbrushlist}
 284
 285 A brush list is a list containing all brushes which have been created.
 286
 287 \wxheading{Derived from}
 288
 289 \helpref{wxList}{wxlist}\\
 290 \helpref{wxObject}{wxobject}
 291
 292 \wxheading{Include files}
 293
 294 <wx/gdicmn.h>
 295
 296 \wxheading{Remarks}
 297
 298 There is only one instance of this class: {\bf wxTheBrushList}.  Use
 299 this object to search for a previously created brush of the desired
 300 type and create it if not already found. In some windowing systems,
 301 the brush may be a scarce resource, so it can pay to reuse old
 302 resources if possible. When an application finishes, all brushes will
 303 be deleted and their resources freed, eliminating the possibility of
 304 `memory leaks'. However, it is best not to rely on this automatic
 305 cleanup because it can lead to double deletion in some circumstances.
 306
 307 There are two mechanisms in recent versions of wxWidgets which make the
 308 brush list less useful than it once was. Under Windows, scarce resources
 309 are cleaned up internally if they are not being used. Also, a referencing
 310 counting mechanism applied to all GDI objects means that some sharing
 311 of underlying resources is possible. You don't have to keep track of pointers,
 312 working out when it is safe delete a brush, because the referencing counting does
 313 it for you. For example, you can set a brush in a device context, and then
 314 immediately delete the brush you passed, because the brush is `copied'.
 315
 316 So you may find it easier to ignore the brush list, and instead create
 317 and copy brushes as you see fit. If your Windows resource meter suggests
 318 your application is using too many resources, you can resort to using
 319 GDI lists to share objects explicitly.
 320
 321 The only compelling use for the brush list is for wxWidgets to keep
 322 track of brushes in order to clean them up on exit. It is also kept for
 323 backward compatibility with earlier versions of wxWidgets.
 324
 325 \wxheading{See also}
 326
 327 \helpref{wxBrush}{wxbrush}
 328
 329 \latexignore{\rtfignore{\wxheading{Members}}}
 330
 331 \membersection{wxBrushList::wxBrushList}\label{wxbrushlistconstr}
 332
 333 \func{void}{wxBrushList}{\void}
 334
 335 Constructor. The application should not construct its own brush list:
 336 use the object pointer {\bf wxTheBrushList}.
 337
 338 \membersection{wxBrushList::AddBrush}\label{wxbrushlistaddbrush}
 339
 340 \func{void}{AddBrush}{\param{wxBrush *}{brush}}
 341
 342 Used internally by wxWidgets to add a brush to the list.
 343
 344 \membersection{wxBrushList::FindOrCreateBrush}\label{wxbrushlistfindorcreatebrush}
 345
 346 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxColour\& }{colour}, \param{int}{ style}}
 347
 348 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 349 to the brush list, and returns it.
 350
 351 \func{wxBrush *}{FindOrCreateBrush}{\param{const wxString\& }{colourName}, \param{int}{ style}}
 352
 353 Finds a brush with the specified attributes and returns it, else creates a new brush, adds it
 354 to the brush list, and returns it.
 355
 356 Finds a brush of the given specification, or creates one and adds it to the list.
 357
 358 \wxheading{Parameters}
 359
 360 \docparam{colour}{Colour object.}
 361
 362 \docparam{colourName}{Colour name, which should be in the colour database.}
 363
 364 \docparam{style}{Brush style. See \helpref{wxBrush::SetStyle}{wxbrushsetstyle} for a list of styles.}
 365
 366 \membersection{wxBrushList::RemoveBrush}\label{wxbrushlistremovebrush}
 367
 368 \func{void}{RemoveBrush}{\param{wxBrush *}{brush}}
 369
 370 Used by wxWidgets to remove a brush from the list.
 371
 372