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1 \section{\class{wxDC}}\label{wxdc}
2
3 A wxDC is a {\it device context} onto which graphics and text can be drawn.
4 It is intended to represent a number of output devices in a generic way,
5 so a window can have a device context associated with it, and a printer also has a device context.
6 In this way, the same piece of code may write to a number of different devices,
7 if the device context is used as a parameter.
8
9 Derived types of wxDC have documentation for specific features
10 only, so refer to this section for most device context information.
11
12 \wxheading{Derived from}
13
14 \helpref{wxObject}{wxobject}
15
16 \wxheading{Include files}
17
18 <wx/dc.h>
19
20 \wxheading{See also}
21
22 \helpref{Overview}{dcoverview}
23
24 \latexignore{\rtfignore{\wxheading{Members}}}
25
26 \membersection{wxDC::wxDC}
27
28 \func{}{wxDC}{\void}
29
30 Constructor.
31
32 \membersection{wxDC::\destruct{wxDC}}
33
34 \func{}{\destruct{wxDC}}{\void}
35
36 Destructor.
37
38 \membersection{wxDC::BeginDrawing}\label{wxdcbegindrawing}
39
40 \func{void}{BeginDrawing}{\void}
41
42 Allows optimization of drawing code under MS Windows. Enclose
43 drawing primitives between {\bf BeginDrawing} and {\bf EndDrawing}\rtfsp
44 calls.
45
46 Drawing to a wxDialog panel device context outside of a
47 system-generated OnPaint event {\it requires} this pair of calls to
48 enclose drawing code. This is because a Windows dialog box does not have
49 a retained device context associated with it, and selections such as pen
50 and brush settings would be lost if the device context were obtained and
51 released for each drawing operation.
52
53 \membersection{wxDC::Blit}\label{wxdcblit}
54
55 \func{bool}{Blit}{\param{wxCoord}{ xdest}, \param{wxCoord}{ ydest}, \param{wxCoord}{ width}, \param{wxCoord}{ height},
56 \param{wxDC* }{source}, \param{wxCoord}{ xsrc}, \param{wxCoord}{ ysrc}, \param{int}{ logicalFunc = wxCOPY},
57 \param{bool }{useMask = FALSE}}
58
59 Copy from a source DC to this DC, specifying the destination
60 coordinates, size of area to copy, source DC, source coordinates, and
61 logical function.
62
63 \wxheading{Parameters}
64
65 \docparam{xdest}{Destination device context x position.}
66
67 \docparam{ydest}{Destination device context y position.}
68
69 \docparam{width}{Width of source area to be copied.}
70
71 \docparam{height}{Height of source area to be copied.}
72
73 \docparam{source}{Source device context.}
74
75 \docparam{xsrc}{Source device context x position.}
76
77 \docparam{ysrc}{Source device context y position.}
78
79 \docparam{logicalFunc}{Logical function to use: see \helpref{wxDC::SetLogicalFunction}{wxdcsetlogicalfunction}.}
80
81 \docparam{useMask}{If TRUE, Blit does a transparent blit using the mask that is associated with the bitmap
82 selected into the source device context. The Windows implementation does the following:
83
84 \begin{enumerate}
85 \item Creates a temporary bitmap and copies the destination area into it.
86 \item Copies the source area into the temporary bitmap using the specified logical function.
87 \item Sets the masked area in the temporary bitmap to BLACK by ANDing the
88 mask bitmap with the temp bitmap with the foreground colour set to WHITE
89 and the bg colour set to BLACK.
90 \item Sets the unmasked area in the destination area to BLACK by ANDing the
91 mask bitmap with the destination area with the foreground colour set to BLACK
92 and the background colour set to WHITE.
93 \item ORs the temporary bitmap with the destination area.
94 \item Deletes the temporary bitmap.
95 \end{enumerate}
96
97 This sequence of operations ensures that the source's transparent area need not be black,
98 and logical functions are supported.
99 }
100
101 \wxheading{Remarks}
102
103 There is partial support for Blit in wxPostScriptDC, under X.
104
105 See \helpref{wxMemoryDC}{wxmemorydc} for typical usage.
106
107 \wxheading{See also}
108
109 \helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxBitmap}{wxbitmap}, \helpref{wxMask}{wxmask}
110
111 \membersection{wxDC::Clear}\label{wxdcclear}
112
113 \func{void}{Clear}{\void}
114
115 Clears the device context using the current background brush.
116
117 \membersection{wxDC::CrossHair}\label{wxdccrosshair}
118
119 \func{void}{CrossHair}{\param{wxCoord}{ x}, \param{wxCoord}{ y}}
120
121 Displays a cross hair using the current pen. This is a vertical
122 and horizontal line the height and width of the window, centred
123 on the given point.
124
125 \membersection{wxDC::DestroyClippingRegion}\label{wxdcdestroyclippingregion}
126
127 \func{void}{DestroyClippingRegion}{\void}
128
129 Destroys the current clipping region so that none of the DC is clipped.
130 See also \helpref{wxDC::SetClippingRegion}{wxdcsetclippingregion}.
131
132 \membersection{wxDC::DeviceToLogicalX}\label{wxdcdevicetologicalx}
133
134 \func{wxCoord}{DeviceToLogicalX}{\param{wxCoord}{ x}}
135
136 Convert device X coordinate to logical coordinate, using the current
137 mapping mode.
138
139 \membersection{wxDC::DeviceToLogicalXRel}\label{wxdcdevicetologicalxrel}
140
141 \func{wxCoord}{DeviceToLogicalXRel}{\param{wxCoord}{ x}}
142
143 Convert device X coordinate to relative logical coordinate, using the current
144 mapping mode. Use this function for converting a width, for example.
145
146 \membersection{wxDC::DeviceToLogicalY}\label{wxdcdevicetologicaly}
147
148 \func{wxCoord}{DeviceToLogicalY}{\param{wxCoord}{ y}}
149
150 Converts device Y coordinate to logical coordinate, using the current
151 mapping mode.
152
153 \membersection{wxDC::DeviceToLogicalYRel}\label{wxdcdevicetologicalyrel}
154
155 \func{wxCoord}{DeviceToLogicalYRel}{\param{wxCoord}{ y}}
156
157 Convert device Y coordinate to relative logical coordinate, using the current
158 mapping mode. Use this function for converting a height, for example.
159
160 \membersection{wxDC::DrawArc}\label{wxdcdrawarc}
161
162 \func{void}{DrawArc}{\param{wxCoord}{ x1}, \param{wxCoord}{ y1}, \param{wxCoord}{ x2}, \param{wxCoord}{ y2}, \param{double}{ xc}, \param{double}{ yc}}
163
164 Draws an arc of a circle, centred on ({\it xc, yc}), with starting point ({\it x1, y1})
165 and ending at ({\it x2, y2}). The current pen is used for the outline
166 and the current brush for filling the shape.
167
168 The arc is drawn in an anticlockwise direction from the start point to the end point.
169
170 \membersection{wxDC::DrawBitmap}\label{wxdcdrawbitmap}
171
172 \func{void}{DrawBitmap}{\param{const wxBitmap\&}{ bitmap}, \param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{bool}{ transparent}}
173
174 Draw a bitmap on the device context at the specified point. If {\it transparent} is TRUE and the bitmap has
175 a transparency mask, the bitmap will be drawn transparently.
176
177 When drawing a mono-bitmap, the current text foreground colour will be used to draw the foreground
178 of the bitmap (all bits set to 1), and the current text background colour to draw the background
179 (all bits set to 0). See also \helpref{SetTextForeground}{wxdcsettextforeground},
180 \helpref{SetTextBackground}{wxdcsettextbackground} and \helpref{wxMemoryDC}{wxmemorydc}.
181
182 \membersection{wxDC::DrawCheckMark}\label{wxdcdrawcheckmark}
183
184 \func{void}{DrawCheckMark}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}}
185
186 \func{void}{DrawCheckMark}{\param{const wxRect \&}{rect}}
187
188 Draws a check mark inside the given rectangle.
189
190 \membersection{wxDC::DrawEllipse}\label{wxdcdrawellipse}
191
192 \func{void}{DrawEllipse}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}}
193
194 Draws an ellipse contained in the rectangle with the given top left corner, and with the
195 given size. The current pen is used for the outline and the current brush for
196 filling the shape.
197
198 \membersection{wxDC::DrawEllipticArc}\label{wxdcdrawellipticarc}
199
200 \func{void}{DrawEllipticArc}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height},
201 \param{double}{ start}, \param{double}{ end}}
202
203 Draws an arc of an ellipse. The current pen is used for drawing the arc and
204 the current brush is used for drawing the pie. This function is currently only available for
205 X window and PostScript device contexts.
206
207 {\it x} and {\it y} specify the x and y coordinates of the upper-left corner of the rectangle that contains
208 the ellipse.
209
210 {\it width} and {\it height} specify the width and height of the rectangle that contains
211 the ellipse.
212
213 {\it start} and {\it end} specify the start and end of the arc relative to the three-o'clock
214 position from the center of the rectangle. Angles are specified
215 in degrees (360 is a complete circle). Positive values mean
216 counter-clockwise motion. If {\it start} is equal to {\it end}, a
217 complete ellipse will be drawn.
218
219 \membersection{wxDC::DrawIcon}\label{wxdcdrawicon}
220
221 \func{void}{DrawIcon}{\param{const wxIcon\&}{ icon}, \param{wxCoord}{ x}, \param{wxCoord}{ y}}
222
223 Draw an icon on the display (does nothing if the device context is PostScript).
224 This can be the simplest way of drawing bitmaps on a window.
225
226 \membersection{wxDC::DrawLine}\label{wxdcdrawline}
227
228 \func{void}{DrawLine}{\param{wxCoord}{ x1}, \param{wxCoord}{ y1}, \param{wxCoord}{ x2}, \param{wxCoord}{ y2}}
229
230 Draws a line from the first point to the second. The current pen is used
231 for drawing the line.
232
233 \membersection{wxDC::DrawLines}\label{wxdcdrawlines}
234
235 \func{void}{DrawLines}{\param{int}{ n}, \param{wxPoint}{ points[]}, \param{wxCoord}{ xoffset = 0}, \param{wxCoord}{ yoffset = 0}}
236
237 \func{void}{DrawLines}{\param{wxList *}{points}, \param{wxCoord}{ xoffset = 0}, \param{wxCoord}{ yoffset = 0}}
238
239 Draws lines using an array of {\it points} of size {\it n}, or list of
240 pointers to points, adding the optional offset coordinate. The current
241 pen is used for drawing the lines. The programmer is responsible for
242 deleting the list of points.
243
244 \pythonnote{The wxPython version of this method accepts a Python list
245 of wxPoint objects.}
246
247 \membersection{wxDC::DrawPolygon}\label{wxdcdrawpolygon}
248
249 \func{void}{DrawPolygon}{\param{int}{ n}, \param{wxPoint}{ points[]}, \param{wxCoord}{ xoffset = 0}, \param{wxCoord}{ yoffset = 0},\\
250 \param{int }{fill\_style = wxODDEVEN\_RULE}}
251
252 \func{void}{DrawPolygon}{\param{wxList *}{points}, \param{wxCoord}{ xoffset = 0}, \param{wxCoord}{ yoffset = 0},\\
253 \param{int }{fill\_style = wxODDEVEN\_RULE}}
254
255 Draws a filled polygon using an array of {\it points} of size {\it n},
256 or list of pointers to points, adding the optional offset coordinate.
257
258 The last argument specifies the fill rule: {\bf wxODDEVEN\_RULE} (the
259 default) or {\bf wxWINDING\_RULE}.
260
261 The current pen is used for drawing the outline, and the current brush
262 for filling the shape. Using a transparent brush suppresses filling.
263 The programmer is responsible for deleting the list of points.
264
265 Note that wxWindows automatically closes the first and last points.
266
267 \pythonnote{The wxPython version of this method accepts a Python list
268 of wxPoint objects.}
269
270 \membersection{wxDC::DrawPoint}\label{wxdcdrawpoint}
271
272 \func{void}{DrawPoint}{\param{wxCoord}{ x}, \param{wxCoord}{ y}}
273
274 Draws a point using the current pen.
275
276 \membersection{wxDC::DrawRectangle}\label{wxdcdrawrectangle}
277
278 \func{void}{DrawRectangle}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}}
279
280 Draws a rectangle with the given top left corner, and with the given
281 size. The current pen is used for the outline and the current brush
282 for filling the shape.
283
284 \membersection{wxDC::DrawRotatedText}\label{wxdcdrawrotatedtext}
285
286 \func{void}{DrawRotatedText}{\param{const wxString\& }{text}, \param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{double}{ angle}}
287
288 Draws the text rotated by {\it angle} degrees.
289
290 \wxheading{See also}
291
292 \helpref{DrawText}{wxdcdrawtext}
293
294 \membersection{wxDC::DrawRoundedRectangle}\label{wxdcdrawroundedrectangle}
295
296 \func{void}{DrawRoundedRectangle}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}, \param{double}{ radius = 20}}
297
298 Draws a rectangle with the given top left corner, and with the given
299 size. The corners are quarter-circles using the given radius. The
300 current pen is used for the outline and the current brush for filling
301 the shape.
302
303 If {\it radius} is positive, the value is assumed to be the
304 radius of the rounded corner. If {\it radius} is negative,
305 the absolute value is assumed to be the {\it proportion} of the smallest
306 dimension of the rectangle. This means that the corner can be
307 a sensible size relative to the size of the rectangle, and also avoids
308 the strange effects X produces when the corners are too big for
309 the rectangle.
310
311 \membersection{wxDC::DrawSpline}\label{wxdcdrawspline}
312
313 \func{void}{DrawSpline}{\param{wxList *}{points}}
314
315 Draws a spline between all given control points, using the current
316 pen. Doesn't delete the wxList and contents. The spline is drawn
317 using a series of lines, using an algorithm taken from the X drawing
318 program `XFIG'.
319
320 \func{void}{DrawSpline}{\param{wxCoord}{ x1}, \param{wxCoord}{ y1}, \param{wxCoord}{ x2}, \param{wxCoord}{ y2}, \param{wxCoord}{ x3}, \param{wxCoord}{ y3}}
321
322 Draws a three-point spline using the current pen.
323
324 \pythonnote{The wxPython version of this method accepts a Python list
325 of wxPoint objects.}
326
327 \membersection{wxDC::DrawText}\label{wxdcdrawtext}
328
329 \func{void}{DrawText}{\param{const wxString\& }{text}, \param{wxCoord}{ x}, \param{wxCoord}{ y}}
330
331 Draws a text string at the specified point, using the current text font,
332 and the current text foreground and background colours.
333
334 The coordinates refer to the top-left corner of the rectangle bounding
335 the string. See \helpref{wxDC::GetTextExtent}{wxdcgettextextent} for how
336 to get the dimensions of a text string, which can be used to position the
337 text more precisely.
338
339 \membersection{wxDC::EndDoc}\label{wxdcenddoc}
340
341 \func{void}{EndDoc}{\void}
342
343 Ends a document (only relevant when outputting to a printer).
344
345 \membersection{wxDC::EndDrawing}\label{wxdcenddrawing}
346
347 \func{void}{EndDrawing}{\void}
348
349 Allows optimization of drawing code under MS Windows. Enclose
350 drawing primitives between {\bf BeginDrawing} and {\bf EndDrawing}\rtfsp
351 calls.
352
353 \membersection{wxDC::EndPage}\label{wxdcendpage}
354
355 \func{void}{EndPage}{\void}
356
357 Ends a document page (only relevant when outputting to a printer).
358
359 \membersection{wxDC::FloodFill}\label{wxdcfloodfill}
360
361 \func{void}{FloodFill}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxColour *}{colour}, \param{int}{ style=wxFLOOD\_SURFACE}}
362
363 Flood fills the device context starting from the given point, in the given colour,
364 and using a style:
365
366 \begin{itemize}\itemsep=0pt
367 \item wxFLOOD\_SURFACE: the flooding occurs until a colour other than the given colour is encountered.
368 \item wxFLOOD\_BORDER: the area to be flooded is bounded by the given colour.
369 \end{itemize}
370
371 {\it Note:} this function is available in MS Windows only.
372
373 \membersection{wxDC::GetBackground}\label{wxdcgetbackground}
374
375 \func{wxBrush\&}{GetBackground}{\void}
376
377 Gets the brush used for painting the background (see \helpref{wxDC::SetBackground}{wxdcsetbackground}).
378
379 \membersection{wxDC::GetBrush}\label{wxdcgetbrush}
380
381 \func{wxBrush\&}{GetBrush}{\void}
382
383 Gets the current brush (see \helpref{wxDC::SetBrush}{wxdcsetbrush}).
384
385 \membersection{wxDC::GetCharHeight}\label{wxdcgetcharheight}
386
387 \func{wxCoord}{GetCharHeight}{\void}
388
389 Gets the character height of the currently set font.
390
391 \membersection{wxDC::GetCharWidth}\label{wxdcgetcharwidth}
392
393 \func{wxCoord}{GetCharWidth}{\void}
394
395 Gets the average character width of the currently set font.
396
397 \membersection{wxDC::GetClippingBox}\label{wxdcgetclippingbox}
398
399 \func{void}{GetClippingBox}{\param{wxCoord}{ *x}, \param{wxCoord}{ *y}, \param{wxCoord}{ *width}, \param{wxCoord}{ *height}}
400
401 Gets the rectangle surrounding the current clipping region.
402
403 \pythonnote{No arguments are required and the four values defining the
404 rectangle are returned as a tuple.}
405
406 \membersection{wxDC::GetFont}\label{wxdcgetfont}
407
408 \func{wxFont\&}{GetFont}{\void}
409
410 Gets the current font (see \helpref{wxDC::SetFont}{wxdcsetfont}).
411
412 \membersection{wxDC::GetLogicalFunction}\label{wxdcgetlogicalfunction}
413
414 \func{int}{GetLogicalFunction}{\void}
415
416 Gets the current logical function (see \helpref{wxDC::SetLogicalFunction}{wxdcsetlogicalfunction}).
417
418 \membersection{wxDC::GetMapMode}\label{wxdcgetmapmode}
419
420 \func{int}{GetMapMode}{\void}
421
422 Gets the {\it mapping mode} for the device context (see \helpref{wxDC::SetMapMode}{wxdcsetmapmode}).
423
424 \membersection{wxDC::GetOptimization}\label{wxdcgetoptimization}
425
426 \func{bool}{GetOptimization}{\void}
427
428 Returns TRUE if device context optimization is on.
429 See \helpref{wxDC::SetOptimization}{wxsetoptimization} for details.
430
431 \membersection{wxDC::GetPen}\label{wxdcgetpen}
432
433 \func{wxPen\&}{GetPen}{\void}
434
435 Gets the current pen (see \helpref{wxDC::SetPen}{wxdcsetpen}).
436
437 \membersection{wxDC::GetPixel}\label{wxdcgetpixel}
438
439 \func{bool}{GetPixel}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxColour *}{colour}}
440
441 Sets {\it colour} to the colour at the specified location. Windows only; an X implementation
442 is being worked on. Not available for wxPostScriptDC or wxMetafileDC.
443
444 \pythonnote{For wxPython the wxColour value is returned and is not
445 required as a parameter.}
446
447 \membersection{wxDC::GetSize}\label{wxdcgetsize}
448
449 \func{void}{GetSize}{\param{wxCoord *}{width}, \param{wxCoord *}{height}}
450
451 For a PostScript device context, this gets the maximum size of graphics
452 drawn so far on the device context.
453
454 For a Windows printer device context, this gets the horizontal and vertical
455 resolution. It can be used to scale graphics to fit the page when using
456 a Windows printer device context. For example, if {\it maxX} and {\it maxY}\rtfsp
457 represent the maximum horizontal and vertical `pixel' values used in your
458 application, the following code will scale the graphic to fit on the
459 printer page:
460
461 \begin{verbatim}
462 wxCoord w, h;
463 dc.GetSize(&w, &h);
464 double scaleX=(double)(maxX/w);
465 double scaleY=(double)(maxY/h);
466 dc.SetUserScale(min(scaleX,scaleY),min(scaleX,scaleY));
467 \end{verbatim}
468
469 \pythonnote{In place of a single overloaded method name, wxPython
470 implements the following methods:\par
471 \indented{2cm}{\begin{twocollist}
472 \twocolitem{{\bf GetSize()}}{Returns a wxSize}
473 \twocolitem{{\bf GetSizeTuple()}}{Returns a 2-tuple (width, height)}
474 \end{twocollist}}
475 }
476
477 \membersection{wxDC::GetTextBackground}\label{wxdcgettextbackground}
478
479 \func{wxColour\&}{GetTextBackground}{\void}
480
481 Gets the current text background colour (see \helpref{wxDC::SetTextBackground}{wxdcsettextbackground}).
482
483 \membersection{wxDC::GetTextExtent}\label{wxdcgettextextent}
484
485 \func{void}{GetTextExtent}{\param{const wxString\& }{string}, \param{wxCoord *}{w}, \param{wxCoord *}{h},\\
486 \param{wxCoord *}{descent = NULL}, \param{wxCoord *}{externalLeading = NULL}, \param{wxFont *}{font = NULL}}
487
488 Gets the dimensions of the string using the currently selected font.
489 \rtfsp{\it string} is the text string to measure, {\it w} and {\it h} are
490 the total width and height respectively, {\it descent} is the
491 dimension from the baseline of the font to the bottom of the
492 descender, and {\it externalLeading} is any extra vertical space added
493 to the font by the font designer (usually is zero).
494
495 The optional parameter {\it font} specifies an alternative
496 to the currently selected font: but note that this does not
497 yet work under Windows, so you need to set a font for
498 the device context first.
499
500 See also \helpref{wxFont}{wxfont}, \helpref{wxDC::SetFont}{wxdcsetfont}.
501
502 \pythonnote{The following methods are implemented in wxPython:\par
503 \indented{2cm}{\begin{twocollist}
504 \twocolitem{{\bf GetTextExtent(string)}}{Returns a 2-tuple, (width, height)}
505 \twocolitem{{\bf GetFullTextExtent(string, font=NULL)}}{Returns a
506 4-tuple, (width, height, descent, externalLeading) }
507 \end{twocollist}}
508 }
509
510 \membersection{wxDC::GetTextForeground}\label{wxdcgettextforeground}
511
512 \func{wxColour\&}{GetTextForeground}{\void}
513
514 Gets the current text foreground colour (see \helpref{wxDC::SetTextForeground}{wxdcsettextforeground}).
515
516
517 \membersection{wxDC::GetUserScale}\label{wxdcgetuserscale}
518
519 \func{void}{GetUserScale}{\param{double}{ *x}, \param{double}{ *y}}
520
521 Gets the current user scale factor (set by \helpref{SetUserScale}{wxdcsetuserscale}).
522
523
524 \membersection{wxDC::LogicalToDeviceX}\label{wxdclogicaltodevicex}
525
526 \func{wxCoord}{LogicalToDeviceX}{\param{wxCoord}{ x}}
527
528 Converts logical X coordinate to device coordinate, using the current
529 mapping mode.
530
531 \membersection{wxDC::LogicalToDeviceXRel}\label{wxdclogicaltodevicexrel}
532
533 \func{wxCoord}{LogicalToDeviceXRel}{\param{wxCoord}{ x}}
534
535 Converts logical X coordinate to relative device coordinate, using the current
536 mapping mode. Use this for converting a width, for example.
537
538 \membersection{wxDC::LogicalToDeviceY}\label{wxdclogicaltodevicey}
539
540 \func{wxCoord}{LogicalToDeviceY}{\param{wxCoord}{ y}}
541
542 Converts logical Y coordinate to device coordinate, using the current
543 mapping mode.
544
545 \membersection{wxDC::LogicalToDeviceYRel}\label{wxdclogicaltodeviceyrel}
546
547 \func{wxCoord}{LogicalToDeviceYRel}{\param{wxCoord}{ y}}
548
549 Converts logical Y coordinate to relative device coordinate, using the current
550 mapping mode. Use this for converting a height, for example.
551
552 \membersection{wxDC::MaxX}\label{wxdcmaxx}
553
554 \func{wxCoord}{MaxX}{\void}
555
556 Gets the maximum horizontal extent used in drawing commands so far.
557
558 \membersection{wxDC::MaxY}\label{wxdcmaxy}
559
560 \func{wxCoord}{MaxY}{\void}
561
562 Gets the maximum vertical extent used in drawing commands so far.
563
564 \membersection{wxDC::MinX}\label{wxdcminx}
565
566 \func{wxCoord}{MinX}{\void}
567
568 Gets the minimum horizontal extent used in drawing commands so far.
569
570 \membersection{wxDC::MinY}\label{wxdcminy}
571
572 \func{wxCoord}{MinY}{\void}
573
574 Gets the minimum vertical extent used in drawing commands so far.
575
576 \membersection{wxDC::Ok}\label{wxdcok}
577
578 \func{bool}{Ok}{\void}
579
580 Returns TRUE if the DC is ok to use.
581
582 \membersection{wxDC::SetDeviceOrigin}\label{wxdcsetdeviceorigin}
583
584 \func{void}{SetDeviceOrigin}{\param{wxCoord}{ x}, \param{wxCoord}{ y}}
585
586 Sets the device origin (i.e., the origin in pixels after scaling has been
587 applied).
588
589 This function may be useful in Windows printing
590 operations for placing a graphic on a page.
591
592 \membersection{wxDC::SetBackground}\label{wxdcsetbackground}
593
594 \func{void}{SetBackground}{\param{const wxBrush\& }{brush}}
595
596 Sets the current background brush for the DC.
597
598 \membersection{wxDC::SetBackgroundMode}\label{wxdcsetbackgroundmode}
599
600 \func{void}{SetBackgroundMode}{\param{int}{ mode}}
601
602 {\it mode} may be one of wxSOLID and wxTRANSPARENT. This setting determines
603 whether text will be drawn with a background colour or not.
604
605 \membersection{wxDC::SetClippingRegion}\label{wxdcsetclippingregion}
606
607 \func{void}{SetClippingRegion}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}}
608
609 \func{void}{SetClippingRegion}{\param{const wxRegion\&}{ region}}
610
611 Sets the clipping region for the DC. The clipping region is an area
612 to which drawing is restricted. Possible uses for the clipping region are for clipping text
613 or for speeding up window redraws when only a known area of the screen is damaged.
614
615 \wxheading{See also}
616
617 \helpref{wxDC::DestroyClippingRegion}{wxdcdestroyclippingregion}, \helpref{wxRegion}{wxregion}
618
619 \membersection{wxDC::SetPalette}\label{wxdcsetpalette}
620
621 \func{void}{SetPalette}{\param{const wxPalette\& }{palette}}
622
623 If this is a window DC or memory DC, assigns the given palette to the window
624 or bitmap associated with the DC. If the argument is wxNullPalette, the current
625 palette is selected out of the device context, and the original palette
626 restored.
627
628 See \helpref{wxPalette}{wxpalette} for further details.
629
630 \membersection{wxDC::SetBrush}\label{wxdcsetbrush}
631
632 \func{void}{SetBrush}{\param{const wxBrush\& }{brush}}
633
634 Sets the current brush for the DC.
635
636 If the argument is wxNullBrush, the current brush is selected out of the device
637 context, and the original brush restored, allowing the current brush to
638 be destroyed safely.
639
640 See also \helpref{wxBrush}{wxbrush}.
641
642 See also \helpref{wxMemoryDC}{wxmemorydc} for the interpretation of colours
643 when drawing into a monochrome bitmap.
644
645 \membersection{wxDC::SetFont}\label{wxdcsetfont}
646
647 \func{void}{SetFont}{\param{const wxFont\& }{font}}
648
649 Sets the current font for the DC.
650
651 If the argument is wxNullFont, the current font is selected out of the device
652 context, and the original font restored, allowing the current font to
653 be destroyed safely.
654
655 See also \helpref{wxFont}{wxfont}.
656
657 \membersection{wxDC::SetLogicalFunction}\label{wxdcsetlogicalfunction}
658
659 \func{void}{SetLogicalFunction}{\param{int}{ function}}
660
661 Sets the current logical function for the device context. This determines how
662 a source pixel (from a pen or brush colour, or source device context if
663 using \helpref{wxDC::Blit}{wxdcblit}) combines with a destination pixel in the
664 current device context.
665
666 The possible values
667 and their meaning in terms of source and destination pixel values are
668 as follows:
669
670 \begin{verbatim}
671 wxAND src AND dst
672 wxAND_INVERT (NOT src) AND dst
673 wxAND_REVERSE src AND (NOT dst)
674 wxCLEAR 0
675 wxCOPY src
676 wxEQUIV (NOT src) XOR dst
677 wxINVERT NOT dst
678 wxNAND (NOT src) OR (NOT dst)
679 wxNOR (NOT src) AND (NOT dst)
680 wxNO_OP dst
681 wxOR src OR dst
682 wxOR_INVERT (NOT src) OR dst
683 wxOR_REVERSE src OR (NOT dst)
684 wxSET 1
685 wxSRC_INVERT NOT src
686 wxXOR src XOR dst
687 \end{verbatim}
688
689 The default is wxCOPY, which simply draws with the current colour.
690 The others combine the current colour and the background using a
691 logical operation. wxINVERT is commonly used for drawing rubber bands or
692 moving outlines, since drawing twice reverts to the original colour.
693
694 \membersection{wxDC::SetMapMode}\label{wxdcsetmapmode}
695
696 \func{void}{SetMapMode}{\param{int}{ int}}
697
698 The {\it mapping mode} of the device context defines the unit of
699 measurement used to convert logical units to device units. Note that
700 in X, text drawing isn't handled consistently with the mapping mode; a
701 font is always specified in point size. However, setting the {\it
702 user scale} (see \helpref{wxDC::SetUserScale}{wxdcsetuserscale}) scales the text appropriately. In
703 Windows, scaleable TrueType fonts are always used; in X, results depend
704 on availability of fonts, but usually a reasonable match is found.
705
706 Note that the coordinate origin should ideally be selectable, but for
707 now is always at the top left of the screen/printer.
708
709 Drawing to a Windows printer device context under UNIX
710 uses the current mapping mode, but mapping mode is currently ignored for
711 PostScript output.
712
713 The mapping mode can be one of the following:
714
715 \begin{twocollist}\itemsep=0pt
716 \twocolitem{wxMM\_TWIPS}{Each logical unit is 1/20 of a point, or 1/1440 of
717 an inch.}
718 \twocolitem{wxMM\_POINTS}{Each logical unit is a point, or 1/72 of an inch.}
719 \twocolitem{wxMM\_METRIC}{Each logical unit is 1 mm.}
720 \twocolitem{wxMM\_LOMETRIC}{Each logical unit is 1/10 of a mm.}
721 \twocolitem{wxMM\_TEXT}{Each logical unit is 1 pixel.}
722 \end{twocollist}
723
724 \membersection{wxDC::SetOptimization}\label{wxsetoptimization}
725
726 \func{void}{SetOptimization}{\param{bool }{optimize}}
727
728 If {\it optimize} is TRUE (the default), this function sets optimization mode on.
729 This currently means that under X, the device context will not try to set a pen or brush
730 property if it is known to be set already. This approach can fall down
731 if non-wxWindows code is using the same device context or window, for example
732 when the window is a panel on which the windowing system draws panel items.
733 The wxWindows device context 'memory' will now be out of step with reality.
734
735 Setting optimization off, drawing, then setting it back on again, is a trick
736 that must occasionally be employed.
737
738 \membersection{wxDC::SetPen}\label{wxdcsetpen}
739
740 \func{void}{SetPen}{\param{const wxPen\& }{pen}}
741
742 Sets the current pen for the DC.
743
744 If the argument is wxNullPen, the current pen is selected out of the device
745 context, and the original pen restored.
746
747 See also \helpref{wxMemoryDC}{wxmemorydc} for the interpretation of colours
748 when drawing into a monochrome bitmap.
749
750 \membersection{wxDC::SetTextBackground}\label{wxdcsettextbackground}
751
752 \func{void}{SetTextBackground}{\param{const wxColour\& }{colour}}
753
754 Sets the current text background colour for the DC.
755
756 \membersection{wxDC::SetTextForeground}\label{wxdcsettextforeground}
757
758 \func{void}{SetTextForeground}{\param{const wxColour\& }{colour}}
759
760 Sets the current text foreground colour for the DC.
761
762 See also \helpref{wxMemoryDC}{wxmemorydc} for the interpretation of colours
763 when drawing into a monochrome bitmap.
764
765 \membersection{wxDC::SetUserScale}\label{wxdcsetuserscale}
766
767 \func{void}{SetUserScale}{\param{double}{ xScale}, \param{double}{ yScale}}
768
769 Sets the user scaling factor, useful for applications which require
770 `zooming'.
771
772 \membersection{wxDC::StartDoc}\label{wxdcstartdoc}
773
774 \func{bool}{StartDoc}{\param{const wxString\& }{message}}
775
776 Starts a document (only relevant when outputting to a printer).
777 Message is a message to show whilst printing.
778
779 \membersection{wxDC::StartPage}\label{wxdcstartpage}
780
781 \func{bool}{StartPage}{\void}
782
783 Starts a document page (only relevant when outputting to a printer).
784