1wxDC(3) Erlang Module Definition wxDC(3)
2
6 wxDC - Functions for wxDC class
7
9 A wxDC is a "device context" onto which graphics and text can be drawn.
10 It is intended to represent different output devices and offers a com‐
11 mon abstract API for drawing on any of them.
12 wxWidgets offers an alternative drawing API based on the modern drawing
14 backends GDI+, CoreGraphics, Cairo and Direct2D. See wxGraphicsContext,
15 wxGraphicsRenderer and related classes. There is also a wxGCDC linking
16 the APIs by offering the wxDC API on top of a wxGraphicsContext.
17 wxDC is an abstract base class and cannot be created directly. Use wx‐
19 PaintDC, wxClientDC, wxWindowDC, wxScreenDC, wxMemoryDC or wxPrinterDC
20 (not implemented in wx). Notice that device contexts which are associ‐
21 ated with windows (i.e. wxClientDC, wxWindowDC and wxPaintDC) use the
22 window font and colours by default (starting with wxWidgets 2.9.0) but
23 the other device context classes use system-default values so you al‐
24 ways must set the appropriate fonts and colours before using them.
25 In addition to the versions of the methods documented below, there are
27 also versions which accept single {X,Y} parameter instead of the two
28 wxCoord ones or {X,Y} and {Width,Height} instead of the four wxCoord
29 parameters.
30 Beginning with wxWidgets 2.9.0 the entire wxDC code has been reorga‐
32 nized. All platform dependent code (actually all drawing code) has been
33 moved into backend classes which derive from a common wxDCImpl class.
34 The user-visible classes such as wxClientDC and wxPaintDC merely for‐
35 ward all calls to the backend implementation.
36 Device and logical units
38 In the wxDC context there is a distinction between logical units and
40 device units.
41 Device units are the units native to the particular device; e.g. for a
43 screen, a device unit is a pixel. For a printer, the device unit is de‐
44 fined by the resolution of the printer (usually given in DPI: dot-per-
45 inch).
46 All wxDC functions use instead logical units, unless where explicitly
48 stated. Logical units are arbitrary units mapped to device units using
49 the current mapping mode (see setMapMode/2).
50 This mechanism allows reusing the same code which prints on e.g. a win‐
52 dow on the screen to print on e.g. a paper.
53 Support for Transparency / Alpha Channel
55 In general wxDC methods don't support alpha transparency and the alpha
57 component of wx_color() is simply ignored and you need to use wxGraph‐
58 icsContext for full transparency support. There are, however, a few ex‐
59 ceptions: first, under macOS and GTK+ 3 colours with alpha channel are
60 supported in all the normal wxDC-derived classes as they use wxGraphic‐
61 sContext internally. Second, under all platforms wxSVGFileDC (not im‐
62 plemented in wx) also fully supports alpha channel. In both of these
63 cases the instances of wxPen or wxBrush that are built from wx_color()
64 use the colour's alpha values when stroking or filling.
65 Support for Transformation Matrix
67 On some platforms (currently under MSW, GTK+ 3, macOS) wxDC has support
69 for applying an arbitrary affine transformation matrix to its coordi‐
70 nate system (since 3.1.1 this feature is also supported by wxGCDC in
71 all ports). Call CanUseTransformMatrix() (not implemented in wx) to
72 check if this support is available and then call SetTransformMatrix()
73 (not implemented in wx) if it is. If the transformation matrix is not
74 supported, SetTransformMatrix() (not implemented in wx) always simply
75 returns false and doesn't do anything.
76 This feature is only available when wxUSE_DC_TRANSFORM_MATRIX build op‐
78 tion is enabled.
79 See: Overview dc, wxGraphicsContext, wxDCFontChanger (not implemented
81 in wx), wxDCTextColourChanger (not implemented in wx), wxDCPenChanger
82 (not implemented in wx), wxDCBrushChanger (not implemented in wx), wxD‐
83 CClipper (not implemented in wx)
84 wxWidgets docs: wxDC
86
88 wxDC() = wx:wx_object()
89
91 blit(This, Dest, Size, Source, Src) -> boolean()
92 Types:
94 This = wxDC()
96 Dest = {X :: integer(), Y :: integer()}
97 Size = {W :: integer(), H :: integer()}
98 Source = wxDC()
99 Src = {X :: integer(), Y :: integer()}
100 blit(This, Dest, Size, Source, Src, Options :: [Option]) ->
102 boolean()
103 Types:
105 This = wxDC()
107 Dest = {X :: integer(), Y :: integer()}
108 Size = {W :: integer(), H :: integer()}
109 Source = wxDC()
110 Src = {X :: integer(), Y :: integer()}
111 Option =
112 {rop, wx:wx_enum()} |
113 {useMask, boolean()} |
114 {srcPtMask, {X :: integer(), Y :: integer()}}
115 Copy from a source DC to this DC.
117 With this method you can specify the destination coordinates and
119 the size of area to copy which will be the same for both the
120 source and target DCs. If you need to apply scaling while copy‐
121 ing, use StretchBlit() (not implemented in wx).
122 Notice that source DC coordinates xsrc and ysrc are interpreted
124 using the current source DC coordinate system, i.e. the scale,
125 origin position and axis directions are taken into account when
126 transforming them to physical (pixel) coordinates.
127 Remark: There is partial support for blit/6 in wxPostScriptDC,
129 under X.
130 See: StretchBlit() (not implemented in wx), wxMemoryDC,
132 wxBitmap, wxMask
133 calcBoundingBox(This, X, Y) -> ok
135 Types:
137 This = wxDC()
139 X = Y = integer()
140 Adds the specified point to the bounding box which can be re‐
142 trieved with minX/1, maxX/1 and minY/1, maxY/1 functions.
143 See: resetBoundingBox/1
145 clear(This) -> ok
147 Types:
149 This = wxDC()
151 Clears the device context using the current background brush.
153 Note that setBackground/2 method must be used to set the brush
155 used by clear/1, the brush used for filling the shapes set by
156 setBrush/2 is ignored by it.
157 If no background brush was set, solid white brush is used to
159 clear the device context.
160 crossHair(This, Pt) -> ok
162 Types:
164 This = wxDC()
166 Pt = {X :: integer(), Y :: integer()}
167 This is an overloaded member function, provided for convenience.
169 It differs from the above function only in what argument(s) it
170 accepts.
171 destroyClippingRegion(This) -> ok
173 Types:
175 This = wxDC()
177 Destroys the current clipping region so that none of the DC is
179 clipped.
180 See: setClippingRegion/3
182 deviceToLogicalX(This, X) -> integer()
184 Types:
186 This = wxDC()
188 X = integer()
189 Convert device X coordinate to logical coordinate, using the
191 current mapping mode, user scale factor, device origin and axis
192 orientation.
193 deviceToLogicalXRel(This, X) -> integer()
195 Types:
197 This = wxDC()
199 X = integer()
200 Convert device X coordinate to relative logical coordinate, us‐
202 ing the current mapping mode and user scale factor but ignoring
203 the axis orientation.
204 Use this for converting a width, for example.
206 deviceToLogicalY(This, Y) -> integer()
208 Types:
210 This = wxDC()
212 Y = integer()
213 Converts device Y coordinate to logical coordinate, using the
215 current mapping mode, user scale factor, device origin and axis
216 orientation.
217 deviceToLogicalYRel(This, Y) -> integer()
219 Types:
221 This = wxDC()
223 Y = integer()
224 Convert device Y coordinate to relative logical coordinate, us‐
226 ing the current mapping mode and user scale factor but ignoring
227 the axis orientation.
228 Use this for converting a height, for example.
230 drawArc(This, PtStart, PtEnd, Centre) -> ok
232 Types:
234 This = wxDC()
236 PtStart = PtEnd = Centre = {X :: integer(), Y :: integer()}
237 This is an overloaded member function, provided for convenience.
239 It differs from the above function only in what argument(s) it
240 accepts.
241 drawBitmap(This, Bmp, Pt) -> ok
243 Types:
245 This = wxDC()
247 Bmp = wxBitmap:wxBitmap()
248 Pt = {X :: integer(), Y :: integer()}
249 drawBitmap(This, Bmp, Pt, Options :: [Option]) -> ok
251 Types:
253 This = wxDC()
255 Bmp = wxBitmap:wxBitmap()
256 Pt = {X :: integer(), Y :: integer()}
257 Option = {useMask, boolean()}
258 This is an overloaded member function, provided for convenience.
260 It differs from the above function only in what argument(s) it
261 accepts.
262 drawCheckMark(This, Rect) -> ok
264 Types:
266 This = wxDC()
268 Rect =
269 {X :: integer(),
270 Y :: integer(),
271 W :: integer(),
272 H :: integer()}
273 This is an overloaded member function, provided for convenience.
275 It differs from the above function only in what argument(s) it
276 accepts.
277 drawCircle(This, Pt, Radius) -> ok
279 Types:
281 This = wxDC()
283 Pt = {X :: integer(), Y :: integer()}
284 Radius = integer()
285 This is an overloaded member function, provided for convenience.
287 It differs from the above function only in what argument(s) it
288 accepts.
289 drawEllipse(This, Rect) -> ok
291 Types:
293 This = wxDC()
295 Rect =
296 {X :: integer(),
297 Y :: integer(),
298 W :: integer(),
299 H :: integer()}
300 This is an overloaded member function, provided for convenience.
302 It differs from the above function only in what argument(s) it
303 accepts.
304 drawEllipse(This, Pt, Size) -> ok
306 Types:
308 This = wxDC()
310 Pt = {X :: integer(), Y :: integer()}
311 Size = {W :: integer(), H :: integer()}
312 This is an overloaded member function, provided for convenience.
314 It differs from the above function only in what argument(s) it
315 accepts.
316 drawEllipticArc(This, Pt, Sz, Sa, Ea) -> ok
318 Types:
320 This = wxDC()
322 Pt = {X :: integer(), Y :: integer()}
323 Sz = {W :: integer(), H :: integer()}
324 Sa = Ea = number()
325 This is an overloaded member function, provided for convenience.
327 It differs from the above function only in what argument(s) it
328 accepts.
329 drawIcon(This, Icon, Pt) -> ok
331 Types:
333 This = wxDC()
335 Icon = wxIcon:wxIcon()
336 Pt = {X :: integer(), Y :: integer()}
337 This is an overloaded member function, provided for convenience.
339 It differs from the above function only in what argument(s) it
340 accepts.
341 drawLabel(This, Text, Rect) -> ok
343 Types:
345 This = wxDC()
347 Text = unicode:chardata()
348 Rect =
349 {X :: integer(),
350 Y :: integer(),
351 W :: integer(),
352 H :: integer()}
353 drawLabel(This, Text, Rect, Options :: [Option]) -> ok
355 Types:
357 This = wxDC()
359 Text = unicode:chardata()
360 Rect =
361 {X :: integer(),
362 Y :: integer(),
363 W :: integer(),
364 H :: integer()}
365 Option = {alignment, integer()} | {indexAccel, integer()}
366 This is an overloaded member function, provided for convenience.
368 It differs from the above function only in what argument(s) it
369 accepts.
370 drawLine(This, Pt1, Pt2) -> ok
372 Types:
374 This = wxDC()
376 Pt1 = Pt2 = {X :: integer(), Y :: integer()}
377 This is an overloaded member function, provided for convenience.
379 It differs from the above function only in what argument(s) it
380 accepts.
381 drawLines(This, Points) -> ok
383 Types:
385 This = wxDC()
387 Points = [{X :: integer(), Y :: integer()}]
388 drawLines(This, Points, Options :: [Option]) -> ok
390 Types:
392 This = wxDC()
394 Points = [{X :: integer(), Y :: integer()}]
395 Option = {xoffset, integer()} | {yoffset, integer()}
396 Draws lines using an array of points of size n adding the op‐
398 tional offset coordinate.
399 The current pen is used for drawing the lines.
401 drawPolygon(This, Points) -> ok
403 Types:
405 This = wxDC()
407 Points = [{X :: integer(), Y :: integer()}]
408 drawPolygon(This, Points, Options :: [Option]) -> ok
410 Types:
412 This = wxDC()
414 Points = [{X :: integer(), Y :: integer()}]
415 Option =
416 {xoffset, integer()} |
417 {yoffset, integer()} |
418 {fillStyle, wx:wx_enum()}
419 Draws a filled polygon using an array of points of size n,
421 adding the optional offset coordinate.
422 The first and last points are automatically closed.
424 The last argument specifies the fill rule: wxODDEVEN_RULE (the
426 default) or wxWINDING_RULE.
427 The current pen is used for drawing the outline, and the current
429 brush for filling the shape. Using a transparent brush sup‐
430 presses filling.
431 drawPoint(This, Pt) -> ok
433 Types:
435 This = wxDC()
437 Pt = {X :: integer(), Y :: integer()}
438 This is an overloaded member function, provided for convenience.
440 It differs from the above function only in what argument(s) it
441 accepts.
442 drawRectangle(This, Rect) -> ok
444 Types:
446 This = wxDC()
448 Rect =
449 {X :: integer(),
450 Y :: integer(),
451 W :: integer(),
452 H :: integer()}
453 This is an overloaded member function, provided for convenience.
455 It differs from the above function only in what argument(s) it
456 accepts.
457 drawRectangle(This, Pt, Sz) -> ok
459 Types:
461 This = wxDC()
463 Pt = {X :: integer(), Y :: integer()}
464 Sz = {W :: integer(), H :: integer()}
465 This is an overloaded member function, provided for convenience.
467 It differs from the above function only in what argument(s) it
468 accepts.
469 drawRotatedText(This, Text, Point, Angle) -> ok
471 Types:
473 This = wxDC()
475 Text = unicode:chardata()
476 Point = {X :: integer(), Y :: integer()}
477 Angle = number()
478 This is an overloaded member function, provided for convenience.
480 It differs from the above function only in what argument(s) it
481 accepts.
482 drawRoundedRectangle(This, Rect, Radius) -> ok
484 Types:
486 This = wxDC()
488 Rect =
489 {X :: integer(),
490 Y :: integer(),
491 W :: integer(),
492 H :: integer()}
493 Radius = number()
494 This is an overloaded member function, provided for convenience.
496 It differs from the above function only in what argument(s) it
497 accepts.
498 drawRoundedRectangle(This, Pt, Sz, Radius) -> ok
500 Types:
502 This = wxDC()
504 Pt = {X :: integer(), Y :: integer()}
505 Sz = {W :: integer(), H :: integer()}
506 Radius = number()
507 This is an overloaded member function, provided for convenience.
509 It differs from the above function only in what argument(s) it
510 accepts.
511 drawText(This, Text, Pt) -> ok
513 Types:
515 This = wxDC()
517 Text = unicode:chardata()
518 Pt = {X :: integer(), Y :: integer()}
519 This is an overloaded member function, provided for convenience.
521 It differs from the above function only in what argument(s) it
522 accepts.
523 endDoc(This) -> ok
525 Types:
527 This = wxDC()
529 Ends a document (only relevant when outputting to a printer).
531 endPage(This) -> ok
533 Types:
535 This = wxDC()
537 Ends a document page (only relevant when outputting to a
539 printer).
540 floodFill(This, Pt, Col) -> boolean()
542 Types:
544 This = wxDC()
546 Pt = {X :: integer(), Y :: integer()}
547 Col = wx:wx_colour()
548 floodFill(This, Pt, Col, Options :: [Option]) -> boolean()
550 Types:
552 This = wxDC()
554 Pt = {X :: integer(), Y :: integer()}
555 Col = wx:wx_colour()
556 Option = {style, wx:wx_enum()}
557 This is an overloaded member function, provided for convenience.
559 It differs from the above function only in what argument(s) it
560 accepts.
561 getBackground(This) -> wxBrush:wxBrush()
563 Types:
565 This = wxDC()
567 Gets the brush used for painting the background.
569 See: setBackground/2
571 getBackgroundMode(This) -> integer()
573 Types:
575 This = wxDC()
577 Returns the current background mode: wxPENSTYLE_SOLID or wxPEN‐
579 STYLE_TRANSPARENT.
580 See: setBackgroundMode/2
582 getBrush(This) -> wxBrush:wxBrush()
584 Types:
586 This = wxDC()
588 Gets the current brush.
590 See: setBrush/2
592 getCharHeight(This) -> integer()
594 Types:
596 This = wxDC()
598 Gets the character height of the currently set font.
600 getCharWidth(This) -> integer()
602 Types:
604 This = wxDC()
606 Gets the average character width of the currently set font.
608 getClippingBox(This) -> Result
610 Types:
612 Result =
614 {X :: integer(),
615 Y :: integer(),
616 Width :: integer(),
617 Height :: integer()}
618 This = wxDC()
619 Gets the rectangle surrounding the current clipping region. If
621 no clipping region is set this function returns the extent of
622 the device context. @remarks Clipping region is given in logical
623 coordinates. @param x If non-<span class='literal'>NULL</span>,
624 filled in with the logical horizontal coordinate of the top left
625 corner of the clipping region if the function returns true or 0
626 otherwise. @param y If non-<span class='literal'>NULL</span>,
627 filled in with the logical vertical coordinate of the top left
628 corner of the clipping region if the function returns true or 0
629 otherwise. @param width If non-<span class='lit‐
630 eral'>NULL</span>, filled in with the width of the clipping re‐
631 gion if the function returns true or the device context width
632 otherwise. @param height If non-<span class='lit‐
633 eral'>NULL</span>, filled in with the height of the clipping re‐
634 gion if the function returns true or the device context height
635 otherwise.
636 Return: true if there is a clipping region or false if there is
638 no active clipping region (note that this return value is avail‐
639 able only since wxWidgets 3.1.2, this function didn't return
640 anything in the previous versions).
641 getFont(This) -> wxFont:wxFont()
643 Types:
645 This = wxDC()
647 Gets the current font.
649 Notice that even although each device context object has some
651 default font after creation, this method would return a ?wxNull‐
652 Font initially and only after calling setFont/2 a valid font is
653 returned.
654 getLayoutDirection(This) -> wx:wx_enum()
656 Types:
658 This = wxDC()
660 Gets the current layout direction of the device context.
662 On platforms where RTL layout is supported, the return value
664 will either be wxLayout_LeftToRight or wxLayout_RightToLeft. If
665 RTL layout is not supported, the return value will be wxLay‐
666 out_Default.
667 See: setLayoutDirection/2
669 getLogicalFunction(This) -> wx:wx_enum()
671 Types:
673 This = wxDC()
675 Gets the current logical function.
677 See: setLogicalFunction/2
679 getMapMode(This) -> wx:wx_enum()
681 Types:
683 This = wxDC()
685 Gets the current mapping mode for the device context.
687 See: setMapMode/2
689 getMultiLineTextExtent(This, String) ->
691 {W :: integer(), H :: integer()}
692 Types:
694 This = wxDC()
696 String = unicode:chardata()
697 Gets the dimensions of the string using the currently selected
699 font.
700 string is the text string to measure.
702 Return: The text extent as a {Width,Height} object.
704 Note: This function works with both single-line and multi-line
706 strings.
707 See: wxFont, setFont/2, getPartialTextExtents/2, getTextExtent/3
709 getMultiLineTextExtent(This, String, Options :: [Option]) ->
711 {W :: integer(),
712 H :: integer(),
713 HeightLine :: integer()}
714 Types:
716 This = wxDC()
718 String = unicode:chardata()
719 Option = {font, wxFont:wxFont()}
720 Gets the dimensions of the string using the currently selected
722 font.
723 string is the text string to measure, heightLine, if non NULL,
725 is where to store the height of a single line.
726 The text extent is set in the given w and h pointers.
728 If the optional parameter font is specified and valid, then it
730 is used for the text extent calculation, otherwise the currently
731 selected font is used.
732 If string is empty, its horizontal extent is 0 but, for conve‐
734 nience when using this function for allocating enough space for
735 a possibly multi-line string, its vertical extent is the same as
736 the height of an empty line of text. Please note that this be‐
737 haviour differs from that of getTextExtent/3.
738 Note: This function works with both single-line and multi-line
740 strings.
741 See: wxFont, setFont/2, getPartialTextExtents/2, getTextExtent/3
743 getPartialTextExtents(This, Text) -> Result
745 Types:
747 Result = {Res :: boolean(), Widths :: [integer()]}
749 This = wxDC()
750 Text = unicode:chardata()
751 Fills the widths array with the widths from the beginning of
753 text to the corresponding character of text.
754 The generic version simply builds a running total of the widths
756 of each character using getTextExtent/3, however if the various
757 platforms have a native API function that is faster or more ac‐
758 curate than the generic implementation then it should be used
759 instead.
760 See: getMultiLineTextExtent/3, getTextExtent/3
762 getPen(This) -> wxPen:wxPen()
764 Types:
766 This = wxDC()
768 Gets the current pen.
770 See: setPen/2
772 getPixel(This, Pos) -> Result
774 Types:
776 Result = {Res :: boolean(), Colour :: wx:wx_colour4()}
778 This = wxDC()
779 Pos = {X :: integer(), Y :: integer()}
780 Gets in colour the colour at the specified location.
782 This method isn't available for wxPostScriptDC or wxMetafileDC
784 (not implemented in wx) nor for any DC in wxOSX port and simply
785 returns false there.
786 Note: Setting a pixel can be done using drawPoint/2.
788 Note: This method shouldn't be used with wxPaintDC as accessing
790 the DC while drawing can result in unexpected results, notably
791 in wxGTK.
792 getPPI(This) -> {W :: integer(), H :: integer()}
794 Types:
796 This = wxDC()
798 Returns the resolution of the device in pixels per inch.
800 getSize(This) -> {W :: integer(), H :: integer()}
802 Types:
804 This = wxDC()
806 This is an overloaded member function, provided for convenience.
808 It differs from the above function only in what argument(s) it
809 accepts.
810 getSizeMM(This) -> {W :: integer(), H :: integer()}
812 Types:
814 This = wxDC()
816 This is an overloaded member function, provided for convenience.
818 It differs from the above function only in what argument(s) it
819 accepts.
820 getTextBackground(This) -> wx:wx_colour4()
822 Types:
824 This = wxDC()
826 Gets the current text background colour.
828 See: setTextBackground/2
830 getTextExtent(This, String) -> {W :: integer(), H :: integer()}
832 Types:
834 This = wxDC()
836 String = unicode:chardata()
837 This is an overloaded member function, provided for convenience.
839 It differs from the above function only in what argument(s) it
840 accepts.
841 getTextExtent(This, String, Options :: [Option]) -> Result
843 Types:
845 Result =
847 {W :: integer(),
848 H :: integer(),
849 Descent :: integer(),
850 ExternalLeading :: integer()}
851 This = wxDC()
852 String = unicode:chardata()
853 Option = {theFont, wxFont:wxFont()}
854 Gets the dimensions of the string using the currently selected
856 font.
857 string is the text string to measure, descent is the dimension
859 from the baseline of the font to the bottom of the descender,
860 and externalLeading is any extra vertical space added to the
861 font by the font designer (usually is zero).
862 The text extent is returned in w and h pointers or as a
864 {Width,Height} object depending on which version of this func‐
865 tion is used.
866 If the optional parameter font is specified and valid, then it
868 is used for the text extent calculation. Otherwise the currently
869 selected font is.
870 If string is empty, its extent is 0 in both directions, as ex‐
872 pected.
873 Note: This function only works with single-line strings.
875 See: wxFont, setFont/2, getPartialTextExtents/2, getMultiLine‐
877 TextExtent/3
878 getTextForeground(This) -> wx:wx_colour4()
880 Types:
882 This = wxDC()
884 Gets the current text foreground colour.
886 See: setTextForeground/2
888 getUserScale(This) -> {X :: number(), Y :: number()}
890 Types:
892 This = wxDC()
894 Gets the current user scale factor.
896 See: setUserScale/3
898 gradientFillConcentric(This, Rect, InitialColour, DestColour) ->
900 ok
901 Types:
903 This = wxDC()
905 Rect =
906 {X :: integer(),
907 Y :: integer(),
908 W :: integer(),
909 H :: integer()}
910 InitialColour = DestColour = wx:wx_colour()
911 Fill the area specified by rect with a radial gradient, starting
913 from initialColour at the centre of the circle and fading to
914 destColour on the circle outside.
915 The circle is placed at the centre of rect.
917 Note: Currently this function is very slow, don't use it for
919 real-time drawing.
920 gradientFillConcentric(This, Rect, InitialColour, DestColour,
922 CircleCenter) ->
923 ok
924 Types:
926 This = wxDC()
928 Rect =
929 {X :: integer(),
930 Y :: integer(),
931 W :: integer(),
932 H :: integer()}
933 InitialColour = DestColour = wx:wx_colour()
934 CircleCenter = {X :: integer(), Y :: integer()}
935 Fill the area specified by rect with a radial gradient, starting
937 from initialColour at the centre of the circle and fading to
938 destColour on the circle outside.
939 circleCenter are the relative coordinates of centre of the cir‐
941 cle in the specified rect.
942 Note: Currently this function is very slow, don't use it for
944 real-time drawing.
945 gradientFillLinear(This, Rect, InitialColour, DestColour) -> ok
947 Types:
949 This = wxDC()
951 Rect =
952 {X :: integer(),
953 Y :: integer(),
954 W :: integer(),
955 H :: integer()}
956 InitialColour = DestColour = wx:wx_colour()
957 gradientFillLinear(This, Rect, InitialColour, DestColour,
959 Options :: [Option]) ->
960 ok
961 Types:
963 This = wxDC()
965 Rect =
966 {X :: integer(),
967 Y :: integer(),
968 W :: integer(),
969 H :: integer()}
970 InitialColour = DestColour = wx:wx_colour()
971 Option = {nDirection, wx:wx_enum()}
972 Fill the area specified by rect with a linear gradient, starting
974 from initialColour and eventually fading to destColour.
975 The nDirection specifies the direction of the colour change, de‐
977 fault is to use initialColour on the left part of the rectangle
978 and destColour on the right one.
979 logicalToDeviceX(This, X) -> integer()
981 Types:
983 This = wxDC()
985 X = integer()
986 Converts logical X coordinate to device coordinate, using the
988 current mapping mode, user scale factor, device origin and axis
989 orientation.
990 logicalToDeviceXRel(This, X) -> integer()
992 Types:
994 This = wxDC()
996 X = integer()
997 Converts logical X coordinate to relative device coordinate, us‐
999 ing the current mapping mode and user scale factor but ignoring
1000 the axis orientation.
1001 Use this for converting a width, for example.
1003 logicalToDeviceY(This, Y) -> integer()
1005 Types:
1007 This = wxDC()
1009 Y = integer()
1010 Converts logical Y coordinate to device coordinate, using the
1012 current mapping mode, user scale factor, device origin and axis
1013 orientation.
1014 logicalToDeviceYRel(This, Y) -> integer()
1016 Types:
1018 This = wxDC()
1020 Y = integer()
1021 Converts logical Y coordinate to relative device coordinate, us‐
1023 ing the current mapping mode and user scale factor but ignoring
1024 the axis orientation.
1025 Use this for converting a height, for example.
1027 maxX(This) -> integer()
1029 Types:
1031 This = wxDC()
1033 Gets the maximum horizontal extent used in drawing commands so
1035 far.
1036 maxY(This) -> integer()
1038 Types:
1040 This = wxDC()
1042 Gets the maximum vertical extent used in drawing commands so
1044 far.
1045 minX(This) -> integer()
1047 Types:
1049 This = wxDC()
1051 Gets the minimum horizontal extent used in drawing commands so
1053 far.
1054 minY(This) -> integer()
1056 Types:
1058 This = wxDC()
1060 Gets the minimum vertical extent used in drawing commands so
1062 far.
1063 isOk(This) -> boolean()
1065 Types:
1067 This = wxDC()
1069 Returns true if the DC is ok to use.
1071 resetBoundingBox(This) -> ok
1073 Types:
1075 This = wxDC()
1077 Resets the bounding box: after a call to this function, the
1079 bounding box doesn't contain anything.
1080 See: calcBoundingBox/3
1082 setAxisOrientation(This, XLeftRight, YBottomUp) -> ok
1084 Types:
1086 This = wxDC()
1088 XLeftRight = YBottomUp = boolean()
1089 Sets the x and y axis orientation (i.e. the direction from low‐
1091 est to highest values on the axis).
1092 The default orientation is x axis from left to right and y axis
1094 from top down.
1095 setBackground(This, Brush) -> ok
1097 Types:
1099 This = wxDC()
1101 Brush = wxBrush:wxBrush()
1102 Sets the current background brush for the DC.
1104 setBackgroundMode(This, Mode) -> ok
1106 Types:
1108 This = wxDC()
1110 Mode = integer()
1111 mode may be one of wxPENSTYLE_SOLID and wxPENSTYLE_TRANSPARENT.
1113 This setting determines whether text will be drawn with a back‐
1115 ground colour or not.
1116 setBrush(This, Brush) -> ok
1118 Types:
1120 This = wxDC()
1122 Brush = wxBrush:wxBrush()
1123 Sets the current brush for the DC.
1125 If the argument is ?wxNullBrush (or another invalid brush; see
1127 wxBrush:isOk/1), the current brush is selected out of the device
1128 context (leaving wxDC without any valid brush), allowing the
1129 current brush to be destroyed safely.
1130 See: wxBrush, wxMemoryDC, (for the interpretation of colours
1132 when drawing into a monochrome bitmap)
1133 setClippingRegion(This, Rect) -> ok
1135 Types:
1137 This = wxDC()
1139 Rect =
1140 {X :: integer(),
1141 Y :: integer(),
1142 W :: integer(),
1143 H :: integer()}
1144 This is an overloaded member function, provided for convenience.
1146 It differs from the above function only in what argument(s) it
1147 accepts.
1148 setClippingRegion(This, Pt, Sz) -> ok
1150 Types:
1152 This = wxDC()
1154 Pt = {X :: integer(), Y :: integer()}
1155 Sz = {W :: integer(), H :: integer()}
1156 This is an overloaded member function, provided for convenience.
1158 It differs from the above function only in what argument(s) it
1159 accepts.
1160 setDeviceOrigin(This, X, Y) -> ok
1162 Types:
1164 This = wxDC()
1166 X = Y = integer()
1167 Sets the device origin (i.e. the origin in pixels after scaling
1169 has been applied).
1170 This function may be useful in Windows printing operations for
1172 placing a graphic on a page.
1173 setFont(This, Font) -> ok
1175 Types:
1177 This = wxDC()
1179 Font = wxFont:wxFont()
1180 Sets the current font for the DC.
1182 If the argument is ?wxNullFont (or another invalid font; see wx‐
1184 Font:isOk/1), the current font is selected out of the device
1185 context (leaving wxDC without any valid font), allowing the cur‐
1186 rent font to be destroyed safely.
1187 See: wxFont
1189 setLayoutDirection(This, Dir) -> ok
1191 Types:
1193 This = wxDC()
1195 Dir = wx:wx_enum()
1196 Sets the current layout direction for the device context.
1198 See: getLayoutDirection/1
1200 setLogicalFunction(This, Function) -> ok
1202 Types:
1204 This = wxDC()
1206 Function = wx:wx_enum()
1207 Sets the current logical function for the device context.
1209 Note: This function is not fully supported in all ports, due to
1211 the limitations of the underlying drawing model. Notably, wxIN‐
1212 VERT which was commonly used for drawing rubber bands or other
1213 moving outlines in the past, is not, and will not, be supported
1214 by wxGTK3 and wxMac. The suggested alternative is to draw tempo‐
1215 rarily objects normally and refresh the (affected part of the)
1216 window to remove them later.
1217 It determines how a source pixel (from a pen or brush colour, or
1219 source device context if using blit/6) combines with a destina‐
1220 tion pixel in the current device context. Text drawing is not
1221 affected by this function.
1222 See ?wxRasterOperationMode enumeration values for more info.
1224 The default is wxCOPY, which simply draws with the current
1226 colour. The others combine the current colour and the background
1227 using a logical operation.
1228 setMapMode(This, Mode) -> ok
1230 Types:
1232 This = wxDC()
1234 Mode = wx:wx_enum()
1235 The mapping mode of the device context defines the unit of mea‐
1237 surement used to convert logical units to device units.
1238 Note that in X, text drawing isn't handled consistently with the
1240 mapping mode; a font is always specified in point size. However,
1241 setting the user scale (see setUserScale/3) scales the text ap‐
1242 propriately. In Windows, scalable TrueType fonts are always
1243 used; in X, results depend on availability of fonts, but usually
1244 a reasonable match is found.
1245 The coordinate origin is always at the top left of the
1247 screen/printer.
1248 Drawing to a Windows printer device context uses the current
1250 mapping mode, but mapping mode is currently ignored for Post‐
1251 Script output.
1252 setPalette(This, Palette) -> ok
1254 Types:
1256 This = wxDC()
1258 Palette = wxPalette:wxPalette()
1259 If this is a window DC or memory DC, assigns the given palette
1261 to the window or bitmap associated with the DC.
1262 If the argument is ?wxNullPalette, the current palette is se‐
1264 lected out of the device context, and the original palette re‐
1265 stored.
1266 See: wxPalette
1268 setPen(This, Pen) -> ok
1270 Types:
1272 This = wxDC()
1274 Pen = wxPen:wxPen()
1275 Sets the current pen for the DC.
1277 If the argument is ?wxNullPen (or another invalid pen; see wx‐
1279 Pen:isOk/1), the current pen is selected out of the device con‐
1280 text (leaving wxDC without any valid pen), allowing the current
1281 pen to be destroyed safely.
1282 See: wxMemoryDC, for the interpretation of colours when drawing
1284 into a monochrome bitmap
1285 setTextBackground(This, Colour) -> ok
1287 Types:
1289 This = wxDC()
1291 Colour = wx:wx_colour()
1292 Sets the current text background colour for the DC.
1294 setTextForeground(This, Colour) -> ok
1296 Types:
1298 This = wxDC()
1300 Colour = wx:wx_colour()
1301 Sets the current text foreground colour for the DC.
1303 See: wxMemoryDC, for the interpretation of colours when drawing
1305 into a monochrome bitmap
1306 setUserScale(This, XScale, YScale) -> ok
1308 Types:
1310 This = wxDC()
1312 XScale = YScale = number()
1313 Sets the user scaling factor, useful for applications which re‐
1315 quire 'zooming'.
1316 startDoc(This, Message) -> boolean()
1318 Types:
1320 This = wxDC()
1322 Message = unicode:chardata()
1323 Starts a document (only relevant when outputting to a printer).
1325 message is a message to show while printing.
1327 startPage(This) -> ok
1329 Types:
1331 This = wxDC()
1333 Starts a document page (only relevant when outputting to a
1335 printer).
1336wxWidgets team. wx 2.1 wxDC(3)