DC

A DC is a “device context” onto which graphics and text can be drawn.

It is intended to represent different output devices and offers a common abstract API for drawing on any of them.

wxWidgets offers an alternative drawing API based on the modern drawing backends GDI+, CoreGraphics and Cairo. See GraphicsContext, GraphicsRenderer and related classes. There is also a GCDC linking the APIs by offering the DC API on top of a GraphicsContext.

DC is an abstract base class and cannot be created directly. Use PaintDC, ClientDC, WindowDC, ScreenDC, MemoryDC or PrinterDC. Notice that device contexts which are associated with windows (i.e. ClientDC, WindowDC and PaintDC) use the window font and colours by default (starting with wxWidgets 2.9.0) but the other device context classes use system-default values so you always must set the appropriate fonts and colours before using them.

In addition to the versions of the methods documented below, there are also versions which accept single Point parameter instead of the two Coord ones or Point and Size instead of the four Coord parameters.

Beginning with wxWidgets 2.9.0 the entire DC code has been reorganized. All platform dependent code (actually all drawing code) has been moved into backend classes which derive from a common DCImpl class. The user-visible classes such as ClientDC and PaintDC merely forward all calls to the backend implementation.

Device and logical units

In the DC context there is a distinction between logical units and device units. Device units are the units native to the particular device; e.g. for a screen, a device unit is a pixel. For a printer, the device unit is defined by the resolution of the printer (usually given in DPI: dot-per-inch). All DC functions use instead logical units, unless where explicitly stated. Logical units are arbitrary units mapped to device units using the current mapping mode (see DC.SetMapMode ). This mechanism allows to reuse the same code which prints on e.g. a window on the screen to print on e.g. a paper.

Support for Transparency / Alpha Channel

In general DC methods don’t support alpha transparency and the alpha component of Colour is simply ignored and you need to use GraphicsContext for full transparency support. There are, however, a few exceptions: first, under Mac OS X colours with alpha channel are supported in all the normal DC-derived classes as they use GraphicsContext internally. Second, under all platforms SVGFileDC also fully supports alpha channel. In both of these cases the instances of Pen or Brush that are built from Colour use the colour’s alpha values when stroking or filling.

for Transformation Matrix

On some platforms (currently only under MSW and only on Windows NT, i.e. not Windows 9x/ME, systems) DC has support for applying an arbitrary affine transformation matrix to its coordinate system. Call CanUseTransformMatrix to check if this support is available and then call SetTransformMatrix if it is. If the transformation matrix is not supported, SetTransformMatrix always simply returns False and doesn’t do anything.

See also

Device Contexts, GraphicsContext, DCFontChanger, DCTextColourChanger, DCPenChanger, DCBrushChanger, DCClipper

Todo

Precise definition of default/initial state. Pixelwise definition of operations (e.g. last point of a line not drawn).

Inheritance Diagram

Inheritance diagram for class DC

Known Subclasses

GCDC, MemoryDC, MetafileDC, MirrorDC, PostScriptDC, PrinterDC, ScreenDC, SVGFileDC, WindowDC

Methods Summary

Blit	Copy from a source DC to this DC.
CalcBoundingBox	Adds the specified point to the bounding box which can be retrieved with MinX , MaxX and MinY , MaxY functions.
CanUseTransformMatrix	Check if the use of transformation matrix is supported by the current system.
Clear	Clears the device context using the current background brush.
CopyAttributes	Copy attributes from another DC.
CrossHair	Displays a cross hair using the current pen.
DestroyClippingRegion	Destroys the current clipping region so that none of the DC is clipped.
DeviceToLogicalX	Convert device X coordinate to logical coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.
DeviceToLogicalXRel	Convert device X coordinate to relative logical coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.
DeviceToLogicalY	Converts device Y coordinate to logical coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.
DeviceToLogicalYRel	Convert device Y coordinate to relative logical coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.
DrawArc	Draws an arc of a circle, centred on (xc, yc), with starting point (xStart, yStart) and ending at (xEnd, yEnd).
DrawBitmap	Draw a bitmap on the device context at the specified point.
DrawCheckMark	Draws a check mark inside the given rectangle.
DrawCircle	Draws a circle with the given centre and radius.
DrawEllipse	Draws an ellipse contained in the rectangle specified either with the given top left corner and the given size or directly.
DrawEllipticArc	Draws an arc of an ellipse.
DrawIcon	Draw an icon on the display (does nothing if the device context is PostScript).
DrawLabel	Draw optional bitmap and the text into the given rectangle and aligns it as specified by alignment parameter; it also will emphasize the character with the given index if it is != -1 and return the bounding rectangle if required.
DrawLine	Draws a line from the first point to the second.
DrawLines	This method uses a list of Points, adding the optional offset coordinate.
DrawPoint	Draws a point using the color of the current pen.
DrawPolygon	This method draws a filled polygon using a list of Points, adding the optional offset coordinate.
DrawRectangle	Draws a rectangle with the given top left corner, and with the given size.
DrawRotatedText	Draws the text rotated by angle degrees (positive angles are counterclockwise; the full angle is 360 degrees).
DrawRoundedRectangle	Draws a rectangle with the given top left corner, and with the given size.
DrawSpline	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
DrawText	Draws a text string at the specified point, using the current text font, and the current text foreground and background colours.
EndDoc	Ends a document (only relevant when outputting to a printer).
EndPage	Ends a document page (only relevant when outputting to a printer).
FloodFill	Flood fills the device context starting from the given point, using the current brush colour, and using a style:.
GetBackground	Gets the brush used for painting the background.
GetBackgroundMode	Returns the current background mode: SOLID or TRANSPARENT .
GetBoundingBox	GetBoundingBox() -> (x1,y1, x2,y2)
GetBrush	Gets the current brush.
GetCGContext
GetCharHeight	Gets the character height of the currently set font.
GetCharWidth	Gets the average character width of the currently set font.
GetClippingBox	Gets the rectangle surrounding the current clipping region.
GetClippingRect	Gets the rectangle surrounding the current clipping region
GetDepth	Returns the depth (number of bits/pixel) of this DC.
GetDeviceOrigin	Returns the current device origin.
GetFont	Gets the current font.
GetFontMetrics	Returns the various font characteristics.
GetGdkDrawable
GetHDC
GetLayoutDirection	Gets the current layout direction of the device context.
GetLogicalFunction	Gets the current logical function.
GetLogicalOrigin
GetLogicalScale
GetMapMode	Gets the current mapping mode for the device context.
GetFullMultiLineTextExtent	Gets the dimensions of the string using the currently selected font.
GetPPI	Returns the resolution of the device in pixels per inch.
GetPartialTextExtents	Fills the widths array with the widths from the beginning of text to the corresponding character of text.
GetPen	Gets the current pen.
GetSize	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
GetSizeMM	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
GetTextBackground	Gets the current text background colour.
GetFullTextExtent	Gets the dimensions of the string using the currently selected font.
GetTextForeground	Gets the current text foreground colour.
GetUserScale	Gets the current user scale factor.
GradientFillConcentric	Fill the area specified by rect with a radial gradient, starting from initialColour at the centre of the circle and fading to destColour on the circle outside.
GradientFillLinear	Fill the area specified by rect with a linear gradient, starting from initialColour and eventually fading to destColour.
IsOk	Returns True if the DC is ok to use.
LogicalToDeviceX	Converts logical X coordinate to device coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.
LogicalToDeviceXRel	Converts logical X coordinate to relative device coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.
LogicalToDeviceY	Converts logical Y coordinate to device coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.
LogicalToDeviceYRel	Converts logical Y coordinate to relative device coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.
MaxX	Gets the maximum horizontal extent used in drawing commands so far.
MaxY	Gets the maximum vertical extent used in drawing commands so far.
MinX	Gets the minimum horizontal extent used in drawing commands so far.
MinY	Gets the minimum vertical extent used in drawing commands so far.
ResetBoundingBox	Resets the bounding box: after a call to this function, the bounding box doesn’t contain anything.
ResetTransformMatrix	Revert the transformation matrix to identity matrix.
SetAxisOrientation	Sets the x and y axis orientation (i.e., the direction from lowest to highest values on the axis).
SetBackground	Sets the current background brush for the DC.
SetBackgroundMode	mode may be one of SOLID and TRANSPARENT .
SetBrush	Sets the current brush for the DC.
SetClippingRegion	Sets the clipping region for this device context to the intersection of the given region described by the parameters of this method and the previously set clipping region.
SetDeviceClippingRegion	Sets the clipping region for this device context.
SetDeviceOrigin	Sets the device origin (i.e., the origin in pixels after scaling has been applied).
SetFont	Sets the current font for the DC.
SetLayoutDirection	Sets the current layout direction for the device context.
SetLogicalFunction	Sets the current logical function for the device context.
SetLogicalOrigin
SetLogicalScale
SetMapMode	The mapping mode of the device context defines the unit of measurement used to convert logical units to device units.
SetPalette	If this is a window DC or memory DC, assigns the given palette to the window or bitmap associated with the DC.
SetPen	Sets the current pen for the DC.
SetTextBackground	Sets the current text background colour for the DC.
SetTextForeground	Sets the current text foreground colour for the DC.
SetUserScale	Sets the user scaling factor, useful for applications which require ‘zooming’.
StartDoc	Starts a document (only relevant when outputting to a printer).
StartPage	Starts a document page (only relevant when outputting to a printer).
StretchBlit	Copy from a source DC to this DC possibly changing the scale.
__nonzero__

Properties Summary

Background	See GetBackground and SetBackground
BackgroundMode	See GetBackgroundMode and SetBackgroundMode
BoundingBox	See GetBoundingBox
Brush	See GetBrush and SetBrush
CGContext	See GetCGContext
CharHeight	See GetCharHeight
CharWidth	See GetCharWidth
ClippingRect	See GetClippingRect
Depth	See GetDepth
DeviceOrigin	See GetDeviceOrigin and SetDeviceOrigin
Font	See GetFont and SetFont
FontMetrics	See GetFontMetrics
GdkDrawable	See GetGdkDrawable
HDC	See GetHDC
LayoutDirection	See GetLayoutDirection and SetLayoutDirection
LogicalFunction	See GetLogicalFunction and SetLogicalFunction
MapMode	See GetMapMode and SetMapMode
PPI	See GetPPI
Pen	See GetPen and SetPen
Pixel	See GetPixel
Size	See GetSize
SizeMM	See GetSizeMM
TextBackground	See GetTextBackground and SetTextBackground
TextForeground	See GetTextForeground and SetTextForeground

Class API

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class DC(Object)

A DC is a “device context” onto which graphics and text can be drawn.

Methods

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Blit(self, xdest, ydest, width, height, source, xsrc, ysrc, logicalFunc=COPY, useMask=False, xsrcMask=DefaultCoord, ysrcMask=DefaultCoord)

Copy from a source DC to this DC.

With this method you can specify the destination coordinates and the size of area to copy which will be the same for both the source and target DCs. If you need to apply scaling while copying, use StretchBlit .

Notice that source DC coordinates xsrc and ysrc are interpreted using the current source DC coordinate system, i.e. the scale, origin position and axis directions are taken into account when transforming them to physical (pixel) coordinates.

Parameters:

• xdest (int) – Destination device context x position.
• ydest (int) – Destination device context y position.
• width (int) – Width of source area to be copied.
• height (int) – Height of source area to be copied.
• source (DC) – Source device context.
• xsrc (int) – Source device context x position.
• ysrc (int) – Source device context y position.
• logicalFunc (RasterOperationMode) – Logical function to use, see SetLogicalFunction .
• useMask (bool) – If True, Blit does a transparent blit using the mask that is associated with the bitmap selected into the source device context. The Windows implementation does the following if MaskBlt cannot be used:
  • Creates a temporary bitmap and copies the destination area into it.
  • Copies the source area into the temporary bitmap using the specified logical function.
  • Sets the masked area in the temporary bitmap to BLACK by ANDing the mask bitmap with the temp bitmap with the foreground colour set to WHITE and the bg colour set to BLACK.
  • Sets the unmasked area in the destination area to BLACK by ANDing the mask bitmap with the destination area with the foreground colour set to BLACK and the background colour set to WHITE.
  • ORs the temporary bitmap with the destination area.
  • Deletes the temporary bitmap.

  This sequence of operations ensures that the source’s transparent area need not be black, and logical functions are supported.

  Note: on Windows, blitting with masks can be speeded up considerably by compiling wxWidgets with the USE_DC_CACHEING option enabled. You can also influence whether MaskBlt or the explicit mask blitting code above is used, by using SystemOptions and setting the no-maskblt option to 1.

• xsrcMask (int) – Source x position on the mask. If both xsrcMask and ysrcMask are -1 , xsrc and ysrc will be assumed for the mask source position. Currently only implemented on Windows.
• ysrcMask (int) – Source y position on the mask. If both xsrcMask and ysrcMask are -1 , xsrc and ysrc will be assumed for the mask source position. Currently only implemented on Windows.

Return type:

bool

Note

There is partial support for Blit in PostScriptDC, under X.

See also

StretchBlit , MemoryDC, Bitmap, Mask

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CalcBoundingBox(self, x, y)

Adds the specified point to the bounding box which can be retrieved with MinX , MaxX and MinY , MaxY functions.

Parameters:

• x (int) –
• y (int) –

See also

ResetBoundingBox

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CanUseTransformMatrix(self)

Check if the use of transformation matrix is supported by the current system.

Currently this function always returns False for non-MSW platforms and may return False for old (Windows 9x/ME) Windows systems. Normally support for the transformation matrix is always available in any relatively recent Windows versions.

Return type:bool

New in version 2.9.2.

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Clear(self)

Clears the device context using the current background brush.

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CopyAttributes(self, dc)

Copy attributes from another DC.

The copied attributes currently are:

• Font
• Text foreground and background colours
• Background brush
• Layout direction

Parameters:dc (DC) – A valid (i.e. its IsOk must return True) source device context.

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CrossHair(self, *args, **kw)

Overloaded Implementations:

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CrossHair (self, x, y)

Displays a cross hair using the current pen.

This is a vertical and horizontal line the height and width of the window, centred on the given point.

Parameters:

• x (int) –
• y (int) –

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CrossHair (self, pt)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:pt (Point) –

---

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DestroyClippingRegion(self)

Destroys the current clipping region so that none of the DC is clipped.

See also

SetClippingRegion

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DeviceToLogicalX(self, x)

Convert device X coordinate to logical coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.

Parameters:x (int) – Return type:int

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DeviceToLogicalXRel(self, x)

Convert device X coordinate to relative logical coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.

Use this for converting a width, for example.

Parameters:x (int) – Return type:int

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DeviceToLogicalY(self, y)

Converts device Y coordinate to logical coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.

Parameters:y (int) – Return type:int

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DeviceToLogicalYRel(self, y)

Convert device Y coordinate to relative logical coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.

Use this for converting a height, for example.

Parameters:y (int) – Return type:int

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DrawArc(self, *args, **kw)

Overloaded Implementations:

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DrawArc (self, xStart, yStart, xEnd, yEnd, xc, yc)

Draws an arc of a circle, centred on (xc, yc), with starting point (xStart, yStart) and ending at (xEnd, yEnd).

The current pen is used for the outline and the current brush for filling the shape.

The arc is drawn in a counter-clockwise direction from the start point to the end point.

Parameters:

• xStart (int) –
• yStart (int) –
• xEnd (int) –
• yEnd (int) –
• xc (int) –
• yc (int) –

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DrawArc (self, ptStart, ptEnd, centre)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• ptStart (Point) –
• ptEnd (Point) –
• centre (Point) –

---

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DrawBitmap(self, *args, **kw)

Overloaded Implementations:

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DrawBitmap (self, bitmap, x, y, useMask=False)

Draw a bitmap on the device context at the specified point.

If transparent is True and the bitmap has a transparency mask, the bitmap will be drawn transparently.

When drawing a mono-bitmap, the current text foreground colour will be used to draw the foreground of the bitmap (all bits set to 1), and the current text background colour to draw the background (all bits set to 0).

Parameters:

• bitmap (Bitmap) –
• x (int) –
• y (int) –
• useMask (bool) –

See also

SetTextForeground , SetTextBackground , MemoryDC

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DrawBitmap (self, bmp, pt, useMask=False)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• bmp (Bitmap) –
• pt (Point) –
• useMask (bool) –

---

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DrawCheckMark(self, *args, **kw)

Overloaded Implementations:

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DrawCheckMark (self, x, y, width, height)

Draws a check mark inside the given rectangle.

Parameters:

• x (int) –
• y (int) –
• width (int) –
• height (int) –

---

DrawCheckMark (self, rect)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:rect (Rect) –

---

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DrawCircle(self, *args, **kw)

Overloaded Implementations:

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DrawCircle (self, x, y, radius)

Draws a circle with the given centre and radius.

Parameters:

• x (int) –
• y (int) –
• radius (int) –

See also

DrawEllipse

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DrawCircle (self, pt, radius)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• radius (int) –

---

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DrawEllipse(self, *args, **kw)

Overloaded Implementations:

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DrawEllipse (self, x, y, width, height)

Draws an ellipse contained in the rectangle specified either with the given top left corner and the given size or directly.

The current pen is used for the outline and the current brush for filling the shape.

Parameters:

• x (int) –
• y (int) –
• width (int) –
• height (int) –

See also

DrawCircle

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DrawEllipse (self, pt, size)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• size (Size) –

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DrawEllipse (self, rect)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:rect (Rect) –

---

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DrawEllipticArc(self, *args, **kw)

Overloaded Implementations:

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DrawEllipticArc (self, x, y, width, height, start, end)

Draws an arc of an ellipse.

The current pen is used for drawing the arc and the current brush is used for drawing the pie.

x and y specify the x and y coordinates of the upper-left corner of the rectangle that contains the ellipse.

width and height specify the width and height of the rectangle that contains the ellipse.

start and end specify the start and end of the arc relative to the three-o’clock position from the center of the rectangle. Angles are specified in degrees (360 is a complete circle). Positive values mean counter-clockwise motion. If start is equal to end, a complete ellipse will be drawn.

Parameters:

• x (int) –
• y (int) –
• width (int) –
• height (int) –
• start (float) –
• end (float) –

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DrawEllipticArc (self, pt, sz, sa, ea)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• sz (Size) –
• sa (float) –
• ea (float) –

---

---

DrawIcon(self, *args, **kw)

Overloaded Implementations:

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DrawIcon (self, icon, x, y)

Draw an icon on the display (does nothing if the device context is PostScript).

This can be the simplest way of drawing bitmaps on a window.

Parameters:

• icon (Icon) –
• x (int) –
• y (int) –

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DrawIcon (self, icon, pt)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• icon (Icon) –
• pt (Point) –

---

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DrawLabel(self, *args, **kw)

Overloaded Implementations:

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DrawLabel (self, text, bitmap, rect, alignment=ALIGN_LEFT|ALIGN_TOP, indexAccel=-1)

Draw optional bitmap and the text into the given rectangle and aligns it as specified by alignment parameter; it also will emphasize the character with the given index if it is != -1 and return the bounding rectangle if required.

Parameters:

• text (string) –
• bitmap (Bitmap) –
• rect (Rect) –
• alignment (int) –
• indexAccel (int) –

Return type:

Rect

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DrawLabel (self, text, rect, alignment=ALIGN_LEFT|ALIGN_TOP, indexAccel=-1)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• text (string) –
• rect (Rect) –
• alignment (int) –
• indexAccel (int) –

---

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DrawLine(self, *args, **kw)

Overloaded Implementations:

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DrawLine (self, x1, y1, x2, y2)

Draws a line from the first point to the second.

The current pen is used for drawing the line. Note that the point (x2, y2) is not part of the line and is not drawn by this function (this is consistent with the behaviour of many other toolkits).

Parameters:

• x1 (int) –
• y1 (int) –
• x2 (int) –
• y2 (int) –

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DrawLine (self, pt1, pt2)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt1 (Point) –
• pt2 (Point) –

---

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DrawLines(self, *args, **kw)

This method uses a list of Points, adding the optional offset coordinate.

The programmer is responsible for deleting the list of points.

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DrawPoint(self, *args, **kw)

Overloaded Implementations:

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DrawPoint (self, x, y)

Draws a point using the color of the current pen.

Note that the other properties of the pen are not used, such as width.

Parameters:

• x (int) –
• y (int) –

---

DrawPoint (self, pt)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:pt (Point) –

---

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DrawPolygon(self, *args, **kw)

This method draws a filled polygon using a list of Points, adding the optional offset coordinate.

The first and last points are automatically closed.

The last argument specifies the fill rule: ``ODDEVEN_RULE`` (the default) or ``WINDING_RULE``.

The current pen is used for drawing the outline, and the current brush for filling the shape. Using a transparent brush suppresses filling.

The programmer is responsible for deleting the list of points.

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DrawRectangle(self, *args, **kw)

Overloaded Implementations:

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DrawRectangle (self, x, y, width, height)

Draws a rectangle with the given top left corner, and with the given size.

The current pen is used for the outline and the current brush for filling the shape.

Parameters:

• x (int) –
• y (int) –
• width (int) –
• height (int) –

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DrawRectangle (self, pt, sz)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• sz (Size) –

---

DrawRectangle (self, rect)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:rect (Rect) –

---

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DrawRotatedText(self, *args, **kw)

Overloaded Implementations:

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DrawRotatedText (self, text, x, y, angle)

Draws the text rotated by angle degrees (positive angles are counterclockwise; the full angle is 360 degrees).

Parameters:

• text (string) –
• x (int) –
• y (int) –
• angle (float) –

Note

Under Win9x only TrueType fonts can be drawn by this function. In particular, a font different from NORMAL_FONT should be used as the latter is not a TrueType font. SWISS_FONT is an example of a font which is.

See also

DrawText

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DrawRotatedText (self, text, point, angle)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• text (string) –
• point (Point) –
• angle (float) –

---

---

DrawRoundedRectangle(self, *args, **kw)

Overloaded Implementations:

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DrawRoundedRectangle (self, x, y, width, height, radius)

Draws a rectangle with the given top left corner, and with the given size.

The corners are quarter-circles using the given radius. The current pen is used for the outline and the current brush for filling the shape.

If radius is positive, the value is assumed to be the radius of the rounded corner. If radius is negative, the absolute value is assumed to be the proportion of the smallest dimension of the rectangle. This means that the corner can be a sensible size relative to the size of the rectangle, and also avoids the strange effects X produces when the corners are too big for the rectangle.

Parameters:

• x (int) –
• y (int) –
• width (int) –
• height (int) –
• radius (float) –

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DrawRoundedRectangle (self, pt, sz, radius)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• sz (Size) –
• radius (float) –

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DrawRoundedRectangle (self, rect, radius)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• rect (Rect) –
• radius (float) –

---

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DrawSpline(self, *args, **kw)

Overloaded Implementations:

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DrawSpline (self, points)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:points (PointList) –

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DrawSpline (self, x1, y1, x2, y2, x3, y3)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• x1 (int) –
• y1 (int) –
• x2 (int) –
• y2 (int) –
• x3 (int) –
• y3 (int) –

---

---

DrawText(self, *args, **kw)

Overloaded Implementations:

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DrawText (self, text, x, y)

Draws a text string at the specified point, using the current text font, and the current text foreground and background colours.

The coordinates refer to the top-left corner of the rectangle bounding the string. See GetTextExtent for how to get the dimensions of a text string, which can be used to position the text more precisely and DrawLabel if you need to align the string differently.

Starting from wxWidgets 2.9.2 text parameter can be a multi-line string, i.e. contain new line characters, and will be rendered correctly.

Parameters:

• text (string) –
• x (int) –
• y (int) –

Note

The current logical function is ignored by this function.

---

DrawText (self, text, pt)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• text (string) –
• pt (Point) –

---

---

EndDoc(self)

Ends a document (only relevant when outputting to a printer).

---

EndPage(self)

Ends a document page (only relevant when outputting to a printer).

---

FloodFill(self, *args, **kw)

Overloaded Implementations:

---

FloodFill (self, x, y, colour, style=FLOOD_SURFACE)

Flood fills the device context starting from the given point, using the current brush colour, and using a style:.

• FLOOD_SURFACE: The flooding occurs until a colour other than the given colour is encountered.
• FLOOD_BORDER: The area to be flooded is bounded by the given colour.

Parameters:

• x (int) –
• y (int) –
• colour (Colour) –
• style (FloodFillStyle) –

Return type:

bool

Returns:

False if the operation failed.

Note

The present implementation for non-Windows platforms may fail to find colour borders if the pixels do not match the colour exactly. However the function will still return True. This method shouldn’t be used with PaintDC under non-Windows platforms as it uses GetPixel internally and this may give wrong results, notably in wxGTK. If you need to flood fill PaintDC, create a temporary MemoryDC, flood fill it and then blit it to, or draw as a bitmap on, PaintDC. See the example of doing this in the drawing sample and BufferedPaintDC class.

---

FloodFill (self, pt, col, style=FLOOD_SURFACE)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• col (Colour) –
• style (FloodFillStyle) –

Return type:

bool

---

---

GetBackground(self)

Gets the brush used for painting the background.

Return type: Brush

See also

DC.SetBackground

---

GetBackgroundMode(self)

Returns the current background mode: SOLID or TRANSPARENT .

Return type:int

See also

SetBackgroundMode

---

GetBoundingBox(self)

GetBoundingBox() -> (x1,y1, x2,y2)

Returns the min and max points used in drawing commands so far.

---

GetBrush(self)

Gets the current brush.

Return type: Brush

See also

DC.SetBrush

---

GetCGContext(self)

---

GetCharHeight(self)

Gets the character height of the currently set font.

Return type:int

---

GetCharWidth(self)

Gets the average character width of the currently set font.

Return type:int

---

GetClippingBox(self)

Gets the rectangle surrounding the current clipping region.

Return type:tuple Returns:( x, y, width, height )

---

GetClippingRect(self)

Gets the rectangle surrounding the current clipping region

---

GetDepth(self)

Returns the depth (number of bits/pixel) of this DC.

Return type:int

See also

DisplayDepth

---

GetDeviceOrigin(self)

Returns the current device origin.

Return type: Point

See also

SetDeviceOrigin

---

GetFont(self)

Gets the current font.

Notice that even although each device context object has some default font after creation, this method would return a NullFont initially and only after calling SetFont a valid font is returned.

Return type: Font

---

GetFontMetrics(self)

Returns the various font characteristics.

This method allows to retrieve some of the font characteristics not returned by GetTextExtent , notably internal leading and average character width.

Currently this method returns correct results only under wxMSW, in the other ports the internal leading will always be 0 and the average character width will be computed as the width of the character ‘x’.

Return type: FontMetrics

New in version 2.9.2.

---

GetGdkDrawable(self)

---

GetHDC(self)

Return type:long

---

GetLayoutDirection(self)

Gets the current layout direction of the device context.

On platforms where RTL layout is supported, the return value will either be Layout_LeftToRight or Layout_RightToLeft . If RTL layout is not supported, the return value will be Layout_Default .

Return type: LayoutDirection

See also

SetLayoutDirection

---

GetLogicalFunction(self)

Gets the current logical function.

Return type: RasterOperationMode

See also

SetLogicalFunction

---

GetLogicalOrigin(self)

Return type:tuple Returns:( x, y )

---

GetLogicalScale(self)

Return type:tuple Returns:( x, y )

---

GetMapMode(self)

Gets the current mapping mode for the device context.

Return type: MappingMode

See also

SetMapMode

---

GetFullMultiLineTextExtent(self, *args, **kw)

Overloaded Implementations:

---

GetFullMultiLineTextExtent (self, string, font=None)

Gets the dimensions of the string using the currently selected font.

string is the text string to measure, heightLine, if non None, is where to store the height of a single line.

The text extent is set in the given w and h pointers.

If the optional parameter font is specified and valid, then it is used for the text extent calculation, otherwise the currently selected font is used.

Parameters:

• string (string) –
• font (Font) –

Return type:

tuple

Returns:

( w, h, heightLine )

Note

This function works with both single-line and multi-line strings.

See also

Font, SetFont , GetPartialTextExtents , GetTextExtent

---

GetFullMultiLineTextExtent (self, string)

Gets the dimensions of the string using the currently selected font.

string is the text string to measure, heightLine, if non None, is where to store the height of a single line.

Parameters:string (string) – Return type: Size Returns:The text extent as a Size object.

Note

This function works with both single-line and multi-line strings.

See also

Font, SetFont , GetPartialTextExtents , GetTextExtent

---

---

GetPPI(self)

Returns the resolution of the device in pixels per inch.

Return type: Size

---

GetPartialTextExtents(self, text)

Fills the widths array with the widths from the beginning of text to the corresponding character of text.

The generic version simply builds a running total of the widths of each character using GetTextExtent , however if the various platforms have a native API function that is faster or more accurate than the generic implementation then it should be used instead.

Parameters:text (string) – Return type:list of integers

See also

GetMultiLineTextExtent , GetTextExtent

---

GetPen(self)

Gets the current pen.

Return type: Pen

See also

SetPen

---

GetSize(self, *args, **kw)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

---

GetSizeMM(self, *args, **kw)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

---

GetTextBackground(self)

Gets the current text background colour.

Return type: Colour

See also

SetTextBackground

---

GetFullTextExtent(self, *args, **kw)

Overloaded Implementations:

---

GetFullTextExtent (self, string, font=None)

Gets the dimensions of the string using the currently selected font.

string is the text string to measure, descent is the dimension from the baseline of the font to the bottom of the descender, and externalLeading is any extra vertical space added to the font by the font designer (usually is zero).

The text extent is returned in w and h pointers or as a Size object depending on which version of this function is used.

If the optional parameter font is specified and valid, then it is used for the text extent calculation. Otherwise the currently selected font is.

Parameters:

• string (string) –
• font (Font) –

Return type:

tuple

Returns:

( w, h, descent, externalLeading )

Note

This function only works with single-line strings.

See also

Font, SetFont , GetPartialTextExtents , GetMultiLineTextExtent

---

GetFullTextExtent (self, string)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:string (string) – Return type: Size

---

---

GetTextForeground(self)

Gets the current text foreground colour.

Return type: Colour

See also

SetTextForeground

---

GetUserScale(self)

Gets the current user scale factor.

Return type:tuple Returns:( x, y )

See also

SetUserScale

---

GradientFillConcentric(self, *args, **kw)

Overloaded Implementations:

---

GradientFillConcentric (self, rect, initialColour, destColour)

Fill the area specified by rect with a radial gradient, starting from initialColour at the centre of the circle and fading to destColour on the circle outside.

The circle is placed at the centre of rect.

Parameters:

• rect (Rect) –
• initialColour (Colour) –
• destColour (Colour) –

Note

Currently this function is very slow, don’t use it for real-time drawing.

---

GradientFillConcentric (self, rect, initialColour, destColour, circleCenter)

Fill the area specified by rect with a radial gradient, starting from initialColour at the centre of the circle and fading to destColour on the circle outside.

circleCenter are the relative coordinates of centre of the circle in the specified rect.

Parameters:

• rect (Rect) –
• initialColour (Colour) –
• destColour (Colour) –
• circleCenter (Point) –

Note

Currently this function is very slow, don’t use it for real-time drawing.

---

---

GradientFillLinear(self, rect, initialColour, destColour, nDirection=RIGHT)

Fill the area specified by rect with a linear gradient, starting from initialColour and eventually fading to destColour.

The nDirection specifies the direction of the colour change, default is to use initialColour on the left part of the rectangle and destColour on the right one.

Parameters:

• rect (Rect) –
• initialColour (Colour) –
• destColour (Colour) –
• nDirection (Direction) –

---

IsOk(self)

Returns True if the DC is ok to use.

Return type:bool

---

LogicalToDeviceX(self, x)

Converts logical X coordinate to device coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.

Parameters:x (int) – Return type:int

---

LogicalToDeviceXRel(self, x)

Converts logical X coordinate to relative device coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.

Use this for converting a width, for example.

Parameters:x (int) – Return type:int

---

LogicalToDeviceY(self, y)

Converts logical Y coordinate to device coordinate, using the current mapping mode, user scale factor, device origin and axis orientation.

Parameters:y (int) – Return type:int

---

LogicalToDeviceYRel(self, y)

Converts logical Y coordinate to relative device coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation.

Use this for converting a height, for example.

Parameters:y (int) – Return type:int

---

MaxX(self)

Gets the maximum horizontal extent used in drawing commands so far.

Return type:int

---

MaxY(self)

Gets the maximum vertical extent used in drawing commands so far.

Return type:int

---

MinX(self)

Gets the minimum horizontal extent used in drawing commands so far.

Return type:int

---

MinY(self)

Gets the minimum vertical extent used in drawing commands so far.

Return type:int

---

ResetBoundingBox(self)

Resets the bounding box: after a call to this function, the bounding box doesn’t contain anything.

See also

CalcBoundingBox

---

ResetTransformMatrix(self)

Revert the transformation matrix to identity matrix.

New in version 2.9.2.

---

SetAxisOrientation(self, xLeftRight, yBottomUp)

Sets the x and y axis orientation (i.e., the direction from lowest to highest values on the axis).

The default orientation is x axis from left to right and y axis from top down.

Parameters:

• xLeftRight (bool) – True to set the x axis orientation to the natural left to right orientation, False to invert it.
• yBottomUp (bool) – True to set the y axis orientation to the natural bottom up orientation, False to invert it.

---

SetBackground(self, brush)

Sets the current background brush for the DC.

Parameters:brush (Brush) –

---

SetBackgroundMode(self, mode)

mode may be one of SOLID and TRANSPARENT .

This setting determines whether text will be drawn with a background colour or not.

Parameters:mode (int) –

---

SetBrush(self, brush)

Sets the current brush for the DC.

If the argument is NullBrush (or another invalid brush; see Brush.IsOk ), the current brush is selected out of the device context (leaving DC without any valid brush), allowing the current brush to be destroyed safely.

Parameters:brush (Brush) –

See also

Brush, MemoryDC (for the interpretation of colours when drawing into a monochrome bitmap)

---

SetClippingRegion(self, *args, **kw)

Overloaded Implementations:

---

SetClippingRegion (self, x, y, width, height)

Sets the clipping region for this device context to the intersection of the given region described by the parameters of this method and the previously set clipping region.

The clipping region is an area to which drawing is restricted. Possible uses for the clipping region are for clipping text or for speeding up window redraws when only a known area of the screen is damaged.

Notice that you need to call DestroyClippingRegion if you want to set the clipping region exactly to the region specified.

Also note that if the clipping region is empty, any previously set clipping region is destroyed, i.e. it is equivalent to calling DestroyClippingRegion , and not to clipping out all drawing on the DC as might be expected.

Parameters:

• x (int) –
• y (int) –
• width (int) –
• height (int) –

See also

DestroyClippingRegion , Region

---

SetClippingRegion (self, pt, sz)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

• pt (Point) –
• sz (Size) –

---

SetClippingRegion (self, rect)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:rect (Rect) –

---

---

SetDeviceClippingRegion(self, region)

Sets the clipping region for this device context.

Unlike SetClippingRegion , this function works with physical coordinates and not with the logical ones.

Parameters:region (Region) –

---

SetDeviceOrigin(self, x, y)

Sets the device origin (i.e., the origin in pixels after scaling has been applied).

This function may be useful in Windows printing operations for placing a graphic on a page.

Parameters:

• x (int) –
• y (int) –

---

SetFont(self, font)

Sets the current font for the DC.

If the argument is NullFont (or another invalid font; see Font.IsOk ), the current font is selected out of the device context (leaving DC without any valid font), allowing the current font to be destroyed safely.

Parameters:font (Font) –

See also

Font

---

SetLayoutDirection(self, dir)

Sets the current layout direction for the device context.

Parameters:dir (LayoutDirection) – May be either Layout_Default , Layout_LeftToRight or Layout_RightToLeft .

See also

GetLayoutDirection

---

SetLogicalFunction(self, function)

Sets the current logical function for the device context.

It determines how a source pixel (from a pen or brush colour, or source device context if using Blit ) combines with a destination pixel in the current device context. Text drawing is not affected by this function.

See RasterOperationMode enumeration values for more info.

The default is COPY , which simply draws with the current colour. The others combine the current colour and the background using a logical operation. INVERT is commonly used for drawing rubber bands or moving outlines, since drawing twice reverts to the original colour.

Parameters:function (RasterOperationMode) –

---

SetLogicalOrigin(self, x, y)

Parameters:

• x (int) –
• y (int) –

---

SetLogicalScale(self, x, y)

Parameters:

• x (float) –
• y (float) –

---

SetMapMode(self, mode)

The mapping mode of the device context defines the unit of measurement used to convert logical units to device units.

Note that in X, text drawing isn’t handled consistently with the mapping mode; a font is always specified in point size. However, setting the user scale (see SetUserScale ) scales the text appropriately. In Windows, scalable TrueType fonts are always used; in X, results depend on availability of fonts, but usually a reasonable match is found.

The coordinate origin is always at the top left of the screen/printer.

Drawing to a Windows printer device context uses the current mapping mode, but mapping mode is currently ignored for PostScript output.

Parameters:mode (MappingMode) –

---

SetPalette(self, palette)

If this is a window DC or memory DC, assigns the given palette to the window or bitmap associated with the DC.

If the argument is NullPalette , the current palette is selected out of the device context, and the original palette restored.

Parameters:palette (Palette) –

See also

Palette

---

SetPen(self, pen)

Sets the current pen for the DC.

If the argument is NullPen (or another invalid pen; see Pen.IsOk ), the current pen is selected out of the device context (leaving DC without any valid pen), allowing the current pen to be destroyed safely.

Parameters:pen (Pen) –

See also

MemoryDC for the interpretation of colours when drawing into a monochrome bitmap.

---

SetTextBackground(self, colour)

Sets the current text background colour for the DC.

Parameters:colour (Colour) –

---

SetTextForeground(self, colour)

Sets the current text foreground colour for the DC.

Parameters:colour (Colour) –

See also

MemoryDC for the interpretation of colours when drawing into a monochrome bitmap.

---

SetUserScale(self, xScale, yScale)

Sets the user scaling factor, useful for applications which require ‘zooming’.

Parameters:

• xScale (float) –
• yScale (float) –

---

StartDoc(self, message)

Starts a document (only relevant when outputting to a printer).

message is a message to show while printing.

Parameters:message (string) – Return type:bool

---

StartPage(self)

Starts a document page (only relevant when outputting to a printer).

---

StretchBlit(self, xdest, ydest, dstWidth, dstHeight, source, xsrc, ysrc, srcWidth, srcHeight, logicalFunc=COPY, useMask=False, xsrcMask=DefaultCoord, ysrcMask=DefaultCoord)

Copy from a source DC to this DC possibly changing the scale.

Unlike Blit , this method allows to specify different source and destination region sizes, meaning that it can stretch or shrink it while copying. The same can be achieved by changing the scale of the source or target DC but calling this method is simpler and can also be more efficient if the platform provides a native implementation of it.

The meaning of its other parameters is the same as with Blit , in particular all source coordinates are interpreted using the source DC coordinate system, i.e. are affected by its scale, origin translation and axis direction.

Parameters:

• xdest (int) – Destination device context x position.
• ydest (int) – Destination device context y position.
• dstWidth (int) – Width of destination area.
• dstHeight (int) – Height of destination area.
• source (DC) – Source device context.
• xsrc (int) – Source device context x position.
• ysrc (int) – Source device context y position.
• srcWidth (int) – Width of source area to be copied.
• srcHeight (int) – Height of source area to be copied.
• logicalFunc (RasterOperationMode) – Logical function to use, see SetLogicalFunction .
• useMask (bool) – If True, Blit does a transparent blit using the mask that is associated with the bitmap selected into the source device context. The Windows implementation does the following if MaskBlt cannot be used:
  • Creates a temporary bitmap and copies the destination area into it.
  • Copies the source area into the temporary bitmap using the specified logical function.
  • Sets the masked area in the temporary bitmap to BLACK by ANDing the mask bitmap with the temp bitmap with the foreground colour set to WHITE and the bg colour set to BLACK.
  • Sets the unmasked area in the destination area to BLACK by ANDing the mask bitmap with the destination area with the foreground colour set to BLACK and the background colour set to WHITE.
  • ORs the temporary bitmap with the destination area.
  • Deletes the temporary bitmap.

  This sequence of operations ensures that the source’s transparent area need not be black, and logical functions are supported.

  Note: on Windows, blitting with masks can be speeded up considerably by compiling wxWidgets with the USE_DC_CACHEING option enabled. You can also influence whether MaskBlt or the explicit mask blitting code above is used, by using SystemOptions and setting the no-maskblt option to 1.

• xsrcMask (int) – Source x position on the mask. If both xsrcMask and ysrcMask are DefaultCoord, xsrc and ysrc will be assumed for the mask source position. Currently only implemented on Windows.
• ysrcMask (int) – Source y position on the mask. If both xsrcMask and ysrcMask are DefaultCoord, xsrc and ysrc will be assumed for the mask source position. Currently only implemented on Windows.

Return type:

bool

Blit in PostScriptDC, under X.

See MemoryDC for typical usage.

New in version 2.9.0.

See also

Blit , MemoryDC, Bitmap, Mask

---

__nonzero__(self)

Return type:int

Properties

---

Background

See GetBackground and SetBackground

---

BackgroundMode

See GetBackgroundMode and SetBackgroundMode

---

BoundingBox

See GetBoundingBox

---

Brush

See GetBrush and SetBrush

---

CGContext

See GetCGContext

---

CharHeight

See GetCharHeight

---

CharWidth

See GetCharWidth

---

ClippingRect

See GetClippingRect

---

Depth

See GetDepth

---

DeviceOrigin

See GetDeviceOrigin and SetDeviceOrigin

---

Font

See GetFont and SetFont

---

FontMetrics

See GetFontMetrics

---

GdkDrawable

See GetGdkDrawable

---

HDC

See GetHDC

---

LayoutDirection

See GetLayoutDirection and SetLayoutDirection

---

LogicalFunction

See GetLogicalFunction and SetLogicalFunction

---

MapMode

See GetMapMode and SetMapMode

---

PPI

See GetPPI

---

Pen

See GetPen and SetPen

---

Pixel

See GetPixel

---

Size

See GetSize

---

SizeMM

See GetSizeMM

---

TextBackground

See GetTextBackground and SetTextBackground

---

TextForeground

See GetTextForeground and SetTextForeground