View Source wxGraphicsContext (wx v2.4.2)

Functions for wxGraphicsContext class

A wxGraphicsContext instance is the object that is drawn upon. It is created by a renderer using wxGraphicsRenderer:createContext/2. This can be either directly using a renderer instance, or indirectly using the static convenience create/1 functions of wxGraphicsContext that always delegate the task to the default renderer.

Remark: For some renderers (like Direct2D or Cairo) processing of drawing operations may be deferred (Direct2D render target normally builds up a batch of rendering commands but defers processing of these commands, Cairo operates on a separate surface) so to make drawing results visible you need to update the content of the context by calling wxGraphicsContext::Flush() (not implemented in wx) or by destroying the context.

See: wxGraphicsRenderer:createContext/2, wxGCDC, wxDC

This class is derived (and can use functions) from: wxGraphicsObject

wxWidgets docs: wxGraphicsContext

Summary

Functions

Sets the clipping region to the intersection of the given region and the previously set clipping region.

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

Concatenates the passed in transform with the current transform of this context.

Create a lightweight context that can be used only for measuring text.

Creates a native brush from a wxBrush.

Creates a native graphics font from a wxFont and a text colour.

Creates a font object with the specified attributes.

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

Creates a native brush with a linear gradient. The brush starts at (@a x1, @a y1) and ends at (@a x2, @a y2). Either just the start and end gradient colours (@a c1 and @a c2) or full set of gradient @a stops can be specified. The version taking wxGraphicsGradientStops is new in wxWidgets 2.9.1.

Creates a native affine transformation matrix from the passed in values.

Creates a native graphics path which is initially empty.

Creates a native pen from a wxPen.

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

Creates a native brush with a radial gradient. The brush originates at (@a startX, @a startY) and ends on a circle around (@a endX, @a endY) with the given @a radius. The gradient may be specified either by its start and end colours @a oColor and @a cColor or by a full set of gradient @a stops. The version taking wxGraphicsGradientStops is new in wxWidgets 2.9.1.

Draws an ellipse.

Draws a polygon.

Draws the path by first filling and then stroking.

Draws a rectangle.

Draws text at the defined position.

Draws text at the defined position.

Draws text at the defined position.

Fills the path with the current brush.

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

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

Gets the current transformation matrix of this context.

Resets the clipping to original shape.

Rotates the current transformation matrix (in radians).

Scales the current transformation matrix.

Sets the brush for filling paths.

Sets the font for drawing text.

Sets the font for drawing text.

Sets the pen used for stroking.

Sets the current transformation matrix of this context.

Strokes a single line.

Stroke lines connecting all the points.

Strokes along a path with the current pen.

Translates the current transformation matrix.

Types

-type wxGraphicsContext() :: wx:wx_object().

Functions

-spec clip(This, Region) -> ok when This :: wxGraphicsContext(), Region :: wxRegion:wxRegion().

Sets the clipping region to the intersection of the given region and the previously set clipping region.

The clipping region is an area to which drawing is restricted.

Remark:

-spec clip(This, X, Y, W, H) -> ok
              when
                  This :: wxGraphicsContext(),
                  X :: number(),
                  Y :: number(),
                  W :: number(),
                  H :: number().

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

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concatTransform(This, Matrix)

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-spec concatTransform(This, Matrix) -> ok
                         when This :: wxGraphicsContext(), Matrix :: wxGraphicsMatrix:wxGraphicsMatrix().

Concatenates the passed in transform with the current transform of this context.

-spec create() -> wxGraphicsContext().

Create a lightweight context that can be used only for measuring text.

-spec create(WindowDC) -> wxGraphicsContext()
                when
                    WindowDC ::
                        wxWindowDC:wxWindowDC() |
                        wxWindow:wxWindow() |
                        wxMemoryDC:wxMemoryDC() |
                        wxImage:wxImage().

Creates a wxGraphicsContext from a wxWindowDC.

See: wxGraphicsRenderer:createContext/2

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createBrush(This, Brush)

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-spec createBrush(This, Brush) -> wxGraphicsBrush:wxGraphicsBrush()
                     when This :: wxGraphicsContext(), Brush :: wxBrush:wxBrush().

Creates a native brush from a wxBrush.

-spec createFont(This, Font) -> wxGraphicsFont:wxGraphicsFont()
                    when This :: wxGraphicsContext(), Font :: wxFont:wxFont().
-spec createFont(This, SizeInPixels, Facename) -> wxGraphicsFont:wxGraphicsFont()
                    when
                        This :: wxGraphicsContext(),
                        SizeInPixels :: number(),
                        Facename :: unicode:chardata();
                (This, Font, [Option]) -> wxGraphicsFont:wxGraphicsFont()
                    when
                        This :: wxGraphicsContext(),
                        Font :: wxFont:wxFont(),
                        Option :: {col, wx:wx_colour()}.

Creates a native graphics font from a wxFont and a text colour.

Remark: For Direct2D graphics fonts can be created from TrueType fonts only.

-spec createFont(This, SizeInPixels, Facename, [Option]) -> wxGraphicsFont:wxGraphicsFont()
                    when
                        This :: wxGraphicsContext(),
                        SizeInPixels :: number(),
                        Facename :: unicode:chardata(),
                        Option :: {flags, integer()} | {col, wx:wx_colour()}.

Creates a font object with the specified attributes.

The use of overload taking wxFont is preferred, see wxGraphicsRenderer:createFont/4 for more details.

Remark: For Direct2D graphics fonts can be created from TrueType fonts only.

Since: 2.9.3

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createLinearGradientBrush(This, X1, Y1, X2, Y2, Stops)

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-spec createLinearGradientBrush(This, X1, Y1, X2, Y2, Stops) -> wxGraphicsBrush:wxGraphicsBrush()
                                   when
                                       This :: wxGraphicsContext(),
                                       X1 :: number(),
                                       Y1 :: number(),
                                       X2 :: number(),
                                       Y2 :: number(),
                                       Stops :: wxGraphicsGradientStops:wxGraphicsGradientStops().

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

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createLinearGradientBrush(This, X1, Y1, X2, Y2, C1, C2)

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-spec createLinearGradientBrush(This, X1, Y1, X2, Y2, C1, C2) -> wxGraphicsBrush:wxGraphicsBrush()
                                   when
                                       This :: wxGraphicsContext(),
                                       X1 :: number(),
                                       Y1 :: number(),
                                       X2 :: number(),
                                       Y2 :: number(),
                                       C1 :: wx:wx_colour(),
                                       C2 :: wx:wx_colour().

Creates a native brush with a linear gradient. The brush starts at (@a x1, @a y1) and ends at (@a x2, @a y2). Either just the start and end gradient colours (@a c1 and @a c2) or full set of gradient @a stops can be specified. The version taking wxGraphicsGradientStops is new in wxWidgets 2.9.1.

The matrix parameter was added in wxWidgets 3.1.3

-spec createMatrix(This) -> wxGraphicsMatrix:wxGraphicsMatrix() when This :: wxGraphicsContext().
-spec createMatrix(This, [Option]) -> wxGraphicsMatrix:wxGraphicsMatrix()
                      when
                          This :: wxGraphicsContext(),
                          Option ::
                              {a, number()} |
                              {b, number()} |
                              {c, number()} |
                              {d, number()} |
                              {tx, number()} |
                              {ty, number()}.

Creates a native affine transformation matrix from the passed in values.

The default parameters result in an identity matrix.

-spec createPath(This) -> wxGraphicsPath:wxGraphicsPath() when This :: wxGraphicsContext().

Creates a native graphics path which is initially empty.

-spec createPen(This, Pen) -> wxGraphicsPen:wxGraphicsPen()
                   when This :: wxGraphicsContext(), Pen :: wxPen:wxPen().

Creates a native pen from a wxPen.

Prefer to use the overload taking wxGraphicsPenInfo (not implemented in wx) unless you already have a wxPen as constructing one only to pass it to this method is wasteful.

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createRadialGradientBrush(This, StartX, StartY, EndX, EndY, Radius, Stops)

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-spec createRadialGradientBrush(This, StartX, StartY, EndX, EndY, Radius, Stops) ->
                                   wxGraphicsBrush:wxGraphicsBrush()
                                   when
                                       This :: wxGraphicsContext(),
                                       StartX :: number(),
                                       StartY :: number(),
                                       EndX :: number(),
                                       EndY :: number(),
                                       Radius :: number(),
                                       Stops :: wxGraphicsGradientStops:wxGraphicsGradientStops().

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

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createRadialGradientBrush(This, StartX, StartY, EndX, EndY, Radius, OColor, CColor)

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-spec createRadialGradientBrush(This, StartX, StartY, EndX, EndY, Radius, OColor, CColor) ->
                                   wxGraphicsBrush:wxGraphicsBrush()
                                   when
                                       This :: wxGraphicsContext(),
                                       StartX :: number(),
                                       StartY :: number(),
                                       EndX :: number(),
                                       EndY :: number(),
                                       Radius :: number(),
                                       OColor :: wx:wx_colour(),
                                       CColor :: wx:wx_colour().

Creates a native brush with a radial gradient. The brush originates at (@a startX, @a startY) and ends on a circle around (@a endX, @a endY) with the given @a radius. The gradient may be specified either by its start and end colours @a oColor and @a cColor or by a full set of gradient @a stops. The version taking wxGraphicsGradientStops is new in wxWidgets 2.9.1.

The ability to apply a transformation matrix to the gradient was added in 3.1.3

-spec destroy(This :: wxGraphicsContext()) -> ok.

Creates a wxGraphicsContext from a wxWindow.

See: wxGraphicsRenderer:createContext/2

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drawBitmap(This, Bmp, X, Y, W, H)

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-spec drawBitmap(This, Bmp, X, Y, W, H) -> ok
                    when
                        This :: wxGraphicsContext(),
                        Bmp :: wxBitmap:wxBitmap(),
                        X :: number(),
                        Y :: number(),
                        W :: number(),
                        H :: number().

Draws the bitmap.

In case of a mono bitmap, this is treated as a mask and the current brushed is used for filling.

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drawEllipse(This, X, Y, W, H)

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-spec drawEllipse(This, X, Y, W, H) -> ok
                     when
                         This :: wxGraphicsContext(),
                         X :: number(),
                         Y :: number(),
                         W :: number(),
                         H :: number().

Draws an ellipse.

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drawIcon(This, Icon, X, Y, W, H)

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-spec drawIcon(This, Icon, X, Y, W, H) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Icon :: wxIcon:wxIcon(),
                      X :: number(),
                      Y :: number(),
                      W :: number(),
                      H :: number().

Draws the icon.

-spec drawLines(This, Points) -> ok
                   when This :: wxGraphicsContext(), Points :: [{X :: float(), Y :: float()}].
-spec drawLines(This, Points, [Option]) -> ok
                   when
                       This :: wxGraphicsContext(),
                       Points :: [{X :: float(), Y :: float()}],
                       Option :: {fillStyle, wx:wx_enum()}.

Draws a polygon.

-spec drawPath(This, Path) -> ok
                  when This :: wxGraphicsContext(), Path :: wxGraphicsPath:wxGraphicsPath().
-spec drawPath(This, Path, [Option]) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Path :: wxGraphicsPath:wxGraphicsPath(),
                      Option :: {fillStyle, wx:wx_enum()}.

Draws the path by first filling and then stroking.

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drawRectangle(This, X, Y, W, H)

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-spec drawRectangle(This, X, Y, W, H) -> ok
                       when
                           This :: wxGraphicsContext(),
                           X :: number(),
                           Y :: number(),
                           W :: number(),
                           H :: number().

Draws a rectangle.

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drawRoundedRectangle(This, X, Y, W, H, Radius)

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-spec drawRoundedRectangle(This, X, Y, W, H, Radius) -> ok
                              when
                                  This :: wxGraphicsContext(),
                                  X :: number(),
                                  Y :: number(),
                                  W :: number(),
                                  H :: number(),
                                  Radius :: number().

Draws a rounded rectangle.

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drawText(This, Str, X, Y)

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-spec drawText(This, Str, X, Y) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Str :: unicode:chardata(),
                      X :: number(),
                      Y :: number().

Draws text at the defined position.

-spec drawText(This, Str, X, Y, Angle) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Str :: unicode:chardata(),
                      X :: number(),
                      Y :: number(),
                      Angle :: number();
              (This, Str, X, Y, BackgroundBrush) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Str :: unicode:chardata(),
                      X :: number(),
                      Y :: number(),
                      BackgroundBrush :: wxGraphicsBrush:wxGraphicsBrush().

Draws text at the defined position.

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drawText(This, Str, X, Y, Angle, BackgroundBrush)

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-spec drawText(This, Str, X, Y, Angle, BackgroundBrush) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Str :: unicode:chardata(),
                      X :: number(),
                      Y :: number(),
                      Angle :: number(),
                      BackgroundBrush :: wxGraphicsBrush:wxGraphicsBrush().

Draws text at the defined position.

-spec fillPath(This, Path) -> ok
                  when This :: wxGraphicsContext(), Path :: wxGraphicsPath:wxGraphicsPath().
-spec fillPath(This, Path, [Option]) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Path :: wxGraphicsPath:wxGraphicsPath(),
                      Option :: {fillStyle, wx:wx_enum()}.

Fills the path with the current brush.

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getPartialTextExtents(This, Text)

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-spec getPartialTextExtents(This, Text) -> [number()]
                               when This :: wxGraphicsContext(), Text :: unicode:chardata().

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

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getTextExtent(This, Text)

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-spec getTextExtent(This, Text) -> Result
                       when
                           Result ::
                               {Width :: number(),
                                Height :: number(),
                                Descent :: number(),
                                ExternalLeading :: number()},
                           This :: wxGraphicsContext(),
                           Text :: unicode:chardata().

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

-spec getTransform(This) -> wxGraphicsMatrix:wxGraphicsMatrix() when This :: wxGraphicsContext().

Gets the current transformation matrix of this context.

-spec resetClip(This) -> ok when This :: wxGraphicsContext().

Resets the clipping to original shape.

-spec rotate(This, Angle) -> ok when This :: wxGraphicsContext(), Angle :: number().

Rotates the current transformation matrix (in radians).

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scale(This, XScale, YScale)

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-spec scale(This, XScale, YScale) -> ok
               when This :: wxGraphicsContext(), XScale :: number(), YScale :: number().

Scales the current transformation matrix.

-spec setBrush(This, Brush) -> ok
                  when
                      This :: wxGraphicsContext(),
                      Brush :: wxGraphicsBrush:wxGraphicsBrush() | wxBrush:wxBrush().

Sets the brush for filling paths.

-spec setFont(This, Font) -> ok
                 when This :: wxGraphicsContext(), Font :: wxGraphicsFont:wxGraphicsFont().

Sets the font for drawing text.

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setFont(This, Font, Colour)

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-spec setFont(This, Font, Colour) -> ok
                 when This :: wxGraphicsContext(), Font :: wxFont:wxFont(), Colour :: wx:wx_colour().

Sets the font for drawing text.

Remark: For Direct2D only TrueType fonts can be used.

-spec setPen(This, Pen) -> ok
                when This :: wxGraphicsContext(), Pen :: wxPen:wxPen() | wxGraphicsPen:wxGraphicsPen().

Sets the pen used for stroking.

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setTransform(This, Matrix)

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-spec setTransform(This, Matrix) -> ok
                      when This :: wxGraphicsContext(), Matrix :: wxGraphicsMatrix:wxGraphicsMatrix().

Sets the current transformation matrix of this context.

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strokeLine(This, X1, Y1, X2, Y2)

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-spec strokeLine(This, X1, Y1, X2, Y2) -> ok
                    when
                        This :: wxGraphicsContext(),
                        X1 :: number(),
                        Y1 :: number(),
                        X2 :: number(),
                        Y2 :: number().

Strokes a single line.

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strokeLines(This, Points)

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-spec strokeLines(This, Points) -> ok
                     when This :: wxGraphicsContext(), Points :: [{X :: float(), Y :: float()}].

Stroke lines connecting all the points.

Unlike the other overload of this function, this method draws a single polyline and not a number of disconnected lines.

-spec strokePath(This, Path) -> ok
                    when This :: wxGraphicsContext(), Path :: wxGraphicsPath:wxGraphicsPath().

Strokes along a path with the current pen.

-spec translate(This, Dx, Dy) -> ok when This :: wxGraphicsContext(), Dx :: number(), Dy :: number().

Translates the current transformation matrix.