--- name: "wxGraphicsContext" section: "3erl" platform: "linux" package: "erlang-manpages" version: "1:25.2.3+dfsg-1+deb12u4" release: "Debian 12 (Bookworm)" platforms: ["linux"] url: "https://new.carta.tech/wxGraphicsContext" --- # wxGraphicsContext(3erl) Functions for wxGraphicsContext class ## NAME wxGraphicsContext - Functions for wxGraphicsContext class ## DESCRIPTION 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 ## DATA TYPES ``` wxGraphicsContext() = wx:wx_object() ``` ## EXPORTS ``` destroy(This :: wxGraphicsContext()) -> ok ``` Creates a *wxGraphicsContext* from a *wxWindow*. See: *wxGraphicsRenderer:createContext/2* ``` create() -> wxGraphicsContext() ``` Create a lightweight context that can be used only for measuring text. ``` create(WindowDC) -> wxGraphicsContext() ``` Types: WindowDC = \ \ wxWindowDC:wxWindowDC() \|\ \ wxWindow:wxWindow() \|\ \ wxMemoryDC:wxMemoryDC() \|\ \ wxImage:wxImage()\ Creates a *wxGraphicsContext* from a *wxWindowDC*. See: *wxGraphicsRenderer:createContext/2* ``` createPen(This, Pen) -> wxGraphicsPen:wxGraphicsPen() ``` Types: 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. ``` createBrush(This, Brush) -> wxGraphicsBrush:wxGraphicsBrush() ``` Types: This = wxGraphicsContext()\ Brush = wxBrush:wxBrush()\ Creates a native brush from a *wxBrush*. ``` createRadialGradientBrush(This, StartX, StartY, EndX, EndY, Radius, Stops) -> wxGraphicsBrush:wxGraphicsBrush() ``` Types: This = wxGraphicsContext()\ StartX = StartY = EndX = EndY = 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. ``` createRadialGradientBrush(This, StartX, StartY, EndX, EndY, Radius, OColor, CColor) -> wxGraphicsBrush:wxGraphicsBrush() ``` Types: This = wxGraphicsContext()\ StartX = StartY = EndX = EndY = Radius = number()\ OColor = 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 ``` createLinearGradientBrush(This, X1, Y1, X2, Y2, Stops) -> wxGraphicsBrush:wxGraphicsBrush() ``` Types: This = wxGraphicsContext()\ X1 = Y1 = X2 = 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. ``` createLinearGradientBrush(This, X1, Y1, X2, Y2, C1, C2) -> wxGraphicsBrush:wxGraphicsBrush() ``` Types: This = wxGraphicsContext()\ X1 = Y1 = X2 = Y2 = number()\ C1 = 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 ``` createFont(This, Font) -> wxGraphicsFont:wxGraphicsFont() ``` Types: This = wxGraphicsContext()\ Font = wxFont:wxFont()\ ``` createFont(This, SizeInPixels, Facename) -> wxGraphicsFont:wxGraphicsFont() ``` ``` createFont(This, Font, Facename :: [Option]) -> wxGraphicsFont:wxGraphicsFont() ``` Types: 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. ``` createFont(This, SizeInPixels, Facename, Options :: [Option]) -> wxGraphicsFont:wxGraphicsFont() ``` Types: 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 ``` createMatrix(This) -> wxGraphicsMatrix:wxGraphicsMatrix() ``` Types: This = wxGraphicsContext()\ ``` createMatrix(This, Options :: [Option]) -> wxGraphicsMatrix:wxGraphicsMatrix() ``` Types: 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. ``` createPath(This) -> wxGraphicsPath:wxGraphicsPath() ``` Types: This = wxGraphicsContext()\ Creates a native graphics path which is initially empty. ``` clip(This, Region) -> ok ``` Types: 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: ``` clip(This, X, Y, W, H) -> ok ``` Types: This = wxGraphicsContext()\ X = Y = W = H = number()\ This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. ``` resetClip(This) -> ok ``` Types: This = wxGraphicsContext()\ Resets the clipping to original shape. ``` drawBitmap(This, Bmp, X, Y, W, H) -> ok ``` Types: This = wxGraphicsContext()\ Bmp = wxBitmap:wxBitmap()\ X = Y = W = 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. ``` drawEllipse(This, X, Y, W, H) -> ok ``` Types: This = wxGraphicsContext()\ X = Y = W = H = number()\ Draws an ellipse. ``` drawIcon(This, Icon, X, Y, W, H) -> ok ``` Types: This = wxGraphicsContext()\ Icon = wxIcon:wxIcon()\ X = Y = W = H = number()\ Draws the icon. ``` drawLines(This, Points) -> ok ``` Types: This = wxGraphicsContext()\ Points = \[{X :: float(), Y :: float()}\]\ ``` drawLines(This, Points, Options :: [Option]) -> ok ``` Types: This = wxGraphicsContext()\ Points = \[{X :: float(), Y :: float()}\]\ Option = {fillStyle, wx:wx\_enum()}\ Draws a polygon. ``` drawPath(This, Path) -> ok ``` Types: This = wxGraphicsContext()\ Path = wxGraphicsPath:wxGraphicsPath()\ ``` drawPath(This, Path, Options :: [Option]) -> ok ``` Types: This = wxGraphicsContext()\ Path = wxGraphicsPath:wxGraphicsPath()\ Option = {fillStyle, wx:wx\_enum()}\ Draws the path by first filling and then stroking. ``` drawRectangle(This, X, Y, W, H) -> ok ``` Types: This = wxGraphicsContext()\ X = Y = W = H = number()\ Draws a rectangle. ``` drawRoundedRectangle(This, X, Y, W, H, Radius) -> ok ``` Types: This = wxGraphicsContext()\ X = Y = W = H = Radius = number()\ Draws a rounded rectangle. ``` drawText(This, Str, X, Y) -> ok ``` Types: This = wxGraphicsContext()\ Str = unicode:chardata()\ X = Y = number()\ Draws text at the defined position. ``` drawText(This, Str, X, Y, Angle) -> ok ``` ``` drawText(This, Str, X, Y, BackgroundBrush) -> ok ``` Types: This = wxGraphicsContext()\ Str = unicode:chardata()\ X = Y = number()\ BackgroundBrush = wxGraphicsBrush:wxGraphicsBrush()\ Draws text at the defined position. ``` drawText(This, Str, X, Y, Angle, BackgroundBrush) -> ok ``` Types: This = wxGraphicsContext()\ Str = unicode:chardata()\ X = Y = Angle = number()\ BackgroundBrush = wxGraphicsBrush:wxGraphicsBrush()\ Draws text at the defined position. ``` fillPath(This, Path) -> ok ``` Types: This = wxGraphicsContext()\ Path = wxGraphicsPath:wxGraphicsPath()\ ``` fillPath(This, Path, Options :: [Option]) -> ok ``` Types: This = wxGraphicsContext()\ Path = wxGraphicsPath:wxGraphicsPath()\ Option = {fillStyle, wx:wx\_enum()}\ Fills the path with the current brush. ``` strokePath(This, Path) -> ok ``` Types: This = wxGraphicsContext()\ Path = wxGraphicsPath:wxGraphicsPath()\ Strokes along a path with the current pen. ``` getPartialTextExtents(This, Text) -> [number()] ``` Types: This = wxGraphicsContext()\ Text = unicode:chardata()\ Fills the *widths* array with the widths from the beginning of *text* to the corresponding character of *text*. ``` getTextExtent(This, Text) -> Result ``` Types: 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. ``` rotate(This, Angle) -> ok ``` Types: This = wxGraphicsContext()\ Angle = number()\ Rotates the current transformation matrix (in radians). ``` scale(This, XScale, YScale) -> ok ``` Types: This = wxGraphicsContext()\ XScale = YScale = number()\ Scales the current transformation matrix. ``` translate(This, Dx, Dy) -> ok ``` Types: This = wxGraphicsContext()\ Dx = Dy = number()\ Translates the current transformation matrix. ``` getTransform(This) -> wxGraphicsMatrix:wxGraphicsMatrix() ``` Types: This = wxGraphicsContext()\ Gets the current transformation matrix of this context. ``` setTransform(This, Matrix) -> ok ``` Types: This = wxGraphicsContext()\ Matrix = wxGraphicsMatrix:wxGraphicsMatrix()\ Sets the current transformation matrix of this context. ``` concatTransform(This, Matrix) -> ok ``` Types: This = wxGraphicsContext()\ Matrix = wxGraphicsMatrix:wxGraphicsMatrix()\ Concatenates the passed in transform with the current transform of this context. ``` setBrush(This, Brush) -> ok ``` Types: This = wxGraphicsContext()\ Brush = wxGraphicsBrush:wxGraphicsBrush() \| wxBrush:wxBrush()\ Sets the brush for filling paths. ``` setFont(This, Font) -> ok ``` Types: This = wxGraphicsContext()\ Font = wxGraphicsFont:wxGraphicsFont()\ Sets the font for drawing text. ``` setFont(This, Font, Colour) -> ok ``` Types: This = wxGraphicsContext()\ Font = wxFont:wxFont()\ Colour = wx:wx\_colour()\ Sets the font for drawing text. Remark: For Direct2D only TrueType fonts can be used. ``` setPen(This, Pen) -> ok ``` Types: This = wxGraphicsContext()\ Pen = wxPen:wxPen() \| wxGraphicsPen:wxGraphicsPen()\ Sets the pen used for stroking. ``` strokeLine(This, X1, Y1, X2, Y2) -> ok ``` Types: This = wxGraphicsContext()\ X1 = Y1 = X2 = Y2 = number()\ Strokes a single line. ``` strokeLines(This, Points) -> ok ``` Types: 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.