Documentation
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Index ¶
- type Context
- func (dc *Context) AsMask() *image.Alpha
- func (dc *Context) Clear()
- func (dc *Context) ClearPath()
- func (dc *Context) Clip()
- func (dc *Context) ClipPreserve()
- func (dc *Context) ClosePath()
- func (dc *Context) CubicTo(x1, y1, x2, y2, x3, y3 float64)
- func (dc *Context) DrawArc(x, y, r, angle1, angle2 float64)
- func (dc *Context) DrawCircle(x, y, r float64)
- func (dc *Context) DrawEllipse(x, y, rx, ry float64)
- func (dc *Context) DrawEllipticalArc(x, y, rx, ry, angle1, angle2 float64)
- func (dc *Context) DrawImage(im image.Image, x, y int)
- func (dc *Context) DrawImageAnchored(im image.Image, x, y int, ax, ay float64)
- func (dc *Context) DrawLine(x1, y1, x2, y2 float64)
- func (dc *Context) DrawPoint(x, y, r float64)
- func (dc *Context) DrawRectangle(x, y, w, h float64)
- func (dc *Context) DrawRoundedRectangle(x, y, w, h, r float64)
- func (dc *Context) DrawString(s string, x, y float64)
- func (dc *Context) DrawStringAnchored(s string, x, y, ax, ay float64)
- func (dc *Context) Fill()
- func (dc *Context) FillPreserve()
- func (dc *Context) Height() int
- func (dc *Context) Identity()
- func (dc *Context) Image() image.Image
- func (dc *Context) InvertMask()
- func (dc *Context) LineTo(x, y float64)
- func (dc *Context) LineWidth() float64
- func (dc *Context) Matrix() transform.Matrix
- func (dc *Context) MeasureString(s string) (w, h float64)
- func (dc *Context) MoveTo(x, y float64)
- func (dc *Context) NewSubPath()
- func (dc *Context) Pop()
- func (dc *Context) Push()
- func (dc *Context) QuadraticTo(x1, y1, x2, y2 float64)
- func (dc *Context) ResetClip()
- func (dc *Context) Rotate(angle float64)
- func (dc *Context) RotateAbout(angle, x, y float64)
- func (dc *Context) Scale(x, y float64)
- func (dc *Context) ScaleAbout(sx, sy, x, y float64)
- func (dc *Context) SetColor(c color.Color)
- func (dc *Context) SetDash(dashes ...float64)
- func (dc *Context) SetDashOffset(offset float64)
- func (dc *Context) SetFillRGBA(r, g, b, a float64)
- func (dc *Context) SetFillRule(fillRule context.FillRule)
- func (dc *Context) SetFillStyle(pattern context.Pattern)
- func (dc *Context) SetHexColor(x string)
- func (dc *Context) SetLineCap(lineCap context.LineCap)
- func (dc *Context) SetLineJoin(lineJoin context.LineJoin)
- func (dc *Context) SetLineWidth(lineWidth float64)
- func (dc *Context) SetMask(mask *image.Alpha) error
- func (dc *Context) SetMatrix(m transform.Matrix)
- func (dc *Context) SetPixel(x, y int)
- func (dc *Context) SetRGB(r, g, b float64)
- func (dc *Context) SetRGB255(r, g, b int)
- func (dc *Context) SetRGBA(r, g, b, a float64)
- func (dc *Context) SetRGBA255(r, g, b, a int)
- func (dc *Context) SetStrokeRGBA(r, g, b, a float64)
- func (dc *Context) SetStrokeStyle(pattern context.Pattern)
- func (dc *Context) Shear(x, y float64)
- func (dc *Context) ShearAbout(sx, sy, x, y float64)
- func (dc *Context) Stroke()
- func (dc *Context) StrokePreserve()
- func (dc *Context) TextState() *context.TextState
- func (dc *Context) Transform(x, y float64) (tx, ty float64)
- func (dc *Context) Translate(x, y float64)
- func (dc *Context) Width() int
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Context ¶
type Context struct {
// contains filtered or unexported fields
}
Context represents an image rendering context.
func NewContext ¶
NewContext creates a new image.RGBA with the specified width and height and prepares a context for rendering onto that image.
func NewContextForImage ¶
NewContextForImage copies the specified image into a new image.RGBA and prepares a context for rendering onto that image.
func NewContextForRGBA ¶
NewContextForRGBA prepares a context for rendering onto the specified image. No copy is made.
func (*Context) AsMask ¶
AsMask returns an *image.Alpha representing the alpha channel of this context. This can be useful for advanced clipping operations where you first render the mask geometry and then use it as a mask.
func (*Context) Clear ¶
func (dc *Context) Clear()
Clear fills the entire image with the current color.
func (*Context) ClearPath ¶
func (dc *Context) ClearPath()
ClearPath clears the current path. There is no current point after this operation.
func (*Context) Clip ¶
func (dc *Context) Clip()
Clip updates the clipping region by intersecting the current clipping region with the current path as it would be filled by dc.Fill(). The path is cleared after this operation.
func (*Context) ClipPreserve ¶
func (dc *Context) ClipPreserve()
ClipPreserve updates the clipping region by intersecting the current clipping region with the current path as it would be filled by dc.Fill(). The path is preserved after this operation.
func (*Context) ClosePath ¶
func (dc *Context) ClosePath()
ClosePath adds a line segment from the current point to the beginning of the current subpath. If there is no current point, this is a no-op.
func (*Context) CubicTo ¶
CubicTo adds a cubic bezier curve to the current path starting at the current point. If there is no current point, it first performs MoveTo(x1, y1). Because freetype/raster does not support cubic beziers, this is emulated with many small line segments.
func (*Context) DrawCircle ¶
DrawCircle draws a circle of radius r at position x,y.
func (*Context) DrawEllipse ¶
DrawEllipse draws an ellipse of size rx,ry at position x,y.
func (*Context) DrawEllipticalArc ¶
DrawEllipticalArc draws an elliptical arc described by r, angle1, angle2 at position x,y.
func (*Context) DrawImageAnchored ¶
DrawImageAnchored draws the specified image at the specified anchor point. The anchor point is x - w * ax, y - h * ay, where w, h is the size of the image. Use ax=0.5, ay=0.5 to center the image at the specified point.
func (*Context) DrawPoint ¶
DrawPoint is like DrawCircle but ensures that a circle of the specified size is drawn regardless of the current transformation matrix. The position is still transformed, but not the shape of the point.
func (*Context) DrawRectangle ¶
DrawRectangle draws a rectangle of size w,h at position x,y.
func (*Context) DrawRoundedRectangle ¶
DrawRoundedRectangle draws a rounded rectangle of size w,h at position x,y.
func (*Context) DrawString ¶
DrawString draws the specified text at the specified point.
func (*Context) DrawStringAnchored ¶
DrawStringAnchored draws the specified text at the specified anchor point. The anchor point is x - w * ax, y - h * ay, where w, h is the size of the text. Use ax=0.5, ay=0.5 to center the text at the specified point.
func (*Context) Fill ¶
func (dc *Context) Fill()
Fill fills the current path with the current color. Open subpaths are implicity closed. The path is cleared after this operation.
func (*Context) FillPreserve ¶
func (dc *Context) FillPreserve()
FillPreserve fills the current path with the current color. Open subpaths are implicity closed. The path is preserved after this operation.
func (*Context) Identity ¶
func (dc *Context) Identity()
Identity resets the current transformation matrix to the identity matrix. This results in no translating, scaling, rotating, or shearing.
func (*Context) InvertMask ¶
func (dc *Context) InvertMask()
InvertMask inverts the alpha values in the current clipping mask such that a fully transparent region becomes fully opaque and vice versa.
func (*Context) LineTo ¶
LineTo adds a line segment to the current path starting at the current point. If there is no current point, it is equivalent to MoveTo(x, y)
func (*Context) MeasureString ¶
MeasureString returns the rendered width and height of the specified text given the current font face.
func (*Context) MoveTo ¶
MoveTo starts a new subpath within the current path starting at the specified point.
func (*Context) NewSubPath ¶
func (dc *Context) NewSubPath()
NewSubPath starts a new subpath within the current path. There is no current point after this operation.
func (*Context) Pop ¶
func (dc *Context) Pop()
Pop restores the last saved context state from the stack.
func (*Context) Push ¶
func (dc *Context) Push()
Push saves the current state of the context for later retrieval. These can be nested.
func (*Context) QuadraticTo ¶
QuadraticTo adds a quadratic bezier curve to the current path starting at the current point. If there is no current point, it first performs MoveTo(x1, y1)
func (*Context) Rotate ¶
Rotate updates the current matrix with a anticlockwise rotation. Rotation occurs about the origin. Angle is specified in radians.
func (*Context) RotateAbout ¶
RotateAbout updates the current matrix with a anticlockwise rotation. Rotation occurs about the specified point. Angle is specified in radians.
func (*Context) Scale ¶
Scale updates the current matrix with a scaling factor. Scaling occurs about the origin.
func (*Context) ScaleAbout ¶
ScaleAbout updates the current matrix with a scaling factor. Scaling occurs about the specified point.
func (*Context) SetDash ¶
SetDash sets the current dash pattern to use. Call with zero arguments to disable dashes. The values specify the lengths of each dash, with alternating on and off lengths.
func (*Context) SetDashOffset ¶
SetDashOffset sets the initial offset into the dash pattern to use when stroking dashed paths.
func (*Context) SetFillRGBA ¶
SetFillRGBA sets the current color for fill operations. r, g, b, a values must be in range 0-1.
func (*Context) SetFillRule ¶
SetFillRule sets the fill rule.
func (*Context) SetFillStyle ¶
SetFillStyle sets current fill style
func (*Context) SetHexColor ¶
SetHexColor sets the current color using a hex string. The leading pound sign (#) is optional. Both 3- and 6-digit variations are supported. 8 digits may be provided to set the alpha value as well.
func (*Context) SetLineCap ¶
SetLineCap sets the line cap style.
func (*Context) SetLineJoin ¶
SetLineJoin sets the line join style.
func (*Context) SetLineWidth ¶
SetLineWidth sets the line width of the context.
func (*Context) SetMask ¶
SetMask allows you to directly set the *image.Alpha to be used as a clipping mask. It must be the same size as the context, else an error is returned and the mask is unchanged.
func (*Context) SetRGB ¶
SetRGB sets the current color. r, g, b values should be between 0 and 1, inclusive. Alpha will be set to 1 (fully opaque).
func (*Context) SetRGB255 ¶
SetRGB255 sets the current color. r, g, b values should be between 0 and 255, inclusive. Alpha will be set to 255 (fully opaque).
func (*Context) SetRGBA ¶
SetRGBA sets the current color. r, g, b, a values should be between 0 and 1, inclusive.
func (*Context) SetRGBA255 ¶
SetRGBA255 sets the current color. r, g, b, a values should be between 0 and 255, inclusive.
func (*Context) SetStrokeRGBA ¶
SetStrokeRGBA sets the current color for stroking operations. r, g, b, a values must be in range 0-1.
func (*Context) SetStrokeStyle ¶
SetStrokeStyle sets current stroke style
func (*Context) Shear ¶
Shear updates the current matrix with a shearing angle. Shearing occurs about the origin.
func (*Context) ShearAbout ¶
ShearAbout updates the current matrix with a shearing angle. Shearing occurs about the specified point.
func (*Context) Stroke ¶
func (dc *Context) Stroke()
Stroke strokes the current path with the current color, line width, line cap, line join and dash settings. The path is cleared after this operation.
func (*Context) StrokePreserve ¶
func (dc *Context) StrokePreserve()
StrokePreserve strokes the current path with the current color, line width, line cap, line join and dash settings. The path is preserved after this operation.
func (*Context) Transform ¶
Transform multiplies the specified point by the current matrix, returning a transformed position.
Source Files