draw

package
v0.7.1 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Jun 30, 2020 License: BSD-3-Clause Imports: 10 Imported by: 0

Documentation

Index

Examples

Constants

View Source 
const (
	PosLeft   = -1
	PosBottom = -1
	PosCenter = 0
	PosTop    = +1
	PosRight  = +1
)

Position specifies the text position.

Variables

This section is empty.

Functions

func NewFormattedCanvas 

func NewFormattedCanvas(w, h vg.Length, format string) (vg.CanvasWriterTo, error)

NewFormattedCanvas creates a new vg.CanvasWriterTo with the specified image format.

Supported formats are: 

eps, jpg|jpeg, pdf, png, svg, tex and tif|tiff.

Types

type BoxGlyph 

type BoxGlyph struct{}

BoxGlyph is a glyph that draws a filled square.

func (BoxGlyph) DrawGlyph 

func (BoxGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type Canvas 

type Canvas struct {
	vg.Canvas
	vg.Rectangle
}

A Canvas is a vector graphics canvas along with an associated Rectangle defining a section of the canvas to which drawing should take place.

func Crop 

func Crop(c Canvas, left, right, bottom, top vg.Length) Canvas

Crop returns a new Canvas corresponding to the Canvas c with the given lengths added to the minimum and maximum x and y values of the Canvas's Rectangle. Note that cropping the right and top sides of the canvas requires specifying negative values of right and top.

Example (SplitHorizontal) 
c := draw.New(vgimg.New(vg.Points(10), vg.Points(16)))

// Split c along a vertical line centered on the canvas.
left, right := SplitHorizontal(c, c.Size().X/2)
fmt.Printf("left:  %#v\n", left.Rectangle)
fmt.Printf("right: %#v\n", right.Rectangle)

Output:

left:  vg.Rectangle{Min:vg.Point{X:0, Y:0}, Max:vg.Point{X:5, Y:16}}
right: vg.Rectangle{Min:vg.Point{X:5, Y:0}, Max:vg.Point{X:10, Y:16}}
Example (SplitVertical) 
c := draw.New(vgimg.New(vg.Points(10), vg.Points(16)))

// Split c along a horizontal line centered on the canvas.
bottom, top := SplitVertical(c, c.Size().Y/2)
fmt.Printf("top:    %#v\n", top.Rectangle)
fmt.Printf("bottom: %#v\n", bottom.Rectangle)

Output:

top:    vg.Rectangle{Min:vg.Point{X:0, Y:8}, Max:vg.Point{X:10, Y:16}}
bottom: vg.Rectangle{Min:vg.Point{X:0, Y:0}, Max:vg.Point{X:10, Y:8}}

func New 

func New(c vg.CanvasSizer) Canvas

New returns a new (bounded) draw.Canvas.

func NewCanvas 

func NewCanvas(c vg.Canvas, w, h vg.Length) Canvas

NewCanvas returns a new (bounded) draw.Canvas of the given size.

func (*Canvas) Center 

func (c *Canvas) Center() vg.Point

Center returns the center point of the area

func (*Canvas) ClipLinesX 

func (c *Canvas) ClipLinesX(lines ...[]vg.Point) (clipped [][]vg.Point)

ClipLinesX returns a slice of lines that represent the given line clipped in the X direction.

func (*Canvas) ClipLinesXY 

func (c *Canvas) ClipLinesXY(lines ...[]vg.Point) [][]vg.Point

ClipLinesXY returns a slice of lines that represent the given line clipped in both X and Y directions.

func (*Canvas) ClipLinesY 

func (c *Canvas) ClipLinesY(lines ...[]vg.Point) (clipped [][]vg.Point)

ClipLinesY returns a slice of lines that represent the given line clipped in the Y direction.

func (*Canvas) ClipPolygonX 

func (c *Canvas) ClipPolygonX(pts []vg.Point) []vg.Point

ClipPolygonX returns a slice of lines that represent the given polygon clipped in the X direction.

func (*Canvas) ClipPolygonXY 

func (c *Canvas) ClipPolygonXY(pts []vg.Point) []vg.Point

ClipPolygonXY returns a slice of lines that represent the given polygon clipped in both X and Y directions.

func (*Canvas) ClipPolygonY 

func (c *Canvas) ClipPolygonY(pts []vg.Point) []vg.Point

ClipPolygonY returns a slice of lines that represent the given polygon clipped in the Y direction.

func (*Canvas) Contains 

func (c *Canvas) Contains(p vg.Point) bool

Contains returns true if the Canvas contains the point.

func (*Canvas) ContainsX 

func (c *Canvas) ContainsX(x vg.Length) bool

ContainsX returns true if the Canvas contains the x coordinate.

func (*Canvas) ContainsY 

func (c *Canvas) ContainsY(y vg.Length) bool

ContainsY returns true if the Canvas contains the y coordinate.

func (*Canvas) DrawGlyph 

func (c *Canvas) DrawGlyph(sty GlyphStyle, pt vg.Point)

DrawGlyph draws the given glyph to the draw area. If the point is not within the Canvas or the sty.Shape is nil then nothing is drawn.

func (*Canvas) DrawGlyphNoClip 

func (c *Canvas) DrawGlyphNoClip(sty GlyphStyle, pt vg.Point)

DrawGlyphNoClip draws the given glyph to the draw area. If the sty.Shape is nil then nothing is drawn.

func (*Canvas) FillPolygon 

func (c *Canvas) FillPolygon(clr color.Color, pts []vg.Point)

FillPolygon fills a polygon with the given color.

func (*Canvas) FillText 

func (c *Canvas) FillText(sty TextStyle, pt vg.Point, txt string)

FillText fills lines of text in the draw area. pt specifies the location where the text is to be drawn.

func (*Canvas) SetLineStyle 

func (c *Canvas) SetLineStyle(sty LineStyle)

SetLineStyle sets the current line style

func (*Canvas) StrokeLine2 

func (c *Canvas) StrokeLine2(sty LineStyle, x0, y0, x1, y1 vg.Length)

StrokeLine2 draws a line between two points in the given Canvas.

func (*Canvas) StrokeLines 

func (c *Canvas) StrokeLines(sty LineStyle, lines ...[]vg.Point)

StrokeLines draws a line connecting a set of points in the given Canvas.

func (*Canvas) X 

func (c *Canvas) X(x float64) vg.Length

X returns the value of x, given in the unit range, in the drawing coordinates of this draw area. A value of 0, for example, will return the minimum x value of the draw area and a value of 1 will return the maximum.

func (*Canvas) Y 

func (c *Canvas) Y(y float64) vg.Length

Y returns the value of x, given in the unit range, in the drawing coordinates of this draw area. A value of 0, for example, will return the minimum y value of the draw area and a value of 1 will return the maximum.

type CircleGlyph 

type CircleGlyph struct{}

CircleGlyph is a glyph that draws a solid circle.

func (CircleGlyph) DrawGlyph 

func (CircleGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the GlyphDrawer interface.

type CrossGlyph 

type CrossGlyph struct{}

CrossGlyph is a glyph that draws a big X.

func (CrossGlyph) DrawGlyph 

func (CrossGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type GlyphDrawer 

type GlyphDrawer interface {
	// DrawGlyph draws the glyph at the given
	// point, with the given color and radius.
	DrawGlyph(*Canvas, GlyphStyle, vg.Point)
}

A GlyphDrawer wraps the DrawGlyph function.

type GlyphStyle 

type GlyphStyle struct {
	// Color is the color used to draw the glyph.
	color.Color

	// Radius specifies the size of the glyph's radius.
	Radius vg.Length

	// Shape draws the shape of the glyph.
	Shape GlyphDrawer
}

A GlyphStyle specifies the look of a glyph used to draw a point on a plot.

func (GlyphStyle) Rectangle 

func (g GlyphStyle) Rectangle() vg.Rectangle

Rectangle returns the rectangle surrounding this glyph, assuming that it is drawn centered at 0,0

type LineStyle 

type LineStyle struct {
	// Color is the color of the line.
	Color color.Color

	// Width is the width of the line.
	Width vg.Length

	Dashes   []vg.Length
	DashOffs vg.Length
}

LineStyle describes what a line will look like.

type PlainTextHandler 

type PlainTextHandler struct{}

PlainTextHandler is a text/plain handler.

func (PlainTextHandler) Box 

func (hdlr PlainTextHandler) Box(txt string, fnt vg.Font) (width, height, depth vg.Length)

Box returns the bounding box of the given text where:

  • width is the horizontal space from the origin.
  • height is the vertical space above the baseline.
  • depth is the vertical space below the baseline, a negative number.

func (PlainTextHandler) Draw 

func (hdlr PlainTextHandler) Draw(c *Canvas, txt string, sty TextStyle, pt vg.Point)

Draw renders the given text with the provided style and position on the canvas.

type PlusGlyph 

type PlusGlyph struct{}

PlusGlyph is a glyph that draws a plus sign

func (PlusGlyph) DrawGlyph 

func (PlusGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type PyramidGlyph 

type PyramidGlyph struct{}

PyramidGlyph is a glyph that draws a filled triangle.

func (PyramidGlyph) DrawGlyph 

func (PyramidGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type RingGlyph 

type RingGlyph struct{}

RingGlyph is a glyph that draws the outline of a circle.

func (RingGlyph) DrawGlyph 

func (RingGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type SquareGlyph 

type SquareGlyph struct{}

SquareGlyph is a glyph that draws the outline of a square.

func (SquareGlyph) DrawGlyph 

func (SquareGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type TextHandler 

type TextHandler interface {
	// Box returns the bounding box of the given text where:
	//  - width is the horizontal space from the origin.
	//  - height is the vertical space above the baseline.
	//  - depth is the vertical space below the baseline, a negative number.
	Box(txt string, fnt vg.Font) (width, height, depth vg.Length)

	// Draw renders the given text with the provided style and position
	// on the canvas.
	Draw(c *Canvas, txt string, sty TextStyle, pt vg.Point)
}

TextHandler parses, formats and renders text.

type TextStyle 

type TextStyle struct {
	// Color is the text color.
	Color color.Color

	// Font is the font description.
	Font vg.Font

	// Rotation is the text rotation in radians, performed around the axis
	// defined by XAlign and YAlign.
	Rotation float64

	// XAlign and YAlign specify the alignment of the text.
	XAlign XAlignment
	YAlign YAlignment

	// TextHandler parses and formats text according to a given
	// dialect (Markdown, LaTeX, plain, ...)
	// The default is a plain text handler.
	Handler TextHandler
}

TextStyle describes what text will look like.

func (TextStyle) Height 

func (sty TextStyle) Height(txt string) vg.Length

Height returns the height of the text when using the given font before any text rotation is applied.

func (TextStyle) Rectangle 

func (sty TextStyle) Rectangle(txt string) vg.Rectangle

Rectangle returns a rectangle giving the bounds of this text assuming that it is drawn at (0, 0).

func (TextStyle) Width 

func (sty TextStyle) Width(txt string) (max vg.Length)

Width returns the width of lines of text when using the given font before any text rotation is applied.

type Tiles 

type Tiles struct {
	// Cols and Rows specify the number of rows and columns of tiles.
	Cols, Rows int
	// PadTop, PadBottom, PadRight, and PadLeft specify the padding
	// on the corresponding side of each tile.
	PadTop, PadBottom, PadRight, PadLeft vg.Length
	// PadX and PadY specify the padding between columns and rows
	// of tiles respectively..
	PadX, PadY vg.Length
}

Tiles creates regular subcanvases from a Canvas.

func (Tiles) At 

func (ts Tiles) At(c Canvas, x, y int) Canvas

At returns the subcanvas within c that corresponds to the tile at column x, row y.

type TriangleGlyph 

type TriangleGlyph struct{}

TriangleGlyph is a glyph that draws the outline of a triangle.

func (TriangleGlyph) DrawGlyph 

func (TriangleGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt vg.Point)

DrawGlyph implements the Glyph interface.

type XAlignment 

type XAlignment float64

XAlignment specifies text alignment in the X direction. Three preset options are available, but an arbitrary alignment can also be specified using XAlignment(desired number). 

const (
	// XLeft aligns the left edge of the text with the specified location.
	XLeft XAlignment = 0
	// XCenter aligns the horizontal center of the text with the specified location.
	XCenter XAlignment = -0.5
	// XRight aligns the right edge of the text with the specified location.
	XRight XAlignment = -1
)

type YAlignment 

type YAlignment float64

YAlignment specifies text alignment in the Y direction. Three preset options are available, but an arbitrary alignment can also be specified using YAlignment(desired number). 

const (
	// YTop aligns the top of of the text with the specified location.
	YTop YAlignment = -1
	// YCenter aligns the vertical center of the text with the specified location.
	YCenter YAlignment = -0.5
	// YBottom aligns the bottom of the text with the specified location.
	YBottom YAlignment = 0
)

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.