Golang Path.Line方法代码示例

// crosshair draws a plus at the given point.
func crosshair(img draw.Image, x, y int, str string) {
	c := vgimg.NewImage(img)

	// drawPlots here because NewImage
	// clears the canvas.  Instead, the canvas
	// should just be stored instead of being
	// recreated at each redraw.
	drawPlots(img)

	c.SetColor(color.RGBA{R: 255, A: 255})

	xc := vg.Inches(float64(x) / c.DPI())
	yc := vg.Inches(float64(y) / c.DPI())
	radius := vg.Points(5)

	var p vg.Path
	p.Move(xc-radius, yc)
	p.Line(xc+radius, yc)
	c.Stroke(p)

	p = vg.Path{}
	p.Move(xc, yc+radius)
	p.Line(xc, yc-radius)
	c.Stroke(p)

	c.SetColor(color.Black)
	c.FillString(font, vg.Length(0), vg.Length(0), str)
}

func (s *SparkLines) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)

	w := vg.Length(1)

	da.SetLineWidth(w)

	_, _, ymin, ymax := s.DataRange()

	for _, d := range s.XYs {
		perc := float64(d.Y-ymin) / float64(ymax-ymin)
		c := BrightColorGradient.GetInterpolatedColorFor((perc*-1+1)*0.5 + 0.6)
		da.SetColor(c)

		// Transform the data x, y coordinate of this bubble
		// to the corresponding drawing coordinate.
		x := trX(d.X)
		y := trY(d.Y * 0.9)

		//rad := vg.Length(10)
		var p vg.Path
		p.Move(x-w, y)
		p.Line(x-w, 0)
		//p.Close()
		da.Stroke(p)

		//da.StrokeLine2(*sty, x, 0, x, y)
	}
}

// DrawGlyph implements the Glyph interface.
func (PyramidGlyph) DrawGlyph(da *DrawArea, sty GlyphStyle, pt Point) {
	r := sty.Radius + (sty.Radius-sty.Radius*sinπover6)/2
	var p vg.Path
	p.Move(pt.X, pt.Y+r)
	p.Line(pt.X-r*cosπover6, pt.Y-r*sinπover6)
	p.Line(pt.X+r*cosπover6, pt.Y-r*sinπover6)
	p.Close()
	da.Fill(p)
}

// FillPolygon fills a polygon with the given color.
func (da *DrawArea) FillPolygon(clr color.Color, pts []Point) {
	if len(pts) == 0 {
		return
	}

	da.SetColor(clr)
	var p vg.Path
	p.Move(pts[0].X, pts[0].Y)
	for _, pt := range pts[1:] {
		p.Line(pt.X, pt.Y)
	}
	p.Close()
	da.Fill(p)
}

// DrawArcs draws some arcs to the canvas.
// The canvas is assumed to be 4 inches square.
func DrawArcs(c vg.Canvas) {
	green := color.RGBA{G: 255, A: 255}

	var p vg.Path
	p.Move(vg.Inches(3), vg.Inches(2))
	p.Arc(vg.Inches(2), vg.Inches(2), vg.Inches(1), 0, 2*math.Pi)
	c.SetColor(color.RGBA{B: 255, A: 255})
	c.Fill(p)

	p = vg.Path{}
	p.Move(vg.Inches(4), vg.Inches(2))
	p.Line(vg.Inches(3), vg.Inches(2))
	p.Arc(vg.Inches(2), vg.Inches(2), vg.Inches(1), 0, 5*math.Pi/2)
	p.Line(vg.Inches(2), vg.Inches(4))
	c.SetColor(color.RGBA{R: 255, A: 255})
	c.SetLineWidth(vg.Points(3))
	c.Stroke(p)

	p = vg.Path{}
	p.Move(vg.Inches(0), vg.Inches(2))
	p.Line(vg.Inches(1), vg.Inches(2))
	p.Arc(vg.Inches(2), vg.Inches(2), vg.Inches(1), math.Pi, -7*math.Pi/2)
	p.Line(vg.Inches(2), vg.Inches(0))
	c.SetColor(color.Black)
	c.SetLineWidth(vg.Points(1))
	c.Stroke(p)

	p = vg.Path{}
	p.Move(vg.Inches(0), vg.Inches(1))
	p.Arc(vg.Inches(1), vg.Inches(1), vg.Inches(1), math.Pi, math.Pi/2)
	c.SetLineWidth(vg.Points(3))
	c.SetColor(green)
	c.Stroke(p)

	p = vg.Path{}
	p.Move(vg.Inches(1), vg.Inches(0))
	p.Arc(vg.Inches(1), vg.Inches(1), vg.Inches(1), 3*math.Pi/2, -math.Pi/2)
	c.SetLineWidth(vg.Points(1))
	c.SetColor(color.Black)
	c.Stroke(p)

	p = vg.Path{}
	p.Move(vg.Inches(3), vg.Inches(2))
	p.Arc(vg.Inches(3), vg.Inches(3), vg.Inches(1), 3*math.Pi/2, 3*math.Pi/2)
	c.SetLineWidth(vg.Points(3))
	c.SetColor(green)
	c.Stroke(p)

	p = vg.Path{}
	p.Move(vg.Inches(2), vg.Inches(3))
	p.Arc(vg.Inches(3), vg.Inches(3), vg.Inches(1), math.Pi, -3*math.Pi/2)
	c.SetLineWidth(vg.Points(1))
	c.SetColor(color.Black)
	c.Stroke(p)
}

// StrokeLines draws a line connecting a set of points
// in the given DrawArea.
func (da *DrawArea) StrokeLines(sty LineStyle, lines ...[]Point) {
	if len(lines) == 0 {
		return
	}

	da.SetLineStyle(sty)

	for _, l := range lines {
		if len(l) == 0 {
			continue
		}
		var p vg.Path
		p.Move(l[0].X, l[0].Y)
		for _, pt := range l[1:] {
			p.Line(pt.X, pt.Y)
		}
		da.Stroke(p)
	}
}

// DrawFontExtents draws some text and denotes the
// various extents and width with lines. Expects
// about a 4x4 inch canvas.
func DrawFontExtents(c vg.Canvas) {
	x, y := vg.Inches(1), vg.Inches(2)
	str := "Eloquent"
	font, err := vg.MakeFont("Times-Roman", 18)
	if err != nil {
		panic(err)
	}
	width := font.Width(str)
	ext := font.Extents()
	des := ext.Descent
	asc := ext.Ascent

	c.FillString(font, x, y, str)

	// baseline
	path := vg.Path{}
	path.Move(x, y)
	path.Line(x+width, y)
	c.Stroke(path)

	// descent
	c.SetColor(color.RGBA{G: 255, A: 255})
	path = vg.Path{}
	path.Move(x, y+des)
	path.Line(x+width, y+des)
	c.Stroke(path)

	// ascent
	c.SetColor(color.RGBA{B: 255, A: 255})
	path = vg.Path{}
	path.Move(x, y+asc)
	path.Line(x+width, y+asc)
	c.Stroke(path)
}

func pathRectangle(top vg.Length, right vg.Length, bottom vg.Length, left vg.Length) vg.Path {
	p := vg.Path{}
	p.Move(left, top)
	p.Line(right, top)
	p.Line(right, bottom)
	p.Line(left, bottom)
	p.Close()
	return p
}

// Plot draws the Line, implementing the plot.Plotter
// interface.
func (pts *Line) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)
	ps := make([]plot.Point, len(pts.XYs))

	for i, p := range pts.XYs {
		ps[i].X = trX(p.X)
		ps[i].Y = trY(p.Y)
	}

	if pts.ShadeColor != nil && len(ps) > 0 {
		da.SetColor(*pts.ShadeColor)
		minY := trY(plt.Y.Min)
		var pa vg.Path
		pa.Move(ps[0].X, minY)
		for i := range pts.XYs {
			pa.Line(ps[i].X, ps[i].Y)
		}
		pa.Line(ps[len(pts.XYs)-1].X, minY)
		pa.Close()
		da.Fill(pa)
	}

	da.StrokeLines(pts.LineStyle, da.ClipLinesXY(ps)...)
}

// DrawFonts draws some text in all of the various
// fonts along with a box to make sure that their
// sizes are computed correctly.
func DrawFonts(c vg.Canvas) {
	y := vg.Points(0)
	var fonts []string
	for fname := range vg.FontMap {
		fonts = append(fonts, fname)
	}
	sort.Strings(fonts)
	for _, fname := range fonts {
		font, err := vg.MakeFont(fname, 20)
		if err != nil {
			panic(err)
		}

		w := font.Width(fname + "Xqg")
		h := font.Extents().Ascent

		c.FillString(font, 0, y-font.Extents().Descent, fname+"Xqg")
		fmt.Println(fname)

		var path vg.Path
		path.Move(0, y+h)
		path.Line(w, y+h)
		path.Line(w, y)
		path.Line(0, y)
		path.Close()
		c.Stroke(path)

		path = vg.Path{}
		c.SetColor(color.RGBA{B: 255, A: 255})
		c.SetLineDash([]vg.Length{vg.Points(5), vg.Points(3)}, 0)
		path.Move(0, y-font.Extents().Descent)
		path.Line(w, y-font.Extents().Descent)
		c.Stroke(path)
		c.SetColor(color.Black)
		c.SetLineDash([]vg.Length{}, 0)

		y += h
	}
}