Golang PngCanvas.WriteTo方法代码示例

func PlotGraph(title string, timestamps []int64, w io.Writer) error {
	p, err := plot.New()
	if err != nil {
		return err
	}

	p.Title.Text = title
	p.X.Label.Text = "Time"
	p.Y.Label.Text = "Number of stars"
	p.Y.Min = 0

	points := make(plotter.XYs, len(timestamps))
	for i, timestamp := range timestamps {
		points[i].X = float64(timestamp)
		points[i].Y = float64(i + 1)
	}
	plotutil.AddLinePoints(p, "Stars", points)

	c := vgimg.New(4*vg.Inch, 4*vg.Inch)
	cpng := vgimg.PngCanvas{c}

	p.Draw(draw.New(cpng))

	if _, err := cpng.WriteTo(w); err != nil {
		return err
	}
	return nil
}

func TestTextGrobs(t *testing.T) {
	// Output
	file, err := os.Create("text.png")
	if err != nil {
		t.Fatalf("%", err)
	}

	pngCanvas := vgimg.PngCanvas{Canvas: vgimg.New(10*vg.Inch, 8*vg.Inch)}
	vg.Initialize(pngCanvas)

	allVP := Viewport{
		X0:     0,
		Y0:     0,
		Width:  10 * vg.Inch,
		Height: 8 * vg.Inch,
		Canvas: pngCanvas,
	}
	bg := GrobRect{xmin: 0, ymin: 0, xmax: 1, ymax: 1, fill: BuiltinColors["gray60"]}
	bg.Draw(allVP)

	gridVP := allVP.Sub(0.1, 0.1, 0.35, 0.35)
	drawTextGrid(gridVP, 0)
	gridVP = allVP.Sub(0.55, 0.1, 0.35, 0.35)
	drawTextGrid(gridVP, 45./180*math.Pi)
	gridVP = allVP.Sub(0.1, 0.55, 0.35, 0.35)
	drawTextGrid(gridVP, 135./180*math.Pi)
	gridVP = allVP.Sub(0.55, 0.55, 0.35, 0.35)
	drawTextGrid(gridVP, 90./180*math.Pi)

	pngCanvas.WriteTo(file)
	file.Close()
}

// WritePNG renders plot to a png file of size width x height.
func (p *Plot) WritePNG(filename string, width, height vg.Length) error {
	file, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer file.Close()

	canvas := vgimg.PngCanvas{Canvas: vgimg.New(width, height)}
	canvas.Translate(-width/2, -height/2)
	p.DumpTo(canvas, width, height)
	canvas.WriteTo(file)
	return nil
}

//.........这里部分代码省略.........
	}
	data = panel.Layers[2].Data
	if data.N != 20 {
		t.Errorf("Got %d data in label df.", panel.Layers[2].Data.N)
	}
	// StatBin produces bins
	if fields := panel.Layers[3].Data.FieldNames(); !same(fields, []string{"x", "count", "ncount", "density", "ndensity"}) {
		t.Errorf("Layer 3 %q has fields %v", panel.Layers[3].Name, fields)
	}
	data = panel.Layers[3].Data
	if data.N != 11 {
		t.Errorf("Got %d data in binned df.", panel.Layers[3].Data.N)
	}

	// 4. Wireing
	panel.WireStatToGeom()

	for a, s := range panel.Scales {
		fmt.Printf("====== Scale %s %q ========\n", a, s.Name)
		fmt.Printf("%s\n", s.String())
	}

	// 5. Test Construct ConstructGeoms. This shouldn't change much as
	// GeomABLine doesn't reparametrize and we don't do position adjustments.
	panel.ConstructGeoms()

	// 6. FinalizeScales
	panel.FinalizeScales()
	// Only x and y are set up
	if sx, ok := panel.Scales["x"]; !ok {
		t.Errorf("Missing x scale")
	} else {
		if sx.Pos == nil {
			t.Errorf("Missing Pos for x scale.")
		}
		if sx.DomainMin > 1.62 || sx.DomainMax < 1.95 {
			t.Errorf("Bad training: %f %f", sx.DomainMin, sx.DomainMax)
		}
	}
	fmt.Printf("%s\n", panel.Scales["x"])
	fmt.Printf("%s\n", panel.Scales["y"])

	// 7. Render Geoms to Grobs using scales (Step7).
	panel.RenderGeoms()
	fmt.Println("Layer 0, raw data")
	for _, grob := range panel.Layers[0].Grobs {
		fmt.Println("  ", grob.String())
	}
	fmt.Println("Layer 1, linear regression")
	for _, grob := range panel.Layers[1].Grobs {
		fmt.Println("  ", grob.String())
	}
	fmt.Println("Layer 2, labels")
	for _, grob := range panel.Layers[2].Grobs {
		fmt.Println("  ", grob.String())
	}
	fmt.Println("Layer 3, histogram")
	for _, grob := range panel.Layers[3].Grobs {
		fmt.Println("  ", grob.String())
	}

	// Output
	pngCanvas := vgimg.PngCanvas{Canvas: vgimg.New(800, 600)}
	pngCanvas.Translate(-400, -300)
	vp := Viewport{
		X0:     50,
		Y0:     50,
		Width:  700,
		Height: 500,
		Canvas: pngCanvas,
	}
	file, err := os.Create("example.png")
	if err != nil {
		t.Fatalf("%", err)
	}

	panel.Draw(vp, true, true)
	if false {
		fmt.Println("Layer 0, raw data")
		for _, grob := range panel.Layers[0].Grobs {
			grob.Draw(vp)
		}
		fmt.Println("Layer 1, linear regression")
		for _, grob := range panel.Layers[1].Grobs {
			grob.Draw(vp)
		}
		fmt.Println("Layer 2, labels")
		for _, grob := range panel.Layers[2].Grobs {
			grob.Draw(vp)
		}
		fmt.Println("Layer 3, histogram")
		for _, grob := range panel.Layers[3].Grobs {
			grob.Draw(vp)
		}
	}

	pngCanvas.WriteTo(file)
	file.Close()

}

func drawPng(b *bytes.Buffer, p *plot.Plot, width, height float64) {
	w, h := vg.Inches(width), vg.Inches(height)
	c := vgimg.PngCanvas{Canvas: vgimg.New(w, h)}
	p.Draw(plot.MakeDrawArea(c))
	c.WriteTo(b)
}

//.........这里部分代码省略.........
		)
		p.X.Label.Text = "Iteration number"
		p.Y.Label.Text = "Atomic mass of nuclei"

		for i, n := range engine.Population {

			line, err := plotter.NewLine(table[i])
			if err != nil {
				log.Fatalf(
					"error adding data points for nucleus %v: %v\n",
					n, err,
				)
			}
			line.LineStyle.Color = col(n)
			line.LineStyle.Width = vg.Points(1)
			p.Add(line)
			p.Legend.Add(label(n), line)
		}

		p.Add(plotter.NewGrid())
		p.Legend.Top = true
		p.Legend.XOffs = -1 * vg.Centimeter

		figX := 25 * vg.Centimeter
		figY := figX / vg.Length(math.Phi)

		// Create a Canvas for writing SVG images.
		canvas := vgsvg.New(figX, figY)

		// Draw to the Canvas.
		p.Draw(draw.New(canvas))

		outsvg := new(bytes.Buffer)
		_, err = canvas.WriteTo(outsvg)
		if err != nil {
			log.Printf("error svg: %v\n", err)
			return
		}

		err = websocket.JSON.Send(c.ws, plotReply{
			ID: id, Err: err, SVG: outsvg.String(), Stage: "plot-done",
		})
		if err != nil {
			log.Printf("error sending data: %v\n", err)
			return
		}

		pngcanvas := vgimg.PngCanvas{Canvas: vgimg.New(figX, figY)}
		p.Draw(draw.New(pngcanvas))
		outpng := new(bytes.Buffer)
		_, err = pngcanvas.WriteTo(outpng)
		if err != nil {
			log.Printf("error png: %v\n", err)
			return
		}

		href := filepath.Join(dir, fmt.Sprintf("output-%d.zip", id))
		zipf, err := os.Create(href)
		if err != nil {
			log.Printf("error creating zip file: %v\n", err)
		}
		defer zipf.Close()

		zipw := zip.NewWriter(zipf)
		defer zipw.Close()

//.........这里部分代码省略.........
			size:  10,
			color: BuiltinColors["black"],
			vjust: 0.5,
			hjust: 0.5,
		}
		points = append(points, g)
		x += 3 * 0.021
	}
	for _, grob := range points {
		grob.Draw(innerVP)
	}

	// Draw lines with different styles and widths.
	lines := []Grob{}
	x, y = 0.1, 0.45
	for lt := SolidLine; lt <= TwodashLine; lt++ {
		x = 0.1
		for size := 1; size < 8; size += 2 {
			g := GrobLine{
				x0:       x,
				y0:       y,
				x1:       x + 0.18,
				y1:       y,
				size:     float64(size),
				linetype: lt,
				color:    BuiltinColors["black"],
			}
			lines = append(lines, g)
			x += 0.22
		}
		y += 0.04
	}
	for _, grob := range lines {
		grob.Draw(innerVP)
	}

	// Draw rectangles
	rectVP := innerVP.Sub(0.1, 0.7, 0.4, 0.3)
	rect := []Grob{}
	bgr := GrobRect{xmin: 0, ymin: 0, xmax: 1, ymax: 1, fill: BuiltinColors["gray40"]}
	bgr.Draw(rectVP)
	x, y = 0.0, 0.0
	w, h := 0.5, 0.5
	for _, col := range cols {
		g := GrobRect{
			xmin: x,
			ymin: y,
			xmax: x + w,
			ymax: y + h,
			fill: BuiltinColors[col],
		}
		rect = append(rect, g)
		x += w
		y += h
		w /= 2
		h /= 2
	}
	for _, grob := range rect {
		grob.Draw(rectVP)
	}

	// Draw path
	pathVP := innerVP.Sub(0.55, 0.7, 0.4, 0.3)
	bgp := GrobRect{xmin: 0, ymin: 0, xmax: 1, ymax: 1, fill: BuiltinColors["gray"]}
	bgp.Draw(pathVP)
	sin := make([]struct{ x, y float64 }, 50)
	for i := range sin {
		k := float64(i) / float64(len(sin)-1)
		x = k * 2 * math.Pi
		println(float64(i)/float64(len(sin)), x, math.Sin(x))
		y = 0.4 * math.Sin(x)
		sin[i].x = k
		sin[i].y = 0.55 + y
	}
	g := GrobPath{
		points:   sin,
		size:     4,
		linetype: SolidLine,
		color:    BuiltinColors["white"],
	}
	g.Draw(pathVP)
	cos := make([]struct{ x, y float64 }, 25)
	for i := range cos {
		k := float64(i) / float64(len(cos)-1)
		x = k * 4 * math.Pi
		y = 0.3 * math.Cos(x)
		cos[i].x = k
		cos[i].y = 0.45 + y
	}
	g = GrobPath{
		points:   cos,
		size:     2,
		linetype: DottedLine,
		color:    BuiltinColors["green"],
	}
	g.Draw(pathVP)

	pngCanvas.WriteTo(file)
	file.Close()
}