Golang draw.Canvas类代码示例

// Plot implements the plot.Plotter interface.
func (b *BarChart) Plot(c draw.Canvas, plt *plot.Plot) {
	trX, trY := plt.Transforms(&c)

	for i, ht := range b.Values {
		x := b.XMin + float64(i)
		xmin := trX(float64(x))
		if !c.ContainsX(xmin) {
			continue
		}
		xmin = xmin - b.Width/2 + b.Offset
		xmax := xmin + b.Width
		bottom := b.stackedOn.BarHeight(i)
		ymin := trY(bottom)
		ymax := trY(bottom + ht)

		pts := []draw.Point{
			{xmin, ymin},
			{xmin, ymax},
			{xmax, ymax},
			{xmax, ymin},
		}
		poly := c.ClipPolygonY(pts)
		c.FillPolygon(b.Color, poly)

		pts = append(pts, draw.Point{xmin, ymin})
		outline := c.ClipLinesY(pts)
		c.StrokeLines(b.LineStyle, outline...)
	}
}

// Plot implements the Plotter interface, drawing a line
// that connects each point in the Line.
func (f *Function) Plot(c draw.Canvas, p *plot.Plot) {
	trX, trY := p.Transforms(&c)

	d := (p.X.Max - p.X.Min) / float64(f.Samples-1)
	line := make([]draw.Point, f.Samples)
	for i := range line {
		x := p.X.Min + float64(i)*d
		line[i].X = trX(x)
		line[i].Y = trY(f.F(x))
	}

	// For every continuous block of non-NaN Y values, stroke lines
	for i := 0; i < len(line); i++ {
		if !math.IsNaN(float64(line[i].Y)) {
			j := i + 1
			for ; j < len(line); j++ {
				if math.IsNaN(float64(line[j].Y)) {
					break
				}
			}
			c.StrokeLines(f.LineStyle, c.ClipLinesXY(line[i:j])...)
			i = j
		}
	}
}

// Plot draws the Line, implementing the plot.Plotter interface.
func (rp *ResponsePlotter) Plot(canvas vgdraw.Canvas, plt *plot.Plot) {
	trX, trY := plt.Transforms(&canvas)

	start := float64(rp.Response.GetStartTime())
	step := float64(rp.Response.GetStepTime())
	absent := rp.Response.IsAbsent

	lines := make([][]vgdraw.Point, 1)
	lines[0] = make([]vgdraw.Point, 0, len(rp.Response.Values))

	/* ikruglov
	 * swithing between lineMode and looping inside
	 * is more branch-prediction friendly i.e. potentially faster */
	switch rp.lineMode {
	case "slope":
		currentLine := 0
		lastAbsent := false
		for i, v := range rp.Response.Values {
			if absent[i] {
				lastAbsent = true
			} else if lastAbsent {
				currentLine++
				lines = append(lines, make([]vgdraw.Point, 1))
				lines[currentLine][0] = vgdraw.Point{X: trX(start + float64(i)*step), Y: trY(v)}
				lastAbsent = false
			} else {
				lines[currentLine] = append(lines[currentLine], vgdraw.Point{X: trX(start + float64(i)*step), Y: trY(v)})
			}
		}

	case "connected":
		for i, v := range rp.Response.Values {
			if absent[i] {
				continue
			}

			lines[0] = append(lines[0], vgdraw.Point{X: trX(start + float64(i)*step), Y: trY(v)})
		}

	case "drawAsInfinite":
		for i, v := range rp.Response.Values {
			if !absent[i] && v > 0 {
				infiniteLine := []vgdraw.Point{
					vgdraw.Point{X: trX(start + float64(i)*step), Y: canvas.Y(1)},
					vgdraw.Point{X: trX(start + float64(i)*step), Y: canvas.Y(0)},
				}
				lines = append(lines, infiniteLine)
			}
		}

	//case "staircase": // TODO
	default:
		panic("Unimplemented " + rp.lineMode)
	}

	canvas.StrokeLines(rp.LineStyle, lines...)
}

// DataCanvas returns a new draw.Canvas that
// is the subset of the given draw area into which
// the plot data will be drawn.
func (p *Plot) DataCanvas(da draw.Canvas) draw.Canvas {
	if p.Title.Text != "" {
		da.Max.Y -= p.Title.Height(p.Title.Text) - p.Title.Font.Extents().Descent
		da.Max.Y -= p.Title.Padding
	}
	p.X.sanitizeRange()
	x := horizontalAxis{p.X}
	p.Y.sanitizeRange()
	y := verticalAxis{p.Y}
	return padY(p, padX(p, da.Crop(y.size(), x.size(), 0, 0)))
}

// Plot implements the Plotter interface, drawing a line
// that connects each point in the Line.
func (f *Function) Plot(c draw.Canvas, p *plot.Plot) {
	trX, trY := p.Transforms(&c)

	d := (p.X.Max - p.X.Min) / float64(f.Samples-1)
	line := make([]draw.Point, f.Samples)
	for i := range line {
		x := p.X.Min + float64(i)*d
		line[i].X = trX(x)
		line[i].Y = trY(f.F(x))
	}
	c.StrokeLines(f.LineStyle, c.ClipLinesXY(line)...)
}

// Plot implements the Plotter interface, drawing labels.
func (l *Labels) Plot(c draw.Canvas, p *plot.Plot) {
	trX, trY := p.Transforms(&c)
	for i, label := range l.Labels {
		x := trX(l.XYs[i].X)
		y := trY(l.XYs[i].Y)
		if !c.Contains(draw.Point{x, y}) {
			continue
		}
		x += l.XOffset
		y += l.YOffset
		c.FillText(l.TextStyle, x, y, l.XAlign, l.YAlign, label)
	}
}

// Plot implements the Plotter interface, drawing labels.
func (e *YErrorBars) Plot(c draw.Canvas, p *plot.Plot) {
	trX, trY := p.Transforms(&c)
	for i, err := range e.YErrors {
		x := trX(e.XYs[i].X)
		ylow := trY(e.XYs[i].Y - math.Abs(err.Low))
		yhigh := trY(e.XYs[i].Y + math.Abs(err.High))

		bar := c.ClipLinesY([]draw.Point{{x, ylow}, {x, yhigh}})
		c.StrokeLines(e.LineStyle, bar...)
		e.drawCap(&c, x, ylow)
		e.drawCap(&c, x, yhigh)
	}
}

// bottomMost returns the bottom-most GlyphBox.
func bottomMost(c *draw.Canvas, boxes []GlyphBox) GlyphBox {
	miny := c.Min.Y
	l := GlyphBox{}
	for _, b := range boxes {
		if b.Size().Y <= 0 {
			continue
		}
		if y := c.Y(b.Y) + b.Min.Y; y < miny && b.Y >= 0 {
			miny = y
			l = b
		}
	}
	return l
}

// topMost returns the top-most GlyphBox.
func topMost(c *draw.Canvas, boxes []GlyphBox) GlyphBox {
	maxy := c.Max.Y
	t := GlyphBox{Y: 1}
	for _, b := range boxes {
		if b.Size().Y <= 0 {
			continue
		}
		if y := c.Y(b.Y) + b.Min.Y + b.Size().Y; y > maxy && b.Y <= 1 {
			maxy = y
			t = b
		}
	}
	return t
}

// leftMost returns the left-most GlyphBox.
func leftMost(c *draw.Canvas, boxes []GlyphBox) GlyphBox {
	minx := c.Min.X
	l := GlyphBox{}
	for _, b := range boxes {
		if b.Size().X <= 0 {
			continue
		}
		if x := c.X(b.X) + b.Min.X; x < minx && b.X >= 0 {
			minx = x
			l = b
		}
	}
	return l
}

// rightMost returns the right-most GlyphBox.
func rightMost(c *draw.Canvas, boxes []GlyphBox) GlyphBox {
	maxx := c.Max.X
	r := GlyphBox{X: 1}
	for _, b := range boxes {
		if b.Size().X <= 0 {
			continue
		}
		if x := c.X(b.X) + b.Min.X + b.Size().X; x > maxx && b.X <= 1 {
			maxx = x
			r = b
		}
	}
	return r
}

// Draw draws a plot to a draw.Canvas.
//
// Plotters are drawn in the order in which they were
// added to the plot.  Plotters that  implement the
// GlyphBoxer interface will have their GlyphBoxes
// taken into account when padding the plot so that
// none of their glyphs are clipped.
func (p *Plot) Draw(c draw.Canvas) {
	if p.BackgroundColor != nil {
		c.SetColor(p.BackgroundColor)
		c.Fill(c.Rectangle.Path())
	}
	if p.Title.Text != "" {
		c.FillText(p.Title.TextStyle, c.Center().X, c.Max.Y, -0.5, -1, p.Title.Text)
		c.Max.Y -= p.Title.Height(p.Title.Text) - p.Title.Font.Extents().Descent
		c.Max.Y -= p.Title.Padding
	}

	p.X.sanitizeRange()
	x := horizontalAxis{p.X}
	p.Y.sanitizeRange()
	y := verticalAxis{p.Y}

	ywidth := y.size()
	x.draw(padX(p, draw.Crop(c, ywidth, 0, 0, 0)))
	xheight := x.size()
	y.draw(padY(p, draw.Crop(c, 0, 0, xheight, 0)))

	dataC := padY(p, padX(p, draw.Crop(c, ywidth, 0, xheight, 0)))
	for _, data := range p.plotters {
		data.Plot(dataC, p)
	}

	p.Legend.draw(draw.Crop(draw.Crop(c, ywidth, 0, 0, 0), 0, 0, xheight, 0))
}

// Plot implements the plot.Plotter interface.
func (g *Grid) Plot(c draw.Canvas, plt *plot.Plot) {
	trX, trY := plt.Transforms(&c)

	if g.Vertical.Color == nil {
		goto horiz
	}
	for _, tk := range plt.X.Tick.Marker.Ticks(plt.X.Min, plt.X.Max) {
		if tk.IsMinor() {
			continue
		}
		x := trX(tk.Value)
		c.StrokeLine2(g.Vertical, x, c.Min.Y, x, c.Min.Y+c.Size().Y)
	}

horiz:
	if g.Horizontal.Color == nil {
		return
	}
	for _, tk := range plt.Y.Tick.Marker.Ticks(plt.Y.Min, plt.Y.Max) {
		if tk.IsMinor() {
			continue
		}
		y := trY(tk.Value)
		c.StrokeLine2(g.Horizontal, c.Min.X, y, c.Min.X+c.Size().X, y)
	}
}

// DrawGlyphBoxes draws red outlines around the plot's
// GlyphBoxes.  This is intended for debugging.
func (p *Plot) DrawGlyphBoxes(c *draw.Canvas) {
	c.SetColor(color.RGBA{R: 255, A: 255})
	for _, b := range p.GlyphBoxes(p) {
		b.Rectangle.Min.X += c.X(b.X)
		b.Rectangle.Min.Y += c.Y(b.Y)
		c.Stroke(b.Rectangle.Path())
	}
}

func (b *BarChart) Thumbnail(c *draw.Canvas) {
	pts := []draw.Point{
		{c.Min.X, c.Min.Y},
		{c.Min.X, c.Max.Y},
		{c.Max.X, c.Max.Y},
		{c.Max.X, c.Min.Y},
	}
	poly := c.ClipPolygonY(pts)
	c.FillPolygon(b.Color, poly)

	pts = append(pts, draw.Point{c.Min.X, c.Min.Y})
	outline := c.ClipLinesY(pts)
	c.StrokeLines(b.LineStyle, outline...)
}