Golang Canvas.FillText方法代码示例

// 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 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)
	}
}

// draw draws the axis along the left side of a draw.Canvas.
func (a *verticalAxis) draw(c draw.Canvas) {
	x := c.Min.X
	if a.Label.Text != "" {
		x += a.Label.Height(a.Label.Text)
		c.Push()
		c.Rotate(math.Pi / 2)
		c.FillText(a.Label.TextStyle, c.Center().Y, -x, -0.5, 0, a.Label.Text)
		c.Pop()
		x += -a.Label.Font.Extents().Descent
	}
	marks := a.Tick.Marker.Ticks(a.Min, a.Max)
	if w := tickLabelWidth(a.Tick.Label, marks); len(marks) > 0 && w > 0 {
		x += w
	}
	major := false
	for _, t := range marks {
		y := c.Y(a.Norm(t.Value))
		if !c.ContainsY(y) || t.IsMinor() {
			continue
		}
		c.FillText(a.Tick.Label, x, y, -1, -0.5, t.Label)
		major = true
	}
	if major {
		x += a.Tick.Label.Width(" ")
	}
	if a.drawTicks() && len(marks) > 0 {
		len := a.Tick.Length
		for _, t := range marks {
			y := c.Y(a.Norm(t.Value))
			if !c.ContainsY(y) {
				continue
			}
			start := t.lengthOffset(len)
			c.StrokeLine2(a.Tick.LineStyle, x+start, y, x+len, y)
		}
		x += len
	}
	c.StrokeLine2(a.LineStyle, x, c.Min.Y, x, c.Max.Y)
}

// draw draws the legend to the given draw.Canvas.
func (l *Legend) draw(c draw.Canvas) {
	iconx := c.Min.X
	textx := iconx + l.ThumbnailWidth + l.TextStyle.Width(" ")
	xalign := 0.0
	if !l.Left {
		iconx = c.Max.X - l.ThumbnailWidth
		textx = iconx - l.TextStyle.Width(" ")
		xalign = -1
	}
	textx += l.XOffs
	iconx += l.XOffs

	enth := l.entryHeight()
	y := c.Max.Y - enth
	if !l.Top {
		y = c.Min.Y + (enth+l.Padding)*(vg.Length(len(l.entries))-1)
	}
	y += l.YOffs

	icon := &draw.Canvas{
		Canvas: c.Canvas,
		Rectangle: draw.Rectangle{
			Min: draw.Point{iconx, y},
			Max: draw.Point{iconx + l.ThumbnailWidth, y + enth},
		},
	}
	for _, e := range l.entries {
		for _, t := range e.thumbs {
			t.Thumbnail(icon)
		}
		yoffs := (enth - l.TextStyle.Height(e.text)) / 2
		c.FillText(l.TextStyle, textx, icon.Min.Y+yoffs, xalign, 0, e.text)
		icon.Min.Y -= enth + l.Padding
		icon.Max.Y -= enth + l.Padding
	}
}