Method draw

axis.go:380–433

draw draws the axis along the left side of a draw.Canvas.

(c draw.Canvas)

// draw draws the axis along the left side of a draw.Canvas.
func (a verticalAxis) draw(c draw.Canvas) {
	var (
		x = c.Min.X
		y vg.Length
	)
	if a.Label.Text != "" {
		sty := a.Label.TextStyle
		sty.Rotation += math.Pi / 2
		x += a.Label.TextStyle.Height(a.Label.Text)
		switch a.Label.Position {
		case draw.PosCenter:
			y = c.Center().Y
		case draw.PosTop:
			y = c.Max.Y
			y -= a.Label.TextStyle.Width(a.Label.Text) / 2
		}
		descent := a.Label.TextStyle.FontExtents().Descent
		c.FillText(sty, vg.Point{X: x - descent, Y: y}, a.Label.Text)
		x += descent
		x += a.Label.Padding
	}
	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
	descent := a.Tick.Label.FontExtents().Descent
	for _, t := range marks {
		y := c.Y(a.Norm(t.Value))
		if !c.ContainsY(y) || t.IsMinor() {
			continue
		}
		c.FillText(a.Tick.Label, vg.Point{X: x, Y: y + descent}, 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)
}

// GlyphBoxes returns the GlyphBoxes for the tick labels
func (a verticalAxis) GlyphBoxes(p *Plot) []GlyphBox {