// 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 axis along the lower edge of a draw.Canvas.
func (a *horizontalAxis) draw(c draw.Canvas) {
y := c.Min.Y
if a.Label.Text != "" {
y -= a.Label.Font.Extents().Descent
c.FillText(a.Label.TextStyle, c.Center().X, y, -0.5, 0, a.Label.Text)
y += a.Label.Height(a.Label.Text)
}
marks := a.Tick.Marker.Ticks(a.Min, a.Max)
for _, t := range marks {
x := c.X(a.Norm(t.Value))
if !c.ContainsX(x) || t.IsMinor() {
continue
}
c.FillText(a.Tick.Label, x, y, -0.5, 0, t.Label)
}
if len(marks) > 0 {
y += tickLabelHeight(a.Tick.Label, marks)
} else {
y += a.Width / 2
}
if len(marks) > 0 && a.drawTicks() {
len := a.Tick.Length
for _, t := range marks {
x := c.X(a.Norm(t.Value))
if !c.ContainsX(x) {
continue
}
start := t.lengthOffset(len)
c.StrokeLine2(a.Tick.LineStyle, x, y+start, x, y+len)
}
y += len
}
c.StrokeLine2(a.LineStyle, c.Min.X, y, c.Max.X, 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
}
}