// 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, c.Crop(ywidth, 0, 0, 0)))
xheight := x.size()
y.draw(padY(p, c.Crop(0, xheight, 0, 0)))
dataC := padY(p, padX(p, c.Crop(ywidth, xheight, 0, 0)))
for _, data := range p.plotters {
data.Plot(dataC, p)
}
p.Legend.draw(c.Crop(ywidth, 0, 0, 0).Crop(0, xheight, 0, 0))
}
// Thumbnail the thumbnail for the Line,
// implementing the plot.Thumbnailer interface.
func (pts *Line) Thumbnail(c *draw.Canvas) {
if pts.ShadeColor != nil {
points := []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(points)
c.FillPolygon(*pts.ShadeColor, poly)
points = append(points, draw.Point{c.Min.X, c.Min.Y})
} else {
y := c.Center().Y
c.StrokeLine2(pts.LineStyle, c.Min.X, y, c.Max.X, y)
}
}
// 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)
}
// Thumbnail draws a line in the given style down the
// center of a DrawArea as a thumbnail representation
// of the LineStyle of the function.
func (f Function) Thumbnail(c *draw.Canvas) {
y := c.Center().Y
c.StrokeLine2(f.LineStyle, c.Min.X, y, c.Max.X, y)
}
// Thumbnail the thumbnail for the Scatter,
// implementing the plot.Thumbnailer interface.
func (pts *Scatter) Thumbnail(c *draw.Canvas) {
c.DrawGlyph(pts.GlyphStyle, c.Center())
}