// Thumbnail the thumbnail for the Scatter,
// implementing the plot.Thumbnailer interface.
func (pts *Scatter) Thumbnail(da *plot.DrawArea) {
da.DrawGlyph(pts.GlyphStyle, da.Center())
}
// 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(da *plot.DrawArea) {
y := da.Center().Y
da.StrokeLine2(f.LineStyle, da.Min.X, y, da.Max().X, y)
}
// Thumbnail the thumbnail for the Line,
// implementing the plot.Thumbnailer interface.
func (pts *Line) Thumbnail(da *plot.DrawArea) {
y := da.Center().Y
da.StrokeLine2(pts.LineStyle, da.Min.X, y, da.Max().X, y)
}