fixed dependencies

vendor/gonum.org/v1/plot/text/text.go

@@ -0,0 +1,200 @@
+// Copyright ©2021 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package text
+
+import (
+	"image/color"
+	"math"
+
+	"gonum.org/v1/plot/font"
+	"gonum.org/v1/plot/vg"
+)
+
+// Handler parses, formats and renders text.
+type Handler interface {
+	// Cache returns the cache of fonts used by the text handler.
+	Cache() *font.Cache
+
+	// Extents returns the Extents of a font.
+	Extents(fnt font.Font) font.Extents
+
+	// Lines splits a given block of text into separate lines.
+	Lines(txt string) []string
+
+	// Box returns the bounding box of the given non-multiline text where:
+	//  - width is the horizontal space from the origin.
+	//  - height is the vertical space above the baseline.
+	//  - depth is the vertical space below the baseline, a positive number.
+	Box(txt string, fnt font.Font) (width, height, depth vg.Length)
+
+	// Draw renders the given text with the provided style and position
+	// on the canvas.
+	Draw(c vg.Canvas, txt string, sty Style, pt vg.Point)
+}
+
+// XAlignment specifies text alignment in the X direction. Three preset
+// options are available, but an arbitrary alignment
+// can also be specified using XAlignment(desired number).
+type XAlignment float64
+
+const (
+	// XLeft aligns the left edge of the text with the specified location.
+	XLeft XAlignment = 0
+	// XCenter aligns the horizontal center of the text with the specified location.
+	XCenter XAlignment = -0.5
+	// XRight aligns the right edge of the text with the specified location.
+	XRight XAlignment = -1
+)
+
+// YAlignment specifies text alignment in the Y direction. Three preset
+// options are available, but an arbitrary alignment
+// can also be specified using YAlignment(desired number).
+type YAlignment float64
+
+const (
+	// YTop aligns the top of of the text with the specified location.
+	YTop YAlignment = -1
+	// YCenter aligns the vertical center of the text with the specified location.
+	YCenter YAlignment = -0.5
+	// YBottom aligns the bottom of the text with the specified location.
+	YBottom YAlignment = 0
+)
+
+// Position specifies the text position.
+const (
+	PosLeft   = -1
+	PosBottom = -1
+	PosCenter = 0
+	PosTop    = +1
+	PosRight  = +1
+)
+
+// Style describes what text will look like.
+type Style struct {
+	// Color is the text color.
+	Color color.Color
+
+	// Font is the font description.
+	Font font.Font
+
+	// Rotation is the text rotation in radians, performed around the axis
+	// defined by XAlign and YAlign.
+	Rotation float64
+
+	// XAlign and YAlign specify the alignment of the text.
+	XAlign XAlignment
+	YAlign YAlignment
+
+	// Handler parses and formats text according to a given
+	// dialect (Markdown, LaTeX, plain, ...)
+	// The default is a plain text handler.
+	Handler Handler
+}
+
+// FontExtents returns the extents of this Style's font.
+func (s Style) FontExtents() font.Extents {
+	return s.Handler.Extents(s.Font)
+}
+
+// Width returns the width of lines of text
+// when using the given font before any text rotation is applied.
+func (s Style) Width(txt string) (max vg.Length) {
+	w, _ := s.box(txt)
+	return w
+}
+
+// Height returns the height of the text when using
+// the given font before any text rotation is applied.
+func (s Style) Height(txt string) vg.Length {
+	_, h := s.box(txt)
+	return h
+}
+
+// box returns the bounding box of a possibly multi-line text.
+func (s Style) box(txt string) (w, h vg.Length) {
+	var (
+		lines   = s.Handler.Lines(txt)
+		e       = s.FontExtents()
+		linegap = (e.Height - e.Ascent - e.Descent)
+	)
+	for i, line := range lines {
+		ww, hh, dd := s.Handler.Box(line, s.Font)
+		if ww > w {
+			w = ww
+		}
+		h += hh + dd
+		if i > 0 {
+			h += linegap
+		}
+	}
+
+	return w, h
+}
+
+// Rectangle returns a rectangle giving the bounds of
+// this text assuming that it is drawn at (0, 0).
+func (s Style) Rectangle(txt string) vg.Rectangle {
+	e := s.Handler.Extents(s.Font)
+	w, h := s.box(txt)
+	desc := vg.Length(e.Height - e.Ascent) // descent + linegap
+	xoff := vg.Length(s.XAlign) * w
+	yoff := vg.Length(s.YAlign)*h - desc
+
+	// lower left corner
+	p1 := rotatePoint(s.Rotation, vg.Point{X: xoff, Y: yoff})
+	// upper left corner
+	p2 := rotatePoint(s.Rotation, vg.Point{X: xoff, Y: h + yoff})
+	// lower right corner
+	p3 := rotatePoint(s.Rotation, vg.Point{X: w + xoff, Y: yoff})
+	// upper right corner
+	p4 := rotatePoint(s.Rotation, vg.Point{X: w + xoff, Y: h + yoff})
+
+	return vg.Rectangle{
+		Max: vg.Point{
+			X: max(p1.X, p2.X, p3.X, p4.X),
+			Y: max(p1.Y, p2.Y, p3.Y, p4.Y),
+		},
+		Min: vg.Point{
+			X: min(p1.X, p2.X, p3.X, p4.X),
+			Y: min(p1.Y, p2.Y, p3.Y, p4.Y),
+		},
+	}
+}
+
+// rotatePoint applies rotation theta (in radians) about the origin to point p.
+func rotatePoint(theta float64, p vg.Point) vg.Point {
+	if theta == 0 {
+		return p
+	}
+	x := float64(p.X)
+	y := float64(p.Y)
+
+	sin, cos := math.Sincos(theta)
+
+	return vg.Point{
+		X: vg.Length(x*cos - y*sin),
+		Y: vg.Length(y*cos + x*sin),
+	}
+}
+
+func max(d ...vg.Length) vg.Length {
+	o := vg.Length(math.Inf(-1))
+	for _, dd := range d {
+		if dd > o {
+			o = dd
+		}
+	}
+	return o
+}
+
+func min(d ...vg.Length) vg.Length {
+	o := vg.Length(math.Inf(1))
+	for _, dd := range d {
+		if dd < o {
+			o = dd
+		}
+	}
+	return o
+}