text

type Default ¶

type Default struct {
	// contains filtered or unexported fields
}

Default is the built-in Renderer: DejaVu Sans for text, go-tex/math for TeX.

func NewDefault() *Default

func (d *Default) Layout(s string, sizePx float64) Layout

func (d *Default) LayoutPlain(s string, sizePx float64) Layout

func (d *Default) LineMetrics(sizePx float64) (float64, float64, float64)

type Layout ¶

type Layout struct {
	Path    *render.Path
	Width   float64
	Ascent  float64 // above the baseline
	Descent float64 // below the baseline
}

Layout is a laid-out line of text. Path holds the glyph outlines in pixels with the pen origin at (0, 0) on the baseline and y pointing down.

Width, Ascent and Descent are the metrics matplotlib aligns text by. The box starts at the pen origin. For plain text the width is the advance of the string (kerned), which is what FreeType's bounding box of the rendered string comes to in matplotlib within a pixel or two (matplotlib's is hinted, each glyph a whole number of pixels); the ascent and descent are those of the ink. For math, the TeX box.

type PlainRenderer ¶ added in v0.2.0

type PlainRenderer interface {
	Renderer
	LayoutPlain(s string, sizePx float64) Layout
}

A PlainRenderer can also lay out a string as it is, with no TeX: dollar signs and backslashes are characters. Text that comes from data (a category name, a customer's label) goes through it, so that "$5 and $6" is not typeset as math and no input reaches the TeX typesetter.

type Renderer ¶

type Renderer interface {
	Layout(s string, sizePx float64) Layout
	// LineMetrics returns the font's typographic ascent, descent and line gap
	// at sizePx: the minimum box matplotlib gives every line.
	LineMetrics(sizePx float64) (ascent, descent, gap float64)
}

A Renderer lays out one line of text at a size in pixels.