5.3 Fonts

The library use zpb-ttf to extract path from TTF fonts.

While paths-from-string handle kerning between each pair of character, it is up to the user to scale the font, compute alignment (center,..), compute bounding box, break text into several lines if necessary, and so on, according to information obtained from zpb-ttf directly. However, more convenient support may be added in the future to cl-vectors.

Note that hinting is not supported at all. It may be a problem for rendering fonts at very small sizes. But otherwise, paths extracted from zpb-ttf are sufficient for most uses.

Function PATHS-FROM-GLYPH

Syntax:

• paths-from-glyph glyph &key (offset (make-point 0 0)) (scale-x 1.0) (scale-y 1.0) => paths

Arguments and Values:

• glyph -- a glyph object from zpb-ttf

  offset -- a point

  scale-x -- a real number

  scale-y -- a real number

Description:

• Create paths from the glyph extracted by the zpb-ttf library.

Examples:

(zpb-ttf:with-font-loader (loader "font.ttf")
  (show-annotated-path (paths-from-glyph (zpb-ttf:find-glyph #\π loader)
                                         :offset (make-point 200 550)
                                         :scale-x 0.3
                                         :scale-y -0.3)))

Function PATHS-FROM-STRING

Syntax:

• paths-from-string font-loader string &key (offset (make-point 0 0)) (scale-x 1.0) (scale-y 1.0) (kerning t) => paths

Arguments and Values:

• font-loader -- a font loader from zpb-ttf

  string -- a string

  offset -- a point

  scale-x -- a real number

  scale-y -- a real number

  kerning -- a boolean (available in version >=0.1.4)

Description:

• Return a list of paths describing the given string. Kerning is taken into account if kerning is true.

Examples:

(zpb-ttf:with-font-loader (loader "font.ttf")
  (paths-from-string loader "Hello World!"
                     :offset (make-point 200 550)
                     :scale-x 0.3
                     :scale-y -0.3)))

Function MAKE-STRING-PATH

Syntax:

• make-string-path font-loader text &key position size halign valign inverted kerning => paths

Arguments and Values:

• font-loader -- a font loader from zpb-ttf

  text -- a string

  position -- a point

  size -- an integer

  halign -- either :none, :left, :right or :center

  valign -- either :baseline, :top, :bottom or :center

  inverted -- a boolean

  kerning -- a boolean

Description:

• To be added in 0.1.4.

  This function is a convenient wrapper around paths-from-string.