Wumpus.Basic.FontLoader.Base

AFM file parser.

Note - AFM Version 2.0 used by GhostScript and Version 3.0+ have numerous differences.

Afm Unit

data AfmUnit

Wrapped Double representing 1/1000 of the scale factor (Point size) of a font. AFM files encode all measurements as these units.

Instances

Eq AfmUnit

Floating AfmUnit

Fractional AfmUnit

Num AfmUnit

Ord AfmUnit

Real AfmUnit

RealFloat AfmUnit

RealFrac AfmUnit

Show AfmUnit

afmValue :: FromPtSize u => AfmUnit -> PtSize -> u

Compute the size of a measurement in Afm units scaled by the point size of the font.

afmUnitScale :: AfmUnit -> PtSize

Glyph metrics

type PSCharCode = Int

Afm files index glyphs by PostScript character code. This is not the same as Unicode, ASCII...

It is expected to be determined by EncodingScheme in the Global Font Information Section.

type PSEncodingScheme = String

type AfmBoundingBox = BoundingBox AfmUnit

type AfmKey = String

type GlobalInfo = Map AfmKey String

data AfmFile

Wumpus needs a very small subset of AFM files, common to both version 2.0 and version 4.1.

Note - Bounding Box is mandatory for AFM versions 3.0 and 4.1

Cap Height is optional in AFM versions 3.0 and 4.1. As Wumpus uses cap height in calculations, glyph metrics must be build with an arbitrary value if it is not present.

Encoding Scheme is optional in AFM files.

Constructors

AfmFile

Fields

afm_encoding :: Maybe String

afm_font_bbox :: AfmBoundingBox

afm_cap_height :: Maybe AfmUnit

afm_glyph_metrics :: [AfmGlyphMetrics]

Instances

Show AfmFile

data AfmGlyphMetrics

Constructors

AfmGlyphMetrics

Fields

afm_char_code :: !PSCharCode

afm_width_vector :: !(Vec2 AfmUnit)

afm_char_name :: !String

Instances

Eq AfmGlyphMetrics

Show AfmGlyphMetrics

Font loading

type FontLoadErr = String

type FontLoadResult cu = Either FontLoadErr (GlyphMetricsTable cu)

data FontLoader cu

Constructors

forall interim . FontLoader

Fields

unit_scale_fun :: cu -> PtSize

path_to_font_dir :: FilePath

file_name_locator :: FontName -> FilePath

font_parser :: FilePath -> IO (Either String interim)

post_process :: interim -> GlyphMetricsTable cu

loadFont :: FontLoader cu -> FontName -> IO (FontLoadResult cu)

type BaseGlyphMetrics = Map FontName GlyphMetrics

loadBaseGlyphMetrics :: FontLoader u -> [FontName] -> IO BaseGlyphMetrics

buildGlyphMetricsTable :: BoundingBox AfmUnit -> Vec2 AfmUnit -> AfmUnit -> AfmFile -> GlyphMetricsTable AfmUnit