Gelatin.FreeType2.Internal

This module provides easy freetype2 font rendering using gelatin's graphics primitives.

Documentation

type WordMap = Map String (V2 Float, Renderer2)

loadWords

Arguments

:: MonadIO m

=> Backend GLuint e V2V2 (V2 Float) Float Raster

The V2V2 backend needed to render font glyphs.

-> Atlas

The atlas to load the words into.

-> String

The string of words to load, with each word separated by spaces.

-> m Atlas

Load a string of words into the Atlas.

unloadMissingWords

Arguments

:: MonadIO m

=> Atlas

The Atlas to unload words from.

-> String

The source string.

-> m Atlas

Unload any words not contained in the source string.

data GlyphSize

Constructors

CharSize Float Float Int Int

PixelSize Int Int

Instances

Eq GlyphSize

Methods

(==) :: GlyphSize -> GlyphSize -> Bool

(/=) :: GlyphSize -> GlyphSize -> Bool

Ord GlyphSize

Methods

compare :: GlyphSize -> GlyphSize -> Ordering

(<) :: GlyphSize -> GlyphSize -> Bool

(<=) :: GlyphSize -> GlyphSize -> Bool

(>) :: GlyphSize -> GlyphSize -> Bool

(>=) :: GlyphSize -> GlyphSize -> Bool

max :: GlyphSize -> GlyphSize -> GlyphSize

min :: GlyphSize -> GlyphSize -> GlyphSize

Show GlyphSize

Methods

showsPrec :: Int -> GlyphSize -> ShowS

show :: GlyphSize -> String

showList :: [GlyphSize] -> ShowS

glyphWidth :: GlyphSize -> Float

glyphHeight :: GlyphSize -> Float

data GlyphMetrics

https://www.freetype.org/freetype2/docs/tutorial/step2.html

Constructors

GlyphMetrics

Fields

• glyphTexBB :: (V2 Int, V2 Int)
• glyphTexSize :: V2 Int
• glyphSize :: V2 Int
• glyphHoriBearing :: V2 Int
• glyphVertBearing :: V2 Int
• glyphAdvance :: V2 Int

Instances

Eq GlyphMetrics

Methods

(==) :: GlyphMetrics -> GlyphMetrics -> Bool

(/=) :: GlyphMetrics -> GlyphMetrics -> Bool

Show GlyphMetrics

Methods

showsPrec :: Int -> GlyphMetrics -> ShowS

show :: GlyphMetrics -> String

showList :: [GlyphMetrics] -> ShowS

data Atlas

Constructors

Atlas

Fields

• atlasTexture :: GLuint
• atlasTextureSize :: V2 Int
• atlasLibrary :: FT_Library
• atlasFontFace :: FT_Face
• atlasMetrics :: IntMap GlyphMetrics
• atlasGlyphSize :: GlyphSize
• atlasWordMap :: WordMap
• atlasFilePath :: FilePath

emptyAtlas :: FT_Library -> FT_Face -> GLuint -> Atlas

data AtlasMeasure

Constructors

AM

Fields

• amWH :: V2 Int
• amXY :: V2 Int
• rowHeight :: Int
• amMap :: IntMap (V2 Int)

Instances

Eq AtlasMeasure

Methods

(==) :: AtlasMeasure -> AtlasMeasure -> Bool

(/=) :: AtlasMeasure -> AtlasMeasure -> Bool

Show AtlasMeasure

Methods

showsPrec :: Int -> AtlasMeasure -> ShowS

show :: AtlasMeasure -> String

showList :: [AtlasMeasure] -> ShowS

emptyAM :: AtlasMeasure

spacing :: Int

measure :: FT_Face -> Int -> AtlasMeasure -> Char -> FreeTypeIO AtlasMeasure

texturize :: IntMap (V2 Int) -> Atlas -> Char -> FreeTypeIO Atlas

allocAtlas

Arguments

:: MonadIO m

=> FilePath

FilePath of the Font to use for this Atlas.

-> GlyphSize

Size of glyphs in this Atlas

-> String

The characters to include in this Atlas.

-> m (Maybe Atlas)

Allocate a new Atlas. When creating a new Atlas you must pass all the characters that you might need during the life of the Atlas. Character texturization only happens here.

freeAtlas :: MonadIO m => Atlas -> m ()

Releases all resources associated with the given Atlas.

makeCharQuad :: MonadIO m => Atlas -> Bool -> (Int, Maybe FT_UInt) -> Char -> VerticesT (V2 Float, V2 Float) m (Int, Maybe FT_UInt)

asciiChars :: String

A string containing all standard ASCII characters. This is often passed as the String parameter in allocAtlas.

stringTris :: MonadIO m => Atlas -> Bool -> String -> VerticesT (V2 Float, V2 Float) m ()

freetypePicture

Arguments

:: MonadIO m

=> Atlas

The Atlas from which to read font textures word geometry.

-> String

The word to render.

-> TexturePictureT m ()

Returns a textured picture computation representing the texture and geometry of the input word.

Constructs a TexturePictureT of one word in all red. Colorization can then be done using setReplacementColor in the picture computation, or by using redChannelReplacement and passing that to the renderer after compilation, at render time. Keep in mind that any new word geometry will be discarded, since this computation does not return a new Atlas. For that reason it is advised that you load the needed words before using this function. For loading words, see loadWords.

This is used in freetypeRenderer2 to construct the geometry of each word. freetypeRenderer2 goes further and stores these geometries, looking them up and constructing a string of word renderers for each input String.

freetypeRenderer2

Arguments

:: MonadIO m

=> Backend GLuint e V2V2 (V2 Float) Float Raster

The V2V2 backend to use for compilation.

-> Atlas

The Atlas to read character textures from and load word geometry into.

-> V4 Float

The solid color to render the string with.

-> String

The string to render. This string can contain newlines, which will be respected.

-> m (Renderer2, V2 Float, Atlas)

Returns the Renderer2, the size of the text and the new Atlas with the loaded geometry of the string.

Constructs a Renderer2 from the given color and string. The WordMap record of the given Atlas is used to construct the string geometry, greatly improving performance and allowing longer strings to be compiled and renderered in real time. To create a new Atlas see allocAtlas.

Note that since word geometries are stored in the Atlas WordMap and multiple renderers can reference the same Atlas, the returned Renderer2 contains a clean up operation that does nothing. It is expected that the programmer will call freeAtlas manually when the Atlas is no longer needed.