Typograffiti.Atlas

This module provides a font-character atlas to use in font rendering with opengl.

Documentation

data TypograffitiError

Represents a failure to render text.

Constructors

TypograffitiErrorNoMetricsForGlyph Int

The are no glyph metrics for this character. This probably means the character has not been loaded into the atlas.

TypograffitiErrorFreetype String Int32

There was a problem while interacting with the freetype2 library.

TypograffitiErrorGL String

There was a problem while interacting with OpenGL.

Instances

Eq TypograffitiError

Defined in Typograffiti.Atlas

Methods

(==) :: TypograffitiError -> TypograffitiError -> Bool

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

Show TypograffitiError

Defined in Typograffiti.Atlas

Methods

showsPrec :: Int -> TypograffitiError -> ShowS

show :: TypograffitiError -> String

showList :: [TypograffitiError] -> ShowS

data GlyphMetrics

Size & position of a Glyph in the Atlas.

Constructors

GlyphMetrics

Fields

• glyphTexBB :: (V2 Int, V2 Int)

  Bounding box of the glyph in the texture.

• glyphSize :: V2 Int

  Size of the glyph onscreen.

Instances

Eq GlyphMetrics

Defined in Typograffiti.Atlas

Methods

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

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

Show GlyphMetrics

Defined in Typograffiti.Atlas

Methods

showsPrec :: Int -> GlyphMetrics -> ShowS

show :: GlyphMetrics -> String

showList :: [GlyphMetrics] -> ShowS

data Atlas

Cache of rendered glyphs to be composited into place on the GPU.

Constructors

Atlas

Fields

• atlasTexture :: GLuint

  The texture holding the pre-rendered glyphs.

• atlasTextureSize :: V2 Int

  The size of the texture.

• atlasMetrics :: IntMap GlyphMetrics

  Mapping from glyphs to their position in the texture.

Instances

Show Atlas

Defined in Typograffiti.Atlas

Methods

showsPrec :: Int -> Atlas -> ShowS

show :: Atlas -> String

showList :: [Atlas] -> ShowS

emptyAtlas :: GLuint -> Atlas

Initializes an empty atlas.

data AtlasMeasure

Precomputed positioning of glyphs in an Atlas texture.

Constructors

AM

Fields

• amWH :: V2 Int

  Current size of the atlas as it has been laid out so far.

• amXY :: V2 Int

  Tentative position for the next glyph added to the atlas.

• rowHeight :: Int

  Height of the current row, for the sake of line wrapping.

• amMap :: IntMap (V2 Int)

  Position of each glyph in the atlas.

Instances

Eq AtlasMeasure

Defined in Typograffiti.Atlas

Methods

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

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

Show AtlasMeasure

Defined in Typograffiti.Atlas

Methods

showsPrec :: Int -> AtlasMeasure -> ShowS

show :: AtlasMeasure -> String

showList :: [AtlasMeasure] -> ShowS

emptyAM :: AtlasMeasure

Initializes a new AtlasMeasure.

spacing :: Int

The amount of spacing between glyphs rendered into the atlas's texture.

type GlyphRetriever m = Word32 -> m (FT_Bitmap, FT_Glyph_Metrics)

Callback for looking up a glyph from an atlas. Useful for applying synthetic styles to fonts which lack them, when calling the low-level APIs.

glyphRetriever :: (MonadIO m, MonadError TypograffitiError m) => FT_Face -> GlyphRetriever m

Default callback for glyph lookups, with no modifications.

measure :: (MonadIO m, MonadError TypograffitiError m) => GlyphRetriever m -> Int -> AtlasMeasure -> Word32 -> m AtlasMeasure

Extract the measurements of a character in the FT_Face and append it to the given AtlasMeasure.

texturize :: (MonadIO m, MonadError TypograffitiError m) => GlyphRetriever m -> IntMap (V2 Int) -> Atlas -> Word32 -> m Atlas

Uploads glyphs into an Atlas texture for the GPU to composite.

allocAtlas :: (MonadIO m, MonadFail m, MonadError TypograffitiError m) => GlyphRetriever m -> [Word32] -> m 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 once.

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

Releases all resources associated with the given Atlas.

type Quads = (Float, Float, [Vector (V2 Float, V2 Float)])

The geometry needed to render some text, with the position for the next glyph.

makeCharQuad :: (MonadIO m, MonadError TypograffitiError m) => Atlas -> Quads -> (GlyphInfo, GlyphPos) -> m Quads

Construct the geometry needed to render the given character.

stringTris :: (MonadIO m, MonadError TypograffitiError m) => Atlas -> [(GlyphInfo, GlyphPos)] -> m Quads

Generate the geometry of the given string, with next-glyph position.

stringTris' :: (MonadIO m, MonadError TypograffitiError m) => Atlas -> [(GlyphInfo, GlyphPos)] -> m (Vector (V2 Float, V2 Float))

Generate the geometry of the given string.

liftFreetype :: (MonadIO m, MonadError TypograffitiError m) => IO a -> m a

Internal utility to propagate FreeType errors into Typograffiti errors.