pango-0.13.1.0: Binding to the Pango text rendering engine.

Maintainer | gtk2hs-users@lists.sourceforge.net
Stability | provisional
Portability | portable (depends on GHC)
Safe Haskell | None
Language | Haskell98

Graphics.Rendering.Pango.Font

Description

Fonts. The selection of an appropriate font to render text becomes a substantial task in the presence of Unicode where a single font does not cover the whole range of possible characters. Pango provides several concepts to find appropriate fonts and to query information about them:

- `FontDescription`: Font descriptions provide a way to query and state requirements on fonts. This data structure has several fields describing different characteristics of a font. Each of these fields can be set of left unspecified.
- `FontMap` : A font map represents the set of fonts available for a particular rendering system. In particular this map defines the relation between font size and pixel size in terms of the output medium.
- `FontFamily` : A font family represents a set of fonts that have related faces, that is, their faces share a common design, but differ in slant, weight, width and other aspects.
- `FontFace`: A face is a specific font where all characteristics are fixed except for the size.
- `Font`: A font in the underlying rendering system.
- `FontMetrics`: Information about the font that will be used to render a specific `Context` or `PangoItem`.

Synopsis

- data FontDescription
- fontDescriptionNew :: IO FontDescription
- fontDescriptionCopy :: FontDescription -> IO FontDescription
- fontDescriptionSetFamily :: GlibString string => FontDescription -> string -> IO ()
- fontDescriptionGetFamily :: GlibString string => FontDescription -> IO (Maybe string)
- fontDescriptionSetStyle :: FontDescription -> FontStyle -> IO ()
- fontDescriptionGetStyle :: FontDescription -> IO (Maybe FontStyle)
- fontDescriptionSetVariant :: FontDescription -> Variant -> IO ()
- fontDescriptionGetVariant :: FontDescription -> IO (Maybe Variant)
- fontDescriptionSetWeight :: FontDescription -> Weight -> IO ()
- fontDescriptionGetWeight :: FontDescription -> IO (Maybe Weight)
- fontDescriptionSetStretch :: FontDescription -> Stretch -> IO ()
- fontDescriptionGetStretch :: FontDescription -> IO (Maybe Stretch)
- fontDescriptionSetSize :: FontDescription -> Double -> IO ()
- fontDescriptionGetSize :: FontDescription -> IO (Maybe Double)
- data FontMask
  - = PangoFontMaskFamily
  - | PangoFontMaskStyle
  - | PangoFontMaskVariant
  - | PangoFontMaskWeight
  - | PangoFontMaskStretch
  - | PangoFontMaskSize
  - | PangoFontMaskGravity
- fontDescriptionUnsetFields :: FontDescription -> [FontMask] -> IO ()
- fontDescriptionMerge :: FontDescription -> FontDescription -> Bool -> IO ()
- fontDescriptionBetterMatch :: FontDescription -> FontDescription -> FontDescription -> Bool
- fontDescriptionFromString :: GlibString string => string -> IO FontDescription
- fontDescriptionToString :: GlibString string => FontDescription -> IO string
- data FontMap
- class GObjectClass o => FontMapClass o
- pangoFontMapListFamilies :: FontMap -> IO [FontFamily]
- data FontFamily
- class GObjectClass o => FontFamilyClass o
- pangoFontFamilyIsMonospace :: FontFamily -> Bool
- pangoFontFamilyListFaces :: FontFamily -> IO [FontFace]
- data FontFace
- class GObjectClass o => FontFaceClass o
- pangoFontFaceListSizes :: FontFace -> IO (Maybe [Double])
- pangoFontFaceDescribe :: FontFace -> IO FontDescription
- data Font
- class GObjectClass o => FontClass o

# Documentation

data FontDescription Source

A possibly partial description of font(s).

Instances

Show FontDescription Source |

fontDescriptionNew :: IO FontDescription Source

Create a new font description.

- All field are unset.

fontDescriptionCopy :: FontDescription -> IO FontDescription Source

Make a deep copy of a font description.

fontDescriptionSetFamily :: GlibString string => FontDescription -> string -> IO () Source

Set the font famliy.

- A font family is a name designating the design of the font (e.g. Sans or Times) without the variant.
- In some contexts a comma separated list of font families can be used.

fontDescriptionGetFamily :: GlibString string => FontDescription -> IO (Maybe string) Source

Get the font family.

- `Nothing` is returned if the font family is not set.

fontDescriptionSetStyle :: FontDescription -> FontStyle -> IO () Source

fontDescriptionGetStyle :: FontDescription -> IO (Maybe FontStyle) Source

Get the style field.

fontDescriptionSetVariant :: FontDescription -> Variant -> IO () Source

Set the variant field.

fontDescriptionGetVariant :: FontDescription -> IO (Maybe Variant) Source

Get the variant field.

fontDescriptionSetWeight :: FontDescription -> Weight -> IO () Source

Set the weight field.

fontDescriptionGetWeight :: FontDescription -> IO (Maybe Weight) Source

Get the weight field.

fontDescriptionSetStretch :: FontDescription -> Stretch -> IO () Source

Set the stretch field.

fontDescriptionGetStretch :: FontDescription -> IO (Maybe Stretch) Source

Get the stretch field.

fontDescriptionSetSize :: FontDescription -> Double -> IO () Source

Set the size field.

- The given size is in points (pts). One point is 1/72 inch.

fontDescriptionGetSize :: FontDescription -> IO (Maybe Double) Source

Get the size field.

data FontMask Source

Flags denoting which fields in a font description are set.

Constructors

PangoFontMaskFamily |
PangoFontMaskStyle |
PangoFontMaskVariant |
PangoFontMaskWeight |
PangoFontMaskStretch |
PangoFontMaskSize |
PangoFontMaskGravity |

Instances

Bounded FontMask Source |

Enum FontMask Source

Set the style field.

- Most fonts will have either a `StyleItalic` or `StyleOblique` but rarely both.

Flags FontMask Source |

fontDescriptionUnsetFields :: FontDescription -> [FontMask] -> IO () Source

Reset fields in a font description.

fontDescriptionMerge :: FontDescription -> FontDescription -> Bool -> IO () Source

Merge two font descriptions.

- Copy fields from the second description to the first. If the boolean parameter is set, existing fields in the first description will be replaced.

fontDescriptionBetterMatch :: FontDescription -> FontDescription -> FontDescription -> Bool Source

Determine which of two descriptions matches a given description better.

- Returns `True` if the last description is a better match to the first arguement than the middle one.
- Approximate matching is done on weight and style. If the other attributes do not match, the function returns `False`.

fontDescriptionFromString :: GlibString string => string -> IO FontDescription Source

Create a font description from a string.

- The given argument must have the form `[FAMILY-LIST] [STYLE-OPTIONS] [SIZE]` where `FAMILY_LIST` is a comma separated list of font families optionally terminated by a comma, `STYLE_OPTIONS` is a whitespace separated list of words where each word describes one of style, variant, weight or stretch. `SIZE` is a decimal number giving the size of the font in points. If any of these fields is absent, the resulting `FontDescription` will have the corresponing fields unset.

fontDescriptionToString :: GlibString string => FontDescription -> IO string Source

Convert a font description to a string.

- Creates a string representation of a font description. See `fontDescriptionFromString` for the format of the string.

data FontMap Source

Instances

Eq FontMap Source |
Ord FontMap Source |
GObjectClass FontMap Source |
FontMapClass FontMap Source |

class GObjectClass o => FontMapClass o Source

Instances

FontMapClass FontMap Source |

pangoFontMapListFamilies :: FontMap -> IO [FontFamily] Source

Ask for the different font families that a particular back-end supports.

- The `FontMap` can be acquired by calling `cairoFontMapGetDefault`.

data FontFamily Source

Instances

Eq FontFamily Source |
Ord FontFamily Source |
GObjectClass FontFamily Source |
FontFamilyClass FontFamily Source |

class GObjectClass o => FontFamilyClass o Source

Instances

FontFamilyClass FontFamily Source |

pangoFontFamilyIsMonospace :: FontFamily -> Bool Source

Ask if the given family contains monospace fonts.

- A monospace font is a font designed for text display where the characters form a regular grid. For Western languages this would mean that the advance width of all characters are the same, but this categorization also includes Asian fonts which include double-width characters: characters that occupy two grid cells.
- The best way to find out the grid-cell size is to query the members of the according `FontMetrics` structure.

pangoFontFamilyListFaces :: FontFamily -> IO [FontFace] Source

Ask for the faces contained in a particular family.

- Asks for all font faces in the given family. The faces in a family share a common design, but differ in slant, weight, width and other aspects. For example, the font family Sans contains several fonts such as Helvetica and Arial.

data FontFace Source

Instances

Eq FontFace Source |
Ord FontFace Source |
GObjectClass FontFace Source |
FontFaceClass FontFace Source |

class GObjectClass o => FontFaceClass o Source

Instances

FontFaceClass FontFace Source |

pangoFontFaceListSizes :: FontFace -> IO (Maybe [Double]) Source

Ask for available sizes of this font face.

- List the available sizes for a font. This is only applicable to bitmap fonts since all other fonts can be scaled arbitrarily. For scalable fonts, this function returns `Nothing`. The sizes returned are in ascending order, their unit is points (1/72 inch).

pangoFontFaceDescribe :: FontFace -> IO FontDescription Source

Ask for a description of this face.

- Returns the family, style, variant, weight and stretch of a `FontFace`. The size field of the resulting font description will be unset.

data Font Source

Instances

Eq Font Source |
Ord Font Source |
GObjectClass Font Source |
FontClass Font Source |

class GObjectClass o => FontClass o Source

Instances

FontClass Font Source |