| Portability | portable (depends on GHC) |
|---|---|
| Stability | provisional |
| Maintainer | gtk2hs-users@lists.sourceforge.net |
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 specificContextorPangoItem.
- data FontDescription
- fontDescriptionNew :: IO FontDescription
- fontDescriptionCopy :: FontDescription -> IO FontDescription
- fontDescriptionSetFamily :: FontDescription -> String -> IO ()
- fontDescriptionGetFamily :: 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
- fontDescriptionUnsetFields :: FontDescription -> [FontMask] -> IO ()
- fontDescriptionMerge :: FontDescription -> FontDescription -> Bool -> IO ()
- fontDescriptionBetterMatch :: FontDescription -> FontDescription -> FontDescription -> Bool
- fontDescriptionFromString :: String -> IO FontDescription
- fontDescriptionToString :: 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
fontDescriptionNew :: IO FontDescription
Create a new font description.
- All field are unset.
fontDescriptionCopy :: FontDescription -> IO FontDescription
Make a deep copy of a font description.
fontDescriptionSetFamily :: FontDescription -> String -> IO ()
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 :: FontDescription -> IO (Maybe String)
Get the font family.
-
Nothingis returned if the font family is not set.
fontDescriptionSetStyle :: FontDescription -> FontStyle -> IO ()
fontDescriptionGetStyle :: FontDescription -> IO (Maybe FontStyle)
Get the style field.
fontDescriptionSetVariant :: FontDescription -> Variant -> IO ()
Set the variant field.
fontDescriptionGetVariant :: FontDescription -> IO (Maybe Variant)
Get the variant field.
fontDescriptionSetWeight :: FontDescription -> Weight -> IO ()
Set the weight field.
fontDescriptionGetWeight :: FontDescription -> IO (Maybe Weight)
Get the weight field.
fontDescriptionSetStretch :: FontDescription -> Stretch -> IO ()
Set the stretch field.
fontDescriptionGetStretch :: FontDescription -> IO (Maybe Stretch)
Get the stretch field.
fontDescriptionSetSize :: FontDescription -> Double -> IO ()
Set the size field.
- The given size is in points (pts). One point is 1/72 inch.
fontDescriptionGetSize :: FontDescription -> IO (Maybe Double)
Get the size field.
data FontMask
Flags denoting which fields in a font description are set.
Constructors
| PangoFontMaskFamily | |
| PangoFontMaskStyle | |
| PangoFontMaskVariant | |
| PangoFontMaskWeight | |
| PangoFontMaskStretch | |
| PangoFontMaskSize | |
| PangoFontMaskGravity |
Instances
| Bounded FontMask | |
| Enum FontMask | Set the style field.
|
| Flags FontMask |
fontDescriptionUnsetFields :: FontDescription -> [FontMask] -> IO ()
Reset fields in a font description.
fontDescriptionMerge :: FontDescription -> FontDescription -> Bool -> IO ()
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
Determine which of two descriptions matches a given description better.
- Returns
Trueif 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 :: String -> IO FontDescription
Create a font description from a string.
- The given argument must have the form
[FAMILY-LIST] [STYLE-OPTIONS] [SIZE]whereFAMILY_LISTis a comma separated list of font families optionally terminated by a comma,STYLE_OPTIONSis a whitespace separated list of words where each word describes one of style, variant, weight or stretch.SIZEis a decimal number giving the size of the font in points. If any of these fields is absent, the resultingFontDescriptionwill have the corresponing fields unset.
fontDescriptionToString :: FontDescription -> IO String
Convert a font description to a string.
- Creates a string representation of a font description. See
fontDescriptionFromStringfor the format of the string.
data FontMap
Instances
class GObjectClass o => FontMapClass o
Instances
pangoFontMapListFamilies :: FontMap -> IO [FontFamily]
Ask for the different font families that a particular back-end supports.
- The
FontMapcan be acquired by callingGraphics.Rendering.Pango.Cairo.cairoFontMapGetDefault.
data FontFamily
class GObjectClass o => FontFamilyClass o
Instances
pangoFontFamilyIsMonospace :: FontFamily -> Bool
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
FontMetricsstructure.
pangoFontFamilyListFaces :: FontFamily -> IO [FontFace]
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
class GObjectClass o => FontFaceClass o
Instances
pangoFontFaceListSizes :: FontFace -> IO (Maybe [Double])
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
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.
class GObjectClass o => FontClass o