Gtk2HsContentsIndex
Graphics.UI.Gtk.Pango.Context
Portabilityportable (depends on GHC)
Stabilityprovisional
Maintainergtk2hs-users@lists.sourceforge.net
Contents
Types and Methods for PangoContexts
Description

This module defines PangoContexts, an environment that provides information on available fonts, internationalization and output capabilities of the medium. Given such a context, text can be rendered into strings of glyphs (see Rendering) or, at a more abstract level, using layouts (see Layout).

  • A PangoContext is a prerequisite for all text rendering functions. A context can be created from scratch or, more conveniently, by using default settings that are already used in the application. When text is rendered through Gdk, use widgetCreatePangoContext, if you use the Cairo rendering engine, a new context can be acquired using cairoCreateContext.
  • The properties of a PangoContext can be changed which, in turn, has an effect on how text is rendered. To reflect such a change in the rendered text, call layoutContextChanged.
Synopsis
data PangoContext
data PangoDirection
= PangoDirectionLtr
| PangoDirectionRtl
| PangoDirectionWeakLtr
| PangoDirectionWeakRtl
| PangoDirectionNeutral
contextListFamilies :: PangoContext -> IO [FontFamily]
contextGetMetrics :: PangoContext -> FontDescription -> Language -> IO FontMetrics
contextSetFontDescription :: PangoContext -> FontDescription -> IO ()
contextGetFontDescription :: PangoContext -> IO FontDescription
data Language
languageFromString :: String -> IO Language
contextSetLanguage :: PangoContext -> Language -> IO ()
contextGetLanguage :: PangoContext -> IO Language
contextSetTextDir :: PangoContext -> PangoDirection -> IO ()
contextGetTextDir :: PangoContext -> IO PangoDirection
Types and Methods for PangoContexts
data PangoContext
show/hide Instances
data PangoDirection

The PangoDirection type represents a direction in the Unicode bidirectional algorithm.

  • The "weak" values denote a left-to-right or right-to-left direction only if there is no character with a strong direction in a paragraph. An example is a sequence of special, graphical characters which are neutral with respect to their rendering direction. A fresh PangoContext is by default weakly left-to-right.
  • Not every value in this enumeration makes sense for every usage of PangoDirection; for example, the return value of unicharDirection and findBaseDir cannot be PangoDirectionWeakLtr or PangoDirectionWeakRtl, since every character is either neutral or has a strong direction; on the other hand PangoDirectionNeutral doesn't make sense to pass to log2visGetEmbeddingLevels.
Constructors
PangoDirectionLtr
PangoDirectionRtl
PangoDirectionWeakLtr
PangoDirectionWeakRtl
PangoDirectionNeutral
show/hide Instances
contextListFamilies :: PangoContext -> IO [FontFamily]

Retrieve a list of all available font families.

  • A font family is the name of the font without further attributes like slant, variant or size.
contextGetMetrics :: PangoContext -> FontDescription -> Language -> IO FontMetrics
Query the metrics of the given font implied by the font description.
contextSetFontDescription :: PangoContext -> FontDescription -> IO ()
Set the default FontDescription of this context.
contextGetFontDescription :: PangoContext -> IO FontDescription
Get the current FontDescription of this context.
data Language
An RFC-3066 language designator to choose scripts.
show/hide Instances
languageFromString :: String -> IO Language

Take a RFC-3066 format language tag as a string and convert it to a Language type that can be efficiently passed around and compared with other language tags.

  • This function first canonicalizes the string by converting it to lowercase, mapping '_' to '-', and stripping all characters other than letters and '-'.
contextSetLanguage :: PangoContext -> Language -> IO ()
Set the default Language of this context.
contextGetLanguage :: PangoContext -> IO Language
Get the current Language of this context.
contextSetTextDir :: PangoContext -> PangoDirection -> IO ()
Set the default text direction of this context.
contextGetTextDir :: PangoContext -> IO PangoDirection
Get the current text direction of this context.
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