gi-pango-1.0.21: Pango bindings

CopyrightWill Thompson Iñaki García Etxebarria and Jonas Platte
LicenseLGPL-2.1
MaintainerIñaki García Etxebarria (inaki@blueleaf.cc)
Safe HaskellNone
LanguageHaskell2010

GI.Pango.Structs.FontMetrics

Contents

Description

A FontMetrics structure holds the overall metric information for a font (possibly restricted to a script). The fields of this structure are private to implementations of a font backend. See the documentation of the corresponding getters for documentation of their meaning.

Synopsis

Exported types

newtype FontMetrics Source #

Memory-managed wrapper type.

Instances
BoxedObject FontMetrics Source # 
Instance details

Defined in GI.Pango.Structs.FontMetrics

tag ~ AttrSet => Constructible FontMetrics tag Source # 
Instance details

Defined in GI.Pango.Structs.FontMetrics

newZeroFontMetrics :: MonadIO m => m FontMetrics Source #

Construct a FontMetrics struct initialized to zero.

Methods

getApproximateCharWidth

fontMetricsGetApproximateCharWidth Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the character width, in Pango units.

Gets the approximate character width for a font metrics structure. This is merely a representative value useful, for example, for determining the initial size for a window. Actual characters in text will be wider and narrower than this.

getApproximateDigitWidth

fontMetricsGetApproximateDigitWidth Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the digit width, in Pango units.

Gets the approximate digit width for a font metrics structure. This is merely a representative value useful, for example, for determining the initial size for a window. Actual digits in text can be wider or narrower than this, though this value is generally somewhat more accurate than the result of fontMetricsGetApproximateCharWidth for digits.

getAscent

fontMetricsGetAscent Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the ascent, in Pango units.

Gets the ascent from a font metrics structure. The ascent is the distance from the baseline to the logical top of a line of text. (The logical top may be above or below the top of the actual drawn ink. It is necessary to lay out the text to figure where the ink will be.)

getDescent

fontMetricsGetDescent Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the descent, in Pango units.

Gets the descent from a font metrics structure. The descent is the distance from the baseline to the logical bottom of a line of text. (The logical bottom may be above or below the bottom of the actual drawn ink. It is necessary to lay out the text to figure where the ink will be.)

getStrikethroughPosition

fontMetricsGetStrikethroughPosition Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the suggested strikethrough position, in Pango units.

Gets the suggested position to draw the strikethrough. The value returned is the distance <emphasis>above</emphasis> the baseline of the top of the strikethrough.

Since: 1.6

getStrikethroughThickness

fontMetricsGetStrikethroughThickness Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the suggested strikethrough thickness, in Pango units.

Gets the suggested thickness to draw for the strikethrough.

Since: 1.6

getUnderlinePosition

fontMetricsGetUnderlinePosition Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the suggested underline position, in Pango units.

Gets the suggested position to draw the underline. The value returned is the distance <emphasis>above</emphasis> the baseline of the top of the underline. Since most fonts have underline positions beneath the baseline, this value is typically negative.

Since: 1.6

getUnderlineThickness

fontMetricsGetUnderlineThickness Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure

-> m Int32

Returns: the suggested underline thickness, in Pango units.

Gets the suggested thickness to draw for the underline.

Since: 1.6

new

fontMetricsNew Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> m FontMetrics

Returns: a newly-created FontMetrics structure with a reference count of 1.

Creates a new FontMetrics structure. This is only for internal use by Pango backends and there is no public way to set the fields of the structure.

ref

fontMetricsRef Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure, may be Nothing

-> m (Maybe FontMetrics)

Returns: metrics

Increase the reference count of a font metrics structure by one.

unref

fontMetricsUnref Source #

Arguments

:: (HasCallStack, MonadIO m) 
=> FontMetrics

metrics: a FontMetrics structure, may be Nothing

-> m () 

Decrease the reference count of a font metrics structure by one. If the result is zero, frees the structure and any associated memory.