GI.Pango.Structs.FontMetrics

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.

Exported types

newtype FontMetrics

Memory-managed wrapper type.

Constructors

FontMetrics (ManagedPtr FontMetrics)

Instances

Eq FontMetrics

Defined in GI.Pango.Structs.FontMetrics

Methods

(==) :: FontMetrics -> FontMetrics -> Bool

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

BoxedObject FontMetrics

Defined in GI.Pango.Structs.FontMetrics

Methods

boxedType :: FontMetrics -> IO GType

IsGValue FontMetrics

Convert FontMetrics to and from GValue with toGValue and fromGValue.

Defined in GI.Pango.Structs.FontMetrics

Methods

toGValue :: FontMetrics -> IO GValue

fromGValue :: GValue -> IO FontMetrics

tag ~ 'AttrSet => Constructible FontMetrics tag

Defined in GI.Pango.Structs.FontMetrics

Methods

new :: MonadIO m => (ManagedPtr FontMetrics -> FontMetrics) -> [AttrOp FontMetrics tag] -> m FontMetrics

newZeroFontMetrics :: MonadIO m => m FontMetrics

Construct a FontMetrics struct initialized to zero.

noFontMetrics :: Maybe FontMetrics

A convenience alias for Nothing :: Maybe FontMetrics.

Methods

Overloaded methods

getApproximateCharWidth

fontMetricsGetApproximateCharWidth

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

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

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

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

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

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

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

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

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

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

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.