|Portability||portable (depends on GHC)|
Functions to run the rendering pipeline.
- This module provides elementary rendering functions. For a simpler
interface, consider using
- The Pango rendering pipeline takes a string of Unicode characters,
divides them into sequences of letters that have the same characteristics
such as font, size, color, etc. Such a sequence is called
PangoItemis then converted into one
GlyphItem, that is an actual sequence of glyphs, where several characters might be turned into legatures or clusters, e.g. an "e" and an accent modifier are turned into a single glyph. These
GlyphItems can then be rendered onto the output device with functions such as
- data PangoItem
- pangoItemize :: PangoContext -> String -> [PangoAttribute] -> IO [PangoItem]
- pangoItemGetFontMetrics :: PangoItem -> IO FontMetrics
- pangoItemGetFont :: PangoItem -> IO Font
- pangoItemGetLanguage :: PangoItem -> IO Language
- data GlyphItem
- pangoShape :: PangoItem -> IO GlyphItem
- glyphItemExtents :: GlyphItem -> IO (PangoRectangle, PangoRectangle)
- glyphItemExtentsRange :: GlyphItem -> Int -> Int -> IO (PangoRectangle, PangoRectangle)
- glyphItemIndexToX :: GlyphItem -> Int -> Bool -> IO Double
- glyphItemXToIndex :: GlyphItem -> Double -> IO (Int, Bool)
- glyphItemGetLogicalWidths :: GlyphItem -> Maybe Bool -> IO [Double]
- glyphItemSplit :: GlyphItem -> Int -> IO (GlyphItem, GlyphItem)
PangoItem: Partition text into units with similar attributes.
A sequence of characters that are rendered with the same settings.
Turn a string into a sequence of glyphs.
- Partitions the input string into segments with the same text direction and shaping engine. The generated list of items will be in logical order (the start offsets of the items are ascending).
Retrieve the metrics of the font that was chosen to break the given
GlyphItem: Turn text segments into glyph sequences.
A sequence of glyphs for a chunk of a string.
- A glyph item contains the graphical representation of a
PangoItem. Clusters (like
eand an accent modifier) as well as legatures (such as
ffiturning into a single letter that omits the dot over the
i) are usually represented as a single glyph.
Ask for bounding rectangles of this glyph sequence.
- Compute the logical and ink extents of a glyph string. The logical extend is used for positioning, the ink size is the smallest bounding box that includes all character pixels. The ink size can be smaller or larger that the logical layout.
Ask for bounding rectangles for a sub-range of a glyph sequence.
- The returned rectangles are relative to the given sub-range, that is,
the result of this function is the same as if
glyphItemExtentswere called on the sub-string.
the rendered string
the index into the string
return the beginning (
|-> IO Double|
Get the horizontal position of a character.
- Clusters (e.g. "e" with an accent modifier) are divided up into equal portions.
Get the character at the given horizontal position.
- The position is clipped to the width of this line.
- The function returns the position in the string that corresponds
to the given horizontal location. Furthermore, if the position lies
on the first half of the character,
Retrieve the width of every character in a string.
- The boolean parameter
determines if the returned array starts with the leftmost glyph
False) or with the rightmost glyph (
Nothingis passed in, the direction is taken from the
GlyphItem, i.e., the array starts with the leftmost glyph for left-to-rigth text and with the rightmost glyph for right-to-left text. When multiple characters compose a single glyph, the width of this glyph is divided among the characters that compose this cluster.