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Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Cache ¶
type Cache struct {
// contains filtered or unexported fields
}
Cache implements cached layout and shaping of text from a set of registered fonts.
If a font matches no registered shape, Cache falls back to the first registered face.
The LayoutString and ShapeString results are cached and re-used if possible.
func (*Cache) Layout ¶
func (c *Cache) Layout(font Font, size fixed.Int26_6, maxWidth int, lc system.Locale, txt io.RuneReader) ([]Line, error)
Layout implements the Shaper interface.
type Face ¶
type Face interface {
Layout(ppem fixed.Int26_6, maxWidth int, lc system.Locale, txt io.RuneReader) ([]Line, error)
Shape(ppem fixed.Int26_6, str Layout) clip.PathSpec
}
Face implements text layout and shaping for a particular font. All methods must be safe for concurrent use.
type Font ¶
type Font struct {
Typeface Typeface
Variant Variant
Style Style
// Weight is the text weight. If zero, Normal is used instead.
Weight Weight
}
Font specify a particular typeface variant, style and weight.
type Glyph ¶
type Glyph struct {
// ID is this glyph's identifier within the font it was shaped with.
ID GlyphID
// ClusterIndex is the identifier for the text shaping cluster that
// this glyph is part of.
ClusterIndex int
// GlyphCount is the number of glyphs in the same cluster as this glyph.
GlyphCount int
// RuneCount is the quantity of runes in the source text that this glyph
// corresponds to.
RuneCount int
// XAdvance and YAdvance describe the distance the dot moves when
// laying out the glyph on the X or Y axis.
XAdvance, YAdvance fixed.Int26_6
// XOffset and YOffset describe offsets from the dot that should be
// applied when rendering the glyph.
XOffset, YOffset fixed.Int26_6
}
Glyph contains the metadata needed to render a glyph.
type GlyphCluster ¶
type GlyphCluster struct {
// Advance is the cumulative advance of all glyphs in the cluster.
Advance fixed.Int26_6
// Runes indicates the position and quantity of the runes represented by
// this cluster within the text.
Runes Range
// Glyphs indicates the position and quantity of the glyphs within this
// cluster in a Layout's Glyphs slice.
Glyphs Range
}
GlyphCluster provides metadata about a sequence of indivisible shaped glyphs.
func (GlyphCluster) RuneWidth ¶
func (c GlyphCluster) RuneWidth() fixed.Int26_6
RuneWidth returns the effective width of one rune for this cluster. If the cluster contains multiple runes, the width of the glyphs of the cluster is divided evenly among the runes.
type Layout ¶
type Layout struct {
// Glyphs are the actual font characters for the text. They are ordered
// from left to right regardless of the text direction of the underlying
// text.
Glyphs []Glyph
// Clusters are metadata about the shaped glyphs. They are mostly useful for
// interactive text widgets like editors. The order of clusters is logical,
// so the first cluster will describe the beginning of the text and may
// refer to the final glyphs in the Glyphs field if the text is RTL.
Clusters []GlyphCluster
// Runes describes the position of the text data this layout represents
// within the overall body of text being shaped.
Runes Range
// Direction is the layout direction of the text.
Direction system.TextDirection
}
type Line ¶
type Line struct {
Layout Layout
// Width is the width of the line.
Width fixed.Int26_6
// Ascent is the height above the baseline.
Ascent fixed.Int26_6
// Descent is the height below the baseline, including
// the line gap.
Descent fixed.Int26_6
// Bounds is the visible bounds of the line.
Bounds fixed.Rectangle26_6
}
A Line contains the measurements of a line of text.
type Range ¶
type Range struct {
// Count describes the number of items represented by the Range.
Count int
// Offset describes the start position of the represented
// items within a larger list.
Offset int
}
Range describes the position and quantity of a range of text elements within a larger slice. The unit is usually runes of unicode data or glyphs of shaped font data.
type Shaper ¶
type Shaper interface {
// Layout a text according to a set of options.
Layout(font Font, size fixed.Int26_6, maxWidth int, lc system.Locale, txt io.RuneReader) ([]Line, error)
// LayoutString is Layout for strings.
LayoutString(font Font, size fixed.Int26_6, maxWidth int, lc system.Locale, str string) []Line
// Shape a line of text and return a clipping operation for its outline.
Shape(font Font, size fixed.Int26_6, layout Layout) clip.PathSpec
}
Shaper implements layout and shaping of text.
type Typeface ¶
type Typeface string
Typeface identifies a particular typeface design. The empty string denotes the default typeface.
type Variant ¶
type Variant string
Variant denotes a typeface variant such as "Mono" or "Smallcaps".
type Weight ¶
type Weight int
Weight is a font weight, in CSS units subtracted 400 so the zero value is normal text weight.
const ( Thin Weight = 100 - 400 Hairline Weight = Thin ExtraLight Weight = 200 - 400 UltraLight Weight = ExtraLight Light Weight = 300 - 400 Normal Weight = 400 - 400 Medium Weight = 500 - 400 SemiBold Weight = 600 - 400 DemiBold Weight = SemiBold Bold Weight = 700 - 400 ExtraBold Weight = 800 - 400 UltraBold Weight = ExtraBold Black Weight = 900 - 400 Heavy Weight = Black ExtraBlack Weight = 950 - 400 UltraBlack Weight = ExtraBlack )
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