shaping

type Bounds struct {
	// Ascent is the maximum ascent away from the baseline. This value is typically
	// positive in coordiate systems that grow up.
	Ascent fixed.Int26_6
	// Descent is the maximum descent away from the baseline. This value is typically
	// negative in coordinate systems that grow up.
	Descent fixed.Int26_6
	// Gap is the height of empty pixels between lines. This value is typically positive
	// in coordinate systems that grow up.
	Gap fixed.Int26_6
}

type FontFeature struct {
	Tag   loader.Tag
	Value uint32
}

type Fontmap interface {
	// ResolveFace is called by `SplitByFace` for each input rune potentially
	// triggering a face change.
	// It must always return a valid (non nil) font.Face value.
	ResolveFace(r rune) font.Face
}

type Glyph struct {
	// Width is the width of the glyph content,
	// expressed as a distance from the [XBearing],
	// typically positive
	Width fixed.Int26_6
	// Height is the height of the glyph content,
	// expressed as a distance from the [YBearing],
	// typically negative
	Height fixed.Int26_6
	// XBearing is the distance between the dot (with offset applied) and
	// the glyph content, typically positive for horizontal text;
	// often negative for vertical text.
	XBearing fixed.Int26_6
	// YBearing is the distance between the dot (with offset applied) and
	// the top of the glyph content, typically positive
	YBearing fixed.Int26_6
	// XAdvance is the distance between the current dot (without offset applied) and the next dot.
	// It is typically positive for horizontal text, and always zero for vertical text.
	XAdvance fixed.Int26_6
	// YAdvance is the distance between the current dot (without offset applied) and the next dot.
	// It is typically negative for vertical text, and always zero for horizontal text.
	YAdvance fixed.Int26_6

	// Offsets to be applied to the dot before actually drawing
	// the glyph.
	// For vertical text, YOffset is typically used to position the glyph
	// below the horizontal line at the dot
	XOffset, YOffset fixed.Int26_6

	// ClusterIndex is the lowest rune index of all runes shaped into
	// this glyph cluster. All glyphs sharing the same cluster value
	// are part of the same cluster and will have identical RuneCount
	// and GlyphCount fields.
	ClusterIndex int
	// RuneCount is the number of input runes shaped into this output
	// glyph cluster.
	RuneCount int
	// GlyphCount is the number of glyphs in this output glyph cluster.
	GlyphCount int
	GlyphID    font.GID
	Mask       font.GlyphMask
}

type HarfbuzzShaper struct {
	// contains filtered or unexported fields
}

type Input struct {
	// Text is the body of text being shaped. Only the range Text[RunStart:RunEnd] is considered
	// for shaping, with the rest provided as context for the shaper. This helps with, for example,
	// cross-run Arabic shaping or handling combining marks at the start of a run.
	Text []rune
	// RunStart and RunEnd indicate the subslice of Text being shaped.
	RunStart, RunEnd int
	// Direction is the directionality of the text.
	Direction di.Direction
	// Face is the font face to render the text in.
	Face font.Face

	// FontFeatures activates or deactivates optional features
	// provided by the font.
	// The settings are applied to the whole [Text].
	FontFeatures []FontFeature

	// Size is the requested size of the font.
	// More generally, it is a scale factor applied to the resulting metrics.
	// For instance, given a device resolution (in dpi) and a point size (like 14), the `Size` to
	// get result in pixels is given by : pointSize * dpi / 72
	Size fixed.Int26_6

	// Script is an identifier for the writing system used in the text.
	Script language.Script

	// Language is an identifier for the language of the text.
	Language language.Language
}

type Line []Output

type LineBreakPolicy uint8

type LineWrapper struct {
	// contains filtered or unexported fields
}

type Output struct {
	// Advance is the distance the Dot has advanced.
	// It is typically positive for horizontal text, negative for vertical.
	Advance fixed.Int26_6
	// Size is copied from the shaping.Input.Size that produced this Output.
	Size fixed.Int26_6
	// Glyphs are the shaped output text.
	Glyphs []Glyph
	// LineBounds describes the font's suggested line bounding dimensions. The
	// dimensions described should contain any glyphs from the given font.
	LineBounds Bounds
	// GlyphBounds describes a tight bounding box on the specific glyphs contained
	// within this output. The dimensions may not be sufficient to contain all
	// glyphs within the chosen font.
	//
	// Its [Gap] field is always zero.
	GlyphBounds Bounds

	// Direction is the direction used to shape the text,
	// as provided in the Input.
	Direction di.Direction

	// Runes describes the runes this output represents from the input text.
	Runes Range

	// Face is the font face that this output is rendered in. This is needed in
	// the output in order to render each run in a multi-font sequence in the
	// correct font.
	Face font.Face
}

type Range struct {
	Offset int
	Count  int
}

type RunIterator interface {
	// Next returns the next run in the iterator, if any. If there is a next run,
	// its index, content, and true will be returned, and the iterator will advance
	// to the following element. Otherwise Next returns an undefined index, an empty
	// Output, and false.
	Next() (index int, run Output, isValid bool)
	// Peek returns the same thing Next() would, but does not advance the iterator (so the
	// next call to Next() will return the same thing).
	Peek() (index int, run Output, isValid bool)
	// Save marks the current iterator position such that the iterator can return to it later
	// when Restore() is called. Only one position may be saved at a time, with subsequent
	// calls to Save() overriding the current value.
	Save()
	// Restore resets the iteration state to the most recently Save()-ed position.
	Restore()
}

type Segmenter struct {
	// contains filtered or unexported fields
}

type Shaper interface {
	// Shape takes an Input and shapes it into the Output.
	Shape(Input) Output
}

type WrapConfig struct {
	// TruncateAfterLines is the number of lines of text to allow before truncating
	// the text. A value of zero means no limit.
	TruncateAfterLines int
	// Truncator, if provided, will be inserted at the end of a truncated line. This
	// feature is only active if TruncateAfterLines is nonzero.
	Truncator Output
	// TextContinues indicates that the paragraph wrapped by this config is not the
	// final paragraph in the text. This alters text truncation when filling the
	// final line permitted by TruncateAfterLines. If the text of this paragraph
	// does fit entirely on TruncateAfterLines, normally the truncator symbol would
	// not be inserted. However, if the overall body of text continues beyond this
	// paragraph (indicated by TextContinues), the truncator should still be inserted
	// to indicate that further paragraphs of text were truncated. This field has
	// no effect if TruncateAfterLines is zero.
	TextContinues bool
	// BreakPolicy determines under what circumstances the wrapper will consider
	// breaking in between UAX#14 line breaking candidates, or "within words" in
	// many scripts.
	BreakPolicy LineBreakPolicy
}

type WrappedLine struct {
	// Line is the content of the line, as a slice of shaped runs
	Line Line
	// Truncated is the count of runes truncated from the end of the line,
	// if this line was truncated.
	Truncated int
	// NextLine is the indice (in the input text slice) of the begining
	// of the next line. It will equal len(text) if all the text
	// fit in one line.
	NextLine int
}