~eliasnaur/gio

b331407e8145648c6804788a41e89fe77c9a2a2d — Elias Naur 8 months ago 16d2a3a
text: add io.Reader Layout method to Shaper

use them for Editor, which is no longer required to construct a string
for laying out its content.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
6 files changed, 123 insertions(+), 53 deletions(-)

M font/opentype/opentype.go
M text/shaper.go
M text/text.go
M widget/buffer.go
M widget/editor.go
M widget/label.go
M font/opentype/opentype.go => font/opentype/opentype.go +64 -31
@@ 85,8 85,12 @@ func (c *Collection) Font(i int) (*Font, error) {
	return &Font{font: fnt}, nil
}

func (f *Font) Layout(ppem fixed.Int26_6, str string, opts text.LayoutOptions) []text.Line {
	return layoutText(&f.buf, ppem, str, &opentype{Font: f.font, Hinting: font.HintingFull}, opts)
func (f *Font) Layout(ppem fixed.Int26_6, txt io.Reader, opts text.LayoutOptions) ([]text.Line, error) {
	glyphs, err := readGlyphs(txt)
	if err != nil {
		return nil, err
	}
	return layoutText(&f.buf, ppem, &opentype{Font: f.font, Hinting: font.HintingFull}, glyphs, opts)
}

func (f *Font) Shape(ppem fixed.Int26_6, str []text.Glyph) op.CallOp {


@@ 98,59 102,59 @@ func (f *Font) Metrics(ppem fixed.Int26_6) font.Metrics {
	return o.Metrics(&f.buf, ppem)
}

func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, opts text.LayoutOptions) []text.Line {
	m := f.Metrics(buf, ppem)
func layoutText(sbuf *sfnt.Buffer, ppem fixed.Int26_6, f *opentype, glyphs []text.Glyph, opts text.LayoutOptions) ([]text.Line, error) {
	m := f.Metrics(sbuf, ppem)
	lineTmpl := text.Line{
		Ascent: m.Ascent,
		// m.Height is equal to m.Ascent + m.Descent + linegap.
		// Compute the descent including the linegap.
		Descent: m.Height - m.Ascent,
		Bounds:  f.Bounds(buf, ppem),
		Bounds:  f.Bounds(sbuf, ppem),
	}
	var lines []text.Line
	maxDotX := fixed.I(opts.MaxWidth)
	type state struct {
		r      rune
		layout []text.Glyph
		adv    fixed.Int26_6
		x      fixed.Int26_6
		idx    int
		valid  bool
		r     rune
		adv   fixed.Int26_6
		x     fixed.Int26_6
		idx   int
		len   int
		valid bool
	}
	var prev, word state
	endLine := func() {
		line := lineTmpl
		line.Layout = prev.layout
		line.Len = prev.idx
		line.Layout = glyphs[:prev.idx:prev.idx]
		line.Len = prev.len
		line.Width = prev.x + prev.adv
		line.Bounds.Max.X += prev.x
		lines = append(lines, line)
		str = str[prev.idx:]
		glyphs = glyphs[prev.idx:]
		prev = state{}
		word = state{}
	}
	for prev.idx < len(str) {
		c, s := utf8.DecodeRuneInString(str[prev.idx:])
		a, valid := f.GlyphAdvance(buf, ppem, c)
	for prev.idx < len(glyphs) {
		g := &glyphs[prev.idx]
		a, valid := f.GlyphAdvance(sbuf, ppem, g.Rune)
		next := state{
			r:      c,
			layout: prev.layout,
			idx:    prev.idx + s,
			x:      prev.x + prev.adv,
			adv:    a,
			valid:  valid,
			r:     g.Rune,
			idx:   prev.idx + 1,
			len:   prev.len + utf8.RuneLen(g.Rune),
			x:     prev.x + prev.adv,
			adv:   a,
			valid: valid,
		}
		if c == '\n' {
		if g.Rune == '\n' {
			// The newline is zero width; use the previous
			// character for line measurements.
			prev.layout = append(prev.layout, text.Glyph{Rune: c, Advance: 0})
			prev.idx = next.idx
			prev.len = next.len
			endLine()
			continue
		}
		var k fixed.Int26_6
		if prev.valid {
			k = f.Kern(buf, ppem, prev.r, next.r)
			k = f.Kern(sbuf, ppem, prev.r, next.r)
		}
		// Break the line if we're out of space.
		if prev.idx > 0 && next.x+next.adv+k > maxDotX {


@@ 160,21 164,21 @@ func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, o
			}
			next.x -= word.x + word.adv
			next.idx -= word.idx
			next.layout = next.layout[len(word.layout):]
			next.len -= word.len
			prev = word
			endLine()
		} else if k != 0 {
			next.layout[len(next.layout)-1].Advance += k
			glyphs[prev.idx-1].Advance += k
			next.x += k
		}
		next.layout = append(next.layout, text.Glyph{Rune: c, Advance: next.adv})
		if unicode.IsSpace(c) {
		g.Advance = next.adv
		if unicode.IsSpace(g.Rune) {
			word = next
		}
		prev = next
	}
	endLine()
	return lines
	return lines, nil
}

func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, f *opentype, str []text.Glyph) op.CallOp {


@@ 237,6 241,35 @@ func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, f *opentype, str []text.Glyp
	return op.CallOp{Ops: ops}
}

func readGlyphs(r io.Reader) ([]text.Glyph, error) {
	var glyphs []text.Glyph
	buf := make([]byte, 0, 1024)
	for {
		n, err := r.Read(buf[len(buf):cap(buf)])
		buf = buf[:len(buf)+n]
		lim := len(buf)
		// Read full runes if possible.
		if err != io.EOF {
			lim -= utf8.UTFMax - 1
		}
		i := 0
		for i < lim {
			c, s := utf8.DecodeRune(buf[i:])
			i += s
			glyphs = append(glyphs, text.Glyph{Rune: c})
		}
		n = copy(buf, buf[i:])
		buf = buf[:n]
		if err != nil {
			if err == io.EOF {
				break
			}
			return nil, err
		}
	}
	return glyphs, nil
}

func (f *opentype) GlyphAdvance(buf *sfnt.Buffer, ppem fixed.Int26_6, r rune) (advance fixed.Int26_6, ok bool) {
	g, err := f.Font.GlyphIndex(buf, r)
	if err != nil {

M text/shaper.go => text/shaper.go +33 -8
@@ 3,6 3,9 @@
package text

import (
	"io"
	"strings"

	"golang.org/x/image/font"

	"gioui.org/op"


@@ 13,17 16,27 @@ import (
// Shaper implements layout and shaping of text.
type Shaper interface {
	// Layout a text according to a set of options.
	Layout(c unit.Converter, font Font, str string, opts LayoutOptions) []Line
	// Shape a line of text previously laid out by Layout.
	Shape(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp
	Layout(c unit.Converter, font Font, txt io.Reader, opts LayoutOptions) ([]Line, error)
	// Shape a line of text and return a clipping operation for its outline.
	Shape(c unit.Converter, font Font, layout []Glyph) op.CallOp

	// LayoutString is like Layout, but for strings..
	LayoutString(c unit.Converter, font Font, str string, opts LayoutOptions) []Line
	// ShapeString is like Shape for lines previously laid out by LayoutString.
	ShapeString(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp

	// Metrics returns the font metrics for font.
	Metrics(c unit.Converter, font Font) font.Metrics
}

// FontRegistry implements layout and shaping of text and a cache of
// computed results.
// FontRegistry implements layout and shaping of text from a set of
// registered fonts.
//
// If a font matches no registered shape, FontRegistry falls back to the
// first registered face.
//
// The LayoutString and ShapeString results are cached and re-used if
// possible.
type FontRegistry struct {
	def   Typeface
	faces map[Font]*face


@@ 50,12 63,24 @@ func (s *FontRegistry) Register(font Font, tf Face) {
	}
}

func (s *FontRegistry) Layout(c unit.Converter, font Font, str string, opts LayoutOptions) []Line {
func (s *FontRegistry) Layout(c unit.Converter, font Font, txt io.Reader, opts LayoutOptions) ([]Line, error) {
	tf := s.faceForFont(font)
	ppem := fixed.I(c.Px(font.Size))
	return tf.face.Layout(ppem, txt, opts)
}

func (s *FontRegistry) Shape(c unit.Converter, font Font, layout []Glyph) op.CallOp {
	tf := s.faceForFont(font)
	ppem := fixed.I(c.Px(font.Size))
	return tf.face.Shape(ppem, layout)
}

func (s *FontRegistry) LayoutString(c unit.Converter, font Font, str string, opts LayoutOptions) []Line {
	tf := s.faceForFont(font)
	return tf.layout(fixed.I(c.Px(font.Size)), str, opts)
}

func (s *FontRegistry) Shape(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp {
func (s *FontRegistry) ShapeString(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp {
	tf := s.faceForFont(font)
	return tf.shape(fixed.I(c.Px(font.Size)), str, layout)
}


@@ 108,7 133,7 @@ func (t *face) layout(ppem fixed.Int26_6, str string, opts LayoutOptions) []Line
	if l, ok := t.layoutCache.Get(lk); ok {
		return l
	}
	l := t.face.Layout(ppem, str, opts)
	l, _ := t.face.Layout(ppem, strings.NewReader(str), opts)
	t.layoutCache.Put(lk, l)
	return l
}

M text/text.go => text/text.go +3 -1
@@ 3,6 3,8 @@
package text

import (
	"io"

	"gioui.org/op"
	"gioui.org/unit"
	"golang.org/x/image/font"


@@ 54,7 56,7 @@ type Font struct {

// Face implements text layout and shaping for a particular font.
type Face interface {
	Layout(ppem fixed.Int26_6, str string, opts LayoutOptions) []Line
	Layout(ppem fixed.Int26_6, txt io.Reader, opts LayoutOptions) ([]Line, error)
	Shape(ppem fixed.Int26_6, str []Glyph) op.CallOp
	Metrics(ppem fixed.Int26_6) font.Metrics
}

M widget/buffer.go => widget/buffer.go +17 -5
@@ 95,18 95,30 @@ func (e *editBuffer) gapLen() int {
	return e.gapend - e.gapstart
}

func (e *editBuffer) Reset() {
	e.pos = 0
}

func (e *editBuffer) Read(p []byte) (int, error) {
	if e.pos == e.len() {
		return 0, io.EOF
	}
	var n int
	var total int
	if e.pos < e.gapstart {
		n += copy(p, e.text[e.pos:e.gapstart])
		n := copy(p, e.text[e.pos:e.gapstart])
		p = p[n:]
		total += n
		e.pos += n
	}
	if e.pos >= e.gapstart {
		n := copy(p, e.text[e.pos+e.gapLen():])
		total += n
		e.pos += n
	}
	if e.pos > e.len() {
		panic("hey!")
	}
	n += copy(p, e.text[e.gapend:])
	e.pos += n
	return n, nil
	return total, nil
}

func (e *editBuffer) ReadRune() (rune, int, error) {

M widget/editor.go => widget/editor.go +4 -6
@@ 273,13 273,11 @@ func (e *Editor) layout(gtx *layout.Context, sh text.Shaper) {
	}
	e.shapes = e.shapes[:0]
	for {
		start, end, layout, off, ok := it.Next()
		_, _, layout, off, ok := it.Next()
		if !ok {
			break
		}
		// TODO: remove
		str := e.rr.String()[start:end]
		path := sh.Shape(gtx, e.font, str, layout)
		path := sh.Shape(gtx, e.font, layout)
		e.shapes = append(e.shapes, line{off, path})
	}



@@ 433,9 431,9 @@ func (e *Editor) moveCoord(c unit.Converter, pos image.Point) {
}

func (e *Editor) layoutText(c unit.Converter, s text.Shaper, font text.Font) ([]text.Line, layout.Dimensions) {
	txt := e.rr.String()
	e.rr.Reset()
	opts := text.LayoutOptions{MaxWidth: e.maxWidth}
	lines := s.Layout(c, font, txt, opts)
	lines, _ := s.Layout(c, font, &e.rr, opts)
	dims := linesDimens(lines)
	for i := 0; i < len(lines)-1; i++ {
		// To avoid layout flickering while editing, assume a soft newline takes

M widget/label.go => widget/label.go +2 -2
@@ 85,7 85,7 @@ func (l *lineIterator) Next() (int, int, []text.Glyph, f32.Point, bool) {

func (l Label) Layout(gtx *layout.Context, s text.Shaper, font text.Font, txt string) {
	cs := gtx.Constraints
	lines := s.Layout(gtx, font, txt, text.LayoutOptions{MaxWidth: cs.Width.Max})
	lines := s.LayoutString(gtx, font, txt, text.LayoutOptions{MaxWidth: cs.Width.Max})
	if max := l.MaxLines; max > 0 && len(lines) > max {
		lines = lines[:max]
	}


@@ 109,7 109,7 @@ func (l Label) Layout(gtx *layout.Context, s text.Shaper, font text.Font, txt st
		stack.Push(gtx.Ops)
		op.TransformOp{}.Offset(off).Add(gtx.Ops)
		str := txt[start:end]
		s.Shape(gtx, font, str, layout).Add(gtx.Ops)
		s.ShapeString(gtx, font, str, layout).Add(gtx.Ops)
		paint.PaintOp{Rect: lclip}.Add(gtx.Ops)
		stack.Pop()
	}