all: initial import

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2026-07-07 18:35:34 +00:00 · 2019-03-30 13:18:49 +01:00
commit 0f05231c35
102 changed files with 17926 additions and 0 deletions
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package text
+
+import (
+	"image"
+	"math"
+	"unicode/utf8"
+
+	"gioui.org/ui/draw"
+	"gioui.org/ui/f32"
+	"gioui.org/ui/layout"
+	"gioui.org/ui"
+
+	"golang.org/x/image/math/fixed"
+)
+
+type Label struct {
+	Face      Face
+	Src       image.Image
+	Alignment Alignment
+	Text      string
+
+	it lineIterator
+}
+
+type lineIterator struct {
+	Lines     []Line
+	Clip      image.Rectangle
+	Alignment Alignment
+	Width     int
+	Offset    image.Point
+
+	y, prevDesc fixed.Int26_6
+}
+
+func (l *lineIterator) Next() (String, f32.Point, bool) {
+	for len(l.Lines) > 0 {
+		line := l.Lines[0]
+		l.Lines = l.Lines[1:]
+		x := align(l.Alignment, line.Width, l.Width) + fixed.I(l.Offset.X)
+		l.y += l.prevDesc + line.Ascent
+		l.prevDesc = line.Descent
+		// Align baseline and line start to the pixel grid.
+		off := fixed.Point26_6{X: fixed.I(x.Floor()), Y: fixed.I(l.y.Ceil())}
+		x, l.y = off.X, off.Y
+		off.Y += fixed.I(l.Offset.Y)
+		if (off.Y + line.Bounds.Min.Y).Floor() > l.Clip.Max.Y {
+			break
+		}
+		if (off.Y + line.Bounds.Max.Y).Ceil() < l.Clip.Min.Y {
+			continue
+		}
+		str := line.Text
+		for len(str.Advances) > 0 {
+			adv := str.Advances[0]
+			if (off.X + adv + line.Bounds.Max.X - line.Width).Ceil() >= l.Clip.Min.X {
+				break
+			}
+			off.X += adv
+			_, s := utf8.DecodeRuneInString(str.String)
+			str.String = str.String[s:]
+			str.Advances = str.Advances[1:]
+		}
+		n := 0
+		endx := off.X
+		for i, adv := range str.Advances {
+			if (endx + line.Bounds.Min.X).Floor() > l.Clip.Max.X {
+				str.String = str.String[:n]
+				str.Advances = str.Advances[:i]
+				break
+			}
+			_, s := utf8.DecodeRuneInString(str.String[n:])
+			n += s
+			endx += adv
+		}
+		offf := f32.Point{X: float32(off.X) / 64, Y: float32(off.Y) / 64}
+		return str, offf, true
+	}
+	return String{}, f32.Point{}, false
+}
+
+func (l Label) Layout(cs layout.Constraints) (ui.Op, layout.Dimens) {
+	textLayout := l.Face.Layout(l.Text, false, cs.Width.Max)
+	lines := textLayout.Lines
+	dims := linesDimens(lines)
+	dims.Size = cs.Constrain(dims.Size)
+	padTop, padBottom := textPadding(lines)
+	clip := image.Rectangle{
+		Min: image.Point{X: -ui.Inf, Y: -padTop},
+		Max: image.Point{X: ui.Inf, Y: dims.Size.Y + padBottom},
+	}
+	var ops ui.Ops = make([]ui.Op, len(lines))[:0]
+	l.it = lineIterator{
+		Lines:     lines,
+		Clip:      clip,
+		Alignment: l.Alignment,
+		Width:     dims.Size.X,
+	}
+	for {
+		str, off, ok := l.it.Next()
+		if !ok {
+			break
+		}
+		path := l.Face.Path(str)
+		lclip := toRectF(clip).Sub(off)
+		op := ui.OpTransform{
+			Transform: ui.Offset(off),
+			Op:        draw.OpClip{Path: path, Op: draw.OpImage{Rect: lclip, Src: l.Src, SrcRect: l.Src.Bounds()}},
+		}
+		ops = append(ops, op)
+	}
+	return ops, dims
+}
+
+func itof(i int) float32 {
+	switch i {
+	case ui.Inf:
+		return float32(math.Inf(+1))
+	case -ui.Inf:
+		return float32(math.Inf(-1))
+	default:
+		return float32(i)
+	}
+}
+
+func toRectF(r image.Rectangle) f32.Rectangle {
+	return f32.Rectangle{
+		Min: f32.Point{X: itof(r.Min.X), Y: itof(r.Min.Y)},
+		Max: f32.Point{X: itof(r.Max.X), Y: itof(r.Max.Y)},
+	}
+}
+
+func textPadding(lines []Line) (padTop int, padBottom int) {
+	if len(lines) > 0 {
+		first := lines[0]
+		if d := -first.Bounds.Min.Y - first.Ascent; d > 0 {
+			padTop = d.Ceil()
+		}
+		last := lines[len(lines)-1]
+		if d := last.Bounds.Max.Y - last.Descent; d > 0 {
+			padBottom = d.Ceil()
+		}
+	}
+	return
+}