examples: add examples/texti18n

This example shows how to render complex glyphs like Thai and Arabic. Updates hajimehoshi#675
kalanertim · Jul 1, 2023 · 3ab50c9 · 3ab50c9
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diff --git a/examples/texti18n/LICENSE.md b/examples/texti18n/LICENSE.md
@@ -0,0 +1,23 @@
+# `NotoSansArabic-Regular.ttf`
+
+Open Font License 1.1
+
+https://fonts.google.com/noto/specimen/Noto+Sans+Arabic/about
+
+# `NotoSansDevanagari-Regular.ttf`
+
+Open Font License 1.1
+
+https://fonts.google.com/noto/specimen/Noto+Sans+Devanagari/about
+
+# `NotoSansJP-Regular.ttf`
+
+Open Font License 1.1
+
+https://fonts.google.com/noto/specimen/Noto+Sans+JP/about
+
+# `NotoSansThai-Regular.ttf`
+
+Open Font License 1.1
+
+https://fonts.google.com/noto/specimen/Noto+Sans+Thai/about
diff --git a/examples/texti18n/NotoSansArabic-Regular.ttf b/examples/texti18n/NotoSansArabic-Regular.ttf
diff --git a/examples/texti18n/NotoSansDevanagari-Regular.ttf b/examples/texti18n/NotoSansDevanagari-Regular.ttf
diff --git a/examples/texti18n/NotoSansThai-Regular.ttf b/examples/texti18n/NotoSansThai-Regular.ttf
diff --git a/examples/texti18n/main.go b/examples/texti18n/main.go
@@ -0,0 +1,338 @@
+// Copyright 2023 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"bytes"
+	_ "embed"
+	"image"
+	"image/color"
+	"image/draw"
+	"log"
+	"math"
+
+	"github.com/go-text/typesetting/di"
+	"github.com/go-text/typesetting/font"
+	"github.com/go-text/typesetting/language"
+	"github.com/go-text/typesetting/opentype/api"
+	"github.com/go-text/typesetting/shaping"
+	"golang.org/x/image/math/fixed"
+	"golang.org/x/image/vector"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/examples/resources/fonts"
+)
+
+//go:embed NotoSansArabic-Regular.ttf
+var arabicTTF []byte
+
+var arabicOut shaping.Output
+
+func init() {
+	face, err := font.ParseTTF(bytes.NewReader(arabicTTF))
+	if err != nil {
+		log.Fatal(err)
+	}
+	runes := []rune("لمّا كان الاعتراف بالكرامة المتأصلة في جميع")
+	input := shaping.Input{
+		Text:      runes,
+		RunStart:  0,
+		RunEnd:    len(runes),
+		Direction: di.DirectionRTL,
+		Face:      face,
+		Size:      fixed.I(24),
+		Script:    language.Arabic,
+		Language:  "ar",
+	}
+	arabicOut = (&shaping.HarfbuzzShaper{}).Shape(input)
+}
+
+//go:embed NotoSansDevanagari-Regular.ttf
+var devanagariTTF []byte
+
+var devanagariOut shaping.Output
+
+func init() {
+	face, err := font.ParseTTF(bytes.NewReader(devanagariTTF))
+	if err != nil {
+		log.Fatal(err)
+	}
+	runes := []rune("चूंकि मानव परिवार के सभी सदस्यों के जन्मजात गौरव और समान")
+	input := shaping.Input{
+		Text:      runes,
+		RunStart:  0,
+		RunEnd:    len(runes),
+		Direction: di.DirectionLTR,
+		Face:      face,
+		Size:      fixed.I(24),
+		Script:    language.Devanagari,
+		Language:  "hi",
+	}
+	devanagariOut = (&shaping.HarfbuzzShaper{}).Shape(input)
+}
+
+//go:embed NotoSansThai-Regular.ttf
+var thaiTTF []byte
+
+var thaiOut shaping.Output
+
+func init() {
+	face, err := font.ParseTTF(bytes.NewReader(thaiTTF))
+	if err != nil {
+		log.Fatal(err)
+	}
+	runes := []rune("โดยที่การไม่นำพาและการหมิ่นในคุณค่าของสิทธิมนุษยชน")
+	input := shaping.Input{
+		Text:      runes,
+		RunStart:  0,
+		RunEnd:    len(runes),
+		Direction: di.DirectionLTR,
+		Face:      face,
+		Size:      fixed.I(24),
+		Script:    language.Thai,
+		Language:  "th",
+	}
+	thaiOut = (&shaping.HarfbuzzShaper{}).Shape(input)
+}
+
+var japaneseOut shaping.Output
+
+func init() {
+	face, err := font.ParseTTF(bytes.NewReader(fonts.MPlus1pRegular_ttf))
+	if err != nil {
+		log.Fatal(err)
+	}
+	runes := []rune("ラーメン。")
+	input := shaping.Input{
+		Text:      runes,
+		RunStart:  0,
+		RunEnd:    len(runes),
+		Direction: di.DirectionTTB,
+		Face:      face,
+		Size:      fixed.I(24),
+		Script:    language.Katakana_Or_Hiragana,
+		Language:  "ja",
+	}
+	japaneseOut = (&shaping.HarfbuzzShaper{}).Shape(input)
+}
+
+var (
+	whiteImage = ebiten.NewImage(3, 3)
+
+	// whiteSubImage is an internal sub image of whiteImage.
+	// Use whiteSubImage at DrawTriangles instead of whiteImage in order to avoid bleeding edges.
+	whiteSubImage = whiteImage.SubImage(image.Rect(1, 1, 2, 2)).(*ebiten.Image)
+)
+
+func init() {
+	whiteImage.Fill(color.White)
+}
+
+const (
+	screenWidth  = 640
+	screenHeight = 480
+)
+
+type Game struct {
+	vertices []ebiten.Vertex
+	indices  []uint16
+
+	glyphCache map[glyphCacheKey]glyphCacheValue
+}
+
+type glyphCacheKey struct {
+	output  *shaping.Output // TODO: This should be a font.Face instead of shaping.Output.
+	glyphID api.GID
+	origin  fixed.Point26_6
+}
+
+type glyphCacheValue struct {
+	image *ebiten.Image
+	point image.Point
+}
+
+func (g *Game) Update() error {
+	return nil
+}
+
+func (g *Game) Draw(screen *ebiten.Image) {
+	g.drawGlyphs(screen, &arabicOut, 20, 100)
+	g.drawGlyphs(screen, &devanagariOut, 20, 150)
+	g.drawGlyphs(screen, &thaiOut, 20, 200)
+	g.drawGlyphs(screen, &japaneseOut, 20, 250)
+}
+
+func fixed26_6ToFloat32(x fixed.Int26_6) float32 {
+	return float32(x>>6) + (float32(x&(1<<6-1)) / (1 << 6))
+}
+
+func float32ToFixed26_6(x float32) fixed.Int26_6 {
+	i := float32(math.Floor(float64(x)))
+	return (fixed.Int26_6(i) << 6) + fixed.Int26_6((x-i)*(1<<6))
+}
+
+func (g *Game) drawGlyphs(dst *ebiten.Image, output *shaping.Output, originX, originY float32) {
+	g.vertices = g.vertices[:0]
+	g.indices = g.indices[:0]
+
+	scale := fixed26_6ToFloat32(output.Size) / float32(output.Face.Font.Upem())
+
+	orig := fixed.Point26_6{
+		X: float32ToFixed26_6(originX),
+		Y: float32ToFixed26_6(originY),
+	}
+	for _, glyph := range output.Glyphs {
+		key := glyphCacheKey{
+			output:  output,
+			glyphID: glyph.GlyphID,
+			origin:  orig,
+		}
+
+		v, ok := g.glyphCache[key]
+		if !ok {
+			data := output.Face.GlyphData(glyph.GlyphID).(api.GlyphOutline)
+			if len(data.Segments) == 0 {
+				continue
+			}
+
+			segs := make([]api.Segment, len(data.Segments))
+			for i, seg := range data.Segments {
+				segs[i] = seg
+				for j := range seg.Args {
+					segs[i].Args[j].X *= scale
+					segs[i].Args[j].Y *= scale
+					segs[i].Args[j].Y *= -1
+				}
+			}
+
+			v.image, v.point = segmentsToImage(segs, orig)
+			if g.glyphCache == nil {
+				g.glyphCache = map[glyphCacheKey]glyphCacheValue{}
+			}
+			g.glyphCache[key] = v
+		}
+
+		if v.image != nil {
+			op := &ebiten.DrawImageOptions{}
+			op.GeoM.Translate(float64(v.point.X), float64(v.point.Y))
+			dst.DrawImage(v.image, op)
+		}
+
+		orig = orig.Add(fixed.Point26_6{X: glyph.XAdvance, Y: glyph.YAdvance * -1})
+	}
+}
+
+func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
+	return screenWidth, screenHeight
+}
+
+func main() {
+	ebiten.SetWindowSize(screenWidth, screenHeight)
+	ebiten.SetWindowTitle("Text I18N (Ebitengine Demo)")
+	if err := ebiten.RunGame(&Game{}); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func segmentsToRect(segs []api.Segment) fixed.Rectangle26_6 {
+	if len(segs) == 0 {
+		return fixed.Rectangle26_6{}
+	}
+
+	minX := float32(math.Inf(1))
+	minY := float32(math.Inf(1))
+	maxX := float32(math.Inf(-1))
+	maxY := float32(math.Inf(-1))
+
+	for _, seg := range segs {
+		n := 1
+		switch seg.Op {
+		case api.SegmentOpQuadTo:
+			n = 2
+		case api.SegmentOpCubeTo:
+			n = 3
+		}
+		for i := 0; i < n; i++ {
+			x := seg.Args[i].X
+			y := seg.Args[i].Y
+			if minX > x {
+				minX = x
+			}
+			if minY > y {
+				minY = y
+			}
+			if maxX < x {
+				maxX = x
+			}
+			if maxY < y {
+				maxY = y
+			}
+		}
+	}
+
+	return fixed.Rectangle26_6{
+		Min: fixed.Point26_6{
+			X: float32ToFixed26_6(minX),
+			Y: float32ToFixed26_6(minY),
+		},
+		Max: fixed.Point26_6{
+			X: float32ToFixed26_6(maxX),
+			Y: float32ToFixed26_6(maxY),
+		},
+	}
+}
+
+func segmentsToImage(segs []api.Segment, orig fixed.Point26_6) (*ebiten.Image, image.Point) {
+	dBounds := segmentsToRect(segs).Add(orig)
+	dr := image.Rect(
+		dBounds.Min.X.Floor(),
+		dBounds.Min.Y.Floor(),
+		dBounds.Max.X.Ceil(),
+		dBounds.Max.Y.Ceil(),
+	)
+	biasX := fixed26_6ToFloat32(orig.X) - float32(dr.Min.X)
+	biasY := fixed26_6ToFloat32(orig.Y) - float32(dr.Min.Y)
+
+	width, height := dr.Dx(), dr.Dy()
+	if width <= 0 || height <= 0 {
+		return nil, image.Point{}
+	}
+
+	rast := vector.NewRasterizer(width, height)
+	rast.DrawOp = draw.Src
+	for _, seg := range segs {
+		switch seg.Op {
+		case api.SegmentOpMoveTo:
+			rast.MoveTo(seg.Args[0].X+biasX, seg.Args[0].Y+biasY)
+		case api.SegmentOpLineTo:
+			rast.LineTo(seg.Args[0].X+biasX, seg.Args[0].Y+biasY)
+		case api.SegmentOpQuadTo:
+			rast.QuadTo(
+				seg.Args[0].X+biasX, seg.Args[0].Y+biasY,
+				seg.Args[1].X+biasX, seg.Args[1].Y+biasY,
+			)
+		case api.SegmentOpCubeTo:
+			rast.CubeTo(
+				seg.Args[0].X+biasX, seg.Args[0].Y+biasY,
+				seg.Args[1].X+biasX, seg.Args[1].Y+biasY,
+				seg.Args[2].X+biasX, seg.Args[2].Y+biasY,
+			)
+		}
+	}
+
+	dst := image.NewAlpha(image.Rect(0, 0, width, height))
+	rast.Draw(dst, dst.Bounds(), image.Opaque, image.Point{})
+	return ebiten.NewImageFromImage(dst), dr.Min
+}
diff --git a/go.mod b/go.mod
@@ -5,6 +5,7 @@ go 1.18
 require (
 	github.com/ebitengine/purego v0.4.0-alpha.4
 	github.com/go-gl/glfw/v3.3/glfw v0.0.0-20221017161538-93cebf72946b
+	github.com/go-text/typesetting v0.0.0-20230618175549-b5753034b590
 	github.com/hajimehoshi/bitmapfont/v3 v3.0.0
 	github.com/hajimehoshi/go-mp3 v0.3.4
 	github.com/hajimehoshi/oto/v2 v2.5.0-alpha.0.20230315035531-31c83ff4311d

diff --git a/go.sum b/go.sum
@@ -3,6 +3,9 @@ github.com/ebitengine/purego v0.4.0-alpha.4 h1:Y7yIV06Yo5M2BAdD7EVPhfp6LZ0tEcQo5
 github.com/ebitengine/purego v0.4.0-alpha.4/go.mod h1:ah1In8AOtksoNK6yk5z1HTJeUkC1Ez4Wk2idgGslMwQ=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20221017161538-93cebf72946b h1:GgabKamyOYguHqHjSkDACcgoPIz3w0Dis/zJ1wyHHHU=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20221017161538-93cebf72946b/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
+github.com/go-text/typesetting v0.0.0-20230618175549-b5753034b590 h1:n6u3xKVUsKptNLSgG4IbJIuha5tS++YpMHVBCNk4ssE=
+github.com/go-text/typesetting v0.0.0-20230618175549-b5753034b590/go.mod h1:evDBbvNR/KaVFZ2ZlDSOWWXIUKq0wCOEtzLxRM8SG3k=
+github.com/go-text/typesetting-utils v0.0.0-20230616150549-2a7df14b6a22 h1:LBQTFxP2MfsyEDqSKmUBZaDuDHN1vpqDyOZjcqS7MYI=
 github.com/hajimehoshi/bitmapfont/v3 v3.0.0 h1:r2+6gYK38nfztS/et50gHAswb9hXgxXECYgE8Nczmi4=
 github.com/hajimehoshi/bitmapfont/v3 v3.0.0/go.mod h1:+CxxG+uMmgU4mI2poq944i3uZ6UYFfAkj9V6WqmuvZA=
 github.com/hajimehoshi/go-mp3 v0.3.4 h1:NUP7pBYH8OguP4diaTZ9wJbUbk3tC0KlfzsEpWmYj68=