Add a benchmark + fix sub image allocations

text/v2/atlas.go

@@ -27,10 +27,11 @@ type glyphAtlas struct {
 type glyphImage struct {
 	atlas *glyphAtlas
 	node  *packing.Node
+	img   *ebiten.Image
 }
 
 func (i *glyphImage) Image() *ebiten.Image {
-	return i.atlas.image.SubImage(i.node.Region()).(*ebiten.Image)
+	return i.img
 }
 
 func newGlyphAtlas() *glyphAtlas {
@@ -54,6 +55,7 @@ func (g *glyphAtlas) NewImage(w, h int) *glyphImage {
 	return &glyphImage{
 		atlas: g,
 		node:  n,
+		img:   g.image.SubImage(n.Region()).(*ebiten.Image),
 	}
 }
 

text/v2/text_test.go

@@ -15,6 +15,7 @@
 package text_test
 
 import (
+	"bytes"
 	"image"
 	"image/color"
 	"regexp"
@@ -23,6 +24,7 @@ import (
 
 	"github.com/hajimehoshi/bitmapfont/v3"
 	"golang.org/x/image/font"
+	"golang.org/x/image/font/gofont/goregular"
 	"golang.org/x/image/math/fixed"
 
 	"github.com/hajimehoshi/ebiten/v2"
@@ -371,3 +373,23 @@ func TestDrawOptionsNotModified(t *testing.T) {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
 }
+
+func BenchmarkDrawText(b *testing.B) {
+	var txt string
+	for i := 0; i < 32; i++ {
+		txt += "The quick brown fox jumps over the lazy dog.\n"
+	}
+	screen := ebiten.NewImage(16, 16)
+	source, err := text.NewGoTextFaceSource(bytes.NewReader(goregular.TTF))
+	if err != nil {
+		b.Fatal(err)
+	}
+	f := &text.GoTextFace{
+		Source: source,
+		Size:   10,
+	}
+	op := &text.DrawOptions{}
+	for i := 0; i < b.N; i++ {
+		text.Draw(screen, txt, f, op)
+	}
+}