text: update fuzzer to sometimes truncate

This commit updates the shaper fuzzer to try truncating the text, exposing
new edge cases.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>

text/gotext_test.go

@@ -567,10 +567,10 @@ func TestComputeVisualOrder(t *testing.T) {
 func FuzzLayout(f *testing.F) {
 	ltrFace, _ := opentype.Parse(goregular.TTF)
 	rtlFace, _ := opentype.Parse(nsareg.TTF)
-	f.Add("د عرمثال dstي met لم aqل جدmوpمg lرe dرd  لو عل ميrةsdiduntut lab renنيتذدagلaaiua.ئPocttأior رادرsاي mيrbلmnonaيdتد ماةعcلخ.", true, uint8(10), uint16(200))
+	f.Add("د عرمثال dstي met لم aqل جدmوpمg lرe dرd  لو عل ميrةsdiduntut lab renنيتذدagلaaiua.ئPocttأior رادرsاي mيrbلmnonaيdتد ماةعcلخ.", true, false, uint8(10), uint16(200))
 
 	shaper := testShaper(ltrFace, rtlFace)
-	f.Fuzz(func(t *testing.T, txt string, rtl bool, fontSize uint8, width uint16) {
+	f.Fuzz(func(t *testing.T, txt string, rtl bool, truncate bool, fontSize uint8, width uint16) {
 		locale := system.Locale{
 			Direction: system.LTR,
 		}
@@ -580,9 +580,14 @@ func FuzzLayout(f *testing.F) {
 		if fontSize < 1 {
 			fontSize = 1
 		}
+		maxLines := 0
+		if truncate {
+			maxLines = 1
+		}
 		lines := shaper.LayoutRunes(Parameters{
 			PxPerEm:  fixed.I(int(fontSize)),
 			MaxWidth: int(width),
+			MaxLines: maxLines,
 			Locale:   locale,
 		}, []rune(txt))
 		validateLines(t, lines.lines, len([]rune(txt)))

text/testdata/fuzz/FuzzLayout/2a7730fcbcc3550718b37415eb6104cf09159c7d756cc3530ccaa9007c0a2c06

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\x1d")
 bool(true)
+bool(false)
 byte('\x1c')
 uint16(227)

text/testdata/fuzz/FuzzLayout/3fc3ee939f0df44719bee36a67df3aa3a562e2f2f1cfb665a650f60e7e0ab4e6

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("0")
 bool(true)
+bool(false)
 uint8(27)
 uint16(200)

text/testdata/fuzz/FuzzLayout/40894369fe6a0c11

@@ -0,0 +1,6 @@
+go test fuzz v1
+string("\n")
+bool(false)
+bool(true)
+byte('±')
+uint16(0)

text/testdata/fuzz/FuzzLayout/4197f52af4459898

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\n")
 bool(false)
+bool(false)
 byte('±')
 uint16(0)

text/testdata/fuzz/FuzzLayout/594e4fda2e3462061d50b6a74279d7e3e486d8ac211e45049cfa4833257ef236

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\u2029")
 bool(false)
+bool(false)
 byte('*')
 uint16(72)

text/testdata/fuzz/FuzzLayout/6b452fd81f16c000dbe525077b6f4ba91b040119d82d55991d568014f4ba671e

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("Aͮ000000000000000")
 bool(false)
+bool(false)
 byte('\u0087')
 uint16(111)

text/testdata/fuzz/FuzzLayout/6b5a1e9cd750a9aa8dafe11bc74e2377c0664f64bbf2ac8b1cdd0ce9f55461b3

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\x1e")
 bool(true)
+bool(false)
 byte('\n')
 uint16(254)

text/testdata/fuzz/FuzzLayout/940ce2b5ed93df01

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("000000000000000 00000000 ٰ00000")
 bool(true)
+bool(false)
 byte('\n')
 uint16(121)

text/testdata/fuzz/FuzzLayout/be56090b98f3c84da6ff9e857d5487d1a89309f7312ccde5ff8b94fcd29521eb

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\r")
 bool(false)
+bool(false)
 byte('T')
 uint16(200)

text/testdata/fuzz/FuzzLayout/dda958d1b1bb9df71f81c575cb8900f97fc1c20e19de09fc0ffca8ff0c8d9e5a

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\u0085")
 bool(true)
+bool(false)
 byte('\x10')
 uint16(271)

text/testdata/fuzz/FuzzLayout/de31ec6b1ac7797daefecf39baaace51fa4348bed0e3b662dd50aa341f67d10c

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("0")
 bool(false)
+bool(false)
 byte('\x00')
 uint16(142)

text/testdata/fuzz/FuzzLayout/e79034d6c7a6ce74d7a689f4ea99e50a6ecd0d4134e3a77234172d13787ac4ea

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\n")
 bool(true)
+bool(false)
 byte('\t')
 uint16(200)

text/testdata/fuzz/FuzzLayout/f1f0611baadc20469863e483f58a3ca4eba895087316b31e598f0b05c978d87c

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("ع0 ׂ0")
 bool(false)
+bool(false)
 byte('\u0098')
 uint16(198)

text/testdata/fuzz/FuzzLayout/f2ebea678c72f6c394d7f860599b281593098b0aad864231d756c3e9699029c1

@@ -1,5 +1,6 @@
 go test fuzz v1
 string("\x1c")
 bool(true)
+bool(false)
 byte('\u009c')
 uint16(200)