3 files changed, 73 insertions(+), 7 deletions(-)

M text/gotext.go
M text/gotext_test.go
M widget/index_test.go

@@ 480,16 480,19 @@ func (s *shaperImpl) LayoutRunes(params Parameters, minWidth, maxWidth int, lc s
 		}
 		textLines[i] = otLine
 	}
-	alignWidth := maxWidth
-	if len(textLines) == 1 {
-		alignWidth = max(minWidth, textLines[0].width.Ceil())
-	}
 	calculateYOffsets(textLines)
 	return document{
 		lines:      textLines,
 		alignment:  params.Alignment,
-		alignWidth: alignWidth,
+		alignWidth: alignWidth(minWidth, textLines),
+	}
+}
+
+func alignWidth(minWidth int, lines []line) int {
+	for _, l := range lines {
+		minWidth = max(minWidth, l.width.Ceil())
 	}
+	return minWidth
 }
 
 // Shape converts the provided glyphs into a path.

@@ 55,6 55,69 @@ func TestEmptyString(t *testing.T) {
 	}
 }
 
+func TestAlignWidth(t *testing.T) {
+	lines := []line{
+		{width: fixed.I(50)},
+		{width: fixed.I(75)},
+		{width: fixed.I(25)},
+	}
+	for _, minWidth := range []int{0, 50, 100} {
+		width := alignWidth(minWidth, lines)
+		if width < minWidth {
+			t.Errorf("expected width >= %d, got %d", minWidth, width)
+		}
+	}
+}
+
+func TestShapingAlignWidth(t *testing.T) {
+	ppem := fixed.I(10)
+	ltrFace, _ := opentype.Parse(goregular.TTF)
+	shaper := testShaper(ltrFace)
+
+	type testcase struct {
+		name               string
+		minWidth, maxWidth int
+		expected           int
+		str                string
+	}
+	for _, tc := range []testcase{
+		{
+			name:     "zero min",
+			maxWidth: 100,
+			str:      "a\nb\nc",
+			expected: 22,
+		},
+		{
+			name:     "min == max",
+			minWidth: 100,
+			maxWidth: 100,
+			str:      "a\nb\nc",
+			expected: 100,
+		},
+		{
+			name:     "min < max",
+			minWidth: 50,
+			maxWidth: 100,
+			str:      "a\nb\nc",
+			expected: 50,
+		},
+		{
+			name:     "min < max, text > min",
+			minWidth: 50,
+			maxWidth: 100,
+			str:      "aphabetic\nb\nc",
+			expected: 60,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			lines := shaper.LayoutString(Parameters{PxPerEm: ppem}, tc.minWidth, tc.maxWidth, english, tc.str)
+			if lines.alignWidth != tc.expected {
+				t.Errorf("expected line alignWidth to be %d, got %d", tc.expected, lines.alignWidth)
+			}
+		})
+	}
+}
+
 // TestNewlineSynthesis ensures that the shaper correctly inserts synthetic glyphs
 // representing newline runes.
 func TestNewlineSynthesis(t *testing.T) {

@@ 36,11 36,11 @@ func makePosTestText(fontSize, lineWidth int, alignOpposite bool) (bidiLTR, bidi
 		ltrParams.Alignment = text.End
 		rtlParams.Alignment = text.Start
 	}
-	shaper.LayoutString(ltrParams, 0, lineWidth, english, bidiSource)
+	shaper.LayoutString(ltrParams, lineWidth, lineWidth, english, bidiSource)
 	for g, ok := shaper.NextGlyph(); ok; g, ok = shaper.NextGlyph() {
 		bidiLTR = append(bidiLTR, g)
 	}
-	shaper.LayoutString(rtlParams, 0, lineWidth, arabic, bidiSource)
+	shaper.LayoutString(rtlParams, lineWidth, lineWidth, arabic, bidiSource)
 	for g, ok := shaper.NextGlyph(); ok; g, ok = shaper.NextGlyph() {
 		bidiRTL = append(bidiRTL, g)
 	}