diff --git a/layout/layout.go b/layout/layout.go
index 0b91a21b..3e9da75f 100644
--- a/layout/layout.go
+++ b/layout/layout.go
@@ -102,6 +102,36 @@ func (c Constraints) Constrain(size image.Point) image.Point {
 	return size
 }
 
+// AddMin returns a copy of Constraints with the Min constraint enlarged by up to delta
+// while still fitting within the Max constraint. The Max is unchanged, and the Min constraint
+// will not go negative.
+func (c Constraints) AddMin(delta image.Point) Constraints {
+	c.Min = c.Min.Add(delta)
+	if c.Min.X < 0 {
+		c.Min.X = 0
+	}
+	if c.Min.Y < 0 {
+		c.Min.Y = 0
+	}
+	c.Min = c.Constrain(c.Min)
+	return c
+}
+
+// SubMax returns a copy of Constraints with the Max constraint shrunk by up to delta
+// while not going negative. The values of delta are expected to be positive.
+// The Min constraint is adjusted to fit within the new Max constraint.
+func (c Constraints) SubMax(delta image.Point) Constraints {
+	c.Max = c.Max.Sub(delta)
+	if c.Max.X < 0 {
+		c.Max.X = 0
+	}
+	if c.Max.Y < 0 {
+		c.Max.Y = 0
+	}
+	c.Min = c.Constrain(c.Min)
+	return c
+}
+
 // Inset adds space around a widget by decreasing its maximum
 // constraints. The minimum constraints will be adjusted to ensure
 // they do not exceed the maximum.
diff --git a/layout/layout_test.go b/layout/layout_test.go
index c6434b2c..54f2e826 100644
--- a/layout/layout_test.go
+++ b/layout/layout_test.go
@@ -76,3 +76,69 @@ func TestDirection(t *testing.T) {
 		})
 	}
 }
+
+func TestConstraints(t *testing.T) {
+	type testcase struct {
+		name     string
+		in       Constraints
+		subMax   image.Point
+		addMin   image.Point
+		expected Constraints
+	}
+	for _, tc := range []testcase{
+		{
+			name:     "no-op",
+			in:       Constraints{Max: image.Pt(100, 100)},
+			expected: Constraints{Max: image.Pt(100, 100)},
+		},
+		{
+			name:     "shrink max",
+			in:       Constraints{Max: image.Pt(100, 100)},
+			subMax:   image.Pt(25, 25),
+			expected: Constraints{Max: image.Pt(75, 75)},
+		},
+		{
+			name:     "shrink max below min",
+			in:       Constraints{Max: image.Pt(100, 100), Min: image.Pt(50, 50)},
+			subMax:   image.Pt(75, 75),
+			expected: Constraints{Max: image.Pt(25, 25), Min: image.Pt(25, 25)},
+		},
+		{
+			name:     "shrink max below zero",
+			in:       Constraints{Max: image.Pt(100, 100), Min: image.Pt(50, 50)},
+			subMax:   image.Pt(125, 125),
+			expected: Constraints{Max: image.Pt(0, 0), Min: image.Pt(0, 0)},
+		},
+		{
+			name:     "enlarge min",
+			in:       Constraints{Max: image.Pt(100, 100)},
+			addMin:   image.Pt(25, 25),
+			expected: Constraints{Max: image.Pt(100, 100), Min: image.Pt(25, 25)},
+		},
+		{
+			name:     "enlarge min beyond max",
+			in:       Constraints{Max: image.Pt(100, 100)},
+			addMin:   image.Pt(125, 125),
+			expected: Constraints{Max: image.Pt(100, 100), Min: image.Pt(100, 100)},
+		},
+		{
+			name:     "decrease min below zero",
+			in:       Constraints{Max: image.Pt(100, 100), Min: image.Pt(50, 50)},
+			addMin:   image.Pt(-125, -125),
+			expected: Constraints{Max: image.Pt(100, 100), Min: image.Pt(0, 0)},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			start := tc.in
+			if tc.subMax != (image.Point{}) {
+				start = start.SubMax(tc.subMax)
+			}
+			if tc.addMin != (image.Point{}) {
+				start = start.AddMin(tc.addMin)
+			}
+			if start != tc.expected {
+				t.Errorf("expected %#+v, got %#+v", tc.expected, start)
+			}
+		})
+	}
+}