handle uneven disribution of space

ui/ui.go

@@ -56,22 +56,35 @@ func (c *Container) Draw(s tcell.Screen) {
 
 func (c *Container) SetSize(x, y, h, w int) {
 	c.x, c.y, c.h, c.w = x, y, h, w
+	carry := 0
 	if c.layoutMethod == LayoutVerticalEven {
 		num := len(c.contents)
+		extra := c.h % num
 		for r := range c.contents {
 			w := c.w
 			h := c.h / num
 			x := c.x
-			y := c.y + (h * r)
+			y := c.y + (h * r) + carry
+			if extra > 0 { // distribute "extra" space to containers as we have some left
+				h++
+				extra--
+				carry++
+			}
 			c.contents[r].Container.SetSize(x, y, h, w)
 		}
 	} else if c.layoutMethod == LayoutHorizontalEven {
 		num := len(c.contents)
+		extra := c.w % num
 		for r := range c.contents {
 			w := c.w / num
 			h := c.h
-			x := c.x + (w * r)
+			x := c.x + (w * r) + carry
 			y := c.y
+			if extra > 0 { // distribute "extra" space to containers as we have some left
+				w++
+				extra--
+				carry++
+			}
 			c.contents[r].Container.SetSize(x, y, h, w)
 		}
 	} else {

ui/ui_test.go

@@ -55,6 +55,32 @@ func TestContainerTwoBoxesHStack(t *testing.T) {
 		t.Fail()
 	}
 }
+func TestContainerThreeBoxesUnevenHStack(t *testing.T) {
+	expect := `┌─ one ──┐┌─ two ──┐┌─ three 
+│        ││        ││       │
+│        ││        ││       │
+│        ││        ││       │
+└────────┘└────────┘└───────┘
+`
+	m := &MockScreen{}
+	one := NewBox("one", nil, Contents{})
+	two := NewBox("two", nil, Contents{})
+	three := NewBox("three", nil, Contents{})
+	container := NewContainer(
+		Contents{{Container: one}, {Container: two}, {Container: three}},
+		LayoutHorizontalEven,
+	)
+	m.Init()
+	m.Resize(0, 0, 5, 29)
+	container.SetSize(0, 0, 5, 29)
+	container.Draw(m)
+	result := m.DumpContents()
+	if result != expect {
+		fmt.Printf("expected:\n%+v", expect)
+		fmt.Printf("actual:\n%+v", result)
+		t.Fail()
+	}
+}
 
 func TestContainerTwoBoxesVStack(t *testing.T) {
 	expect := `┌─ one ──┐