slightly more rigorous bounds checking and auto-fit

box_test.go

@@ -0,0 +1,87 @@
+package chart
+
+import (
+	"math"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestBoxClone(t *testing.T) {
+	assert := assert.New(t)
+	a := Box{Top: 5, Left: 5, Right: 15, Bottom: 15}
+	b := a.Clone()
+	assert.True(a.Equals(b))
+	assert.True(b.Equals(a))
+}
+
+func TestBoxEquals(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 5, Left: 5, Right: 15, Bottom: 15}
+	b := Box{Top: 10, Left: 10, Right: 30, Bottom: 30}
+	c := Box{Top: 5, Left: 5, Right: 15, Bottom: 15}
+	assert.True(a.Equals(a))
+	assert.True(a.Equals(c))
+	assert.True(c.Equals(a))
+	assert.False(a.Equals(b))
+	assert.False(c.Equals(b))
+	assert.False(b.Equals(a))
+	assert.False(b.Equals(c))
+}
+
+func TestBoxIsBiggerThan(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 5, Left: 5, Right: 25, Bottom: 25}
+	b := Box{Top: 10, Left: 10, Right: 20, Bottom: 20} // only half bigger
+	c := Box{Top: 1, Left: 1, Right: 30, Bottom: 30}   //bigger
+	assert.True(a.IsBiggerThan(b))
+	assert.False(a.IsBiggerThan(c))
+	assert.True(c.IsBiggerThan(a))
+}
+
+func TestBoxIsSmallerThan(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 5, Left: 5, Right: 25, Bottom: 25}
+	b := Box{Top: 10, Left: 10, Right: 20, Bottom: 20} // only half bigger
+	c := Box{Top: 1, Left: 1, Right: 30, Bottom: 30}   //bigger
+	assert.False(a.IsSmallerThan(b))
+	assert.True(a.IsSmallerThan(c))
+	assert.False(c.IsSmallerThan(a))
+}
+
+func TestBoxGrow(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 1, Left: 2, Right: 15, Bottom: 15}
+	b := Box{Top: 4, Left: 5, Right: 30, Bottom: 35}
+	c := a.Grow(b)
+	assert.False(c.Equals(b))
+	assert.False(c.Equals(a))
+	assert.Equal(1, c.Top)
+	assert.Equal(2, c.Left)
+	assert.Equal(30, c.Right)
+	assert.Equal(35, c.Bottom)
+}
+
+func TestBoxFit(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 64, Left: 64, Right: 192, Bottom: 192}
+	b := Box{Top: 16, Left: 16, Right: 256, Bottom: 170}
+	c := Box{Top: 16, Left: 16, Right: 170, Bottom: 256}
+
+	fab := a.Fit(b)
+	assert.Equal(a.Left, fab.Left)
+	assert.Equal(a.Right, fab.Right)
+	assert.True(fab.Top < fab.Bottom)
+	assert.True(fab.Left < fab.Right)
+	assert.True(math.Abs(b.Aspect()-fab.Aspect()) < 0.02)
+
+	fac := a.Fit(c)
+	assert.Equal(a.Top, fac.Top)
+	assert.Equal(a.Bottom, fac.Bottom)
+	assert.True(math.Abs(c.Aspect()-fac.Aspect()) < 0.02)
+}