added bounds function to rtree

index/rtree/rtree.go

@@ -163,6 +163,20 @@ func (tr *RTree) RemoveAll() {
 	tr.root = nil
 }
 
+func (tr *RTree) Bounds() (minX, minY, maxX, maxY float64) {
+	var rect rectT
+	if tr.root != nil {
+		if tr.root.count > 0 {
+			rect = tr.root.branch[0].rect
+			for i := 1; i < tr.root.count; i++ {
+				rect = combineRect(rect, tr.root.branch[i].rect)
+			}
+		}
+	}
+	minX, minY, maxX, maxY = rect.min[0], rect.min[1], rect.max[0], rect.max[1]
+	return
+}
+
 func countRec(node *nodeT, counter int) int {
 	if node.isInternalNode() { // not a leaf node
 		for index := 0; index < node.count; index++ {

index/rtree/rtree_test.go

@@ -38,7 +38,12 @@ func wp(min, max []float64) *Rect {
 		MaxY: max[1],
 	}
 }
-
+func wpp(x, y float64) *Rect {
+	return &Rect{
+		x, y,
+		x, y,
+	}
+}
 func TestA(t *testing.T) {
 	tr := New()
 	item1 := wp([]float64{10, 10, 10, 10}, []float64{20, 20, 20, 20})
@@ -70,7 +75,18 @@ func TestMemory(t *testing.T) {
 	runtime.ReadMemStats(&m)
 	println(int(m.HeapAlloc)/tr.Count(), "bytes/rect")
 }
-
+func TestBounds(t *testing.T) {
+	tr := New()
+	tr.Insert(wpp(10, 10))
+	tr.Insert(wpp(10, 20))
+	tr.Insert(wpp(10, 30))
+	tr.Insert(wpp(20, 10))
+	tr.Insert(wpp(30, 10))
+	minX, minY, maxX, maxY := tr.Bounds()
+	if minX != 10 || minY != 10 || maxX != 30 || maxY != 30 {
+		t.Fatalf("expected 10,10 30,30, got %v,%v %v,%v\n", minX, minY, maxX, maxY)
+	}
+}
 func BenchmarkInsert(b *testing.B) {
 	rand.Seed(0)
 	tr := New()