Added PointF32 implementation of some methods.

point.go

@@ -2,6 +2,7 @@ package geom
 
 import (
 	_image "image"
+	"strconv"
 )
 
 // Point is exposing the standard library image.Point in the geom package.
@@ -11,3 +12,8 @@ type Point _image.Point
 func Pt(x, y int) Point {
 	return Point{x, y}
 }
+
+// String formats the point p as a string.
+func (p Point) String() string {
+	return "(" + strconv.Itoa(p.X) + "," + strconv.Itoa(p.Y) + ")"
+}

pointf.go

@@ -2,7 +2,6 @@ package geom
 
 import (
 	"math"
-	"strconv"
 )
 
 // PointF is an X, Y coordinate pair (floating point).
@@ -18,11 +17,6 @@ func PtF(x, y float64) PointF {
 	return PointF{X: x, Y: y}
 }
 
-// String formats the point p as a string.
-func (p Point) String() string {
-	return "(" + strconv.Itoa(p.X) + "," + strconv.Itoa(p.Y) + ")"
-}
-
 // To32 transforms the point p into a PointF32.
 func (p PointF) To32() PointF32 {
 	return PointF32{float32(p.X), float32(p.Y)}

pointf32.go

@@ -1,5 +1,9 @@
 package geom
 
+import (
+	"math"
+)
+
 // PointF32 is an X, Y coordinate pair (floating point, 32 bits).
 type PointF32 struct {
 	X, Y float32
@@ -13,6 +17,45 @@ func PtF32(x, y float32) PointF32 {
 	return PointF32{x, y}
 }
 
+// To64 transforms the point p into a PointF.
+func (p PointF32) To64() PointF {
+	return PointF{float64(p.X), float64(p.Y)}
+}
+
+// Add adds q as a vector to p.
+func (p PointF32) Add(q PointF32) PointF32 {
+	return PointF32{p.X + q.X, p.Y + q.Y}
+}
+
+// Sub subtracts q as a vector from p.
+func (p PointF32) Sub(q PointF32) PointF32 {
+	return PointF32{p.X - q.X, p.Y - q.Y}
+}
+
+// AngleTo calculates the angle [0..2*Pi) from point p to point q.
+func (p PointF32) AngleTo(q PointF32) float32 {
+	a := float32(math.Atan(float64((p.Y - q.Y) / (p.X - q.X))))
+	if q.X < p.X {
+		return a + math.Pi
+	}
+	if a < 0 {
+		a += 2 * math.Pi
+	}
+	return a
+}
+
+// Distance calculates the distance between points p and q.
+func (p PointF32) Distance(q PointF32) float32 {
+	return float32(math.Sqrt(float64(p.Distance2(q))))
+}
+
+// Distance2 calculates the squared distance between points p and q.
+func (p PointF32) Distance2(q PointF32) float32 {
+	dx := q.X - p.X
+	dy := q.Y - p.Y
+	return dx*dx + dy*dy
+}
+
 // In tests if the point p is inside the rectangle r.
 func (p PointF32) In(r RectangleF32) bool {
 	if p.X < r.Min.X || p.X >= r.Max.X || p.Y < r.Min.Y || p.Y >= r.Max.Y {