1 files changed, 55 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/detect/projector.go b/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/detect/projector.go
new file mode 100644
index 000000000..1ebd6db59
--- /dev/null
+++ b/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/detect/projector.go
@@ -0,0 +1,55 @@
+// Copyright 2011 The Graphics-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package detect
+
+import (
+	"image"
+)
+
+// projector allows projecting from a source Rectangle onto a target Rectangle.
+type projector struct {
+	// rx, ry is the scaling factor.
+	rx, ry float64
+	// dx, dy is the translation factor.
+	dx, dy float64
+	// r is the clipping region of the target.
+	r image.Rectangle
+}
+
+// newProjector creates a Projector with source src and target dst.
+func newProjector(dst image.Rectangle, src image.Rectangle) *projector {
+	return &projector{
+		rx: float64(dst.Dx()) / float64(src.Dx()),
+		ry: float64(dst.Dy()) / float64(src.Dy()),
+		dx: float64(dst.Min.X - src.Min.X),
+		dy: float64(dst.Min.Y - src.Min.Y),
+		r:  dst,
+	}
+}
+
+// pt projects p from the source rectangle onto the target rectangle.
+func (s *projector) pt(p image.Point) image.Point {
+	return image.Point{
+		clamp(s.rx*float64(p.X)+s.dx, s.r.Min.X, s.r.Max.X),
+		clamp(s.ry*float64(p.Y)+s.dy, s.r.Min.Y, s.r.Max.Y),
+	}
+}
+
+// rect projects r from the source rectangle onto the target rectangle.
+func (s *projector) rect(r image.Rectangle) image.Rectangle {
+	return image.Rectangle{s.pt(r.Min), s.pt(r.Max)}
+}
+
+// clamp rounds and clamps o to the integer range [x0, x1].
+func clamp(o float64, x0, x1 int) int {
+	x := int(o + 0.5)
+	if x < x0 {
+		return x0
+	}
+	if x > x1 {
+		return x1
+	}
+	return x
+}