From 2a8c17c33c724bf04bd099d7519e2b8516b3df39 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Wed, 5 Jul 2017 19:51:54 +0200
Subject: [PATCH] add Rect.Intersect
---
geometry.go | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/geometry.go b/geometry.go
index 56283a9..1c61477 100644
--- a/geometry.go
+++ b/geometry.go
@@ -160,8 +160,8 @@ type Rect struct {
// Note that the returned rectangle is not automatically normalized.
func R(minX, minY, maxX, maxY float64) Rect {
return Rect{
- Min: V(minX, minY),
- Max: V(maxX, maxY),
+ Min: Vec{minX, minY},
+ Max: Vec{maxX, maxY},
}
}
@@ -257,7 +257,7 @@ func (r Rect) Contains(u Vec) bool {
return r.Min.X <= u.X && u.X <= r.Max.X && r.Min.Y <= u.Y && u.Y <= r.Max.Y
}
-// Union returns a minimal Rect which covers both r and s. Rects r and s should be normalized.
+// Union returns the minimal Rect which covers both r and s. Rects r and s must be normalized.
func (r Rect) Union(s Rect) Rect {
return R(
math.Min(r.Min.X, s.Min.X),
@@ -267,6 +267,20 @@ func (r Rect) Union(s Rect) Rect {
)
}
+// Intersect returns the maximal Rect which is covered by both r and s. Rects r and s must be normalized.
+func (r Rect) Intersect(s Rect) Rect {
+ t := R(
+ math.Min(r.Max.X, s.Max.X),
+ math.Min(r.Max.Y, s.Max.Y),
+ math.Max(r.Min.X, s.Min.X),
+ math.Max(r.Min.Y, s.Min.Y),
+ )
+ if t.Min.X >= t.Max.X || t.Min.Y >= t.Max.Y {
+ return Rect{}
+ }
+ return t
+}
+
// Matrix is a 3x2 affine matrix that can be used for all kinds of spatial transforms, such
// as movement, scaling and rotations.
//
--
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