math/fixed: add some Point and Rectangle methods.
These are analogous to the image.Point and image.Rectangle methods in
the standard library.
Change-Id: If8997421a9aeb31d29cfe5eefb79cc481a39df82
Reviewed-on: https://go-review.googlesource.com/34753
Reviewed-by: David Crawshaw <crawshaw@golang.org>
diff --git a/font/font.go b/font/font.go
index 2556ebb..05f4357 100644
--- a/font/font.go
+++ b/font/font.go
@@ -222,7 +222,7 @@
}
b.Min.X += advance
b.Max.X += advance
- bounds = grow(bounds, b)
+ bounds = bounds.Union(b)
advance += a
prevC = c
}
@@ -246,41 +246,13 @@
}
b.Min.X += advance
b.Max.X += advance
- bounds = grow(bounds, b)
+ bounds = bounds.Union(b)
advance += a
prevC = c
}
return
}
-func empty(r fixed.Rectangle26_6) bool {
- return r.Min.X >= r.Max.X || r.Min.Y >= r.Max.Y
-}
-
-// grow returns the smallest rectangle containing both b and b2.
-func grow(b, b2 fixed.Rectangle26_6) fixed.Rectangle26_6 {
- if empty(b) {
- return b2
- }
- if empty(b2) {
- return b
- }
-
- if b.Min.X > b2.Min.X {
- b.Min.X = b2.Min.X
- }
- if b.Min.Y > b2.Min.Y {
- b.Min.Y = b2.Min.Y
- }
- if b.Max.X < b2.Max.X {
- b.Max.X = b2.Max.X
- }
- if b.Max.Y < b2.Max.Y {
- b.Max.Y = b2.Max.Y
- }
- return b
-}
-
// MeasureBytes returns how far dot would advance by drawing s with f.
//
// It is equivalent to MeasureString(string(s)) but may be more efficient.
diff --git a/math/fixed/fixed.go b/math/fixed/fixed.go
index 2c76ed4..3d91663 100644
--- a/math/fixed/fixed.go
+++ b/math/fixed/fixed.go
@@ -167,6 +167,11 @@
return Point26_6{p.X * 64 / k, p.Y * 64 / k}
}
+// In returns whether p is in r.
+func (p Point26_6) In(r Rectangle26_6) bool {
+ return r.Min.X <= p.X && p.X < r.Max.X && r.Min.Y <= p.Y && p.Y < r.Max.Y
+}
+
// Point52_12 is a 52.12 fixed-point coordinate pair.
//
// It is analogous to the image.Point type in the standard library.
@@ -194,6 +199,11 @@
return Point52_12{p.X * 4096 / k, p.Y * 4096 / k}
}
+// In returns whether p is in r.
+func (p Point52_12) In(r Rectangle52_12) bool {
+ return r.Min.X <= p.X && p.X < r.Max.X && r.Min.Y <= p.Y && p.Y < r.Max.Y
+}
+
// R returns the integer values minX, minY, maxX, maxY as a Rectangle26_6.
//
// For example, passing the integer values (0, 1, 2, 3) yields
@@ -230,6 +240,86 @@
Min, Max Point26_6
}
+// Add returns the rectangle r translated by p.
+func (r Rectangle26_6) Add(p Point26_6) Rectangle26_6 {
+ return Rectangle26_6{
+ Point26_6{r.Min.X + p.X, r.Min.Y + p.Y},
+ Point26_6{r.Max.X + p.X, r.Max.Y + p.Y},
+ }
+}
+
+// Sub returns the rectangle r translated by -p.
+func (r Rectangle26_6) Sub(p Point26_6) Rectangle26_6 {
+ return Rectangle26_6{
+ Point26_6{r.Min.X - p.X, r.Min.Y - p.Y},
+ Point26_6{r.Max.X - p.X, r.Max.Y - p.Y},
+ }
+}
+
+// Intersect returns the largest rectangle contained by both r and s. If the
+// two rectangles do not overlap then the zero rectangle will be returned.
+func (r Rectangle26_6) Intersect(s Rectangle26_6) Rectangle26_6 {
+ if r.Min.X < s.Min.X {
+ r.Min.X = s.Min.X
+ }
+ if r.Min.Y < s.Min.Y {
+ r.Min.Y = s.Min.Y
+ }
+ if r.Max.X > s.Max.X {
+ r.Max.X = s.Max.X
+ }
+ if r.Max.Y > s.Max.Y {
+ r.Max.Y = s.Max.Y
+ }
+ // Letting r0 and s0 be the values of r and s at the time that the method
+ // is called, this next line is equivalent to:
+ //
+ // if max(r0.Min.X, s0.Min.X) >= min(r0.Max.X, s0.Max.X) || likewiseForY { etc }
+ if r.Empty() {
+ return Rectangle26_6{}
+ }
+ return r
+}
+
+// Union returns the smallest rectangle that contains both r and s.
+func (r Rectangle26_6) Union(s Rectangle26_6) Rectangle26_6 {
+ if r.Empty() {
+ return s
+ }
+ if s.Empty() {
+ return r
+ }
+ if r.Min.X > s.Min.X {
+ r.Min.X = s.Min.X
+ }
+ if r.Min.Y > s.Min.Y {
+ r.Min.Y = s.Min.Y
+ }
+ if r.Max.X < s.Max.X {
+ r.Max.X = s.Max.X
+ }
+ if r.Max.Y < s.Max.Y {
+ r.Max.Y = s.Max.Y
+ }
+ return r
+}
+
+// Empty returns whether the rectangle contains no points.
+func (r Rectangle26_6) Empty() bool {
+ return r.Min.X >= r.Max.X || r.Min.Y >= r.Max.Y
+}
+
+// In returns whether every point in r is in s.
+func (r Rectangle26_6) In(s Rectangle26_6) bool {
+ if r.Empty() {
+ return true
+ }
+ // Note that r.Max is an exclusive bound for r, so that r.In(s)
+ // does not require that r.Max.In(s).
+ return s.Min.X <= r.Min.X && r.Max.X <= s.Max.X &&
+ s.Min.Y <= r.Min.Y && r.Max.Y <= s.Max.Y
+}
+
// Rectangle52_12 is a 52.12 fixed-point coordinate rectangle. The Min bound is
// inclusive and the Max bound is exclusive. It is well-formed if Min.X <=
// Max.X and likewise for Y.
@@ -238,3 +328,83 @@
type Rectangle52_12 struct {
Min, Max Point52_12
}
+
+// Add returns the rectangle r translated by p.
+func (r Rectangle52_12) Add(p Point52_12) Rectangle52_12 {
+ return Rectangle52_12{
+ Point52_12{r.Min.X + p.X, r.Min.Y + p.Y},
+ Point52_12{r.Max.X + p.X, r.Max.Y + p.Y},
+ }
+}
+
+// Sub returns the rectangle r translated by -p.
+func (r Rectangle52_12) Sub(p Point52_12) Rectangle52_12 {
+ return Rectangle52_12{
+ Point52_12{r.Min.X - p.X, r.Min.Y - p.Y},
+ Point52_12{r.Max.X - p.X, r.Max.Y - p.Y},
+ }
+}
+
+// Intersect returns the largest rectangle contained by both r and s. If the
+// two rectangles do not overlap then the zero rectangle will be returned.
+func (r Rectangle52_12) Intersect(s Rectangle52_12) Rectangle52_12 {
+ if r.Min.X < s.Min.X {
+ r.Min.X = s.Min.X
+ }
+ if r.Min.Y < s.Min.Y {
+ r.Min.Y = s.Min.Y
+ }
+ if r.Max.X > s.Max.X {
+ r.Max.X = s.Max.X
+ }
+ if r.Max.Y > s.Max.Y {
+ r.Max.Y = s.Max.Y
+ }
+ // Letting r0 and s0 be the values of r and s at the time that the method
+ // is called, this next line is equivalent to:
+ //
+ // if max(r0.Min.X, s0.Min.X) >= min(r0.Max.X, s0.Max.X) || likewiseForY { etc }
+ if r.Empty() {
+ return Rectangle52_12{}
+ }
+ return r
+}
+
+// Union returns the smallest rectangle that contains both r and s.
+func (r Rectangle52_12) Union(s Rectangle52_12) Rectangle52_12 {
+ if r.Empty() {
+ return s
+ }
+ if s.Empty() {
+ return r
+ }
+ if r.Min.X > s.Min.X {
+ r.Min.X = s.Min.X
+ }
+ if r.Min.Y > s.Min.Y {
+ r.Min.Y = s.Min.Y
+ }
+ if r.Max.X < s.Max.X {
+ r.Max.X = s.Max.X
+ }
+ if r.Max.Y < s.Max.Y {
+ r.Max.Y = s.Max.Y
+ }
+ return r
+}
+
+// Empty returns whether the rectangle contains no points.
+func (r Rectangle52_12) Empty() bool {
+ return r.Min.X >= r.Max.X || r.Min.Y >= r.Max.Y
+}
+
+// In returns whether every point in r is in s.
+func (r Rectangle52_12) In(s Rectangle52_12) bool {
+ if r.Empty() {
+ return true
+ }
+ // Note that r.Max is an exclusive bound for r, so that r.In(s)
+ // does not require that r.Max.In(s).
+ return s.Min.X <= r.Min.X && r.Max.X <= s.Max.X &&
+ s.Min.Y <= r.Min.Y && r.Max.Y <= s.Max.Y
+}
