geo: github.com/golang/geo/r2

## package r2

`import "github.com/golang/geo/r2"`

Package r2 implements types and functions for working with geometry in ℝ².

See package s2 for a more detailed overview.

### type Point¶Uses

```type Point struct {
X, Y float64
}```

Point represents a point in ℝ².

`func (p Point) Add(op Point) Point`

Add returns the sum of p and op.

#### func (Point) Cross¶Uses

`func (p Point) Cross(op Point) float64`

Cross returns the cross product of p and op.

#### func (Point) Dot¶Uses

`func (p Point) Dot(op Point) float64`

Dot returns the dot product between p and op.

#### func (Point) Mul¶Uses

`func (p Point) Mul(m float64) Point`

Mul returns the scalar product of p and m.

#### func (Point) Norm¶Uses

`func (p Point) Norm() float64`

Norm returns the vector's norm.

#### func (Point) Normalize¶Uses

`func (p Point) Normalize() Point`

Normalize returns a unit point in the same direction as p.

#### func (Point) Ortho¶Uses

`func (p Point) Ortho() Point`

Ortho returns a counterclockwise orthogonal point with the same norm.

#### func (Point) String¶Uses

`func (p Point) String() string`

#### func (Point) Sub¶Uses

`func (p Point) Sub(op Point) Point`

Sub returns the difference of p and op.

### type Rect¶Uses

```type Rect struct {
X, Y r1.Interval
}```

Rect represents a closed axis-aligned rectangle in the (x,y) plane.

#### func EmptyRect¶Uses

`func EmptyRect() Rect`

EmptyRect constructs the canonical empty rectangle. Use IsEmpty() to test for empty rectangles, since they have more than one representation. A Rect{} is not the same as the EmptyRect.

#### func RectFromCenterSize¶Uses

`func RectFromCenterSize(center, size Point) Rect`

RectFromCenterSize constructs a rectangle with the given center and size. Both dimensions of size must be non-negative.

#### func RectFromPoints¶Uses

`func RectFromPoints(pts ...Point) Rect`

RectFromPoints constructs a rect that contains the given points.

`func (r Rect) AddPoint(p Point) Rect`

AddPoint expands the rectangle to include the given point. The rectangle is expanded by the minimum amount possible.

`func (r Rect) AddRect(other Rect) Rect`

AddRect expands the rectangle to include the given rectangle. This is the same as replacing the rectangle by the union of the two rectangles, but is more efficient.

#### func (Rect) ApproxEqual¶Uses

`func (r Rect) ApproxEqual(r2 Rect) bool`

ApproxEqual returns true if the x- and y-intervals of the two rectangles are the same up to the given tolerance.

#### func (Rect) Center¶Uses

`func (r Rect) Center() Point`

Center returns the center of the rectangle in (x,y)-space

#### func (Rect) ClampPoint¶Uses

`func (r Rect) ClampPoint(p Point) Point`

ClampPoint returns the closest point in the rectangle to the given point. The rectangle must be non-empty.

#### func (Rect) Contains¶Uses

`func (r Rect) Contains(other Rect) bool`

Contains reports whether the rectangle contains the given rectangle.

#### func (Rect) ContainsPoint¶Uses

`func (r Rect) ContainsPoint(p Point) bool`

ContainsPoint reports whether the rectangle contains the given point. Rectangles are closed regions, i.e. they contain their boundary.

#### func (Rect) Expanded¶Uses

`func (r Rect) Expanded(margin Point) Rect`

Expanded returns a rectangle that has been expanded in the x-direction by margin.X, and in y-direction by margin.Y. If either margin is empty, then shrink the interval on the corresponding sides instead. The resulting rectangle may be empty. Any expansion of an empty rectangle remains empty.

#### func (Rect) ExpandedByMargin¶Uses

`func (r Rect) ExpandedByMargin(margin float64) Rect`

ExpandedByMargin returns a Rect that has been expanded by the amount on all sides.

#### func (Rect) Hi¶Uses

`func (r Rect) Hi() Point`

Hi returns the high corner of the rect.

#### func (Rect) InteriorContains¶Uses

`func (r Rect) InteriorContains(other Rect) bool`

InteriorContains reports whether the interior of this rectangle contains all of the points of the given other rectangle (including its boundary).

#### func (Rect) InteriorContainsPoint¶Uses

`func (r Rect) InteriorContainsPoint(p Point) bool`

InteriorContainsPoint returns true iff the given point is contained in the interior of the region (i.e. the region excluding its boundary).

#### func (Rect) InteriorIntersects¶Uses

`func (r Rect) InteriorIntersects(other Rect) bool`

InteriorIntersects reports whether the interior of this rectangle intersects any point (including the boundary) of the given other rectangle.

#### func (Rect) Intersection¶Uses

`func (r Rect) Intersection(other Rect) Rect`

Intersection returns the smallest rectangle containing the intersection of this rectangle and the given rectangle.

#### func (Rect) Intersects¶Uses

`func (r Rect) Intersects(other Rect) bool`

Intersects reports whether this rectangle and the other rectangle have any points in common.

#### func (Rect) IsEmpty¶Uses

`func (r Rect) IsEmpty() bool`

IsEmpty reports whether the rectangle is empty.

#### func (Rect) IsValid¶Uses

`func (r Rect) IsValid() bool`

IsValid reports whether the rectangle is valid. This requires the width to be empty iff the height is empty.

#### func (Rect) Lo¶Uses

`func (r Rect) Lo() Point`

Lo returns the low corner of the rect.

#### func (Rect) Size¶Uses

`func (r Rect) Size() Point`

Size returns the width and height of this rectangle in (x,y)-space. Empty rectangles have a negative width and height.

#### func (Rect) String¶Uses

`func (r Rect) String() string`

#### func (Rect) Union¶Uses

`func (r Rect) Union(other Rect) Rect`

Union returns the smallest rectangle containing the union of this rectangle and the given rectangle.

#### func (Rect) VertexIJ¶Uses

`func (r Rect) VertexIJ(i, j int) Point`

VertexIJ returns the vertex in direction i along the X-axis (0=left, 1=right) and direction j along the Y-axis (0=down, 1=up).

#### func (Rect) Vertices¶Uses

`func (r Rect) Vertices() Point`

Vertices returns all four vertices of the rectangle. Vertices are returned in CCW direction starting with the lower left corner.

Package r2 imports 3 packages (graph) and is imported by 19 packages. Updated 2019-01-24. Refresh now. Tools for package owners.