Metron
Geometry, simplified.
Metron is a comprehensive collection of geometric functions and types that extend the 2D geometric primitives provided by CoreGraphics. Completely written in Swift, Metron allows you to express complex geometric calculations in very intuitive statements:
Example 1.
Circle(in: viewFrame).contains(touchPoint)
↳ creates a Circle
that fits (centered) inside viewFrame
, and checks if the touchPoint
is inside that circle.
Example 2.
(Angle(.pi) + Angle(270, unit: .degrees)).normalized // Angle of 0.5pi (90°)
↳ adds two Angles
, one expressed in radians (default) and one in degrees. The sum is normalized to within 0 and 2𝛑 radians (or 0 and 360 degrees).
Example 3.
LineSegment(a: startPoint, b: currentPoint).intersection(with: viewFrame.lineSegment(for: minYEdge))
↳ creates a LineSegment
between a (touch) start point and current point, and returns the intersection with the minYEdge
of a view's frame (if these line segments indeed intersect).
Example 4.
let rotatedPoints = viewFrame.points.map { $0.applying(rotationTransform, anchorPoint: rotationPoint) }
let path: CGPath = Polygon(points: rotatedPoints).path
↳ maps each corner point of a view's frame (a CGRect
) to a point to which a rotationTransform
is applied, taking rotationPoint
as the anchor point for the transform.
With these points, a Polygon
is initialized, representing the rotated rectangular frame of the view. From that polygon, we derive a CGPath
that can then be drawn.
And there's much more...
Extensions
For CGPoint
 Distance to other
CGPoint
 Clipping to
CGRect
 Relative position in
CGRect
 Normalized position in
CGRect
 Convert to
CGVector
 Round to nondecimal components
 Addition, subtraction, multiplication...
 Convex hull for an array of
CGPoints
(returns aPolygon
)
For CGVector
 Magnitude
 Angle
 Convenience initializer with magnitude and angle
 Convert to
CGPoint
 Inverse
 Dominant edge
 Dominant corner
 Derive line through point
 Derive line segment from point

CGAffineTransform
extensions  Addition, subtraction, multiplication...
For CGSize
 Area
 Swap width and height
 Clip to other
CGSize
 Scaling using multiplication and division
For CGRect
 Many convenience initializers, including AspectFit / AspectFill for size
 Scaling
 Corner points
 Edges as line segments
 Area
 Center
 Perimeter

CGPath
For CGRectEdge
 Axis (x or y)
 Adjacent corners
 Opposite edge
For CGAffineTransform
 Create translation transform using
CGVector
 Apply transform with a specified anchor point
New Types
Line
 Slope
 Yintercept
 Xintercept
 Horizontal? / vertical? / parallel(to: ...)?
 Get a perpendicular line
 Determine intersection with other
Line
orLineSegment
LineSegment
 Length
 Derive a
Line
 Rotate
 Determine intersection with other
Line
orLineSegment

CGPath
Circle
 Radius
 Diameter
 Circumference
 Area
 Center
 Width / Height
 Bounding rect
 Contains point?

CGPath
 Points along the perimeter (divide the circle into steps, rotating in a specific direction...)
Triangle
 Vertices (as
CGPoint
)  Sides (as
LineSegment
)  Angles (as
Angle
, see further on)  Angle bisectors (as
LineSegment
)  Altitudes (as
LineSegment
)  Equilateral? / isosceles? / scalene? / right? / oblique? / acute? / obtuse?
 Centroid
 Circumcenter
 Incenter
 Orthocenter
 Area
 Bounding rect
 Contains point?

CGPath
Square
 Edge length
 Area
 Perimeter
 Center

CGPath

CGRect
Polygon
 Init with points or with line segments
 Edge count
 Selfintersecting?
 Convex? / concave?
 Area
 Perimeter
 Center
 Bounding rect
 Contains point?

CGPath
Corner
 Adjacent edges (
CGRectEdges
)  Opposite corner
Angle
 Init with radians or degrees
 Convert unit
 Normalize
 Invert
 Compare
 Addition, subtraction, multiplication...
 Basic trigonometric functions also accept
Angle
 Create rotation
CGAffineTransform
withAngle
Installation
CocoaPods
Metron is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod "Metron"
Carthage
Metron is also available through Carthage. To install it, simply add the following line to your Cartfile:
github "toineheuvelmans/Metron"
Swift Package Manager
Metron can also be used with the Swift Package Manager. Add Metron to the dependencies
value of your Package.swift
:
dependencies: [
.Package(url: "https://github.com/toineheuvelmans/metron.git", majorVersion: 1)
]
Suggestions or feedback?
Feel free to create a pull request, open an issue or find me on Twitter.
License
Metron is available under the MIT license. See the LICENSE file for more info.