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SVG path to CGPath converter
//
// SVGPath.swift
// SVGPath
//
// Created by Tim Wood on 1/21/15.
// Updated by Vitaly Domnikov 10/6/2015
// Copyright (c) 2015 Tim Wood, Vitaly Domnikov. All rights reserved.
import Foundation
import CoreGraphics
public extension CGPath {
// Convert SVG path to CGPath
static func fromSvgPath(svgPath: String) -> CGPath? {
let path = CGPathCreateMutable()
CGPathMoveToPoint(path, nil, 0, 0)
let commands = SVGPath(svgPath).commands
for command in commands {
switch command.type {
case .Move: CGPathMoveToPoint(path, nil, command.point.x, command.point.y)
case .Line: CGPathAddLineToPoint(path, nil, command.point.x, command.point.y)
case .QuadCurve:
CGPathAddQuadCurveToPoint(path, nil,
command.control1.x, command.control1.y,
command.point.x, command.point.y)
case .CubeCurve:
CGPathAddCurveToPoint(path, nil,
command.control1.x, command.control1.y,
command.control2.x, command.control2.y,
command.point.x, command.point.y)
case .Close: CGPathCloseSubpath(path)
}
}
return path
}
}
// MARK: Enums
private enum Coordinates {
case Absolute
case Relative
}
// MARK: Class
public class SVGPath {
public var commands: [SVGCommand] = []
private var builder: SVGCommandBuilder = moveTo
private var coords: Coordinates = .Absolute
private var stride: Int = 2
private var numbers = ""
public init(_ string: String) {
commands.reserveCapacity(200)
for char in string.characters {
switch char {
case "M": use(.Absolute, 2, moveTo)
case "m": use(.Relative, 2, moveTo)
case "L": use(.Absolute, 2, lineTo)
case "l": use(.Relative, 2, lineTo)
case "V": use(.Absolute, 1, lineToVertical)
case "v": use(.Relative, 1, lineToVertical)
case "H": use(.Absolute, 1, lineToHorizontal)
case "h": use(.Relative, 1, lineToHorizontal)
case "Q": use(.Absolute, 4, quadBroken)
case "q": use(.Relative, 4, quadBroken)
case "T": use(.Absolute, 2, quadSmooth)
case "t": use(.Relative, 2, quadSmooth)
case "C": use(.Absolute, 6, cubeBroken)
case "c": use(.Relative, 6, cubeBroken)
case "S": use(.Absolute, 4, cubeSmooth)
case "s": use(.Relative, 4, cubeSmooth)
case "Z": use(.Absolute, 0, close)
case "z": use(.Relative, 0, close)
default: numbers.append(char)
}
}
finishLastCommand()
}
private func use(coords: Coordinates, _ stride: Int, _ builder: SVGCommandBuilder) {
finishLastCommand()
self.builder = builder
self.coords = coords
self.stride = stride
}
private func finishLastCommand() {
for command in take(SVGPath.parseNumbers(numbers), stride: stride, coords: coords, last: commands.last, callback: builder) {
commands.append(coords == .Relative ? command.relativeTo(commands.last) : command)
}
numbers = ""
}
}
// MARK: Numbers
private let numberSet = NSCharacterSet(charactersInString: "-.0123456789eE")
private let numberFormatter = NSNumberFormatter()
public extension SVGPath {
class func parseNumbers(numbers: String) -> [CGFloat] {
numberFormatter.numberStyle = .DecimalStyle
numberFormatter.allowsFloats = true
numberFormatter.decimalSeparator = "."
var all: [String] = []
var curr = ""
var last = ""
for char in numbers.unicodeScalars {
let next = String(char)
if next == "-" && last != "" && last != "E" && last != "e" {
if curr.utf16.count > 0 {
all.append(curr)
}
curr = next
} else if numberSet.longCharacterIsMember(char.value) {
curr += next
} else if curr.utf16.count > 0 {
all.append(curr)
curr = ""
}
last = next
}
all.append(curr)
return all
.filter {
numberFormatter.numberFromString($0) != nil
}
.map {
CGFloat((numberFormatter.numberFromString($0)?.floatValue)!)
}
}
}
// MARK: Commands
public struct SVGCommand {
public var point: CGPoint
public var control1: CGPoint
public var control2: CGPoint
public var type: Kind
public enum Kind {
case Move
case Line
case CubeCurve
case QuadCurve
case Close
}
public init() {
let point = CGPoint()
self.init(point, point, point, type: .Close)
}
public init(_ x: CGFloat, _ y: CGFloat, type: Kind) {
let point = CGPoint(x: x, y: y)
self.init(point, point, point, type: type)
}
public init(_ cx: CGFloat, _ cy: CGFloat, _ x: CGFloat, _ y: CGFloat) {
let control = CGPoint(x: cx, y: cy)
self.init(control, control, CGPoint(x: x, y: y), type: .QuadCurve)
}
public init(_ cx1: CGFloat, _ cy1: CGFloat, _ cx2: CGFloat, _ cy2: CGFloat, _ x: CGFloat, _ y: CGFloat) {
self.init(CGPoint(x: cx1, y: cy1), CGPoint(x: cx2, y: cy2), CGPoint(x: x, y: y), type: .CubeCurve)
}
public init(_ control1: CGPoint, _ control2: CGPoint, _ point: CGPoint, type: Kind) {
self.point = point
self.control1 = control1
self.control2 = control2
self.type = type
}
private func relativeTo(other: SVGCommand?) -> SVGCommand {
if let otherPoint = other?.point {
return SVGCommand(control1 + otherPoint, control2 + otherPoint, point + otherPoint, type: type)
}
return self
}
}
// MARK: CGPoint helpers
private func +(a: CGPoint, b: CGPoint) -> CGPoint {
return CGPoint(x: a.x + b.x, y: a.y + b.y)
}
private func -(a: CGPoint, b: CGPoint) -> CGPoint {
return CGPoint(x: a.x - b.x, y: a.y - b.y)
}
// MARK: Command Builders
private typealias SVGCommandBuilder = ([CGFloat], SVGCommand?, Coordinates) -> SVGCommand
private func take(numbers: [CGFloat], stride: Int, coords: Coordinates, last: SVGCommand?, callback: SVGCommandBuilder) -> [SVGCommand] {
var out: [SVGCommand] = []
var lastCommand: SVGCommand? = last
var nums: [CGFloat] = [0, 0, 0, 0, 0, 0];
if stride == 0 {
lastCommand = callback(nums, lastCommand, coords)
out.append(lastCommand!)
} else {
let count = (numbers.count / stride) * stride
for var i = 0; i < count; i += stride {
for var j = 0; j < stride; j++ {
nums[j] = numbers[i + j]
}
lastCommand = callback(nums, lastCommand, coords)
out.append(lastCommand!)
}
}
return out
}
// MARK: Mm - Move
private func moveTo(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand(numbers[0], numbers[1], type: .Move)
}
// MARK: Ll - Line
private func lineTo(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand(numbers[0], numbers[1], type: .Line)
}
// MARK: Vv - Vertical Line
private func lineToVertical(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand(coords == .Absolute ? last?.point.x ?? 0 : 0, numbers[0], type: .Line)
}
// MARK: Hh - Horizontal Line
private func lineToHorizontal(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand(numbers[0], coords == .Absolute ? last?.point.y ?? 0 : 0, type: .Line)
}
// MARK: Qq - Quadratic Curve To
private func quadBroken(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand(numbers[0], numbers[1], numbers[2], numbers[3])
}
// MARK: Tt - Smooth Quadratic Curve To
private func quadSmooth(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
var lastControl = last?.control1 ?? CGPoint()
let lastPoint = last?.point ?? CGPoint()
if (last?.type ?? .Line) != .QuadCurve {
lastControl = lastPoint
}
var control = lastPoint - lastControl
if coords == .Absolute {
control = control + lastPoint
}
return SVGCommand(control.x, control.y, numbers[0], numbers[1])
}
// MARK: Cc - Cubic Curve To
private func cubeBroken(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand(numbers[0], numbers[1], numbers[2], numbers[3], numbers[4], numbers[5])
}
// MARK: Ss - Smooth Cubic Curve To
private func cubeSmooth(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
var lastControl = last?.control2 ?? CGPoint()
let lastPoint = last?.point ?? CGPoint()
if (last?.type ?? .Line) != .CubeCurve {
lastControl = lastPoint
}
var control = lastPoint - lastControl
if coords == .Absolute {
control = control + lastPoint
}
return SVGCommand(control.x, control.y, numbers[0], numbers[1], numbers[2], numbers[3])
}
// MARK: Zz - Close Path
private func close(numbers: [CGFloat], last: SVGCommand?, coords: Coordinates) -> SVGCommand {
return SVGCommand()
}
@jasorod
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jasorod commented Aug 29, 2017

I've forked this gist and updated the code for Swift 4 as well as added some additional parsing rules to support the SVG Paths in Google Material Icons

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