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Improve SVG arc parsing:

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* elliptical arc support
* x-axis-rotation support
* handle invalid values according to specification
This commit is contained in:
Yuri Strot 2018-02-09 21:05:56 +07:00
parent 0d2a0959e7
commit a93d4d80e9
1 changed files with 65 additions and 26 deletions
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87
Source/render/RenderUtils.swift
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@ -358,43 +358,75 @@ class RenderUtils {
}
}
func A(_ rx: Double, ry: Double, angle: Double, largeArc: Bool, sweep: Bool, x: Double, y: Double) {
func A(_ _rx: Double, ry _ry: Double, angle _angle: Double, largeArc: Bool, sweep: Bool, x: Double, y: Double) {
let angle = _angle * .pi / 180
if let cur = currentPoint {
let x1 = Double(cur.x)
let y1 = Double(cur.y)
// find arc center coordinates and points angles as per
// http://www.w3.org/TR/SVG/implnote.html#ArcConversionEndpointToCenter
let x1_ = cos(angle) * (x1 - x) / 2 + sin(angle) * (y1 - y) / 2
let y1_ = -1 * sin(angle) * (x1 - x) / 2 + cos(angle) * (y1 - y) / 2
// make sure the value under the root is positive
let underroot = (rx * rx * ry * ry - rx * rx * y1_ * y1_ - ry * ry * x1_ * x1_)
/ (rx * rx * y1_ * y1_ + ry * ry * x1_ * x1_)
var bigRoot = (underroot > 0) ? sqrt(underroot) : 0
bigRoot = (bigRoot <= 1e-2) ? 0 : bigRoot
let coef: Double = (sweep != largeArc) ? 1 : -1
let cx_ = coef * bigRoot * rx * y1_ / ry
let cy_ = -1 * coef * bigRoot * ry * x1_ / rx
let cx = cos(angle) * cx_ - sin(angle) * cy_ + (x1 + x) / 2
let cy = sin(angle) * cx_ + cos(angle) * cy_ + (y1 + y) / 2
if (_rx == 0 || _ry == 0) {
L(x, y: y)
} else {
var rx = abs(_rx)
var ry = abs(_ry)
let x1_ = cos(angle) * (x1 - x) / 2 + sin(angle) * (y1 - y) / 2
let y1_ = -1 * sin(angle) * (x1 - x) / 2 + cos(angle) * (y1 - y) / 2
let t1 = calcAngle(ux: 1, uy: 0, vx: (x1_ - cx_) / rx, vy: (y1_ - cy_) / ry)
var delta = calcAngle(ux: (x1_ - cx_) / rx, uy: (y1_ - cy_) / ry, vx: (-x1_ - cx_) / rx, vy: (-y1_ - cy_) / ry).truncatingRemainder(dividingBy: .pi * 2)
let rCheck = (x1_ * x1_) / (rx * rx) + (y1_ * y1_) / (ry * ry)
if (rCheck > 1) {
rx = sqrt(rCheck) * rx
ry = sqrt(rCheck) * ry
}
if ((sweep && delta < 0) || (!sweep && delta > 0)) {
delta = -delta
// make sure the value under the root is positive
let underroot = (rx * rx * ry * ry - rx * rx * y1_ * y1_ - ry * ry * x1_ * x1_)
/ (rx * rx * y1_ * y1_ + ry * ry * x1_ * x1_)
var bigRoot = (underroot > 0) ? sqrt(underroot) : 0
bigRoot = (bigRoot <= 1e-2) ? 0 : bigRoot
let coef: Double = (sweep != largeArc) ? 1 : -1
let cx_ = coef * bigRoot * rx * y1_ / ry
let cy_ = -1 * coef * bigRoot * ry * x1_ / rx
let cx = cos(angle) * cx_ - sin(angle) * cy_ + (x1 + x) / 2
let cy = sin(angle) * cx_ + cos(angle) * cy_ + (y1 + y) / 2
let t1 = calcAngle(ux: 1, uy: 0, vx: (x1_ - cx_) / rx, vy: (y1_ - cy_) / ry)
var delta = calcAngle(ux: (x1_ - cx_) / rx, uy: (y1_ - cy_) / ry, vx: (-x1_ - cx_) / rx, vy: (-y1_ - cy_) / ry)
let pi2 = Double.pi * 2
if (delta > 0) {
delta = delta.truncatingRemainder(dividingBy: pi2)
if (!sweep) {
delta -= pi2
}
} else if (delta < 0) {
delta = -1 * ((-1 * delta).truncatingRemainder(dividingBy: pi2))
if (sweep) {
delta += pi2
}
}
E(cx - rx, y: cy - ry, w: 2 * rx, h: 2 * ry, startAngle: t1, arcAngle: delta, rotation: angle)
setPoint(CGPoint(x: CGFloat(x), y: CGFloat(y)))
}
E(cx - rx, y: cy - ry, w: 2 * rx, h: 2 * ry, startAngle: t1, arcAngle: delta)
setPoint(CGPoint(x: CGFloat(x), y: CGFloat(y)))
}
}
func E(_ x: Double, y: Double, w: Double, h: Double, startAngle: Double, arcAngle: Double) {
// TODO: only circle now
func E(_ x: Double, y: Double, w: Double, h: Double, startAngle: Double, arcAngle: Double, rotation: Double = 0) {
let extent = CGFloat(startAngle)
let end = extent + CGFloat(arcAngle)
let center = CGPoint(x: CGFloat(x + w / 2), y: CGFloat(y + h / 2))
bezierPath.addArc(withCenter: center, radius: CGFloat(w / 2), startAngle: extent, endAngle: end, clockwise: arcAngle >= 0)
let cx = CGFloat(x + w / 2)
let cy = CGFloat(y + h / 2)
if (w == h && rotation == 0) {
bezierPath.addArc(withCenter: CGPoint(x: cx, y: cy), radius: CGFloat(w / 2), startAngle: extent, endAngle: end, clockwise: arcAngle >= 0)
} else {
let maxSize = CGFloat(max(w, h))
let path = UIBezierPath(arcCenter: CGPoint.zero, radius: maxSize / 2, startAngle: extent, endAngle: end, clockwise: arcAngle >= 0)
var transform = CGAffineTransform(translationX: cx, y: cy)
transform = transform.rotated(by: CGFloat(rotation))
path.apply(transform.scaledBy(x: CGFloat(w) / maxSize, y: CGFloat(h) / maxSize))
bezierPath.append(path)
}
}
func e(_ x: Double, y: Double, w: Double, h: Double, startAngle: Double, arcAngle: Double) {
@ -515,7 +547,14 @@ class RenderUtils {
class func calcAngle(ux: Double, uy: Double, vx: Double, vy: Double) -> Double {
let sign = copysign(1, ux * vy - uy * vx)
return sign * acos((ux * vx + uy * vy) / (sqrt(ux * ux + uy * uy) * sqrt(vx * vx + vy * vy)))
let value = (ux * vx + uy * vy) / (sqrt(ux * ux + uy * uy) * sqrt(vx * vx + vy * vy))
if (value < -1) {
return sign * .pi
} else if (value > 1) {
return 0
} else {
return sign * acos(value)
}
}
class func num2bool(_ double: Double) -> Bool {