我该如何在NSBezierPath和CGPath之间进行转换？
谢谢。
8个回答
43
直接引用自苹果的文档：从NSBezierPath对象创建CGPathRef
以下是相关代码。
@implementation NSBezierPath (BezierPathQuartzUtilities)
// This method works only in OS X v10.2 and later.
- (CGPathRef)quartzPath
{
int i, numElements;
// Need to begin a path here.
CGPathRef immutablePath = NULL;
// Then draw the path elements.
numElements = [self elementCount];
if (numElements > 0)
{
CGMutablePathRef path = CGPathCreateMutable();
NSPoint points[3];
BOOL didClosePath = YES;
for (i = 0; i < numElements; i++)
{
switch ([self elementAtIndex:i associatedPoints:points])
{
case NSMoveToBezierPathElement:
CGPathMoveToPoint(path, NULL, points[0].x, points[0].y);
break;
case NSLineToBezierPathElement:
CGPathAddLineToPoint(path, NULL, points[0].x, points[0].y);
didClosePath = NO;
break;
case NSCurveToBezierPathElement:
CGPathAddCurveToPoint(path, NULL, points[0].x, points[0].y,
points[1].x, points[1].y,
points[2].x, points[2].y);
didClosePath = NO;
break;
case NSClosePathBezierPathElement:
CGPathCloseSubpath(path);
didClosePath = YES;
break;
}
}
// Be sure the path is closed or Quartz may not do valid hit detection.
if (!didClosePath)
CGPathCloseSubpath(path);
immutablePath = CGPathCreateCopy(path);
CGPathRelease(path);
}
return immutablePath;
}
@end
错误报告者
rdar://15758302: 将 NSBezierPath 转换为 CGPath。
- 0xced
1
43我认为苹果公司将那段代码放入文档中，而不是仅在NSBezierPath中添加一个CGPath访问器，这相当惊人。 - user187676
34
Xcode 8 GM 中的语法已经进一步简化，代码修改自上面 rob-mayoff 的回答。使用此方法和 addLine(to point: CGPoint) 的辅助程序，我可以在多个平台上共享绘图代码。
extension NSBezierPath {
public var cgPath: CGPath {
let path = CGMutablePath()
var points = [CGPoint](repeating: .zero, count: 3)
for i in 0 ..< elementCount {
let type = element(at: i, associatedPoints: &points)
switch type {
case .moveTo:
path.move(to: points[0])
case .lineTo:
path.addLine(to: points[0])
case .curveTo:
path.addCurve(to: points[2], control1: points[0], control2: points[1])
case .closePath:
path.closeSubpath()
@unknown default:
continue
}
}
return path
}
}
- Henrik
19
这适用于 Swift 3.1 及更高版本：
import AppKit
public extension NSBezierPath {
public var cgPath: CGPath {
let path = CGMutablePath()
var points = [CGPoint](repeating: .zero, count: 3)
for i in 0 ..< self.elementCount {
let type = self.element(at: i, associatedPoints: &points)
switch type {
case .moveToBezierPathElement: path.move(to: points[0])
case .lineToBezierPathElement: path.addLine(to: points[0])
case .curveToBezierPathElement: path.addCurve(to: points[2], control1: points[0], control2: points[1])
case .closePathBezierPathElement: path.closeSubpath()
}
}
return path
}
}
- rob mayoff
4
Swift 3 中没有 moveTo 或 addLineTo 这样的东西，对吧？ - El Tomato
这个最好作为
CGPath 的便利初始化器，这样就可以使用更标准的 CGPath(from: bezierPath) 语法。 - Ky -1
NSColor有一个cgColor属性，NSGraphicsContext有一个cgContext属性，NSColorSpace有一个cgColorSpace属性。NSImage有一个 cgImage(forProposedRect:context:hints:) 方法。 - rob mayoff另外，Swift不支持在
CGPath上使用便利初始化器。如果您尝试声明一个，您会得到错误消息“不支持在CF类型的扩展中使用便利初始化器”。 - rob mayoff17
对于 macOS 最好使用 - CGMutablePath
但是，如果你想要 NSBezierPath 的 cgPath:
Swift 5.0
extension NSBezierPath {
var cgPath: CGPath {
let path = CGMutablePath()
var points = [CGPoint](repeating: .zero, count: 3)
for i in 0 ..< self.elementCount {
let type = self.element(at: i, associatedPoints: &points)
switch type {
case .moveTo:
path.move(to: points[0])
case .lineTo:
path.addLine(to: points[0])
case .curveTo:
path.addCurve(to: points[2], control1: points[0], control2: points[1])
case .closePath:
path.closeSubpath()
@unknown default:
break
}
}
return path
}
}
- Yura Voevodin
7
如果有其他人需要，这里提供一份Swift版本的代码：
```Swift // 代码内容 ```
请注意，本文不会对代码进行解释。
```Swift // 代码内容 ```
请注意，本文不会对代码进行解释。
extension IXBezierPath {
// Adapted from : https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CocoaDrawingGuide/Paths/Paths.html#//apple_ref/doc/uid/TP40003290-CH206-SW2
// See also: http://www.dreamincode.net/forums/topic/370959-nsbezierpath-to-cgpathref-in-swift/
func CGPath(forceClose forceClose:Bool) -> CGPathRef? {
var cgPath:CGPathRef? = nil
let numElements = self.elementCount
if numElements > 0 {
let newPath = CGPathCreateMutable()
let points = NSPointArray.alloc(3)
var bDidClosePath:Bool = true
for i in 0 ..< numElements {
switch elementAtIndex(i, associatedPoints:points) {
case NSBezierPathElement.MoveToBezierPathElement:
CGPathMoveToPoint(newPath, nil, points[0].x, points[0].y )
case NSBezierPathElement.LineToBezierPathElement:
CGPathAddLineToPoint(newPath, nil, points[0].x, points[0].y )
bDidClosePath = false
case NSBezierPathElement.CurveToBezierPathElement:
CGPathAddCurveToPoint(newPath, nil, points[0].x, points[0].y, points[1].x, points[1].y, points[2].x, points[2].y )
bDidClosePath = false
case NSBezierPathElement.ClosePathBezierPathElement:
CGPathCloseSubpath(newPath)
bDidClosePath = true
}
if forceClose && !bDidClosePath {
CGPathCloseSubpath(newPath)
}
}
cgPath = CGPathCreateCopy(newPath)
}
return cgPath
}
- Cirec Beback
5
我无法理解为什么被接受的答案增加了一些复杂的闭合路径逻辑（也许在某些情况下是必要的），但对于那些只需要一个原始路径转换的人来说，这里提供了清理过的代码版本，实现为常规方法：
- (CGMutablePathRef)CGPathFromPath:(NSBezierPath *)path
{
CGMutablePathRef cgPath = CGPathCreateMutable();
NSInteger n = [path elementCount];
for (NSInteger i = 0; i < n; i++) {
NSPoint ps[3];
switch ([path elementAtIndex:i associatedPoints:ps]) {
case NSMoveToBezierPathElement: {
CGPathMoveToPoint(cgPath, NULL, ps[0].x, ps[0].y);
break;
}
case NSLineToBezierPathElement: {
CGPathAddLineToPoint(cgPath, NULL, ps[0].x, ps[0].y);
break;
}
case NSCurveToBezierPathElement: {
CGPathAddCurveToPoint(cgPath, NULL, ps[0].x, ps[0].y, ps[1].x, ps[1].y, ps[2].x, ps[2].y);
break;
}
case NSClosePathBezierPathElement: {
CGPathCloseSubpath(cgPath);
break;
}
default: NSAssert(0, @"Invalid NSBezierPathElement");
}
}
return cgPath;
}
顺便说一下，我需要这个来实现“NSBezierPath stroke contains point”方法。
我查找了这个转换以调用CGPathCreateCopyByStrokingPath()，该方法将NSBezierPath描边轮廓转换为常规路径，因此您可以测试笔画的命中情况，以下是解决方案：
// stroke (0,0) to (10,0) width 5 --> rect (0, -2.5) (10 x 5)
NSBezierPath *path = [[NSBezierPath alloc] init];
[path moveToPoint:NSMakePoint(0.0, 0.0)];
[path lineToPoint:NSMakePoint(10.0, 0.0)];
[path setLineWidth:5.0];
CGMutablePathRef cgPath = [self CGPathFromPath:path];
CGPathRef strokePath = CGPathCreateCopyByStrokingPath(cgPath, NULL, [path lineWidth], [path lineCapStyle],
[path lineJoinStyle], [path miterLimit]);
CGPathRelease(cgPath);
NSLog(@"%@", NSStringFromRect(NSRectFromCGRect(CGPathGetBoundingBox(strokePath))));
// {{0, -2.5}, {10, 5}}
CGPoint point = CGPointMake(1.0, 1.0);
BOOL hit = CGPathContainsPoint(strokePath, NULL, point, (bool)[path windingRule]);
NSLog(@"%@: %@", NSStringFromPoint(NSPointFromCGPoint(point)), (hit ? @"yes" : @"no"));
// {1, 1}: yes
CGPathRelease(strokePath);
这类似于Qt中的
QPainterPathStroker，但是针对的是NSBezierPath。- user3125367
2
c# Xamarin
private CGPath convertNSBezierPathToCGPath(NSBezierPath sourcePath)
{
CGPath destinationPath = new CGPath();
int i, numElements;
// Then draw the path elements.
numElements = (int)Convert.ToInt64(sourcePath.ElementCount);
if (numElements > 0)
{
CGPath path = new CGPath();
CGPoint[] points;
bool didClosePath = true;
for (i = 0; i < numElements; i++)
{
switch (sourcePath.ElementAt(i, out points))
{
case NSBezierPathElement.MoveTo:
path.MoveToPoint(points[0]);
break;
case NSBezierPathElement.LineTo:
path.MoveToPoint(points[0]);
didClosePath = false;
break;
case NSBezierPathElement.CurveTo:
path.AddCurveToPoint(cp1: points[0], cp2: points[1], points[2]);
didClosePath = false;
break;
case NSBezierPathElement.ClosePath:
path.CloseSubpath();
didClosePath = true;
break;
}
}
if (!didClosePath)
path.CloseSubpath();
destinationPath = new CGPath(path);
}
return destinationPath;
}
- alexNeutral
0
如果您的目标是macOS 14，那么
WWDC视频：https://developer.apple.com/videos/play/wwdc2023/10054/?time=676 文档：https://developer.apple.com/documentation/appkit/nsbezierpath/4191603-cgpath
cgPath已经是NSBezierPath API的一部分。WWDC视频：https://developer.apple.com/videos/play/wwdc2023/10054/?time=676 文档：https://developer.apple.com/documentation/appkit/nsbezierpath/4191603-cgpath
- Sapozhnik Ivan
网页内容由stack overflow 提供, 点击上面的可以查看英文原文，
原文链接
原文链接
NSBezierPath设置和读取CGPath。 https://github.com/iccir/XUIKit - Wizard of Kneup