我用这个函数在两点之间画了一条路径。我从谷歌的 API 得到坐标,这没有问题。我的问题是,如何指定特定点是否在我绘制的路径内?我正在尝试使用CGContextPathContainsPoint()
,但没有运气。
-(void)updateRouteView {
CGContextRef context = CGBitmapContextCreate(nil,
routeView.frame.size.width,
routeView.frame.size.height,
8,
4 * routeView.frame.size.width,
CGColorSpaceCreateDeviceRGB(),
kCGImageAlphaPremultipliedLast);
CGContextSetStrokeColorWithColor(context, lineColor.CGColor);
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);
CGContextSetLineWidth(context, 5.0);
// routes : array of coordinates of the path
for (int i = 0; i < routes.count; i++) {
CLLocation* location = [routes objectAtIndex:i];
CGPoint point = [mapView convertCoordinate:location.coordinate toPointToView:routeView];
if (i == 0)
CGContextMoveToPoint(context, point.x, routeView.frame.size.height - point.y);
else
CGContextAddLineToPoint(context, point.x, routeView.frame.size.height - point.y);
}
CGContextStrokePath(context);
// this is the point I want to check if it is inside the path
CLLocationCoordinate2D checkedLocation;
checkedLocation.latitude = 37.782756;
checkedLocation.longitude = -122.409647;
CGPoint checkedPoint = [mapView convertCoordinate:checkedLocation toPointToView:routeView];
checkedPoint.y = routeView.frame.size.height - checkedPoint.y;
// even if the checkedPoint is inside the path, the result is false
BOOL checking = CGContextPathContainsPoint(context, checkedPoint, kCGPathStroke);
if (checking)
NSLog(@"YES");
else
NSLog(@"NO");
CGImageRef image = CGBitmapContextCreateImage(context);
UIImage* img = [UIImage imageWithCGImage:image];
routeView.image = img;
CGContextRelease(context);
}