我正在使用 CoreText 来处理 NSTextAttachment。 CoreText 需要 CTRunDelegate 来布局附件。但运行以下代码时出现错误。
class RunDelegate: NSObject {
let image: UIImage
let font: UIFont
init(image: UIImage, font: UIFont) {
self.image = image
self.font = font
}
}
private func generateRunDelegate(attachment: NSTextAttachment, font: UIFont) -> CTRunDelegateRef {
var d = RunDelegate(image: attachment.image!, font: font)
var cbs = CTRunDelegateCallbacks(version: kCTRunDelegateCurrentVersion, dealloc: { (p) -> Void in
}, getAscent: { (p) -> CGFloat in
let d = UnsafeMutablePointer<RunDelegate>(p).memory
return d.image.size.height + d.font.descender // Error here, EXC_BAD_ACCESS(code = 1)
}, getDescent: { (p) -> CGFloat in
let d = UnsafeMutablePointer<RunDelegate>(p).memory
return -d.font.descender
}) { (p) -> CGFloat in
let d = UnsafeMutablePointer<RunDelegate>(p).memory
return d.image.size.width
}
return CTRunDelegateCreate(&cbs, &d)!
}
有人可以帮忙吗？谢谢!
最佳答案
请尝试此代码。
class RunDelegate: NSObject {
let image: UIImage
let font: UIFont
class func object(pointer: UnsafeMutablePointer<Void>) -> RunDelegate {
return Unmanaged<RunDelegate>.fromOpaque(COpaquePointer(pointer)).takeRetainedValue()
}
init(image: UIImage, font: UIFont) {
self.image = image
self.font = font
}
}
private func generateRunDelegate(attachment: NSTextAttachment, font: UIFont) -> CTRunDelegateRef {
var d = RunDelegate(image: attachment.image!, font: font)
var cbs = CTRunDelegateCallbacks(version: kCTRunDelegateCurrentVersion,
dealloc: { (p) -> Void in
}, getAscent: { (p) -> CGFloat in
let d = RunDelegate.object(pointer: p)
return d.image.size.height + d.font.descender
}, getDescent: { (p) -> CGFloat in
let d = RunDelegate.object(pointer: p)
return -d.font.descender
}) { (p) -> CGFloat in
let d = RunDelegate.object(pointer: p)
return d.image.size.width
}
return CTRunDelegateCreate(&cbs, d)!
}
我认为它没有正确生成UnsafePointer。
关于ios - 如何在 Swift 2.0 中创建 CTRunDelegate，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33997481/