write in front
最近有这么一个需求，分享页面，分享的是web订单截图，既然是web 就会有超出屏幕的部分，
生成的图片还要加上我们的二维码，这就涉及到图片的合成了。
有了这样的需求，就是各种google.也算解决了自己的需求，另外，也总结了一下，对需求做了下拓展，目前是swift4.0版本。Integrate into a third-party library, the following is only part of the code, please see the detailed code and demo, github address https://github.com/dudongge/DDGScreenShot
View generates pictures
代码也比较简单 screenShotImage 就是截取后的图片
let context = UIGraphicsGetCurrentContext()
context?.saveGState()
context?.translateBy(x: -self.frame.origin.x, y: -self.frame.origin.y);
self.layer.render(in: context!)
let screenShotImage = UIGraphicsGetImageFromCurrentImageContext()
context?.restoreGState();
UIGraphicsEndImageContext()ScrollView generates pictures
只要实现原理是计算偏移量，每一屏绘制一次，放在内存里，最后将所有的图片组合成一张图片 screenShotImage就是最终图片
public func DDGContentScrollScreenShot (_ completionHandler: @escaping (_ screenShotImage: UIImage?) -> Void) {
self.isShoting = true
let snapShotView = self.snapshotView(afterScreenUpdates: true)
snapShotView?.frame = CGRect(x: self.frame.origin.x, y: self.frame.origin.y, width: (snapShotView?.frame.size.width)!, height: (snapShotView?.frame.size.height)!)
self.superview?.addSubview(snapShotView!)
let bakOffset = self.contentOffset
let page = floorf(Float(self.contentSize.height / self.bounds.height))
UIGraphicsBeginImageContextWithOptions(self.contentSize, false, UIScreen.main.scale)
self.DDGContentScrollPageDraw(0, maxIndex: Int(page), drawCallback: { [weak self] () -> Void in
let strongSelf = self
let screenShotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
strongSelf?.setContentOffset(bakOffset, animated: false)
snapShotView?.removeFromSuperview()
strongSelf?.isShoting = false
completionHandler(screenShotImage)
})
}
fileprivate func DDGContentScrollPageDraw (_ index: Int, maxIndex: Int, drawCallback: @escaping () -> Void) {
self.setContentOffset(CGPoint(x: 0, y: CGFloat(index) * self.frame.size.height), animated: false)
let splitFrame = CGRect(x: 0, y: CGFloat(index) * self.frame.size.height, width: bounds.size.width, height: bounds.size.height)
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + Double(Int64(0.3 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)) { () -> Void in
self.drawHierarchy(in: splitFrame, afterScreenUpdates: true)
if index < maxIndex {
self.DDGContentScrollPageDraw(index + 1, maxIndex: maxIndex, drawCallback: drawCallback)
}else{
drawCallback()
}
}
}UIwebView generates pictures && wkwebView
绘制时大同小异，只是wkwebView 调用的绘制方法为：drawHierarchy 其核心代码如下
采用递归，直到拿到最后一个偏移量。
fileprivate func DDGRenderImageView(_ completionHandler: @escaping (_ screenShotImage: UIImage?) -> Void) {
let ddgTempRenderView = UIView(frame: CGRect(x: 0, y: 0, width: self.contentSize.width, height: self.contentSize.height))
self.removeFromSuperview()
ddgTempRenderView.addSubview(self)
self.contentOffset = CGPoint.zero
self.frame = ddgTempRenderView.bounds
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + Double(Int64(0.3 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)) { () -> Void in
let bounds = self.bounds
UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.main.scale)
if (self.DDGContainsWKWebView()) {
self.drawHierarchy(in: bounds, afterScreenUpdates: true)
}else{
self.layer.render(in: UIGraphicsGetCurrentContext()!)
}
let screenShotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
completionHandler(screenShotImage)
}
}
fileprivate func shotScreenContentScrollPageDraw (_ index: Int, maxIndex: Int, drawCallback: @escaping () -> Void) {
self.scrollView.setContentOffset(CGPoint(x: 0, y: CGFloat(index) * self.scrollView.frame.size.height), animated: false)
let splitFrame = CGRect(x: 0, y: CGFloat(index) * self.scrollView.frame.size.height, width: bounds.size.width, height: bounds.size.height)
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + Double(Int64(0.3 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)) { () -> Void in
self.drawHierarchy(in: splitFrame, afterScreenUpdates: true)
if index < maxIndex {
self.shotScreenContentScrollPageDraw(index + 1, maxIndex: maxIndex, drawCallback: drawCallback)
}else{
drawCallback()
}
}
}Two images combined into one (one base image, one logo)
在UIImage上做了拓展
let imageRef = self.cgImage
let w: CGFloat = CGFloat((imageRef?.width)!)
let h: CGFloat = CGFloat((imageRef?.height)!)
//以1.png的图大小为画布创建上下文
UIGraphicsBeginImageContext(CGSize(width: w, height: h))
self.draw(in: CGRect(x: 0, y: 0, width: w, height: h))
//先把1.png 画到上下文中
logo.draw(in: CGRect(x: logoOrigin.x,
y: logoOrigin.y,
width: logoSize.width,
height:logoSize.height))
//再把小图放在上下文中
let resultImg: UIImage? = UIGraphicsGetImageFromCurrentImageContext()
//从当前上下文中获得最终图片
UIGraphicsEndImageContext()
return resultImg!
Write text/tag on images
同样对UIimage 做了拓展，增加了几个参数
public func drawTextInImage(text: String,
textColor: UIColor,
textFont: CGFloat,
textBgColor: UIColor,
textX: CGFloat,
textY: CGFloat )->UIImage {
//开启图片上下文
UIGraphicsBeginImageContext(self.size)
//图形重绘
self.draw(in: CGRect.init(x: 0, y: 0, width: self.size.width, height: self.size.height))
//水印文字属性
let att = [NSAttributedStringKey.foregroundColor: textColor,
NSAttributedStringKey.font: UIFont.systemFont(ofSize: textFont),
NSAttributedStringKey.backgroundColor: textBgColor]
//水印文字大小
let text = NSString(string: text)
let size = text.size(withAttributes: att)
//绘制文字
text.draw(in: CGRect.init(x: textX, y: textY, width: size.width, height: size.height), withAttributes: att)
//从当前上下文获取图片
let image = UIGraphicsGetImageFromCurrentImageContext()
//关闭上下文
UIGraphicsEndImageContext()
return image!
}concluding remarks
空间有限，所注代码不全，我把上述功能整理成了最新的带三方库，
以后会加上图片的相关处理，比如美颜，剪切，马赛克，组图等，
附上我的git地址：https://github.com/dudongge/DDGScreenShot
有什么问题也可以联系我QQ:532835032
如果对您有帮助，请您不吝star一下，增加我更新的动力Attach part of the READER.ME file on github
## view截屏：
view.DDGScreenShot { (image) in
拿到 image
各种复杂装逼操作
、、、、
}
## ScrollView截屏：
scrollView.DDGContentScrollScreenShot { (image) in
拿到 image
各种复杂装逼操作
、、、、
}
## webView截屏：
webView.DDGContentscreenShot { (image) in
拿到 image
各种复杂装逼操作
、、、、
}
## wkwebView截屏： 方法和webView 一样，内部做了校验
webView.DDGContentscreenShot { (image) in
拿到 image
各种复杂装逼操作
、、、、
}
## image 加 logo
let image = image.composeImageWithLogo( logo: UIImage,
logoOrigin: CGPoint,
logoSize:CGSize)
传入 logo图片，logo位置 logo 大小 就可以得到一张生成好的图片
、、、、
## image 加 标签，水印，文字
let image = image.drawTextInImage(text: String,
textColor: UIColor,
textFont: CGFloat,
textBgColor: UIColor,
textX: CGFloat,
textY: CGFloat )
传入 文字、文字颜色、字体大小、背景颜色，字体起始位置 就可以得到一张生成好的带标签的图片
、、、、
注，此方法在提交pod有问题，故将方法屏蔽，有需要的可以拷贝代码，到本地
## 使用pod
iOS 9.0+, Swift 4.0+(Compatiable)
使用pod 导入
pod 'DDGScreenShot', '~> 1.0.1'
```
Welcome to DDGScreenShot
The rest of the functions are as follows
- (1) DDGScreenShot - complex screenshots (such as view ScrollView webView wkwebView)
- (2) DDGScreenShot--iOS image processing--multiple image stitching
- (3) DDGScreenShot--iOS image cropping, cutting rounded corners, adding borders, you also use cornerRadius, and more advanced usage
- (4) DDGScreenShot—picture erasing function
- (5) DDGScreenShot—capture any part of the picture
- (6) DDGScreenShot — pictures with various filters and high-quality operations
- (7) DDGScreenShot — picture with Gaussian blur, old movie effect