有没有人有很好的方法把PKDrawing清晰地渲染成PDF？

Question

我正在尝试分享我的PKDrawing结果通过PDF文件电子邮件或打印。 我正在创建PDF使用2个其他PDF文件加上顶层的PK绘图。 这2个PDF图层看起来很清晰。 然而，PKDrawing有些颗粒感，特别是与打印的屏幕截图相比。

下面是我当前的代码:

UIGraphicsBeginPDFContextToFile(filePath, CGRect.zero, nil)
    
var drawing: PKDrawing = PKDrawing.init()
let markup: Data = self.pages![pagenum].value(forKey: "markup") as! Data
let drawingHeight = self.pages![pagenum].value(forKey: "height") as! CGFloat
let drawingWidth = self.pages![pagenum].value(forKey: "width") as! CGFloat
            
do {
    try drawing = PKDrawing.init(data: markup)
} catch {
    print("Error loading drawing") 
}

let pageSize = CGSize(width: 0, height: 0)
//let scale: CGFloat = 2.0    THIS VALUE DOESN'T SEEM TO MATTER 
let scale: CGFloat = 1.0 

if landscapeOrientation {
    pageSize = CGSize(width:2048, height: 1408)
} else {
    pageSize = CGSize(width: 1536, height: 1920)
}
                
let canvas = PKCanvasView(frame: CGRect(x: 0.0, y: 0.0, width: drawingWidth, height: drawingHeight))
canvas.drawing = drawing
markupImage = drawing.image(from: canvas.frame, scale: scale)
if pageSize.width != drawingWidth {
   canvas.drawing.transform(using: CGAffineTransform(scaleX: pageSize.width / drawingWidth, y: pageSize.height / drawingHeight))
}
//markupImage = drawing.image(from: canvas.frame, scale: self.view.contentScaleFactor)  THIS CHANGE MADE A BIG DIFFERENCE 
markupImage = drawing.image(from: canvas.frame, scale: 4.0) 
                
UIGraphicsBeginImageContext(pageSize)
backgroundView?.draw(in: CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: pageSize))
templateView?.draw(in: CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: pageSize))
            
markupImage.draw(in: CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: pageSize))
          
let pdfImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
        
let pageRect: CGRect = CGRect(origin: CGPoint.zero, size: pageSize)
UIGraphicsBeginPDFPageWithInfo(pageRect, nil)
let pdfContext: CGContext = UIGraphicsGetCurrentContext()!
pdfContext.scaleBy(x: 1.0, y: 1.0)
pdfImage.draw(at: CGPoint(x: 0.0, y: 0.0))
        
UIGraphicsEndPDFContext()

Answer 1

把我的等级从2.0改成4.0，这让我觉得很清楚，我从来没想过要这么做。 将用我的更改和注释编辑代码。 当然，如果有一个更干净，更清晰的方法来做这件事的话，也可以选择其他的选择。 我不是最擅长分辨率/像素空间的。