UIPrintPageRenderer中断不同页面上的内容并跳过页面的一部分

Question

我在UIPrintPageRenderer的帮助下从html内容渲染pdf，不幸的是，当一个元素被分成不同页面上的部分时，有时会发生错误。有什么方法可以避免id吗？

我的代码和截图如下：

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UIPrintPageRenderer继承以指定pdf详细信息。

public class CustomPrintPageRenderer: UIPrintPageRenderer {
    fileprivate let offsetX: CGFloat = 40.0
    fileprivate let offsetY: CGFloat = 12.0
    fileprivate let kHeaderHeight: CGFloat = 36
    fileprivate let kFooterHeight: CGFloat = 36
    fileprivate let debugFrame = false
    
    fileprivate var name: String?
    fileprivate var policy: String?
    
    init(name: String, policy: String, content: String) {
        self.name = name
        self.policy = policy
        super.init()
        
        // Set the page frame.
        setValue(NSValue(cgRect: App.A4Rect), forKey: "paperRect")
        
        // Set the printing area frame.
        setValue(NSValue(cgRect: App.A4Rect.insetBy(dx: 0, dy: 0)), forKey: "printableRect")

        headerHeight = kHeaderHeight
        footerHeight = kFooterHeight
        
        // Create formatter
        let formatter = UIMarkupTextPrintFormatter(markupText: content)
        formatter.perPageContentInsets = UIEdgeInsets(top: kHeaderHeight + 15, left: 36, bottom: 0, right: 36)
        addPrintFormatter(formatter, startingAtPageAt: 0)
    }

    override public func drawHeaderForPage(at pageIndex: Int, in headerRect: CGRect) {
        if let name = name as NSString?, let policy = policy as NSString? {
            add(name: name, policy: policy, in: headerRect)
        }
        addLogo(in: headerRect)

        if debugFrame {
            let path = UIBezierPath(rect: headerRect)
            UIColor.red.set()
            path.stroke()
        }
    }
    
    override public func drawFooterForPage(at pageIndex: Int, in footerRect: CGRect) {
        addPageNumber(at: pageIndex, in: footerRect)
        
        if debugFrame {
            let path = UIBezierPath(rect: footerRect)
            UIColor.red.set()
            path.stroke()
        }
    }
}

///////////////////////////////////////////////////////////////////////////////////////////////////
// MARK: -

extension CustomPrintPageRenderer {
    fileprivate func addLogo(in headerRect: CGRect) {
        let image = #imageLiteral(resourceName: "mss-logo")
        let desiredHeight: CGFloat = 40
        let newWidth = (desiredHeight * image.size.width) / image.size.height
        
        let imageSize = CGSize(width: newWidth, height: desiredHeight)
        let imageRect = CGRect(
            x: headerRect.width - imageSize.width - offsetX,
            y: headerRect.height - imageSize.height + offsetY,
            width: imageSize.width,
            height: imageSize.height)
        image.draw(in: imageRect)
    }
    
    fileprivate func add(name: NSString, policy: NSString, in headerRect: CGRect) {
        let text = "\(policy) - \(name)"
        
        let font = UIFont(name: "HelveticaNeue", size: 12.0)
        let textSize = getTextSize(text: text as String, font: font!)
        
        let pointX = offsetX
        let pointY = headerRect.height - textSize.height
        
        let attributes = [NSAttributedStringKey.font: font!, NSAttributedStringKey.foregroundColor: Color.lightGray]
        
        text.draw(at: CGPoint(x: pointX, y: pointY), withAttributes: attributes)
    }

    fileprivate func addPageNumber(at pageIndex: Int, in footerRect: CGRect) {
        let footerText: NSString = "Page \(pageIndex + 1) of \(numberOfPages)" as NSString

        let font = UIFont(name: "HelveticaNeue", size: 12.0)
        let textSize = getTextSize(text: footerText as String, font: font!)
        
        let pointX = footerRect.width - textSize.width - offsetX
        let pointY = footerRect.origin.y + footerRect.height - textSize.height - 25
        
        let attributes = [NSAttributedStringKey.font: font!]
        
        footerText.draw(at: CGPoint(x: pointX, y: pointY), withAttributes: attributes)
    }
    
    fileprivate func getTextSize(text: String, font: UIFont!, textAttributes: [NSAttributedStringKey: AnyObject]! = nil) -> CGSize {
        let testLabel = UILabel(frame: CGRect(x: 0.0, y: 0.0, width: paperRect.width, height: footerHeight))
        if let attributes = textAttributes {
            testLabel.attributedText = NSAttributedString(string: text, attributes: attributes)
        }
        else {
            testLabel.text = text
            testLabel.font = font!
        }
        
        testLabel.sizeToFit()
        
        return testLabel.frame.size
    }
}

**提醒html **

我用来编写警报并将其添加到pdf的HTML。

<tr>
    <td></td>
</tr>
<tr>
    <div>
    <td class="alert" colspan="2">#TEXT#</td>
    </div>
</tr>
<tr>
    <td></td>
</tr>

**和pdf绘图**

这就是我用CustomPrintPageRenderer绘制pdf的方法。

   fileprivate func drawPDFUsingPrintPageRenderer(printPageRenderer: UIPrintPageRenderer) -> NSData! {
       let data = NSMutableData()
       
       UIGraphicsBeginPDFContextToData(data, App.A4Rect, nil)
       
       for i in 0 ..< printPageRenderer.numberOfPages {
           UIGraphicsBeginPDFPage()
           printPageRenderer.drawPage(at: i, in: UIGraphicsGetPDFContextBounds())
       }

       UIGraphicsEndPDFContext()
       
       return data
   }

将非常感谢您的任何帮助！

Answer 1

@media print {
.pagebreak-before:first-child { display: block; page-break-before: avoid; }
.pagebreak-before { display: block; page-break-before: always; }
button {
   page-break-inside: avoid;
}
}

然后，您可能会在class元素中使用它们。对图像等使用分页符。