itext7 pdfhtml headers 和屏幕阅读器有问题吗？

Question

我正在使用 html 的 pdf 功能开发 iText7。

我刚刚注意到每个页面上设置的 Header 都有这个问题。 Header 未被屏幕读取 reader。文档的其余部分与屏幕 reader 完美配合。我需要它来检查可访问性。

我是这样设置的 Header:

<html>
<head>
    <link rel="stylesheet" href="{...}pdf/css/style.css" type="text/css" />
    <style>
        #header {
            position: running(header);
        }
        @page {
            margin-top: 100px;
            @top-left {
                content: element(header);
            }
        }
    </style>
</head>
<body>
<div id="header">
    <table width="100%">
        <tr>
            <td colspan="2">&nbsp;</td>
        </tr>
        <tr>
            <td><span class="...">{...}</span></td>
            <td rowspan="2" class="... ..."><span><img src="{...}pdf/images/..." alt="..." /></span></td>
        </tr>
        <tr>
            <td><span class="...">{...}</span></td>
        </tr>
    </table>
</div>...
...
...

Answer 1

对于屏幕 reader 我没有找到任何方法让它在纯 HTML 中工作。

如果将来有人有一些想法，一定会很感激。

目前我正在编写启动新页面的事件处理程序。

我正在做一些改进，但像这样：

public class SomePdfCreationClass {

    public SomeReturnType createPdf {
        ...
        
        Header headerHandler = new Header(String header1, List<String> subHeaders);
        pdf.addEventHandler(PdfDocumentEvent.START_PAGE, headerHandler);
         
        HtmlConverter.convertToPdf(htmlFile, pdf, converterProperties);
        
        writer.close();
        pdf.close();
        
        ...
    }
    
    protected class Header implements IEventHandler {
        
        private String header1;
        private List<String> subHeaders;

        public Header(String header1, List<String> subHeaders) {
            this.header1 = header1;
            this.subHeaders = subHeaders;
        }

        @Override
        public void handleEvent(Event event) {

            try {
                PdfDocumentEvent docEvent = (PdfDocumentEvent) event;
                PdfDocument pdf = docEvent.getDocument();
                PdfPage page = docEvent.getPage();

                PdfDictionary pdfObject = page.getPdfObject();

                PdfCanvas headerPdfCanvas = new PdfCanvas(page.newContentStreamBefore(), page.getResources(), pdf);
                Rectangle headerRect = new Rectangle(35, 740, 495, 96);
                Canvas headerCanvas = new Canvas(headerPdfCanvas, pdf, headerRect);

                headerCanvas.setFontProvider(fontProviderService.getFontProvider());
                PdfFont font = PdfFontFactory.createFont(staticResourcesPath + "...ttf",
                        PdfEncodings.IDENTITY_H, true);
                headerCanvas.setFontSize(18).setFont(font);

                headerCanvas.enableAutoTagging(page);
                CreateHeaderContent(headerCanvas);
                headerCanvas.close();

            } catch (IOException e) {
                ...
            }
        
        }
        
        private void CreateHeaderContent(Canvas canvas) throws MalformedURLException
        {
            Table table = new Table(UnitValue.createPercentArray(new float[] { 80, 20 } ));
            table.setWidth(UnitValue.createPercentValue(100));
    
            Cell cell1 = new Cell().add(new Paragraph(header1).setBold().setFontSize(11).setTextAlignment(TextAlignment.LEFT));
            for (int i = 0; i < subHeaders.size(); i++) {
                cell1.add(new Paragraph(subHeaders.get(i)).setFontSize(8).setTextAlignment(TextAlignment.LEFT));
            }
            cell1.setBorder(Border.NO_BORDER);
            table.addCell(cell1);

            ImageData imageData = ImageDataFactory.create(staticResourcesPath + "...png");
            Image image = new Image(imageData);
            image.getAccessibilityProperties().setAlternateDescription("...");
            Cell cell2 = new Cell().add(image.setTextAlignment(TextAlignment.RIGHT));
            cell2.setBorder(Border.NO_BORDER);
            
            cell2.setVerticalAlignment(VerticalAlignment.MIDDLE);
            table.addCell(cell2);
    
            canvas.add(table);
        }
        
    }
    
}

这样做我不得不为 header 删除 html:

<html>
<head>
    <link rel="stylesheet" href="..." type="text/css" />
</head>
<body>
...

itext7 pdfhtml headers 和屏幕阅读器有问题吗？

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