PDFbox-如何向图层添加内容？

Question

我正在使用pdfbox 2.0.8-需要创建一个层，并在那里添加一些图形。

我从如何修改pdf中的现有层（可选内容组）开始？

然而，这是基于1.8。我试图适应2.0，并设法创建了该层，但完全不清楚如何创建新资源并将其添加到该层，即如何创建道具。putMapping（resourceName，layer）；必须重写1.8中的内容

Answer 1

OP引用的答案中的PDFBox 1.8代码相当于以下代码：

void addTextToLayer(PDDocument document, int pageNumber, String layerName, float x, float y, String text) throws IOException
{
    PDDocumentCatalog catalog = document.getDocumentCatalog();
    PDOptionalContentProperties ocprops = catalog.getOCProperties();
    if (ocprops == null)
    {
        ocprops = new PDOptionalContentProperties();
        catalog.setOCProperties(ocprops);
    }
    PDOptionalContentGroup layer = null;
    if (ocprops.hasGroup(layerName))
    {
        layer = ocprops.getGroup(layerName);
    }
    else
    {
        layer = new PDOptionalContentGroup(layerName);
        ocprops.addGroup(layer);
    }

    PDPage page = (PDPage) document.getPage(pageNumber);

    PDResources resources = page.getResources();
    if (resources == null)
    {
        resources = new PDResources();
        page.setResources(resources);
    }

    PDFont font = PDType1Font.HELVETICA;

    PDPageContentStream contentStream = new PDPageContentStream(document, page, AppendMode.APPEND, true, true);
    contentStream.beginMarkedContent(COSName.OC, layer);
    contentStream.beginText();
    contentStream.setFont(font, 12);
    contentStream.newLineAtOffset(x, y);
    contentStream.showText(text);
    contentStream.endText();
    contentStream.endMarkedContent();

    contentStream.close();
}

（AddContentToOCG）

可以这样使用：

PDDocument document = new PDDocument();
PDPage page = new PDPage();
document.addPage(page);

addTextToLayer(document, 0, "MyLayer", 30, 600, "Text in new layer 'MyLayer'");
addTextToLayer(document, 0, "MyOtherLayer", 230, 550, "Text in new layer 'MyOtherLayer'");
addTextToLayer(document, 0, "MyLayer", 30, 500, "Text in existing layer 'MyLayer'");
addTextToLayer(document, 0, "MyOtherLayer", 230, 450, "Text in existing layer 'MyOtherLayer'");

document.save(new File(RESULT_FOLDER, "TextInOCGs.pdf"));
document.close();

（AddContentToOCG测试TestAddContentToneworexistingCG）