无法在Itext5中将不可去除水印设为透明

Question

我正在尝试在Itext5中制作不可移除的透明水印，我能够使用PdfPatternPainter使水印不可移除，但仍然面临一个问题，即水印不太透明，并且仍然覆盖内容并使其更难阅读

我的代码如下：

public class TestWatermark {

    public static String resourcesPath = "C:\\Users\\java\\Desktop\\TestWaterMark\\";
    public static String FILE_NAME = resourcesPath + "test.pdf";

    public static void main(String[] args) throws IOException {
        System.out.println("########## STARTED ADDING WATERMARK ###########");
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            byte[] byteArray = Files.readAllBytes(Paths.get(FILE_NAME));
            String watermarkText = "confidential";
            String fontPath = resourcesPath + "DINNextLTArabic-Regular.ttf";
            Font arabicFont = FontFactory.getFont(fontPath, BaseFont.IDENTITY_H, 16);

            BaseFont baseFont = arabicFont.getBaseFont();
            PdfReader reader = new PdfReader(byteArray);
            PdfStamper stamper = new PdfStamper(reader, baos);

            int numberOfPages = reader.getNumberOfPages();

            float height = baseFont.getAscentPoint(watermarkText, 24) + baseFont.getDescentPoint(watermarkText, 24);

            for (int i = 1; i <= numberOfPages; i++) {

                Rectangle pageSize = reader.getPageSizeWithRotation(i);
                PdfContentByte overContent = stamper.getOverContent(i);

                PdfPatternPainter bodyPainter = stamper.getOverContent(i).createPattern(pageSize.getWidth(),
                        pageSize.getHeight());
                BaseColor baseColor = new BaseColor(10, 10, 10);
                bodyPainter.setColorStroke(baseColor);
                bodyPainter.setColorFill(baseColor);
                bodyPainter.setLineWidth(0.85f);
                bodyPainter.setLineDash(0.2f, 0.2f, 0.2f);

                PdfGState state = new PdfGState();
                state.setFillOpacity(0.01f);
                overContent.saveState();
                overContent.setGState(state);

                for (float x = 70f; x < pageSize.getWidth(); x += height + 100) {
                    for (float y = 90; y < pageSize.getHeight(); y += height + 100) {

                        bodyPainter.beginText();
                        bodyPainter.setTextRenderingMode(PdfPatternPainter.TEXT_RENDER_MODE_FILL);
                        bodyPainter.setFontAndSize(baseFont, 13);
                        bodyPainter.showTextAlignedKerned(Element.ALIGN_MIDDLE, watermarkText, x, y, 45f);
                        bodyPainter.endText();

                        overContent.setColorFill(new PatternColor(bodyPainter));
                        overContent.rectangle(pageSize.getLeft(), pageSize.getBottom(), pageSize.getWidth(),
                                pageSize.getHeight());
                        overContent.fill();

                    }
                }

                overContent.restoreState();

            }

            stamper.close();
            reader.close();
            byteArray = baos.toByteArray();
            File outputFile = new File(resourcesPath + "output.pdf");
            if (outputFile.exists()) {
                outputFile.delete();
            }
            Files.write(outputFile.toPath(), byteArray);

            System.out.println("########## FINISHED ADDING WATERMARK ###########");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

请告知如何让我的水印不覆盖文字

Answer 1

我能够通过将 overContent 的不透明度设置得非常低来完成要求，如下所示：

state.setFillOpacity(0.01f);

并将画家颜色更改为：

BaseColor baseColor = new BaseColor(10, 10, 10);