iText - 如何设置 PdfAnnotationInk 的描边宽度和不透明度

绘制墨迹类型注释时，应该调用哪些函数来设置笔划宽度和不透明度？ 我已经浏览过 PdfAnnotation 和 PDFStamp 的类 API，但似乎没有直接设置宽度和不透明度的函数。有什么建议么？谢谢。

我的示例程序：

    final String sourceFile = "C:\\PdfAnnotation\\sample.pdf";
    final String destFile = "C:\\PdfAnnotation\\output\\output.pdf";

    PdfReader reader = new PdfReader(sourceFile);
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(destFile));

    Rectangle rect = new Rectangle(52.92f, 397.56f, 173.36f, 530.67f);
    float[][] inkList = {{61.736111f,530.669250f,61.295139f,525.820984f,61.295139f,518.768860f,
            61.295139f,505.986969f,61.295139f,490.560547f,61.295139f,470.726562f,59.972221f,452.214844f,
            57.767361f,434.143890f,56.003471f,418.276703f,53.357639f,404.172516f,51.593750f,391.390625f,
            50.711807f,382.134766f,49.829861f,376.845703f},
            {68.350693f,453.537109f,73.201385f,453.977875f,79.375000f,453.977875f,85.107635f,453.977875f,92.163193f,453.977875f,
                    100.541664f,453.977875f,108.038193f,453.977875f,117.298615f,453.977875f},
            {112.447914f,509.072266f,112.006943f,505.105469f,112.006943f,498.053375f,112.006943f,488.797516f,112.006943f,472.930328f,
                    112.006943f,457.503906f,112.006943f,441.636719f,112.006943f,426.210297f,111.565971f,412.106110f,
                    111.125000f,401.968750f,111.125000f,391.831390f},
            {161.836807f,454.859375f,161.836807f,449.129547f,161.836807f,441.636719f,161.836807f,433.262360f,161.836807f,
                    423.125000f,161.836807f,412.546875f,161.836807f,405.054047f,161.836807f,398.442719f,161.836807f,392.712891f,
                    161.836807f,389.627594f},
            {163.159729f,485.712250f,170.215271f,469.845062f}
    };

    PdfAnnotation an = PdfAnnotation.createInk(stamper.getWriter(), rect, "", inkList);
    an.setColor(new BaseColor(30, 89, 255));
    an.setFlags(PdfAnnotation.FLAGS_PRINT);
    stamper.addAnnotation(an, 1);

    stamper.close();
    reader.close();

绘制墨迹类型注释时，应该调用哪些函数来设置笔划宽度和不透明度？

有两个答案：

如果 PDF 查看器创建外观

The PDF规格提及

BS字典（选修的）指定线条的边框样式字典（参见表 166） 绘制路径时应使用的宽度和虚线图案。

作为特定于的另一个条目Ink注释词典。这至少允许您设置笔划宽度但不是opacity。只需添加这样一行

PdfAnnotation an = PdfAnnotation.createInk(stamper.getWriter(), rect, "", inkList);
an.setColor(new BaseColor(30, 89, 255));
an.setFlags(PdfAnnotation.FLAGS_PRINT);
// vvv set line width to 5:
an.setBorderStyle(new PdfBorderDictionary(5, PdfBorderDictionary.STYLE_SOLID));
// ^^^ set line width to 5:
stamper.addAnnotation(an, 1);

将描边宽度设置为 5 并得到如下结果：

如果 PDF 提供外观

The PDF规格还提到

注释字典的AP条目（如果存在）应优先 超过InkList and BS条目；参见表 168 和 12.5.5，“外观 流。”

因此，您可以创建一个PdfAppearance，使用其方法完全按照您的需要创建外观（包括透明度），并将其设置为注释的正常外观。然后，PDF 查看器将按照您想要的方式显示注释。