如何使用C# iTextSharp检测PDF中的矩形和方框

using iTextSharp.text;
using iTextSharp.text.pdf;

PdfReader reader = new PdfReader("path/to/pdf/file.pdf");

int pageCount = reader.NumberOfPages;

for (int i = 1; i <= pageCount; i++)
{
    // 获取当前页的内容
    PdfDictionary page = reader.GetPageN(i);
    PdfArray annots = page.GetAsArray(PdfName.ANNOTS);

    // 检测矩形和方框
    if (annots != null)
    {
        foreach (PdfObject annot in annots.ArrayList)
        {
            PdfDictionary annotation = (PdfDictionary)PdfReader.GetPdfObject(annot);
            PdfName subType = (PdfName)PdfReader.GetPdfObject(annotation.Get(PdfName.SUBTYPE));

            // 判断是否为矩形或方框注释
            if (subType.Equals(PdfName.RECT) || subType.Equals(PdfName.SQUARE))
            {
                // 获取矩形或方框的坐标信息
                PdfArray rect = annotation.GetAsArray(PdfName.RECT);
                float x = rect.GetAsNumber(0).FloatValue;
                float y = rect.GetAsNumber(1).FloatValue;
                float width = rect.GetAsNumber(2).FloatValue - x;
                float height = rect.GetAsNumber(3).FloatValue - y;

                // 在控制台输出矩形或方框的坐标信息
                Console.WriteLine("矩形或方框坐标：x={0}, y={1}, width={2}, height={3}", x, y, width, height);
            }
        }
    }
}