iText7画发票PDF——小tips

itext7教程：

1、https://blog.csdn.net/allway2/article/details/124295097
2、https://max.book118.com/html/2017/0720/123235195.shtm
3、https://www.cnblogs.com/fonks/p/15090635.html
4、https://www.cnblogs.com/sky-chen/p/13026203.html
5、官方：https://api.itextpdf.com/iText/dotnet/8.0.2/classi_text_1_1_layout_1_1_splitting_1_1_keep_all_split_characters.html
6、git：https://github.com/itext/itext7-dotnet

1.毫米转换磅
itext中是用磅值作为像素位置点的。为方便画PDF，则需要把常规毫米转换成磅值；
转换规则：毫米/10/2.54f*72

2.添加每页的固定表头
（给pdf添加AddEventHandler）

• 创建类PdfEventHandler
  （在PdfEventHandler中将每页要重复的部分画进去。）

PdfEventHandler handler = new PdfEventHandler(model, KT, ST, CN);//

• pdf增加Event，将创建的类新增到pdf中：

pdf.AddEventHandler(PdfDocumentEvent.START_PAGE, handler);

3.金额转换成中文大写金额

 /// <summary>/// 金额转换成中文大写金额/// </summary>/// <param name="LowerMoney">传入的数字金额，eg:10.74</param>/// <returns></returns>private static string MoneyToUpper(string LowerMoney){string functionReturnValue = null;bool IsNegative = false; // 是否是负数if (LowerMoney.Trim().Substring(0, 1) == "-"){// 是负数则先转为正数LowerMoney = LowerMoney.Trim().Remove(0, 1);IsNegative = true;}string strLower = null;string strUpart = null;string strUpper = null;int iTemp = 0;// 保留两位小数 123.489→123.49　　123.4→123.4LowerMoney = Math.Round(double.Parse(LowerMoney), 2).ToString();if (LowerMoney.IndexOf(".") > 0){if (LowerMoney.IndexOf(".") == LowerMoney.Length - 2){LowerMoney = LowerMoney + "0";}}else{LowerMoney = LowerMoney + ".00";}strLower = LowerMoney;iTemp = 1;strUpper = "";while (iTemp <= strLower.Length){switch (strLower.Substring(strLower.Length - iTemp, 1)){case ".":strUpart = "圆";break;case "0":strUpart = "零";break;case "1":strUpart = "壹";break;case "2":strUpart = "贰";break;case "3":strUpart = "叁";break;case "4":strUpart = "肆";break;case "5":strUpart = "伍";break;case "6":strUpart = "陆";break;case "7":strUpart = "柒";break;case "8":strUpart = "捌";break;case "9":strUpart = "玖";break;}switch (iTemp){case 1:strUpart = strUpart + "分";break;case 2:strUpart = strUpart + "角";break;case 3:strUpart = strUpart + "";break;case 4:strUpart = strUpart + "";break;case 5:strUpart = strUpart + "拾";break;case 6:strUpart = strUpart + "佰";break;case 7:strUpart = strUpart + "仟";break;case 8:strUpart = strUpart + "万";break;case 9:strUpart = strUpart + "拾";break;case 10:strUpart = strUpart + "佰";break;case 11:strUpart = strUpart + "仟";break;case 12:strUpart = strUpart + "亿";break;case 13:strUpart = strUpart + "拾";break;case 14:strUpart = strUpart + "佰";break;case 15:strUpart = strUpart + "仟";break;case 16:strUpart = strUpart + "万";break;default:strUpart = strUpart + "";break;}strUpper = strUpart + strUpper;iTemp = iTemp + 1;}strUpper = strUpper.Replace("零拾", "零");strUpper = strUpper.Replace("零佰", "零");strUpper = strUpper.Replace("零仟", "零");strUpper = strUpper.Replace("零零零", "零");strUpper = strUpper.Replace("零零", "零");strUpper = strUpper.Replace("零角零分", "整");strUpper = strUpper.Replace("零分", "整");strUpper = strUpper.Replace("零角", "零");strUpper = strUpper.Replace("零亿零万零圆", "亿圆");strUpper = strUpper.Replace("亿零万零圆", "亿圆");strUpper = strUpper.Replace("零亿零万", "亿");strUpper = strUpper.Replace("零万零圆", "万圆");strUpper = strUpper.Replace("零亿", "亿");strUpper = strUpper.Replace("零万", "万");strUpper = strUpper.Replace("零圆", "圆");strUpper = strUpper.Replace("零零", "零");Console.WriteLine("零角零分");// 对壹圆以下的金额的处理if (strUpper.Substring(0, 1) == "圆"){strUpper = strUpper.Substring(1, strUpper.Length - 1);}if (strUpper.Substring(0, 1) == "零"){strUpper = strUpper.Substring(1, strUpper.Length - 1);}if (strUpper.Substring(0, 1) == "角"){strUpper = strUpper.Substring(1, strUpper.Length - 1);}if (strUpper.Substring(0, 1) == "分"){strUpper = strUpper.Substring(1, strUpper.Length - 1);}if (strUpper.Substring(0, 1) == "整"){strUpper = "零圆整";}functionReturnValue = strUpper;if (IsNegative == true){return "负" + functionReturnValue;}else{return string.Format(functionReturnValue, Encoding.GetEncoding("GB2312"));}}

4、画双横线

pdfCanvas.MoveTo(computeValue.computeUnit(141), computeValue.computeUnit(278.5f));
pdfCanvas.LineTo(computeValue.computeUnit(69), computeValue.computeUnit(278.5f));
pdfCanvas.SetStrokeColor(new DeviceRgb(128, 0, 0));
pdfCanvas.MoveTo(computeValue.computeUnit(141), computeValue.computeUnit(277.5f));
pdfCanvas.LineTo(computeValue.computeUnit(69), computeValue.computeUnit(277.5f));
pdfCanvas.SetStrokeColor(new DeviceRgb(128, 0, 0));
pdfCanvas.ClosePathStroke();

5、创作二维码

//设置扫描二维码后显示的文字或内容
string code = $"01,{发票票种model},," + 发票号码model + "," + 价税合计model + "," + DateTime.Parse(开票日期model).ToString("yyyyMMdd") + ",,";
//将code与转换为CRC16编码后的字节链接
code = code + CRC16(System.Text.Encoding.UTF8.GetBytes(code));
//将链接好的字符串转换为二维码字节
model.qrCode = GetQrCode(code);//model.qrCode为byte[]类型
//在Canvas中添加动态二维码（具体实现可参考下一篇笔记（iText7——画发票PDF（完整）））Image EWM = new Image(ImageDataFactory.Create(_model.qrCode)).SetWidth(computeValue.computeUnit(20)).SetHeight(computeValue.computeUnit(20));canvas.Add(EWM.SetFixedPosition(1, computeValue.computeUnit(7), computeValue.computeUnit(271)));
//若要在二维码中间放图片，则加上图片:
Image S = new Image(ImageDataFactory.Create("E://图片//发票图片//Shui.png")).SetWidth(computeValue.computeUnit(4)).SetHeight(computeValue.computeUnit(4));
canvas.Add(S.SetFixedPosition(1, computeValue.computeUnit(15), computeValue.computeUnit((float)279)));/// <summary>
/// CRC16编码
/// </summary>
/// <param name="data"></param>
/// <returns></returns>
private static string CRC16(byte[] data)
{ushort crc = 0xFFFF;int len = data.Length;for (int i = 0; i < len; i++){crc = (ushort)((crc >> 8) ^ data[i]);for (int j = 0; j < 8; j++)crc = (crc & 1) == 1 ? (ushort)((crc >> 1) ^ 0xA001) : (ushort)(crc >> 1);}return string.Format("{0:X}", crc).PadLeft(4, '0');
}/// <summary>
/// 生成发票二维码
/// </summary>
/// <returns></returns>
private static byte[] GetQrCode(string codeValue)
{// 设定二维码大小QrCodeEncodingOptions qrCode = new QrCodeEncodingOptions();qrCode.ErrorCorrection = ErrorCorrectionLevel.M;qrCode.CharacterSet = "UTF-8";qrCode.Height = 180;qrCode.Width = 180;qrCode.Margin = 1;// 生成二维码BarcodeWriter writer = new BarcodeWriter();writer.Format = BarcodeFormat.QR_CODE;writer.Options = qrCode;writer.Options.PureBarcode = true; // 不显示条码下面的数据Bitmap bitmap = writer.Write(codeValue);MemoryStream ms = new MemoryStream();bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Png);byte[] arr = new byte[ms.Length];ms.Position = 0;ms.Read(arr, 0, (int)ms.Length);ms.Close();return arr;
}