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→123.4
LowerMoney = 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)));
/// 

/// CRC16编码
/// 
/// 
/// 
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');
}
/// 

/// 生成发票二维码
/// 
/// 
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;
}