C# 使用Aspose.Pdf给Pdf文件添加文字水印和图片水印
使用Aspose.Pdf给pdf文件添加水印，代码如下：仅供参考（带一些个人业务，还有些小bug自行修改）
Aspose试用版 pdf超过4页会报错，商用请购买正式版本。
1、添加文字水印
/// <summary>
/// pdf添加文字水印(自定义水印行数和列数)
/// </summary>
/// <param name="pdfStream">pdf文件流</param>
/// <param name="watermarkText">水印文字</param>
/// <param name="fontSize">文字大小</param>
/// <param name="fontColor">文字颜色</param>
/// <param name="typeface">字体：（中文水印请自行查找相应字体的英文名称，如：宋体（SimSun），黑体（SimHei），仿宋（FangSong），微软雅黑（Microsoft YaHei）等等...）</param>
/// <param name="rotation">倾斜角度</param>
/// <param name="opacity">不透明度（值为：0-1）</param>
/// <param name="watermarkRowNum">水印行数</param>
/// <param name="watermarkColumnNum">水印列数</param>
/// <returns></returns>
public Stream AddTextWatermarkCustom(Stream pdfStream, string watermarkText, float fontSize, Aspose.Pdf.Color fontColor, string typeface, double rotation = 0, double opacity = 0, int watermarkRowNum = 1, int watermarkColumnNum = 1)
{
try
{
/*计算倾斜高度-start*/
var angle = Math.Abs(rotation);
var width = watermarkText.Length * fontSize;
var radian = 2 * Math.PI / 360 * angle;
var top = Math.Sin(radian) * width;
/*计算倾斜高度-end*/
Document document = new Document(pdfStream);
for (int i = 1; i <= document.Pages.Count; i++)
{
var pageWidth = document.Pages[i].GetPageRect(false).Width;
var pageHeight = document.Pages[i].GetPageRect(false).Height;
WatermarkArtifact artifact = new WatermarkArtifact();
artifact.SetTextAndState(watermarkText, new TextState
{
FontSize = fontSize,
ForegroundColor = fontColor,
Font = FontRepository.FindFont(typeface),
});
artifact.Rotation = rotation;
artifact.Opacity = opacity;
artifact.IsBackground = false;
if (watermarkRowNum == 1 && watermarkColumnNum == 1)
{
artifact.ArtifactHorizontalAlignment = HorizontalAlignment.Center;
artifact.ArtifactVerticalAlignment = VerticalAlignment.Center;
document.Pages[i].Artifacts.Add(artifact);
}
else
{
artifact.ArtifactHorizontalAlignment = HorizontalAlignment.Left;
artifact.ArtifactVerticalAlignment = VerticalAlignment.Top;
for (int j = 1; j <= watermarkColumnNum; j++)
{
artifact.LeftMargin = (j - 1) * (pageWidth / watermarkColumnNum) + fontSize;
for (int z = 1; z <= watermarkRowNum; z++)
{
artifact.TopMargin = (z - 1) * (pageHeight / watermarkRowNum) + top;
document.Pages[i].Artifacts.Add(artifact);
}
}
}
}
Stream outStream = new MemoryStream();
document.Save(outStream, SaveFormat.Pdf);
outStream.Seek(0, SeekOrigin.Begin);
return outStream;
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// pdf添加文字水印(平铺)
/// </summary>
/// <param name="pdfStream">pdf文件流</param>
/// <param name="watermarkText">水印文字</param>
/// <param name="fontSize">文字大小</param>
/// <param name="fontColor">文字颜色</param>
/// <param name="typeface">字体：（中文水印请自行查找相应字体的英文名称，如：宋体（SimSun），黑体（SimHei），仿宋（FangSong），微软雅黑（Microsoft YaHei）等等...）</param>
/// <param name="rotation">倾斜角度</param>
/// <param name="opacity">不透明度（值为：0-1）</param>
/// <param name="density">水印密度（值为0-1）</param>
/// <returns></returns>
public Stream AddTextWatermarkTile(Stream pdfStream, string watermarkText, float fontSize, Aspose.Pdf.Color fontColor, string typeface, double rotation = 0, double opacity = 0, double density = 1)
{
try
{
Document document = new Document(pdfStream);
/*计算水印详细-start*/
var angle = Math.Abs(rotation);
var width = watermarkText.Length * fontSize;
var radian = 2 * Math.PI / 360 * angle;
var top = Math.Sin(radian) * width;
var row = Math.Cos(radian) * width;
var pageWidth = document.Pages[1].GetPageRect(false).Width;
var pageHeight = document.Pages[1].GetPageRect(false).Height;
int watermarkRowNum = (int)(pageHeight / top * density);
int watermarkColumnNum = (int)(pageHeight / row * density);
if (rotation == 0)
{
watermarkRowNum = (int)(pageHeight / fontSize * density);
watermarkColumnNum = (int)(pageHeight / width * density);
}
/*计算水印详细-end*/
for (int i = 1; i <= document.Pages.Count; i++)
{
WatermarkArtifact artifact = new WatermarkArtifact();
artifact.SetTextAndState(watermarkText, new TextState
{
FontSize = fontSize,
ForegroundColor = fontColor,
Font = FontRepository.FindFont(typeface),
});
artifact.Rotation = rotation;
artifact.Opacity = opacity;
artifact.IsBackground = false;
artifact.ArtifactHorizontalAlignment = HorizontalAlignment.Left;
artifact.ArtifactVerticalAlignment = VerticalAlignment.Top;
for (int j = 1; j <= watermarkColumnNum; j++)
{
artifact.LeftMargin = (j - 1) * (pageWidth / watermarkColumnNum) + fontSize;
for (int z = 1; z <= watermarkRowNum; z++)
{
artifact.TopMargin = (z - 1) * (pageHeight / watermarkRowNum) + top;
document.Pages[i].Artifacts.Add(artifact);
}
}
}
Stream outStream = new MemoryStream();
document.Save(outStream, SaveFormat.Pdf);
outStream.Seek(0, SeekOrigin.Begin);
return outStream;
}
catch (Exception ex)
{
throw ex;
}
}调用代码部分代码：
Stream stream = File.OpenRead(@"C:\Users\HEDY\Desktop\Test\2.pdf");
var outStream = AddTextWatermarkCustom(stream, "测试水印文字", 32, Color.Blue, "SimSun", 45, 0.5, 6, 3);
var saveStream = new FileStream($@"C:\Users\HEDY\Desktop\Test\1_{Guid.NewGuid()}.pdf", FileMode.Create);
outStream.CopyTo(saveStream);
outStream.Close();
saveStream.Close();
2、添加图片水印
/// <summary>
/// pdf添加图片水印(自定义水印行数和列数)
/// </summary>
/// <param name="pdfStream">pdf文件流</param>
/// <param name="imgurl">水印文字</param>
/// <param name="rotation">倾斜角度</param>
/// <param name="opacity">不透明度（值为：0-1）</param>
/// <param name="watermarkRowNum">水印行数</param>
/// <param name="watermarkColumnNum">水印列数</param>
/// <returns></returns>
public Stream AddImgWatermarkCustom(Stream pdfStream, string imgPath, double rotation = 0, double opacity = 0, int watermarkRowNum = 1, int watermarkColumnNum = 1)
{
try
{
/*计算倾斜高度-start*/
var angle = Math.Abs(rotation);
var pic = new Bitmap(imgPath);
var width = pic.Width;
var radian = 2 * Math.PI / 360 * angle;
var top = Math.Sin(radian) * width;
/*计算倾斜高度-end*/
Document document = new Document(pdfStream);
for (int i = 1; i <= document.Pages.Count; i++)
{
var pageWidth = document.Pages[i].GetPageRect(false).Width;
var pageHeight = document.Pages[i].GetPageRect(false).Height;
WatermarkArtifact artifact = new WatermarkArtifact();
artifact.SetImage(File.OpenRead(imgPath));
artifact.Rotation = rotation;
artifact.Opacity = opacity;
artifact.IsBackground = false;
if (watermarkRowNum == 1 && watermarkColumnNum == 1)
{
artifact.ArtifactHorizontalAlignment = HorizontalAlignment.Center;
artifact.ArtifactVerticalAlignment = VerticalAlignment.Center;
document.Pages[i].Artifacts.Add(artifact);
}
else
{
artifact.ArtifactHorizontalAlignment = HorizontalAlignment.Left;
artifact.ArtifactVerticalAlignment = VerticalAlignment.Top;
for (int j = 1; j <= watermarkColumnNum; j++)
{
artifact.LeftMargin = (j - 1) * (pageWidth / watermarkColumnNum) + pic.Height;
for (int z = 1; z <= watermarkRowNum; z++)
{
artifact.TopMargin = (z - 1) * (pageHeight / watermarkRowNum) + top;
document.Pages[i].Artifacts.Add(artifact);
}
}
}
}
Stream outStream = new MemoryStream();
document.Save(outStream, SaveFormat.Pdf);
outStream.Seek(0, SeekOrigin.Begin);
return outStream;
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// pdf添加图片水印(平铺)
/// </summary>
/// <param name="pdfStream">pdf文件流</param>
/// <param name="watermarkText">水印文字</param>
/// <param name="rotation">倾斜角度</param>
/// <param name="opacity">不透明度（值为：0-1）</param>
/// <param name="density">水印密度（值为0-1）</param>
/// <returns></returns>
public Stream AddImgWatermarkTile(Stream pdfStream, string imgPath, double rotation = 0, double opacity = 0, double density = 1)
{
try
{
Document document = new Document(pdfStream);
/*计算水印详细-start*/
var angle = Math.Abs(rotation);
var pic = new Bitmap(imgPath);
var width = pic.Width;
var imgHeight = pic.Height;
var radian = 2 * Math.PI / 360 * angle;
var top = Math.Sin(radian) * width;
var row = Math.Cos(radian) * width;
var pageWidth = document.Pages[1].GetPageRect(false).Width;
var pageHeight = document.Pages[1].GetPageRect(false).Height;
int watermarkRowNum = (int)(pageHeight / top * density);
int watermarkColumnNum = (int)(pageHeight / row * density);
if (rotation == 0)
{
watermarkRowNum = (int)(pageHeight / imgHeight * density);
watermarkColumnNum = (int)(pageHeight / width * density);
}
/*计算水印详细-end*/
for (int i = 1; i <= document.Pages.Count; i++)
{
WatermarkArtifact artifact = new WatermarkArtifact();
artifact.SetImage(File.OpenRead(imgPath));
artifact.Rotation = rotation;
artifact.Opacity = opacity;
artifact.IsBackground = false;
artifact.ArtifactHorizontalAlignment = HorizontalAlignment.Left;
artifact.ArtifactVerticalAlignment = VerticalAlignment.Top;
for (int j = 1; j <= watermarkColumnNum; j++)
{
artifact.LeftMargin = (j - 1) * (pageWidth / watermarkColumnNum) + imgHeight;
for (int z = 1; z <= watermarkRowNum; z++)
{
artifact.TopMargin = (z - 1) * (pageHeight / watermarkRowNum) + top;
document.Pages[i].Artifacts.Add(artifact);
}
}
}
Stream outStream = new MemoryStream();
document.Save(outStream, SaveFormat.Pdf);
outStream.Seek(0, SeekOrigin.Begin);
return outStream;
}
catch (Exception ex)
{
throw ex;
}
}调用代码部分代码：
Stream stream = File.OpenRead(@"C:\Users\HEDY\Desktop\Test\2.pdf");
var outStream = AddImgWatermarkTile(stream, @"C:\Users\HEDY\Desktop\Test\123.jpg", 0, 0.5,0.5);
var saveStream = new FileStream($@"C:\Users\HEDY\Desktop\Test\1_{Guid.NewGuid().ToString("N")}.pdf", FileMode.Create);
outStream.CopyTo(saveStream);
outStream.Close();
saveStream.Close();