C#图片添加水印

1.图片水印封装方法     

/// <summary>
/// 图片水印
/// </summary>
/// <param name="imgPath">服务器图片相对路径</param>
/// <param name="filename">保存文件名</param>
/// <param name="watermarkFilename">水印文件相对路径</param>
/// <param name="watermarkStatus">图片水印位置 0=不使用 1=左上 2=中上 3=右上 4=左中 9=右下 10=底部</param>
/// <param name="quality">附加水印图片质量,0-100</param>
/// <param name="watermarkTransparency">水印的透明度 1--10 10为不透明</param>
public static void AddImageSignPic(string imgPath, string filename, string watermarkFilename, int watermarkStatus, int quality, int watermarkTransparency)
{
if (!File.Exists(GetMapPath(imgPath)))
return;
byte[] _ImageBytes = File.ReadAllBytes(GetMapPath(imgPath));
Image img = Image.FromStream(new System.IO.MemoryStream(_ImageBytes));
filename = GetMapPath(filename); 

if (watermarkFilename.StartsWith("/") == false)
watermarkFilename = "/" + watermarkFilename;
watermarkFilename = GetMapPath(watermarkFilename);
if (!File.Exists(watermarkFilename))
return;
Graphics g = Graphics.FromImage(img);
//设置高质量插值法
//g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
//g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
Image watermark = new Bitmap(watermarkFilename); 

ImageAttributes imageAttributes = new ImageAttributes();
ColorMap colorMap = new ColorMap(); 

colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
ColorMap[] remapTable = { colorMap }; 

imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

 float transparency = 0.5F;

if (watermarkTransparency >= 1 && watermarkTransparency <= 10)
transparency = (watermarkTransparency / 10.0F); 

float[][] colorMatrixElements = {
new float[] {1.0f, 0.0f, 0.0f, 0.0f, 0.0f},
new float[] {0.0f, 1.0f, 0.0f, 0.0f, 0.0f},
new float[] {0.0f, 0.0f, 1.0f, 0.0f, 0.0f},
new float[] {0.0f, 0.0f, 0.0f, transparency, 0.0f},
new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}
}; 

ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements); 

imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap); 

int xpos = 0;
int ypos = 0; 

switch (watermarkStatus)
{
case 1:
xpos = (int)(img.Width * (float).01);
ypos = (int)(img.Height * (float).01);
break;
case 2:
xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
ypos = (int)(img.Height * (float).01);
break;
case 3:
xpos = (int)((img.Width * (float).99) - (watermark.Width));
ypos = (int)(img.Height * (float).01);
break;
case 4:
xpos = (int)(img.Width * (float).01);
ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
break;
case 5:
xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
break;
case 6:
xpos = (int)((img.Width * (float).99) - (watermark.Width));
ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
break;
case 7:
xpos = (int)(img.Width * (float).01);
ypos = (int)((img.Height * (float).99) - watermark.Height);
break;
case 8:
xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
ypos = (int)((img.Height * (float).99) - watermark.Height);
break;
case 9:
xpos = (int)((img.Width * (float).99) - (watermark.Width));
ypos = (int)((img.Height * (float).99) - watermark.Height);
break;
case 10:
ypos = (int)((img.Height * (float).99) - watermark.Height)+10;
break;
} 

g.DrawImage(watermark, new Rectangle(1, ypos, watermark.Width, watermark.Height), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel, imageAttributes);

 ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

ImageCodecInfo ici = null;
foreach (ImageCodecInfo codec in codecs)
{
if (codec.MimeType.IndexOf("jpeg") > -1)
ici = codec;
}
EncoderParameters encoderParams = new EncoderParameters();
long[] qualityParam = new long[1];
if (quality < 0 || quality > 100)
quality = 80; 

qualityParam[0] = quality; 

EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);
encoderParams.Param[0] = encoderParam; 

if (ici != null)
img.Save(filename, ici, encoderParams);
else
img.Save(filename); 

g.Dispose();
img.Dispose();
watermark.Dispose();
imageAttributes.Dispose();
}

2.调用方法

AddImageSignPic(@"~UploadsWaterFace水印_sl.jpg", @"~UploadsWaterFace水印_waternew.jpg", @"UploadsWaterFacemodel_1.png", 10, 100, 10)