C# 图片处理，添加文字、添加图片、圆形切割。处理后图片不失真，不压缩图片 【 程序示例】

图片处理程序示例，实现功能点有

1、远程图片转换Image对象

2、在图片上添加文字

3、在图片上添加图片

4、将图片进行椭圆形（圆形）切割

5、微软程序处理图片失真。不少人发现图片用微软程序重绘之后，即时什么也不做，图片质量也会压缩，微软的Image.Save方法，不设置压缩质量，是默认保存到图片压缩质量为75，所以保存的图片质量偏低。

代码如下，此处是asp.net中的一般处理程序

public void ProcessRequest(HttpContext context)
{//产品图片string ProducePicUrl = "http://img.xxx.com/group1/M00/36/B8/cnHoeV3pxMWANofjAACQFhMkSE0601_s.jpg";Image img = GetStreamByUrl(ProducePicUrl);Graphics grap = Graphics.FromImage(img);//设置输出图片质量grap.CompositingQuality = CompositingQuality.HighQuality;grap.SmoothingMode = SmoothingMode.HighQuality;grap.InterpolationMode = InterpolationMode.HighQualityBicubic;//在图片上添加文字grap.DrawString("中国山东找蓝翔", new Font("宋体", 20, FontStyle.Bold), Brushes.Blue, new PointF(29, 29));//企业logo图片string ComPicUrl = "http://img.xxx.com/group1/M00/2D/62/cnHoeVsfISeAEPqhAAA5bjwdSWo698_s.jpg";Image Comimg = GetStreamByUrl(ComPicUrl);//图片圆形切割Comimg = CutEllipse(Comimg, new Rectangle(0, 0, Comimg.Width, Comimg.Height), new Size(100, 100));//图片上添加图片grap.DrawImage(Comimg, new Rectangle(img.Width - 100, 0, 100, 100),0, 0, Comimg.Width, Comimg.Height, GraphicsUnit.Pixel);EncoderParameters ps = new EncoderParameters(1);EncoderParameter p = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L);ps.Param[0] = p;ImageCodecInfo imgcodec = GetCodecInfo("image/jpeg");img.Save(context.Response.OutputStream, imgcodec, ps);//img.Save(context.Response.OutputStream, ImageFormat.Jpeg);常用图片保存，质量被压缩context.Response.ContentType = "image/jpeg";
}
/// <summary>
/// 图片剪切成椭圆形
/// </summary>
/// <param name="img">原始Image对象</param>
/// <param name="rec">被切割图片的矩形范围</param>
/// <param name="size">椭圆的尺寸</param>
/// <returns></returns>
private Image CutEllipse(Image img, Rectangle rec, Size size)
{Bitmap bitmap = new Bitmap(size.Width, size.Height);using (Graphics g = Graphics.FromImage(bitmap)){using (TextureBrush br = new TextureBrush(img, System.Drawing.Drawing2D.WrapMode.Clamp, rec)){br.ScaleTransform(bitmap.Width / (float)rec.Width, bitmap.Height / (float)rec.Height);g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;g.FillEllipse(br, new Rectangle(Point.Empty, size));}}return bitmap;
}
private ImageCodecInfo GetCodecInfo(string mimeType)
{ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders();foreach (ImageCodecInfo ici in CodecInfo){if (ici.MimeType == mimeType) return ici;}return null;
}/// <summary>
/// 获取远程图片的Image对象
/// </summary>
/// <returns></returns>
public Image GetStreamByUrl(string imgurl)
{WebRequest myrequest = WebRequest.Create(imgurl);myrequest.Timeout = 3 * 1000;WebResponse myresponse = myrequest.GetResponse();Stream imgstream = myresponse.GetResponseStream();Image img = Image.FromStream(imgstream);myrequest.Abort();myresponse.Close();return img;
}

最终效果：右侧圆形区域是企业Logo

参考资料：https://blog.csdn.net/chinacsharper/article/details/50854852