等比例生成高清图片代码,CSharp代码库,德仔网

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【CSharp】等比例生成高清图片
作者:珍冰 / 发布于2014/10/13/ 820
调用：s.CreateImageOutput(660, 840, "http://xxx,jpg", Server.MapPath("~/Upload/byyh/Pimg/d/fdsafas.jpg"));

	private System.Drawing.Image GetImage(string path)
	 {
	 if (path.StartsWith("http"))
	 {
	 System.Net.WebRequest request = System.Net.WebRequest.Create(path);
	 request.Timeout = 10000;
	 System.Net.HttpWebResponse httpresponse = (System.Net.HttpWebResponse)request.GetResponse();
	 Stream s = httpresponse.GetResponseStream();
	 return System.Drawing.Image.FromStream(s);
	 }
	 else
	 {
	 return System.Drawing.Image.FromFile(path);
	 }
	 }

	 public void CreateImageOutput(int width, int height, string oPath, string tPath)
	 {
	Image img = GetImage(oPath);
	 Bitmap originalBmp = null;// new Bitmap(oPath);
	 originalBmp = new Bitmap(img); img.Dispose();
	 // 源图像在新图像中的位置
	 int left, top;
	 if (originalBmp.Width <= width && originalBmp.Height <= height)
	 {
	 // 原图像的宽度和高度都小于生成的图片大小
	 left = (int)Math.Round((decimal)(width - originalBmp.Width) / 2);
	 top = (int)Math.Round((decimal)(height - originalBmp.Height) / 2);
	 // 最终生成的图像
	 Bitmap bmpOut = new Bitmap(width, height);
	 using (Graphics graphics = Graphics.FromImage(bmpOut))
	 {
	 // 设置高质量插值法
	 graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
	 // 清空画布并以白色背景色填充
	 graphics.Clear(Color.White);
	 //加上边框
	 //Pen pen = new Pen(ColorTranslator.FromHtml("#cccccc"));
	 // graphics.DrawRectangle(pen, 0, 0, width - 1, height - 1);
	 // 把源图画到新的画布上
	 graphics.DrawImage(originalBmp, left, top);
	 }
	 bmpOut.Save(tPath);//保存为文件，tpath 为要保存的路径
	 //this.OutputImgToPage(bmpOut);//直接输出到页面
	 bmpOut.Dispose();
	originalBmp.Dispose();
	 return;
	 }

	 // 新图片的宽度和高度，如400*200的图像，想要生成160*120的图且不变形，
	 // 那么生成的图像应该是160*80，然后再把160*80的图像画到160*120的画布上
	 int newWidth, newHeight;
	 if (width * originalBmp.Height < height * originalBmp.Width)
	 {
	 newWidth = width;
	 newHeight = (int)Math.Round((decimal)originalBmp.Height * width / originalBmp.Width);
	 // 缩放成宽度跟预定义的宽度相同的，即left=0，计算top
	 left = 0;
	 top = (int)Math.Round((decimal)(height - newHeight) / 2);
	 }
	 else
	 {
	 newWidth = (int)Math.Round((decimal)originalBmp.Width * height / originalBmp.Height);
	 newHeight = height;
	 // 缩放成高度跟预定义的高度相同的，即top=0，计算left
	 left = (int)Math.Round((decimal)(width - newWidth) / 2);
	 top = 0;
	 }
	 // 生成按比例缩放的图，如：160*80的图
	 Bitmap bmpOut2 = new Bitmap(newWidth, newHeight);
	 using (Graphics graphics = Graphics.FromImage(bmpOut2))
	 {
	 graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
	 graphics.FillRectangle(Brushes.White, 0, 0, newWidth, newHeight);
	 graphics.DrawImage(originalBmp, 0, 0, newWidth, newHeight);
	 }
	 // 再把该图画到预先定义的宽高的画布上，如160*120
	 Bitmap lastbmp = new Bitmap(width, height);
	 using (Graphics graphics = Graphics.FromImage(lastbmp))
	 {
	 // 设置高质量插值法
	 graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
	 // 清空画布并以白色背景色填充
	 graphics.Clear(Color.White);
	 //加上边框
	 //Pen pen = new Pen(ColorTranslator.FromHtml("#cccccc"));
	 //graphics.DrawRectangle(pen, 0, 0, width - 1, height - 1);
	 // 把源图画到新的画布上
	 graphics.DrawImage(bmpOut2, left, top);
	 }
	 lastbmp.Save(tPath);//保存为文件，tpath 为要保存的路径
	 //this.OutputImgToPage(lastbmp);//直接输出到页面
	 lastbmp.Dispose();
	originalBmp.Dispose();
	 }

	 //private void OutputImgToPage(System.Drawing.Bitmap bmp)
	 //{
	 // //输出到页面
	 // MemoryStream ms = new MemoryStream();
	 // bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
	 // Response.ClearContent(); //需要输出图象信息 要修改HTTP头
	 // byte[] buffer = ms.ToArray();
	 // Response.AddHeader("Content-type", "image/jpeg");
	 // Response.BinaryWrite(buffer);
	 // bmp.Dispose();
	 //}
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