C#如何实现图片的剪裁并保存
时间：2021-11-16 16:33:02|栏目：.NET代码|点击： 次
最近需要将一张图片上传并按指定位置剪裁，后来在网上找了一个剪裁图片的插件，但是只有前台没有后端，然后我各种百度，并最终完成，特此写一篇博客略表纪念。
下面是代码：
HttpPostedFile file = context.Request.Files["avatar_file"];
string datasize = context.Request.Params["avatar_data"];
//{"x":30.003846153846148,"y":16.715384615384625,"height":300.8,"width":300.8,"rotate":0} 剪裁之后参数
JavaScriptSerializer jss = new JavaScriptSerializer();
ImgSize imagesize = jss.Deserialize<ImgSize>(datasize);
byte[] FileByte = SetFileToByteArray(file);//图片数组
string strtExtension = System.IO.Path.GetExtension(file.FileName);//图片格式
MemoryStream ms1 = new MemoryStream(FileByte);
Bitmap sBitmap = (Bitmap)Image.FromStream(ms1);
Rectangle section = new Rectangle(new Point(imagesize.ToInt(imagesize.x), imagesize.ToInt(imagesize.y)), new Size(imagesize.ToInt(imagesize.width), imagesize.ToInt(imagesize.height)));
Bitmap CroppedImage = MakeThumbnailImage(sBitmap, section.Width, section.Height, section.Width, section.Height, section.X, section.Y);
上面代码中用到我自己创建了一个ImgSize类，代码如下：
class ImgSize
{
//{"x":30.003846153846148,"y":16.715384615384625,"height":300.8,"width":300.8,"rotate":0}
public double x { get; set; }
public double y { get; set; }
public double width { get; set; }
public double height { get; set; }
public int rotate { get; set; }
public int ToInt(double doubleValue)
{
return Convert.ToInt32(doubleValue);
}
}
上面代码中使用到的几个方法：
文件转化：
/// <summary>
/// 将From表单file文件转化为byte数组
/// </summary>
/// <param name="File">from提交文件流</param>
/// <returns></returns>
private byte[] SetFileToByteArray(HttpPostedFile File)
{
Stream stream = File.InputStream;
byte[] AyyayByte = new byte[File.ContentLength];
stream.Read(AyyayByte, 0, File.ContentLength);
stream.Close();
return AyyayByte;
}
核心剪裁方法：
/// <summary>
/// 裁剪图片并保存
/// </summary>
/// <param name="Image">图片信息</param>
/// <param name="maxWidth">缩略图宽度</param>
/// <param name="maxHeight">缩略图高度</param>
/// <param name="cropWidth">裁剪宽度</param>
/// <param name="cropHeight">裁剪高度</param>
/// <param name="X">X轴</param>
/// <param name="Y">Y轴</param>
public static Bitmap MakeThumbnailImage(Image originalImage, int maxWidth, int maxHeight, int cropWidth, int cropHeight, int X, int Y)
{
Bitmap b = new Bitmap(cropWidth, cropHeight);
try
{
using (Graphics g = Graphics.FromImage(b))
{
//清空画布并以透明背景色填充
g.Clear(Color.Transparent);
//在指定位置并且按指定大小绘制原图片的指定部分
g.DrawImage(originalImage, new Rectangle(0, 0, cropWidth, cropHeight), X, Y, cropWidth, cropHeight, GraphicsUnit.Pixel);
Image displayImage = new Bitmap(b, maxWidth, maxHeight);
displayImage.Save("E:\\cutimg.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
Bitmap bit = new Bitmap(b, maxWidth, maxHeight);
return bit;
}
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
b.Dispose();
}
}
最后的结果是把存到了E盘根目录下面
