public ActionResult InputImageToBackEnd(string image_Base64)
{
Base64Object base64Object = new Base64Object(image_Base64);
base64Object.SaveImage_Jpg(HostingEnvironment.MapPath("~/SaveChartJsImage/test.jpg"));
return(Content("Success !"));
}
public static void SaveImage_Png(this Base64Object base64Object, string path)
{
if (base64Object == null)
{
throw new Exception("base64Object is null !");
}
string x = base64Object.Value.Replace("data:image/png;base64,", "");
// Convert Base64 String to byte[]
byte[] imageBytes = Convert.FromBase64String(x);
MemoryStream ms = new MemoryStream(imageBytes, 0, imageBytes.Length);
// Convert byte[] to Image
ms.Write(imageBytes, 0, imageBytes.Length);
System.Drawing.Image image = System.Drawing.Image.FromStream(ms, true);
image.Save(path, System.Drawing.Imaging.ImageFormat.Png);
}
public static void SaveImage_Jpg(this Base64Object base64Object, string path)
{
if (base64Object == null)
{
throw new Exception("base64Object is null !");
}
string x = base64Object.Value.Replace("data:image/jpeg;base64,", "");
// Convert Base64 String to byte[]
byte[] imageBytes = Convert.FromBase64String(x);
MemoryStream ms = new MemoryStream(imageBytes, 0, imageBytes.Length);
// Convert byte[] to Image
ms.Write(imageBytes, 0, imageBytes.Length);
System.Drawing.Image image = System.Drawing.Image.FromStream(ms, true);
// 因為轉成 jpg 格式，jpg 格式沒有透明，所以先將圖設為 bitmap，將背景改為白色
// 再轉成 jpg 格式，不然原本透明的地方是整片黑 !!!
/// ↓這不知道為毛沒用
//Bitmap bitmap = new Bitmap(image);
//bitmap.MakeTransparent(Color.White);
//bitmap.Save(path, System.Drawing.Imaging.ImageFormat.Jpeg);
// bitmap 設置畫布
// Graphics 負責畫
using (var b = new Bitmap(image.Width, image.Height))
{
b.SetResolution(image.HorizontalResolution, image.VerticalResolution);
// FromImage 就是將畫布設在 bitmap 上的概念
using (var g = Graphics.FromImage(b))
{
g.Clear(Color.White);
g.DrawImageUnscaled(image, 0, 0);
}
ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg);
System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Quality; //給Compression無效
EncoderParameters myEncoderParameters = new EncoderParameters(1);
myEncoderParameters.Param[0] = new EncoderParameter(myEncoder, 100L); // 壓縮品質 100L，數字愈低，破壞性壓縮愈大
b.Save(path, jpgEncoder, myEncoderParameters);
}
}
