public static void SaveMetaFile(
Stream source,
Stream destination,
float scale = 4f,
Color?backgroundColor = null,
ImageFormat format = null,
EncoderParameters parameters = null)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (destination == null)
{
throw new ArgumentNullException(nameof(destination));
}
using (var img = new Metafile(source))
{
var f = format ?? ImageFormat.Png;
//Determine default background color.
//Not all formats support transparency.
if (backgroundColor == null)
{
var transparentFormats = new ImageFormat[] { ImageFormat.Gif, ImageFormat.Png, ImageFormat.Wmf, ImageFormat.Emf };
var isTransparentFormat = transparentFormats.Contains(f);
backgroundColor = isTransparentFormat ? Color.Transparent : Color.White;
}
//header contains DPI information
var header = img.GetMetafileHeader();
//calculate the width and height based on the scale
//and the respective DPI
var width = (int)Math.Round((scale * img.Width / header.DpiX * 100), 0, MidpointRounding.ToEven);
var height = (int)Math.Round((scale * img.Height / header.DpiY * 100), 0, MidpointRounding.ToEven);
using (var bitmap = new Bitmap(width, height))
{
using (var g = System.Drawing.Graphics.FromImage(bitmap))
{
//fills the background
g.Clear(backgroundColor.Value);
//reuse the width and height to draw the image
//in 100% of the square of the bitmap
g.DrawImage(img, 0, 0, bitmap.Width, bitmap.Height);
}
//get codec based on GUID
var codec = ImageCodecInfo.GetImageEncoders().FirstOrDefault(c => c.FormatID == f.Guid);
bitmap.Save(destination, codec, parameters);
}
}
}
public static bool ValidateImage(this IFormFile file, ModelStateDictionary ModelState)
{
// Allowed image formats
ImageFormat[] allowedImageFormats = new ImageFormat[]
{
ImageFormat.Bmp,
ImageFormat.Gif,
ImageFormat.Jpeg,
ImageFormat.Png,
ImageFormat.Tiff
};
string ext = Path.GetExtension(file.FileName).ToLower();
if (!DataConstants.AllowedImageExtensions.Contains(ext))
{
string allowedImageExtensions = string.Join(", ", DataConstants.AllowedImageExtensions);
ModelState.AddModelError(string.Empty, $"Allowed image extensions {allowedImageExtensions}");
return(false);
}
if (file.Length > DataConstants.PosterMaxLength)
{
string mb = $"{DataConstants.ThumbnailMaxLength / 1024 / 1024} MB";
ModelState.AddModelError(string.Empty, $"Allowed max file size {mb}");
return(false);
}
try
{
// Create an Image from the specified data stream
using (Image img = Image.FromStream(file.OpenReadStream()))
{
// Return true if the image format is allowed
if (!allowedImageFormats.Contains(img.RawFormat))
{
ModelState.AddModelError(string.Empty, $"{file.FileName} has no valid image format.");
return(false);
}
}
}
catch
{
ModelState.AddModelError(string.Empty, $"{file.FileName} is not a valid image.");
return(false);
}
return(true);
}
public static bool IsValidFileType(HttpPostedFileBase file)
{
bool flag;
if ((file == null ? false : file.ContentLength > 0))
{
ImageFormat[] jpeg = new ImageFormat[] { ImageFormat.Jpeg, ImageFormat.Png, ImageFormat.Gif, ImageFormat.Bmp, ImageFormat.Jpeg, ImageFormat.Tiff, ImageFormat.Icon };
using (Image image = Image.FromStream(file.InputStream))
{
if (!jpeg.Contains <ImageFormat>(image.RawFormat))
{
flag = false;
return(flag);
}
}
}
flag = true;
return(flag);
}
