/// <summary>
/// Open image and read metadata (.NET 2.0).
/// </summary>
/// <param name="path">Filepath of image</param>
private void InitViaBmp(string path)
{
using (FileStream stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read))
{
if (Utility.IsImage(stream))
{
using (Image img = Image.FromStream(stream, false, false))
{
if (img != null)
{
InitViaBmp(img);
}
}
}
}
}
/// <summary>
/// Creates a thumbnail from the given image file.
/// </summary>
/// <param name="filename">The filename pointing to an image.</param>
/// <param name="size">Requested image size.</param>
/// <param name="useEmbeddedThumbnails">Embedded thumbnail usage.</param>
/// <param name="rotate">Rotation angle.</param>
/// <returns>The image from the given file or null if an error occurs.</returns>
internal static Image GetThumbnailBmp(string filename, Size size, UseEmbeddedThumbnails useEmbeddedThumbnails, int rotate)
{
if (size.Width <= 0 || size.Height <= 0)
{
throw new ArgumentException();
}
// Check if this is an image file
try
{
using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
{
if (!Utility.IsImage(stream))
{
return(null);
}
}
}
catch
{
return(null);
}
Image source = null;
Image thumb = null;
// Try to read the exif thumbnail
if (useEmbeddedThumbnails != UseEmbeddedThumbnails.Never)
{
try
{
using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
{
using (Image img = Image.FromStream(stream, false, false))
{
foreach (int index in img.PropertyIdList)
{
if (index == TagThumbnailData)
{
// Fetch the embedded thumbnail
byte[] rawImage = img.GetPropertyItem(TagThumbnailData).Value;
using (MemoryStream memStream = new MemoryStream(rawImage))
{
source = Image.FromStream(memStream);
}
if (useEmbeddedThumbnails == UseEmbeddedThumbnails.Auto)
{
// Check that the embedded thumbnail is large enough.
if (Math.Max((float)source.Width / (float)size.Width,
(float)source.Height / (float)size.Height) < 1.0f)
{
source.Dispose();
source = null;
}
}
break;
}
}
}
}
}
catch
{
if (source != null)
{
source.Dispose();
}
source = null;
}
}
// Fix for the missing semicolon in GIF files
MemoryStream streamCopy = null;
try
{
if (source == null)
{
using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
{
byte[] gifSignature = new byte[4];
stream.Read(gifSignature, 0, 4);
if (Encoding.ASCII.GetString(gifSignature) == "GIF8")
{
stream.Seek(0, SeekOrigin.Begin);
streamCopy = new MemoryStream();
byte[] buffer = new byte[32768];
int read = 0;
while ((read = stream.Read(buffer, 0, buffer.Length)) > 0)
{
streamCopy.Write(buffer, 0, read);
}
// Append the missing semicolon
streamCopy.Seek(-1, SeekOrigin.End);
if (streamCopy.ReadByte() != 0x3b)
{
streamCopy.WriteByte(0x3b);
}
source = Image.FromStream(streamCopy);
}
}
}
}
catch
{
if (source != null)
{
source.Dispose();
}
source = null;
if (streamCopy != null)
{
streamCopy.Dispose();
}
streamCopy = null;
}
// Revert to source image if an embedded thumbnail of required size
// was not found.
FileStream sourceStream = null;
if (source == null)
{
try
{
sourceStream = new FileStream(filename, FileMode.Open, FileAccess.Read);
source = Image.FromStream(sourceStream);
}
catch
{
if (source != null)
{
source.Dispose();
}
if (sourceStream != null)
{
sourceStream.Dispose();
}
source = null;
sourceStream = null;
}
}
// If all failed, return null.
if (source == null)
{
return(null);
}
// Create the thumbnail
try
{
double scale;
if (rotate % 180 != 0)
{
scale = Math.Min(size.Height / (double)source.Width,
size.Width / (double)source.Height);
}
else
{
scale = Math.Min(size.Width / (double)source.Width,
size.Height / (double)source.Height);
}
thumb = ScaleDownRotateBitmap(source, scale, rotate);
}
catch
{
if (thumb != null)
{
thumb.Dispose();
}
thumb = null;
}
finally
{
if (source != null)
{
source.Dispose();
}
source = null;
if (sourceStream != null)
{
sourceStream.Dispose();
}
sourceStream = null;
if (streamCopy != null)
{
streamCopy.Dispose();
}
streamCopy = null;
}
return(thumb);
}