/// <summary>
/// Gets a stream containing the image binary in the specified property (or the default Binary field).
/// Image dimensions can be determined by providing the width and height values among the parameters.
/// The image is also redacted if the user does not have enough permissions to see the full image
/// in case of preview images, only restricted ones.
/// </summary>
/// <param name="propertyName">Name of the binary property to serve, default is Binary.</param>
/// <param name="parameters">Optional parameters that may include image width and height.</param>
/// <param name="contentType">Out parameter, filled with the binary content type to be served to the client.</param>
/// <param name="fileName">Out parameter, filled with the file name to serve to the client.</param>
public Stream GetImageStream(string propertyName, IDictionary <string, object> parameters, out string contentType, out BinaryFileName fileName)
{
Stream imageStream;
object widthParam = null;
object heightParam = null;
parameters?.TryGetValue("width", out widthParam);
parameters?.TryGetValue("height", out heightParam);
var binaryData = !string.IsNullOrEmpty(propertyName) ? GetBinary(propertyName) : Binary;
contentType = binaryData?.ContentType ?? string.Empty;
fileName = string.IsNullOrEmpty(propertyName) || string.CompareOrdinal(propertyName, "Binary") == 0
? new BinaryFileName(Name)
: binaryData?.FileName ?? string.Empty;
if (DocumentPreviewProvider.Current != null && DocumentPreviewProvider.Current.IsPreviewOrThumbnailImage(NodeHead.Get(Id)))
{
// get preview image with watermark or redaction if necessary
imageStream = DocumentPreviewProvider.Current.GetRestrictedImage(this,
new PreviewImageOptions {
BinaryFieldName = propertyName
});
}
else
{
imageStream = binaryData?.GetStream();
}
if (imageStream == null)
{
return(new MemoryStream());
}
imageStream.Position = 0;
int ConvertImageParameter(object param)
{
if (param != null)
{
// we recognize int and string values as well
switch (param)
{
case int i:
return(i);
case string s when int.TryParse(s, out var pint):
return(pint);
}
}
return(200);
}
// no resize parameters: return the original stream
if (widthParam == null || heightParam == null)
{
return(imageStream);
}
var width = ConvertImageParameter(widthParam);
var height = ConvertImageParameter(heightParam);
// compute a new, resized stream on-the-fly
var resizedStream = ImageResizer.CreateResizedImageFile(imageStream, width, height, 80, getImageFormat(contentType));
// in case the method created a new stream, we have to close the original to prevent memory leak
if (!ReferenceEquals(resizedStream, imageStream))
{
imageStream.Dispose();
}
return(resizedStream);
}
