private static Document GetOrientedDocument(byte[] bytes, out ExifValueCollection exifMetadata)
{
exifMetadata = null;
Document doc = null;
// Load the image into a Bitmap so the EXIF orientation transform can be applied.
using (Bitmap image = WebPFile.Load(bytes))
{
byte[] exifBytes = WebPFile.GetExifBytes(bytes);
if (exifBytes != null)
{
exifMetadata = ExifParser.Parse(exifBytes);
if (exifMetadata.Count > 0)
{
MetadataEntry orientationProperty = exifMetadata.GetAndRemoveValue(MetadataKeys.Image.Orientation);
if (orientationProperty != null)
{
RotateFlipType transform = MetadataHelpers.GetOrientationTransform(orientationProperty);
if (transform != RotateFlipType.RotateNoneFlipNone)
{
image.RotateFlip(transform);
}
}
MetadataEntry xResProperty = exifMetadata.GetAndRemoveValue(MetadataKeys.Image.XResolution);
MetadataEntry yResProperty = exifMetadata.GetAndRemoveValue(MetadataKeys.Image.YResolution);
MetadataEntry resUnitProperty = exifMetadata.GetAndRemoveValue(MetadataKeys.Image.ResolutionUnit);
if (xResProperty != null && yResProperty != null && resUnitProperty != null)
{
if (MetadataHelpers.TryDecodeRational(xResProperty, out double xRes) &&
MetadataHelpers.TryDecodeRational(yResProperty, out double yRes) &&
MetadataHelpers.TryDecodeShort(resUnitProperty, out ushort resUnit))
{
if (xRes > 0.0 && yRes > 0.0)
{
double dpiX, dpiY;
switch ((MeasurementUnit)resUnit)
{
case MeasurementUnit.Centimeter:
dpiX = Document.DotsPerCmToDotsPerInch(xRes);
dpiY = Document.DotsPerCmToDotsPerInch(yRes);
break;
case MeasurementUnit.Inch:
dpiX = xRes;
dpiY = yRes;
break;
default:
// Unknown ResolutionUnit value.
dpiX = 0.0;
dpiY = 0.0;
break;
}
if (dpiX > 0.0 && dpiY > 0.0)
{
try
{
image.SetResolution((float)dpiX, (float)dpiY);
}
catch
{
// Ignore any errors when setting the resolution.
}
}
}
}
}
}
}
doc = Document.FromGdipImage(image);
}
return(doc);
}