diff options
Diffstat (limited to 'Emby.Drawing/Common/ImageHeader.cs')
| -rw-r--r-- | Emby.Drawing/Common/ImageHeader.cs | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/Emby.Drawing/Common/ImageHeader.cs b/Emby.Drawing/Common/ImageHeader.cs index 7b819c2fd..f37f396f5 100644 --- a/Emby.Drawing/Common/ImageHeader.cs +++ b/Emby.Drawing/Common/ImageHeader.cs @@ -121,7 +121,7 @@ namespace Emby.Drawing.Common /// </summary> /// <param name="binaryReader">The binary reader.</param> /// <returns>System.Int16.</returns> - private static short ReadLittleEndianInt16(BinaryReader binaryReader) + private static short ReadLittleEndianInt16(this BinaryReader binaryReader) { var bytes = new byte[sizeof(short)]; @@ -137,7 +137,7 @@ namespace Emby.Drawing.Common /// </summary> /// <param name="binaryReader">The binary reader.</param> /// <returns>System.Int32.</returns> - private static int ReadLittleEndianInt32(BinaryReader binaryReader) + private static int ReadLittleEndianInt32(this BinaryReader binaryReader) { var bytes = new byte[sizeof(int)]; for (int i = 0; i < sizeof(int); i += 1) @@ -205,25 +205,30 @@ namespace Emby.Drawing.Common /// <exception cref="System.ArgumentException"></exception> private static ImageSize DecodeJfif(BinaryReader binaryReader) { + // A JPEG image consists of a sequence of segments, + // each beginning with a marker, each of which begins with a 0xFF byte + // followed by a byte indicating what kind of marker it is. + // Source: https://en.wikipedia.org/wiki/JPEG#Syntax_and_structure while (binaryReader.ReadByte() == 0xff) { byte marker = binaryReader.ReadByte(); - short chunkLength = ReadLittleEndianInt16(binaryReader); - if (marker == 0xc0) + short chunkLength = binaryReader.ReadLittleEndianInt16(); + // SOF0: Indicates that this is a baseline DCT-based JPEG, + // and specifies the width, height, number of components, and component subsampling + // SOF2: Indicates that this is a progressive DCT-based JPEG, + // and specifies the width, height, number of components, and component subsampling + if (marker == 0xc0 || marker == 0xc2) { - binaryReader.ReadByte(); - int height = ReadLittleEndianInt16(binaryReader); - int width = ReadLittleEndianInt16(binaryReader); - return new ImageSize - { - Width = width, - Height = height - }; + // https://help.accusoft.com/ImageGear/v18.2/Windows/ActiveX/IGAX-10-12.html + binaryReader.ReadByte(); // We don't care about the first byte + int height = binaryReader.ReadLittleEndianInt16(); + int width = binaryReader.ReadLittleEndianInt16(); + return new ImageSize(width, height); } if (chunkLength < 0) { - var uchunkLength = (ushort)chunkLength; + ushort uchunkLength = (ushort)chunkLength; binaryReader.ReadBytes(uchunkLength - 2); } else |