public static GifHeaderDirectory ProcessBytes(string file)
{
Com.Drew.Metadata.Metadata metadata = new Com.Drew.Metadata.Metadata();
InputStream stream = new FileInputStream(file);
new GifReader().Extract(new Com.Drew.Lang.StreamReader(stream), metadata);
stream.Close();
GifHeaderDirectory directory = metadata.GetDirectory <GifHeaderDirectory>();
NUnit.Framework.Assert.IsNotNull(directory);
return(directory);
}
public virtual void TestPhotoshopGif()
{
GifHeaderDirectory directory = ProcessBytes("Tests/Data/photoshop-8x12-32colors-alpha.gif");
Sharpen.Tests.IsFalse(directory.HasErrors());
Sharpen.Tests.AreEqual("89a", directory.GetString(GifHeaderDirectory.TagGifFormatVersion));
Sharpen.Tests.AreEqual(8, directory.GetInt(GifHeaderDirectory.TagImageWidth));
Sharpen.Tests.AreEqual(12, directory.GetInt(GifHeaderDirectory.TagImageHeight));
Sharpen.Tests.AreEqual(32, directory.GetInt(GifHeaderDirectory.TagColorTableSize));
Sharpen.Tests.IsFalse(directory.GetBoolean(GifHeaderDirectory.TagIsColorTableSorted));
Sharpen.Tests.AreEqual(5, directory.GetInt(GifHeaderDirectory.TagBitsPerPixel));
Sharpen.Tests.IsTrue(directory.GetBoolean(GifHeaderDirectory.TagHasGlobalColorTable));
Sharpen.Tests.AreEqual(8, directory.GetInt(GifHeaderDirectory.TagTransparentColorIndex));
}
public virtual void TestMsPaintGif()
{
GifHeaderDirectory directory = ProcessBytes("Tests/Data/mspaint-10x10.gif");
Sharpen.Tests.IsFalse(directory.HasErrors());
Sharpen.Tests.AreEqual("89a", directory.GetString(GifHeaderDirectory.TagGifFormatVersion));
Sharpen.Tests.AreEqual(10, directory.GetInt(GifHeaderDirectory.TagImageWidth));
Sharpen.Tests.AreEqual(10, directory.GetInt(GifHeaderDirectory.TagImageHeight));
Sharpen.Tests.AreEqual(256, directory.GetInt(GifHeaderDirectory.TagColorTableSize));
Sharpen.Tests.IsFalse(directory.GetBoolean(GifHeaderDirectory.TagIsColorTableSorted));
Sharpen.Tests.AreEqual(8, directory.GetInt(GifHeaderDirectory.TagBitsPerPixel));
Sharpen.Tests.IsTrue(directory.GetBoolean(GifHeaderDirectory.TagHasGlobalColorTable));
Sharpen.Tests.AreEqual(0, directory.GetInt(GifHeaderDirectory.TagTransparentColorIndex));
}
public virtual void Extract([NotNull] SequentialReader reader, [NotNull] Com.Drew.Metadata.Metadata metadata)
{
GifHeaderDirectory directory = new GifHeaderDirectory();
metadata.AddDirectory(directory);
// FILE HEADER
//
// 3 - signature: "GIF"
// 3 - version: either "87a" or "89a"
//
// LOGICAL SCREEN DESCRIPTOR
//
// 2 - pixel width
// 2 - pixel height
// 1 - screen and color map information flags (0 is LSB)
// 0-2 Size of the global color table
// 3 Color table sort flag (89a only)
// 4-6 Color resolution
// 7 Global color table flag
// 1 - background color index
// 1 - pixel aspect ratio
reader.SetMotorolaByteOrder(false);
try
{
string signature = reader.GetString(3);
if (!signature.Equals("GIF"))
{
directory.AddError("Invalid GIF file signature");
return;
}
string version = reader.GetString(3);
if (!version.Equals(Gif87aVersionIdentifier) && !version.Equals(Gif89aVersionIdentifier))
{
directory.AddError("Unexpected GIF version");
return;
}
directory.SetString(GifHeaderDirectory.TagGifFormatVersion, version);
directory.SetInt(GifHeaderDirectory.TagImageWidth, reader.GetUInt16());
directory.SetInt(GifHeaderDirectory.TagImageHeight, reader.GetUInt16());
short flags = reader.GetUInt8();
// First three bits = (BPP - 1)
int colorTableSize = 1 << ((flags & 7) + 1);
directory.SetInt(GifHeaderDirectory.TagColorTableSize, colorTableSize);
if (version.Equals(Gif89aVersionIdentifier))
{
bool isColorTableSorted = (flags & 8) != 0;
directory.SetBoolean(GifHeaderDirectory.TagIsColorTableSorted, isColorTableSorted);
}
int bitsPerPixel = ((flags & unchecked ((int)(0x70))) >> 4) + 1;
directory.SetInt(GifHeaderDirectory.TagBitsPerPixel, bitsPerPixel);
bool hasGlobalColorTable = (flags & unchecked ((int)(0xf))) != 0;
directory.SetBoolean(GifHeaderDirectory.TagHasGlobalColorTable, hasGlobalColorTable);
directory.SetInt(GifHeaderDirectory.TagTransparentColorIndex, reader.GetUInt8());
int aspectRatioByte = reader.GetUInt8();
if (aspectRatioByte != 0)
{
float pixelAspectRatio = (float)((aspectRatioByte + 15d) / 64d);
directory.SetFloat(GifHeaderDirectory.TagPixelAspectRatio, pixelAspectRatio);
}
}
catch (IOException)
{
directory.AddError("Unable to read BMP header");
}
}
public virtual void Extract([NotNull] SequentialReader reader, [NotNull] Com.Drew.Metadata.Metadata metadata)
{
GifHeaderDirectory directory = new GifHeaderDirectory();
metadata.AddDirectory(directory);
// FILE HEADER
//
// 3 - signature: "GIF"
// 3 - version: either "87a" or "89a"
//
// LOGICAL SCREEN DESCRIPTOR
//
// 2 - pixel width
// 2 - pixel height
// 1 - screen and color map information flags (0 is LSB)
// 0-2 Size of the global color table
// 3 Color table sort flag (89a only)
// 4-6 Color resolution
// 7 Global color table flag
// 1 - background color index
// 1 - pixel aspect ratio
reader.SetMotorolaByteOrder(false);
try
{
string signature = reader.GetString(3);
if (!signature.Equals("GIF"))
{
directory.AddError("Invalid GIF file signature");
return;
}
string version = reader.GetString(3);
if (!version.Equals(Gif87aVersionIdentifier) && !version.Equals(Gif89aVersionIdentifier))
{
directory.AddError("Unexpected GIF version");
return;
}
directory.SetString(GifHeaderDirectory.TagGifFormatVersion, version);
directory.SetInt(GifHeaderDirectory.TagImageWidth, reader.GetUInt16());
directory.SetInt(GifHeaderDirectory.TagImageHeight, reader.GetUInt16());
short flags = reader.GetUInt8();
// First three bits = (BPP - 1)
int colorTableSize = 1 << ((flags & 7) + 1);
directory.SetInt(GifHeaderDirectory.TagColorTableSize, colorTableSize);
if (version.Equals(Gif89aVersionIdentifier))
{
bool isColorTableSorted = (flags & 8) != 0;
directory.SetBoolean(GifHeaderDirectory.TagIsColorTableSorted, isColorTableSorted);
}
int bitsPerPixel = ((flags & unchecked((int)(0x70))) >> 4) + 1;
directory.SetInt(GifHeaderDirectory.TagBitsPerPixel, bitsPerPixel);
bool hasGlobalColorTable = (flags & unchecked((int)(0xf))) != 0;
directory.SetBoolean(GifHeaderDirectory.TagHasGlobalColorTable, hasGlobalColorTable);
directory.SetInt(GifHeaderDirectory.TagTransparentColorIndex, reader.GetUInt8());
int aspectRatioByte = reader.GetUInt8();
if (aspectRatioByte != 0)
{
float pixelAspectRatio = (float)((aspectRatioByte + 15d) / 64d);
directory.SetFloat(GifHeaderDirectory.TagPixelAspectRatio, pixelAspectRatio);
}
}
catch (IOException)
{
directory.AddError("Unable to read BMP header");
}
}
