public void BlockTerminatorTest()
{
ReportStart();
byte[] bytes = new byte[]
{
0x08, // LZW minimum code size
0x05, // block size = 5
// 5 bytes of LZW encoded data follows
0x00, 0x51, 0xFC, 0x1B, 0x28,
0x06, // block size = 6
// 6 bytes of LZW encoded data follows
0x70, 0xA0, 0xC1, 0x83, 0x01, 0x01,
0x00, // block terminator - end of table based image data
};
MemoryStream s = new MemoryStream();
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
int pixelCount = WikipediaExample.FrameSize.Width
* WikipediaExample.FrameSize.Height;
_tbid = new TableBasedImageData( s, pixelCount );
Assert.AreEqual( ErrorState.Ok, _tbid.ConsolidatedState );
Assert.AreEqual( 15, _tbid.Pixels.Count );
Assert.AreEqual( ErrorState.Ok, _tbid.ConsolidatedState );
Assert.AreEqual( 8, _tbid.LzwMinimumCodeSize );
Assert.AreEqual( 9, _tbid.InitialCodeSize );
Assert.AreEqual( Math.Pow( 2, 8 ), _tbid.ClearCode );
Assert.AreEqual( Math.Pow( 2, 8 ) + 1, _tbid.EndOfInformation );
IndexedPixels expectedIndices = new IndexedPixels();
expectedIndices.Add( 40 ); // first pixel is black - index 0 in colour table
expectedIndices.Add( 255 ); // 2nd pixel is white - index 255 in colour table
expectedIndices.Add( 255 ); // 3rd pixel
expectedIndices.Add( 255 ); // 4th pixel
expectedIndices.Add( 40 ); // 5th pixel
expectedIndices.Add( 255 ); // 6th pixel
expectedIndices.Add( 255 ); // 7th pixel
expectedIndices.Add( 255 ); // 8th pixel
expectedIndices.Add( 255 ); // 9th pixel
expectedIndices.Add( 255 ); // 10th pixel
expectedIndices.Add( 255 ); // 11th pixel
expectedIndices.Add( 255 ); // 12th pixel
expectedIndices.Add( 255 ); // 13th pixel
expectedIndices.Add( 255 ); // 14th pixel
expectedIndices.Add( 255 ); // 15th pixel
for( int i = 0; i < 15; i++ )
{
Assert.AreEqual( expectedIndices[i], _tbid.Pixels[i], "pixel " + i );
}
ReportEnd();
}
public GifFrame( Stream inputStream,
LogicalScreenDescriptor lsd,
ColourTable gct,
GraphicControlExtension gce,
GifFrame previousFrame,
GifFrame previousFrameBut1,
bool xmlDebugging )
: base( xmlDebugging )
{
#region guard against null arguments
if( lsd == null )
{
throw new ArgumentNullException( "lsd" );
}
if( gce == null )
{
SetStatus( ErrorState.NoGraphicControlExtension, "" );
// use a default GCE
gce = new GraphicControlExtension( GraphicControlExtension.ExpectedBlockSize,
DisposalMethod.NotSpecified,
false,
false,
100,
0 );
}
#endregion
int transparentColourIndex = gce.TransparentColourIndex;
ImageDescriptor imageDescriptor = new ImageDescriptor( inputStream,
XmlDebugging );
WriteDebugXmlNode( imageDescriptor.DebugXmlReader );
#region determine the colour table to use for this frame
Color backgroundColour = Color.FromArgb( 0 ); // TODO: is this the right background colour?
// TODO: use backgroundColourIndex from the logical screen descriptor?
ColourTable activeColourTable;
if( imageDescriptor.HasLocalColourTable )
{
_localColourTable
= new ColourTable( inputStream,
imageDescriptor.LocalColourTableSize,
XmlDebugging );
WriteDebugXmlNode( _localColourTable.DebugXmlReader );
activeColourTable = _localColourTable; // make local table active
}
else
{
if( gct == null )
{
// We have neither local nor global colour table, so we
// won't be able to decode this frame.
Bitmap emptyBitmap = new Bitmap( lsd.LogicalScreenSize.Width,
lsd.LogicalScreenSize.Height );
_image = emptyBitmap;
_delay = gce.DelayTime;
SetStatus( ErrorState.FrameHasNoColourTable, "" );
return;
}
activeColourTable = gct; // make global table active
if( lsd.BackgroundColourIndex == transparentColourIndex )
{
backgroundColour = Color.FromArgb( 0 );
}
}
#endregion
// decode pixel data
int pixelCount = imageDescriptor.Size.Width * imageDescriptor.Size.Height;
TableBasedImageData indexedPixels
= new TableBasedImageData( inputStream, pixelCount, XmlDebugging );
WriteDebugXmlNode( indexedPixels.DebugXmlReader );
if( indexedPixels.Pixels.Count == 0 )
{
// TESTME: constructor - indexedPixels.Pixels.Count == 0
Bitmap emptyBitmap = new Bitmap( lsd.LogicalScreenSize.Width,
lsd.LogicalScreenSize.Height );
_image = emptyBitmap;
_delay = gce.DelayTime;
SetStatus( ErrorState.FrameHasNoImageData, "" );
WriteDebugXmlFinish();
return;
}
// Skip any remaining blocks up to the next block terminator (in
// case there is any surplus data before the next frame)
SkipBlocks( inputStream );
_indexedPixels = indexedPixels;
_extension = gce;
if( gce != null )
{
_delay = gce.DelayTime;
}
_imageDescriptor = imageDescriptor;
_backgroundColour = backgroundColour;
GifComponentStatus status;
_image = CreateBitmap( indexedPixels,
lsd,
imageDescriptor,
activeColourTable,
gce,
previousFrame,
previousFrameBut1,
out status );
WriteDebugXmlFinish();
}
private void MinimumCodeSizeTooLarge( bool xmlDebugging )
{
byte[] bytes = new byte[]
{
12, // LZW minimum code size
};
MemoryStream s = new MemoryStream();
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
_tbid = new TableBasedImageData( s, 25, xmlDebugging );
// Processing will be abandoned before any pixels are set
Assert.AreEqual( ErrorState.LzwMinimumCodeSizeTooLarge,
_tbid.ConsolidatedState );
// TBID will still return the number of pixels passed to the constructor
Assert.AreEqual( 25, _tbid.Pixels.Count );
Assert.AreEqual( 12, _tbid.LzwMinimumCodeSize );
Assert.AreEqual( 13, _tbid.InitialCodeSize );
Assert.AreEqual( Math.Pow( 2, 12 ), _tbid.ClearCode );
Assert.AreEqual( Math.Pow( 2, 12 ) + 1, _tbid.EndOfInformation );
if( xmlDebugging )
{
Assert.AreEqual( ExpectedDebugXml, _tbid.DebugXml );
}
}
private void MissingPixels( bool xmlDebugging )
{
byte[] bytes = WikipediaExample.ImageDataBytes;
MemoryStream s = new MemoryStream();
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
// The stream contains 15 pixels, this image size implies 18 pixels
_tbid = new TableBasedImageData( s, 18, xmlDebugging );
Assert.AreEqual( 18, _tbid.Pixels.Count );
Assert.AreEqual( ErrorState.TooFewPixelsInImageData, _tbid.ConsolidatedState );
Assert.AreEqual( 8, _tbid.LzwMinimumCodeSize );
Assert.AreEqual( 9, _tbid.InitialCodeSize );
Assert.AreEqual( Math.Pow( 2, 8 ), _tbid.ClearCode );
Assert.AreEqual( Math.Pow( 2, 8 ) + 1, _tbid.EndOfInformation );
IndexedPixels expectedIndices = new IndexedPixels();
expectedIndices.Add( 0 ); // first pixel is black - index 0 in colour table
expectedIndices.Add( 1 ); // 2nd pixel is white - index 1 in colour table
expectedIndices.Add( 1 ); // 3rd pixel
expectedIndices.Add( 1 ); // 4th pixel
expectedIndices.Add( 0 ); // 5th pixel
expectedIndices.Add( 1 ); // 6th pixel
expectedIndices.Add( 1 ); // 7th pixel
expectedIndices.Add( 1 ); // 8th pixel
expectedIndices.Add( 1 ); // 9th pixel
expectedIndices.Add( 1 ); // 10th pixel
expectedIndices.Add( 1 ); // 11th pixel
expectedIndices.Add( 1 ); // 12th pixel
expectedIndices.Add( 1 ); // 13th pixel
expectedIndices.Add( 1 ); // 14th pixel
expectedIndices.Add( 1 ); // 15th pixel
expectedIndices.Add( 0 ); // 16th pixel
expectedIndices.Add( 0 ); // 17th pixel
expectedIndices.Add( 0 ); // 18th pixel
for( int i = 0; i < 18; i++ )
{
Assert.AreEqual( expectedIndices[i], _tbid.Pixels[i], "pixel " + i );
}
}
private void DataBlockTooShort( bool xmlDebugging )
{
byte[] bytes = new byte[]
{
0x08, // LZW minimum code size
0x0b, // block size = 11
// 11 bytes of LZW encoded data follows (actually there's only 10 for this test)
0x00, 0x51, 0xFC, 0x1B, 0x28, 0x70, 0xA0, 0xC1, 0x83, 0x01, //0x01,
// 0x00 // block terminator
};
MemoryStream s = new MemoryStream();
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
int pixelCount = WikipediaExample.FrameSize.Width
* WikipediaExample.FrameSize.Height;
_tbid = new TableBasedImageData( s, pixelCount, xmlDebugging );
Assert.AreEqual( 15, _tbid.Pixels.Count );
Assert.AreEqual( ErrorState.DataBlockTooShort | ErrorState.TooFewPixelsInImageData, _tbid.ConsolidatedState );
Assert.AreEqual( 8, _tbid.LzwMinimumCodeSize );
Assert.AreEqual( 9, _tbid.InitialCodeSize );
Assert.AreEqual( Math.Pow( 2, 8 ), _tbid.ClearCode );
Assert.AreEqual( Math.Pow( 2, 8 ) + 1, _tbid.EndOfInformation );
IndexedPixels expectedIndices = new IndexedPixels();
expectedIndices.Add( 0 ); // first pixel
expectedIndices.Add( 0 ); // 2nd pixel
expectedIndices.Add( 0 ); // 3rd pixel
expectedIndices.Add( 0 ); // 4th pixel
expectedIndices.Add( 0 ); // 5th pixel
expectedIndices.Add( 0 ); // 6th pixel
expectedIndices.Add( 0 ); // 7th pixel
expectedIndices.Add( 0 ); // 8th pixel
expectedIndices.Add( 0 ); // 9th pixel
expectedIndices.Add( 0 ); // 10th pixel
expectedIndices.Add( 0 ); // 11th pixel
expectedIndices.Add( 0 ); // 12th pixel
expectedIndices.Add( 0 ); // 13th pixel
expectedIndices.Add( 0 ); // 14th pixel
expectedIndices.Add( 0 ); // 15th pixel
for( int i = 0; i < 15; i++ )
{
Assert.AreEqual( expectedIndices[i], _tbid.Pixels[i], "pixel " + i );
}
if( xmlDebugging )
{
Assert.AreEqual( ExpectedDebugXml, _tbid.DebugXml );
}
}
private void EmptyDataBlock( bool xmlDebugging )
{
MemoryStream s = new MemoryStream();
s.WriteByte( 8 ); // write a valid LZW min code size
s.WriteByte( 0 );
s.WriteByte( 0 );
s.Seek( 0, SeekOrigin.Begin );
_tbid = new TableBasedImageData( s, 100, xmlDebugging );
Assert.AreEqual( ErrorState.TooFewPixelsInImageData,
_tbid.ConsolidatedState );
if( xmlDebugging )
{
Assert.AreEqual( ExpectedDebugXml, _tbid.DebugXml );
}
}
private void CodeNotInDictionary( bool xmlDebugging )
{
byte[] bytes = WikipediaExample.ImageDataBytes;
bytes[4] = 0xFF; // put an unexpected code into the stream
MemoryStream s = new MemoryStream();
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
int pixelCount = WikipediaExample.FrameSize.Width
* WikipediaExample.FrameSize.Height;
_tbid = new TableBasedImageData( s, pixelCount, xmlDebugging );
Assert.IsTrue( _tbid.TestState( ErrorState.CodeNotInDictionary ) );
Assert.AreEqual( 15, _tbid.Pixels.Count );
Assert.AreEqual( 8, _tbid.LzwMinimumCodeSize );
Assert.AreEqual( 9, _tbid.InitialCodeSize );
Assert.AreEqual( Math.Pow( 2, 8 ), _tbid.ClearCode );
Assert.AreEqual( Math.Pow( 2, 8 ) + 1, _tbid.EndOfInformation );
IndexedPixels expectedIndices = new IndexedPixels();
// Check all the pixels have been zero-filled
expectedIndices.Add( 0 ); // first pixel
expectedIndices.Add( 0 ); // 2nd pixel
expectedIndices.Add( 0 ); // 3rd pixel
expectedIndices.Add( 0 ); // 4th pixel
expectedIndices.Add( 0 ); // 5th pixel
expectedIndices.Add( 0 ); // 6th pixel
expectedIndices.Add( 0 ); // 7th pixel
expectedIndices.Add( 0 ); // 8th pixel
expectedIndices.Add( 0 ); // 9th pixel
expectedIndices.Add( 0 ); // 10th pixel
expectedIndices.Add( 0 ); // 11th pixel
expectedIndices.Add( 0 ); // 12th pixel
expectedIndices.Add( 0 ); // 13th pixel
expectedIndices.Add( 0 ); // 14th pixel
expectedIndices.Add( 0 ); // 15th pixel
for( int i = 0; i < 15; i++ )
{
Assert.AreEqual( expectedIndices[i], _tbid.Pixels[i], "pixel " + i );
}
if( xmlDebugging )
{
Assert.AreEqual( ExpectedDebugXml, _tbid.DebugXml );
}
}
public GifFrame(Stream inputStream,
LogicalScreenDescriptor lsd,
ColourTable gct,
GraphicControlExtension gce,
GifFrame previousFrame,
GifFrame previousFrameBut1,
bool xmlDebugging)
: base(xmlDebugging)
{
#region guard against null arguments
if (lsd == null)
{
throw new ArgumentNullException("lsd");
}
if (gce == null)
{
SetStatus(ErrorState.NoGraphicControlExtension, "");
// use a default GCE
gce = new GraphicControlExtension(GraphicControlExtension.ExpectedBlockSize,
DisposalMethod.NotSpecified,
false,
false,
100,
0);
}
#endregion
int transparentColourIndex = gce.TransparentColourIndex;
ImageDescriptor imageDescriptor = new ImageDescriptor(inputStream,
XmlDebugging);
WriteDebugXmlNode(imageDescriptor.DebugXmlReader);
#region determine the colour table to use for this frame
Color backgroundColour = Color.FromArgb(0); // TODO: is this the right background colour?
// TODO: use backgroundColourIndex from the logical screen descriptor?
ColourTable activeColourTable;
if (imageDescriptor.HasLocalColourTable)
{
_localColourTable
= new ColourTable(inputStream,
imageDescriptor.LocalColourTableSize,
XmlDebugging);
WriteDebugXmlNode(_localColourTable.DebugXmlReader);
activeColourTable = _localColourTable; // make local table active
}
else
{
if (gct == null)
{
// We have neither local nor global colour table, so we
// won't be able to decode this frame.
Bitmap emptyBitmap = new Bitmap(lsd.LogicalScreenSize.Width,
lsd.LogicalScreenSize.Height);
_image = emptyBitmap;
_delay = gce.DelayTime;
SetStatus(ErrorState.FrameHasNoColourTable, "");
return;
}
activeColourTable = gct; // make global table active
if (lsd.BackgroundColourIndex == transparentColourIndex)
{
backgroundColour = Color.FromArgb(0);
}
}
#endregion
// decode pixel data
int pixelCount = imageDescriptor.Size.Width * imageDescriptor.Size.Height;
TableBasedImageData indexedPixels
= new TableBasedImageData(inputStream, pixelCount, XmlDebugging);
WriteDebugXmlNode(indexedPixels.DebugXmlReader);
if (indexedPixels.Pixels.Count == 0)
{
// TESTME: constructor - indexedPixels.Pixels.Count == 0
Bitmap emptyBitmap = new Bitmap(lsd.LogicalScreenSize.Width,
lsd.LogicalScreenSize.Height);
_image = emptyBitmap;
_delay = gce.DelayTime;
SetStatus(ErrorState.FrameHasNoImageData, "");
WriteDebugXmlFinish();
return;
}
// Skip any remaining blocks up to the next block terminator (in
// case there is any surplus data before the next frame)
SkipBlocks(inputStream);
_indexedPixels = indexedPixels;
_extension = gce;
if (gce != null)
{
_delay = gce.DelayTime;
}
_imageDescriptor = imageDescriptor;
_backgroundColour = backgroundColour;
GifComponentStatus status;
_image = CreateBitmap(indexedPixels,
lsd,
imageDescriptor,
activeColourTable,
gce,
previousFrame,
previousFrameBut1,
out status);
WriteDebugXmlFinish();
}
public void HandleRubbish()
{
ReportStart();
string[] files = Directory.GetFiles( Directory.GetCurrentDirectory() );
foreach( string file in files )
{
byte[] bytes = File.ReadAllBytes( file );
MemoryStream s = new MemoryStream();
s.WriteByte( 8 ); // write a valid LZW min code size
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
try
{
_tbid = new TableBasedImageData( s, 1000000 );
}
catch( Exception ex )
{
throw new InvalidOperationException( file + ": ", ex );
}
}
ReportEnd();
}
public void PixelCountTooSmall()
{
ReportStart();
int pixelCount = 0;
try
{
_tbid = new TableBasedImageData( new MemoryStream(), pixelCount );
}
catch( ArgumentOutOfRangeException ex )
{
string message
= "The pixel count must be greater than zero. "
+ "Supplied value was " + pixelCount;
StringAssert.Contains( message, ex.Message );
Assert.AreEqual( "pixelCount", ex.ParamName );
ReportEnd();
throw;
}
}
private static void CheckImageData( Stream s,
ColourTable act,
ImageDescriptor id,
Bitmap expectedBitmap)
{
// read, decode and check image data
// Cannot compare encoded LZW data directly as different encoders
// will create different colour tables, so even if the bitmaps are
// identical, the colour indices will be different
int pixelCount = id.Size.Width * id.Size.Height;
TableBasedImageData tbid = new TableBasedImageData( s, pixelCount );
Assert.AreEqual( ErrorState.Ok, tbid.ConsolidatedState );
for( int y = 0; y < id.Size.Height; y++ )
{
for( int x = 0; x < id.Size.Width; x++ )
{
int i = (y * id.Size.Width) + x;
Assert.AreEqual( expectedBitmap.GetPixel( x, y ),
act[tbid.Pixels[i]],
"X: " + x + ", Y: " + y );
}
}
}
public void WikipediaExampleTest()
{
ReportStart();
_e = new AnimatedGifEncoder();
GifFrame frame = new GifFrame( WikipediaExample.ExpectedBitmap );
frame.Delay = WikipediaExample.DelayTime;
_e.AddFrame( frame );
// TODO: some way of creating/testing a UseLocal version of WikipediaExample
string fileName = "WikipediaExampleUseGlobal.gif";
_e.WriteToFile( fileName );
Stream s = File.OpenRead( fileName );
int code;
// check GIF header
GifHeader gh = new GifHeader( s );
Assert.AreEqual( ErrorState.Ok, gh.ConsolidatedState );
// check logical screen descriptor
LogicalScreenDescriptor lsd = new LogicalScreenDescriptor( s );
Assert.AreEqual( ErrorState.Ok, lsd.ConsolidatedState );
WikipediaExample.CheckLogicalScreenDescriptor( lsd );
// read global colour table
ColourTable gct
= new ColourTable( s, WikipediaExample.GlobalColourTableSize );
Assert.AreEqual( ErrorState.Ok, gct.ConsolidatedState );
// cannot compare global colour table as different encoders will
// produce difference colour tables.
// WikipediaExample.CheckGlobalColourTable( gct );
// check for extension introducer
code = ExampleComponent.CallRead( s );
Assert.AreEqual( GifComponent.CodeExtensionIntroducer, code );
// check for app extension label
code = ExampleComponent.CallRead( s );
Assert.AreEqual( GifComponent.CodeApplicationExtensionLabel, code );
// check netscape extension
ApplicationExtension ae = new ApplicationExtension( s );
Assert.AreEqual( ErrorState.Ok, ae.ConsolidatedState );
NetscapeExtension ne = new NetscapeExtension( ae );
Assert.AreEqual( ErrorState.Ok, ne.ConsolidatedState );
Assert.AreEqual( 0, ne.LoopCount );
// check for extension introducer
code = ExampleComponent.CallRead( s );
Assert.AreEqual( GifComponent.CodeExtensionIntroducer, code );
// check for gce label
code = ExampleComponent.CallRead( s );
Assert.AreEqual( GifComponent.CodeGraphicControlLabel, code );
// check graphic control extension
GraphicControlExtension gce = new GraphicControlExtension( s );
Assert.AreEqual( ErrorState.Ok, gce.ConsolidatedState );
WikipediaExample.CheckGraphicControlExtension( gce );
// check for image separator
code = ExampleComponent.CallRead( s );
Assert.AreEqual( GifComponent.CodeImageSeparator, code );
// check for image descriptor
ImageDescriptor id = new ImageDescriptor( s );
Assert.AreEqual( ErrorState.Ok, id.ConsolidatedState );
WikipediaExample.CheckImageDescriptor( id );
// read, decode and check image data
// Cannot compare encoded LZW data directly as different encoders
// will create different colour tables, so even if the bitmaps are
// identical, the colour indices will be different
int pixelCount = WikipediaExample.FrameSize.Width
* WikipediaExample.FrameSize.Height;
TableBasedImageData tbid = new TableBasedImageData( s, pixelCount );
for( int y = 0; y < WikipediaExample.LogicalScreenSize.Height; y++ )
{
for( int x = 0; x < WikipediaExample.LogicalScreenSize.Width; x++ )
{
int i = (y * WikipediaExample.LogicalScreenSize.Width) + x;
Assert.AreEqual( WikipediaExample.ExpectedBitmap.GetPixel( x, y ),
gct[tbid.Pixels[i]],
"X: " + x + ", Y: " + y );
}
}
// Check for block terminator after image data
code = ExampleComponent.CallRead( s );
Assert.AreEqual( 0x00, code );
// check for GIF trailer
code = ExampleComponent.CallRead( s );
Assert.AreEqual( GifComponent.CodeTrailer, code );
// check we're at the end of the stream
code = ExampleComponent.CallRead( s );
Assert.AreEqual( -1, code );
s.Close();
_d = new GifDecoder( fileName );
_d.Decode();
Assert.AreEqual( ErrorState.Ok, _d.ConsolidatedState );
BitmapAssert.AreEqual( WikipediaExample.ExpectedBitmap,
(Bitmap) _d.Frames[0].TheImage,
"" );
ReportEnd();
}
/// <summary>
/// Sets the pixels of the decoded image.
/// </summary>
/// <param name="imageData">
/// Table based image data containing the indices within the active
/// colour table of the colours of the pixels in this frame.
/// </param>
/// <param name="lsd">
/// The logical screen descriptor for the GIF stream.
/// </param>
/// <param name="id">
/// The image descriptor for this frame.
/// </param>
/// <param name="activeColourTable">
/// The colour table to use with this frame - either the global colour
/// table or a local colour table.
/// </param>
/// <param name="gce">
/// The graphic control extension, if any, which precedes this image in
/// the input stream.
/// </param>
/// <param name="previousFrame">
/// The frame which precedes this one in the GIF stream, if present.
/// </param>
/// <param name="previousFrameBut1">
/// The frame which precedes the frame before this one in the GIF stream,
/// if present.
/// </param>
/// <param name="status">
/// GifComponentStatus containing any errors which occurred during the
/// creation of the bitmap.
/// </param>
private static Bitmap CreateBitmap(TableBasedImageData imageData,
LogicalScreenDescriptor lsd,
ImageDescriptor id,
ColourTable activeColourTable,
GraphicControlExtension gce,
GifFrame previousFrame,
GifFrame previousFrameBut1,
out GifComponentStatus status)
{
status = new GifComponentStatus(ErrorState.Ok, "");
Color[] pixelsForThisFrame = new Color[lsd.LogicalScreenSize.Width
* lsd.LogicalScreenSize.Height];
Bitmap baseImage = GetBaseImage(previousFrame,
previousFrameBut1,
lsd,
gce,
activeColourTable);
// copy each source line to the appropriate place in the destination
int pass = 1;
int interlaceRowIncrement = 8;
int interlaceRowNumber = 0; // the row of pixels we're currently
// setting in an interlaced image.
for (int i = 0; i < id.Size.Height; i++)
{
int pixelRowNumber = i;
if (id.IsInterlaced)
{
#region work out the pixel row we're setting for an interlaced image
if (interlaceRowNumber >= id.Size.Height)
{
pass++;
switch (pass)
{
case 2:
interlaceRowNumber = 4;
break;
case 3:
interlaceRowNumber = 2;
interlaceRowIncrement = 4;
break;
case 4:
interlaceRowNumber = 1;
interlaceRowIncrement = 2;
break;
}
}
#endregion
pixelRowNumber = interlaceRowNumber;
interlaceRowNumber += interlaceRowIncrement;
}
// Colour in the pixels for this row
pixelRowNumber += id.Position.Y;
if (pixelRowNumber < lsd.LogicalScreenSize.Height)
{
int k = pixelRowNumber * lsd.LogicalScreenSize.Width;
int dx = k + id.Position.X; // start of line in dest
int dlim = dx + id.Size.Width; // end of dest line
if ((k + lsd.LogicalScreenSize.Width) < dlim)
{
// TESTME: CreateBitmap - past dest edge
dlim = k + lsd.LogicalScreenSize.Width; // past dest edge
}
int sx = i * id.Size.Width; // start of line in source
while (dx < dlim)
{
// map color and insert in destination
int indexInColourTable = (int)imageData.Pixels[sx++];
// Set this pixel's colour if its index isn't the
// transparent colour index, or if this frame doesn't
// have a transparent colour.
Color c;
if (gce.HasTransparentColour && indexInColourTable == gce.TransparentColourIndex)
{
c = Color.Empty; // transparent pixel
}
else
{
if (indexInColourTable < activeColourTable.Length)
{
c = activeColourTable[indexInColourTable];
}
else
{
// TESTME: CreateBitmap - BadColourIndex
c = Color.Black;
string message
= "Colour index: "
+ indexInColourTable
+ ", colour table length: "
+ activeColourTable.Length
+ " (" + dx + "," + pixelRowNumber + ")";
status = new GifComponentStatus(ErrorState.BadColourIndex,
message);
}
}
pixelsForThisFrame[dx] = c;
dx++;
}
}
}
return(CreateBitmap(baseImage, pixelsForThisFrame));
}
/// <summary>
/// Sets the pixels of the decoded image.
/// </summary>
/// <param name="imageData">
/// Table based image data containing the indices within the active
/// colour table of the colours of the pixels in this frame.
/// </param>
/// <param name="lsd">
/// The logical screen descriptor for the GIF stream.
/// </param>
/// <param name="id">
/// The image descriptor for this frame.
/// </param>
/// <param name="activeColourTable">
/// The colour table to use with this frame - either the global colour
/// table or a local colour table.
/// </param>
/// <param name="gce">
/// The graphic control extension, if any, which precedes this image in
/// the input stream.
/// </param>
/// <param name="previousFrame">
/// The frame which precedes this one in the GIF stream, if present.
/// </param>
/// <param name="previousFrameBut1">
/// The frame which precedes the frame before this one in the GIF stream,
/// if present.
/// </param>
/// <param name="status">
/// GifComponentStatus containing any errors which occurred during the
/// creation of the bitmap.
/// </param>
private static Bitmap CreateBitmap( TableBasedImageData imageData,
LogicalScreenDescriptor lsd,
ImageDescriptor id,
ColourTable activeColourTable,
GraphicControlExtension gce,
GifFrame previousFrame,
GifFrame previousFrameBut1,
out GifComponentStatus status )
{
status = new GifComponentStatus( ErrorState.Ok, "" );
Color[] pixelsForThisFrame = new Color[lsd.LogicalScreenSize.Width
* lsd.LogicalScreenSize.Height];
Bitmap baseImage = GetBaseImage( previousFrame,
previousFrameBut1,
lsd,
gce,
activeColourTable );
// copy each source line to the appropriate place in the destination
int pass = 1;
int interlaceRowIncrement = 8;
int interlaceRowNumber = 0; // the row of pixels we're currently
// setting in an interlaced image.
for( int i = 0; i < id.Size.Height; i++)
{
int pixelRowNumber = i;
if( id.IsInterlaced )
{
#region work out the pixel row we're setting for an interlaced image
if( interlaceRowNumber >= id.Size.Height )
{
pass++;
switch( pass )
{
case 2 :
interlaceRowNumber = 4;
break;
case 3 :
interlaceRowNumber = 2;
interlaceRowIncrement = 4;
break;
case 4 :
interlaceRowNumber = 1;
interlaceRowIncrement = 2;
break;
}
}
#endregion
pixelRowNumber = interlaceRowNumber;
interlaceRowNumber += interlaceRowIncrement;
}
// Colour in the pixels for this row
pixelRowNumber += id.Position.Y;
if( pixelRowNumber < lsd.LogicalScreenSize.Height )
{
int k = pixelRowNumber * lsd.LogicalScreenSize.Width;
int dx = k + id.Position.X; // start of line in dest
int dlim = dx + id.Size.Width; // end of dest line
if( (k + lsd.LogicalScreenSize.Width) < dlim )
{
// TESTME: CreateBitmap - past dest edge
dlim = k + lsd.LogicalScreenSize.Width; // past dest edge
}
int sx = i * id.Size.Width; // start of line in source
while (dx < dlim)
{
// map color and insert in destination
int indexInColourTable = (int) imageData.Pixels[sx++];
// Set this pixel's colour if its index isn't the
// transparent colour index, or if this frame doesn't
// have a transparent colour.
Color c;
if( gce.HasTransparentColour && indexInColourTable == gce.TransparentColourIndex )
{
c = Color.Empty; // transparent pixel
}
else
{
if( indexInColourTable < activeColourTable.Length )
{
c = activeColourTable[indexInColourTable];
}
else
{
// TESTME: CreateBitmap - BadColourIndex
c = Color.Black;
string message
= "Colour index: "
+ indexInColourTable
+ ", colour table length: "
+ activeColourTable.Length
+ " (" + dx + "," + pixelRowNumber + ")";
status = new GifComponentStatus( ErrorState.BadColourIndex,
message );
}
}
pixelsForThisFrame[dx] = c;
dx++;
}
}
}
return CreateBitmap( baseImage, pixelsForThisFrame );
}
private void ConstructorTest( bool xmlDebugging )
{
byte[] bytes = WikipediaExample.ImageDataBytes;
MemoryStream s = new MemoryStream();
s.Write( bytes, 0, bytes.Length );
s.Seek( 0, SeekOrigin.Begin );
int pixelCount = WikipediaExample.FrameSize.Width
* WikipediaExample.FrameSize.Height;
_tbid = new TableBasedImageData( s, pixelCount, xmlDebugging );
Assert.AreEqual( ErrorState.Ok, _tbid.ConsolidatedState );
WikipediaExample.CheckImageData( _tbid );
if( xmlDebugging )
{
Assert.AreEqual( ExpectedDebugXml, _tbid.DebugXml );
}
}
internal static void CheckImageData( TableBasedImageData imageData )
{
TableBasedImageData expectedData = ImageData;
Assert.AreEqual( expectedData.ClearCode,
imageData.ClearCode );
Assert.AreEqual( expectedData.DataBlocks.Length,
imageData.DataBlocks.Length );
Assert.AreEqual( expectedData.EndOfInformation,
imageData.EndOfInformation );
Assert.AreEqual( expectedData.InitialCodeSize,
imageData.InitialCodeSize );
Assert.AreEqual( expectedData.LzwMinimumCodeSize,
imageData.LzwMinimumCodeSize );
Assert.AreEqual( expectedData.Pixels.Count,
imageData.Pixels.Count );
string info;
for( int i = 0; i < expectedData.Pixels.Count; i++ )
{
info = "Pixel index: " + i;
Assert.AreEqual( expectedData.Pixels[i],
imageData.Pixels[i],
info );
}
for( int i = 0; i < expectedData.DataBlocks.Length; i++ )
{
info = "Data block number: " + i;
DataBlock expectedBlock = expectedData.DataBlocks[i];
DataBlock actualBlock = imageData.DataBlocks[i];
Assert.AreEqual( expectedBlock.ActualBlockSize,
actualBlock.ActualBlockSize,
info );
Assert.AreEqual( expectedBlock.DeclaredBlockSize,
actualBlock.DeclaredBlockSize,
info );
for( int b = 0; b < expectedBlock.ActualBlockSize; b++ )
{
Assert.AreEqual( expectedBlock.Data[i],
actualBlock.Data[i],
info + ". Block index " + b );
}
}
}
/// <summary>
/// Encodes _ip and decodes the encoded data, then compares the decoded
/// data against the original.
/// Also calculates the compression rate.
/// </summary>
private void TestIt()
{
MemoryStream s = new MemoryStream();
_e = new LzwEncoder( _ip );
_e.Encode( s );
int encodedByteCount = (int) s.Position;
s.Seek( 0, SeekOrigin.Begin );
TableBasedImageData tbid = new TableBasedImageData( s, _ip.Count );
s.Seek( 0, SeekOrigin.Begin );
byte[] encodedBytes = new byte[encodedByteCount];
s.Read( encodedBytes, 0, encodedByteCount );
Assert.AreEqual( _ip.Count, tbid.Pixels.Count, "Pixel counts differ" );
for( int i = 0; i < _ip.Count; i++ )
{
Assert.AreEqual( _ip[i], tbid.Pixels[i], "pixel index " + i );
}
float compression = 100 - (100 * encodedByteCount / _ip.Count);
WriteMessage( "Original byte count: " + _ip.Count
+ ". Encoded byte count: " + encodedByteCount
+ ". Compression rate: " + compression + "%" );
}
