public GifFrame( Stream inputStream,
LogicalScreenDescriptor lsd,
ColourTable gct,
GraphicControlExtension gce,
GifFrame previousFrame,
GifFrame previousFrameBut1 )
: base( inputStream, lsd, gct, gce, previousFrame, previousFrameBut1 )
{}
public GifFrame(Stream inputStream,
LogicalScreenDescriptor lsd,
ColourTable gct,
GraphicControlExtension gce,
GifFrame previousFrame,
GifFrame previousFrameBut1)
: this(inputStream, lsd, gct, gce, previousFrame, previousFrameBut1, false)
{
}
/// <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 );
}
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();
}
/// <summary>
/// Main file parser. Reads GIF content blocks.
/// </summary>
/// <param name="inputStream">
/// Input stream from which the GIF data is to be read.
/// </param>
private void ReadContents( Stream inputStream )
{
// read GIF file content blocks
bool done = false;
GraphicControlExtension lastGce = null;
string message; // for error conditions
while( !done && ConsolidatedState == ErrorState.Ok )
{
int code = Read( inputStream );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
WriteCodeToDebugXml( code );
switch( code )
{
case CodeImageSeparator:
WriteDebugXmlComment( "0x2C - image separator" );
AddFrame( inputStream, lastGce );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
break;
case CodeExtensionIntroducer:
WriteDebugXmlComment( "0x21 - extension introducer" );
code = Read( inputStream );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
WriteCodeToDebugXml( code );
switch( code )
{
case CodePlaintextLabel:
// FEATURE: handle plain text extension
WriteDebugXmlComment( "0x01 - plain text extension" );
SkipBlocks( inputStream );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
break;
case CodeGraphicControlLabel:
WriteDebugXmlComment( "0xF9 - graphic control label" );
lastGce = new GraphicControlExtension( inputStream,
XmlDebugging );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
WriteDebugXmlNode( lastGce.DebugXmlReader );
break;
case CodeCommentLabel:
// FEATURE: handle comment extension
WriteDebugXmlComment( "0xFE - comment extension" );
SkipBlocks( inputStream );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
break;
case CodeApplicationExtensionLabel:
WriteDebugXmlComment( "0xFF - application extension label" );
ApplicationExtension ext
= new ApplicationExtension( inputStream,
XmlDebugging );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
WriteDebugXmlNode( ext.DebugXmlReader );
if( ext.ApplicationIdentifier == "NETSCAPE"
&& ext.ApplicationAuthenticationCode == "2.0" )
{
_netscapeExtension = new NetscapeExtension( ext );
}
else
{
// TESTME: ReadContents - non-Netscape application extension
_applicationExtensions.Add( ext );
}
break;
default : // uninteresting extension
// TESTME: ReadContents - uninteresting extension
WriteDebugXmlComment( "Ignoring this extension" );
SkipBlocks( inputStream );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
break;
}
break;
case CodeTrailer:
// We've reached an explicit end-of-data marker, so stop
// processing the stream.
WriteDebugXmlComment( "0x3B - end of data" );
done = true;
break;
case 0x00 : // bad byte, but keep going and see what happens
WriteDebugXmlComment( "0x00 - unexpected code" );
message
= "Unexpected block terminator encountered at "
+ "position " + inputStream.Position
+ " after reading " + _frames.Count + " frames.";
SetStatus( ErrorState.UnexpectedBlockTerminator,
message );
break;
case -1: // reached the end of the input stream
WriteDebugXmlComment( "-1 - end of input stream" );
message
= "Reached the end of the input stream without "
+ "encountering trailer 0x3b";
SetStatus( ErrorState.EndOfInputStream, message );
break;
default :
WriteDebugXmlComment( "Not a recognised code" );
message
= "Bad data block introducer: 0x"
+ code.ToString( "X", CultureInfo.InvariantCulture ).PadLeft( 2, '0' )
+ " (" + code + ") at position " + inputStream.Position
+ " ("
+ inputStream.Position.ToString( "X",
CultureInfo.InvariantCulture )
+ " hex) after reading "
+ _frames.Count + " frames.";
SetStatus( ErrorState.BadDataBlockIntroducer, message );
break;
}
}
}
/// <summary>
/// Reads a frame from the input stream and adds it to the collection
/// of frames.
/// </summary>
/// <param name="inputStream">
/// Input stream from which the frame is to be read.
/// </param>
/// <param name="lastGce">
/// The graphic control extension most recently read from the input
/// stream.
/// </param>
private void AddFrame( Stream inputStream,
GraphicControlExtension lastGce )
{
GifFrame previousFrame;
GifFrame previousFrameBut1;
if( _frames.Count > 0 )
{
previousFrame = _frames[_frames.Count - 1];
}
else
{
previousFrame = null;
}
if( _frames.Count > 1 )
{
previousFrameBut1 = _frames[_frames.Count - 2];
}
else
{
previousFrameBut1 = null;
}
GifFrame frame = new GifFrame( inputStream,
_lsd,
_gct,
lastGce,
previousFrame,
previousFrameBut1,
XmlDebugging );
MyProgressCounters[_readStreamCounterText].Value
= (int) inputStream.Position;
_frames.Add( frame );
WriteDebugXmlNode( frame.DebugXmlReader );
}
private static void CheckGraphicControlExtension( Stream s,
Color transparentColour)
{
// check graphic control extension
GraphicControlExtension gce = new GraphicControlExtension( s );
Assert.AreEqual( ErrorState.Ok, gce.ConsolidatedState );
Assert.AreEqual( 10, gce.DelayTime );
if( transparentColour == Color.Empty )
{
Assert.AreEqual( 0, gce.TransparentColourIndex );
Assert.AreEqual( false, gce.HasTransparentColour );
Assert.AreEqual( DisposalMethod.DoNotDispose, gce.DisposalMethod );
}
else
{
Assert.AreEqual( true, gce.HasTransparentColour );
// TODO: a way to check the transparent colour index?
Assert.AreEqual( DisposalMethod.RestoreToBackgroundColour,
gce.DisposalMethod );
}
Assert.AreEqual( false, gce.ExpectsUserInput );
}
public void WriteToStreamTest()
{
ReportStart();
int blockSize = 4;
DisposalMethod disposalMethod = DisposalMethod.DoNotDispose;
bool expectsUserInput = false;
bool hasTransparentColour = true;
int delayTime = 10;
int transparentColourIndex = 6;
_gce = new GraphicControlExtension( blockSize,
disposalMethod,
expectsUserInput,
hasTransparentColour,
delayTime,
transparentColourIndex );
MemoryStream s = new MemoryStream();
_gce.WriteToStream( s );
s.Seek( 0, SeekOrigin.Begin );
_gce = new GraphicControlExtension( s );
Assert.AreEqual( ErrorState.Ok, _gce.ConsolidatedState );
Assert.AreEqual( blockSize, _gce.BlockSize );
Assert.AreEqual( disposalMethod, _gce.DisposalMethod );
Assert.AreEqual( expectsUserInput, _gce.ExpectsUserInput );
Assert.AreEqual( hasTransparentColour, _gce.HasTransparentColour );
Assert.AreEqual( delayTime, _gce.DelayTime );
Assert.AreEqual( transparentColourIndex, _gce.TransparentColourIndex );
ReportEnd();
}
/// <summary>
/// Gets the base image for this frame. This will be overpainted with
/// the pixels for this frame, where they are not transparent.
/// </summary>
/// <param name="previousFrame">
/// The frame which preceded this frame in the GIF stream.
/// Null if this is the first frame in the stream.
/// </param>
/// <param name="previousFrameBut1">
/// The frame which preceded the previous frame in the GIF stream.
/// Null if this is the first or seond frame in the stream.
/// </param>
/// <param name="lsd">
/// The logical screen descriptor for this GIF stream.
/// </param>
/// <param name="gce">
/// The graphic control extension for this frame.
/// </param>
/// <param name="act">
/// The active colour table for this frame.
/// </param>
/// <returns></returns>
private static Bitmap GetBaseImage(GifFrame previousFrame,
GifFrame previousFrameBut1,
LogicalScreenDescriptor lsd,
GraphicControlExtension gce,
ColourTable act)
{
#region Get the disposal method of the previous frame read from the GIF stream
DisposalMethod previousDisposalMethod;
if (previousFrame == null)
{
previousDisposalMethod = DisposalMethod.NotSpecified;
}
else
{
previousDisposalMethod = previousFrame.GraphicControlExtension.DisposalMethod;
}
#endregion
Bitmap baseImage;
int width = lsd.LogicalScreenSize.Width;
int height = lsd.LogicalScreenSize.Height;
#region paint baseImage
switch (previousDisposalMethod)
{
case DisposalMethod.DoNotDispose:
// pre-populate image with previous frame
baseImage = new Bitmap(previousFrame.TheImage);
break;
case DisposalMethod.RestoreToBackgroundColour:
// pre-populate image with background colour
Color backgroundColour;
if (lsd.BackgroundColourIndex == gce.TransparentColourIndex)
{
backgroundColour = Color.Empty;
}
else
{
// TESTME: background colour index different to transparent colour
backgroundColour = act[lsd.BackgroundColourIndex];
}
baseImage = new Bitmap(width, height);
for (int y = 0; y < height; y++)
{
for (int x = 0; x < height; x++)
{
baseImage.SetPixel(x, y, backgroundColour);
}
}
break;
case DisposalMethod.RestoreToPrevious:
// pre-populate image with previous frame but 1
// TESTME: DisposalMethod.RestoreToPrevious
baseImage = new Bitmap(previousFrameBut1.TheImage);
break;
default: // DisposalMethod.NotSpecified
if (previousFrame == null)
{
// this is the first frame so start with an empty bitmap
baseImage = new Bitmap(width, height);
}
else
{
// pre-populate image with previous frame
// TESTME: DisposalMethod.NotSpecified on 2nd frame or later
baseImage = new Bitmap(previousFrame.TheImage);
}
break;
}
#endregion
return(baseImage);
}
/// <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));
}
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 ConstructorTest()
{
ReportStart();
int blockSize = 4;
DisposalMethod method = DisposalMethod.DoNotDispose;
bool expectsUserInput = false;
bool hasTransparentColour = true;
int delayTime = 40;
int transparentColourIndex = 22;
_gce = new GraphicControlExtension( blockSize,
method,
expectsUserInput,
hasTransparentColour,
delayTime,
transparentColourIndex );
Assert.AreEqual( blockSize, _gce.BlockSize );
Assert.AreEqual( method, _gce.DisposalMethod );
Assert.AreEqual( expectsUserInput, _gce.ExpectsUserInput );
Assert.AreEqual( hasTransparentColour, _gce.HasTransparentColour );
Assert.AreEqual( delayTime, _gce.DelayTime );
Assert.AreEqual( transparentColourIndex, _gce.TransparentColourIndex );
Assert.AreEqual( ErrorState.Ok, _gce.ErrorState );
ReportEnd();
}
private void ConstructorStreamTestDisposalMethodNotSpecified( bool xmlDebugging )
{
int blockSize = 4;
DisposalMethod method = DisposalMethod.NotSpecified;
bool expectsUserInput = false;
bool hasTransparentColour = true;
int delayTime = 40;
int transparentColourIndex = 22;
MemoryStream s = new MemoryStream();
s.WriteByte( (byte) blockSize );
// Packed fields:
// bits 1-3 = reserved
// bits 4-6 = disposal method
// bit 7 = user input flag
// bit 8 = transparent flag
byte packedFields = (byte)
(
( (int) method & 7 ) << 2
| ( expectsUserInput ? 1 : 0 ) << 1
| ( hasTransparentColour ? 1 : 0 )
);
s.WriteByte( packedFields );
// Write delay time, least significant byte first
s.WriteByte( (byte) ( delayTime & 0xff ) );
s.WriteByte( (byte) ( ( delayTime & 0xff00 ) >> 8 ) );
s.WriteByte( (byte) transparentColourIndex );
s.WriteByte( 0 ); // block terminator
s.Seek( 0, SeekOrigin.Begin );
_gce = new GraphicControlExtension( s, xmlDebugging );
Assert.AreEqual( blockSize, _gce.BlockSize );
Assert.AreEqual( DisposalMethod.DoNotDispose, _gce.DisposalMethod );
Assert.AreEqual( expectsUserInput, _gce.ExpectsUserInput );
Assert.AreEqual( hasTransparentColour, _gce.HasTransparentColour );
Assert.AreEqual( delayTime, _gce.DelayTime );
Assert.AreEqual( transparentColourIndex, _gce.TransparentColourIndex );
Assert.AreEqual( ErrorState.Ok, _gce.ConsolidatedState );
if( xmlDebugging )
{
Assert.AreEqual( ExpectedDebugXml, _gce.DebugXml );
}
}
/// <summary>
/// Gets the base image for this frame. This will be overpainted with
/// the pixels for this frame, where they are not transparent.
/// </summary>
/// <param name="previousFrame">
/// The frame which preceded this frame in the GIF stream.
/// Null if this is the first frame in the stream.
/// </param>
/// <param name="previousFrameBut1">
/// The frame which preceded the previous frame in the GIF stream.
/// Null if this is the first or seond frame in the stream.
/// </param>
/// <param name="lsd">
/// The logical screen descriptor for this GIF stream.
/// </param>
/// <param name="gce">
/// The graphic control extension for this frame.
/// </param>
/// <param name="act">
/// The active colour table for this frame.
/// </param>
/// <returns></returns>
private static Bitmap GetBaseImage( GifFrame previousFrame,
GifFrame previousFrameBut1,
LogicalScreenDescriptor lsd,
GraphicControlExtension gce,
ColourTable act )
{
#region Get the disposal method of the previous frame read from the GIF stream
DisposalMethod previousDisposalMethod;
if( previousFrame == null )
{
previousDisposalMethod = DisposalMethod.NotSpecified;
}
else
{
previousDisposalMethod = previousFrame.GraphicControlExtension.DisposalMethod;
}
#endregion
Bitmap baseImage;
int width = lsd.LogicalScreenSize.Width;
int height = lsd.LogicalScreenSize.Height;
#region paint baseImage
switch( previousDisposalMethod )
{
case DisposalMethod.DoNotDispose:
// pre-populate image with previous frame
baseImage = new Bitmap( previousFrame.TheImage );
break;
case DisposalMethod.RestoreToBackgroundColour:
// pre-populate image with background colour
Color backgroundColour ;
if( lsd.BackgroundColourIndex == gce.TransparentColourIndex )
{
backgroundColour = Color.Empty;
}
else
{
// TESTME: background colour index different to transparent colour
backgroundColour = act[lsd.BackgroundColourIndex];
}
baseImage = new Bitmap( width, height );
for( int y = 0; y < height; y++ )
{
for( int x = 0; x < height; x++ )
{
baseImage.SetPixel( x, y, backgroundColour );
}
}
break;
case DisposalMethod.RestoreToPrevious:
// pre-populate image with previous frame but 1
// TESTME: DisposalMethod.RestoreToPrevious
baseImage = new Bitmap( previousFrameBut1.TheImage );
break;
default: // DisposalMethod.NotSpecified
if( previousFrame == null )
{
// this is the first frame so start with an empty bitmap
baseImage = new Bitmap( width, height );
}
else
{
// pre-populate image with previous frame
// TESTME: DisposalMethod.NotSpecified on 2nd frame or later
baseImage = new Bitmap( previousFrame.TheImage );
}
break;
}
#endregion
return baseImage;
}
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();
}
internal static void CheckGraphicControlExtension( GraphicControlExtension ext )
{
Assert.AreEqual( GraphicControlExtension.ExpectedBlockSize,
ext.BlockSize,
"ExpectedBlockSize" );
Assert.AreEqual( DelayTime, ext.DelayTime, "DelayTime" );
Assert.AreEqual( DisposalMethod, ext.DisposalMethod, "DisposalMethod" );
Assert.AreEqual( TransparentColourIndex,
ext.TransparentColourIndex,
"TransparentColourIndex" );
Assert.AreEqual( HasTransparentColour, ext.HasTransparentColour, "HasTransparentColour" );
Assert.AreEqual( ExpectsUserInput, ext.ExpectsUserInput, "ExpectsUserInput" );
}
/// <summary>
/// Writes a Graphic Control Extension to the supplied output stream.
/// </summary>
/// <param name="frame">
/// The GifFrame to which this graphic control extension relates.
/// </param>
/// <param name="transparentColourIndex">
/// The index within the active colour table of the transparent colour.
/// </param>
/// <param name="outputStream">
/// The stream to write to.
/// </param>
private void WriteGraphicCtrlExt( GifFrame frame,
int transparentColourIndex,
Stream outputStream )
{
outputStream.WriteByte( GifComponent.CodeExtensionIntroducer );
outputStream.WriteByte( GifComponent.CodeGraphicControlLabel );
// The frame doesn't have have a graphic control extension yet, so we
// need to work out what it would contain.
DisposalMethod disposalMethod;
bool hasTransparentColour;
if( _transparent == Color.Empty ) // TODO: remove reference to _transparent - parameterise?
{
hasTransparentColour = false;
disposalMethod = DisposalMethod.NotSpecified; // dispose = no action
}
else
{
// TESTME: WriteGraphicCtrlExt - _transparent != Color.Empty
hasTransparentColour = true;
disposalMethod = DisposalMethod.RestoreToBackgroundColour; // force clear if using transparent color
}
int blockSize = 4;
GraphicControlExtension gce
= new GraphicControlExtension( blockSize,
disposalMethod,
frame.ExpectsUserInput,
hasTransparentColour,
frame.Delay,
transparentColourIndex );
gce.WriteToStream( outputStream );
}