private ColourTable SetActiveColourTable()
{
ColourTable act; // active colour table
if (_strategy == ColourTableStrategy.UseLocal)
{
if (_quantizerType == QuantizerType.UseSuppliedPalette)
{
if (_frames[_encodingFrame].Palette == null)
{
// TESTME: SetActiveColourTable - SetActiveColourTable, UseSuppliedPalette, no palette supplied
string message
= "You have opted to use a local colour table built "
+ "from a supplied palette, but frame "
+ _encodingFrame
+ "does not have a palette.";
throw new InvalidOperationException(message);
}
else
{
// Build local colour table from colours in the frame's
// supplied palette.
act = new ColourTable();
foreach (Color c in _frames[_encodingFrame].Palette)
{
act.Add(c);
}
act.Pad();
}
}
else
{
// Build local colour table based on colours in the image.
Image thisImage = _frames[_encodingFrame].TheImage;
_pixelAnalysis = new PixelAnalysis(thisImage,
_quantizerType);
_pixelAnalysis.ColourQuality = _quality;
_pixelAnalysis.Analyse();
// make local colour table active
act = _pixelAnalysis.ColourTable;
}
}
else
{
// make global colour table active
act = _globalColourTable;
}
return(act);
}
/// <summary>
/// Creates a colour table directly from the distinct colours in the
/// supplied image(s).
/// </summary>
private void CreateDirectColourTable()
{
//AddCounter( buildColourTableCounterText,
// _distinctColours.Values.Count );
_colourTable = new ColourTable();
int distinctColourIndex = 0;
foreach (Color c in _distinctColours.Values)
{
//MyProgressCounters[buildColourTableCounterText].Value
//= distinctColourIndex;
_colourTable.Add(c);
distinctColourIndex++;
}
_colourTable.Pad();
//RemoveCounter( buildColourTableCounterText );
}
/// <summary>
/// Creates a colour table directly from the distinct colours in the
/// supplied image(s).
/// </summary>
private void CreateDirectColourTable()
{
string buildColourTableCounterText
= "Creating colour table from images";
AddCounter(buildColourTableCounterText,
_distinctColours.Values.Count);
_colourTable = new ColourTable();
int distinctColourIndex = 0;
foreach (Color c in _distinctColours.Values)
{
MyProgressCounters[buildColourTableCounterText].Value
= distinctColourIndex;
_colourTable.Add(c);
distinctColourIndex++;
}
_colourTable.Pad();
RemoveCounter(buildColourTableCounterText);
}
/// <summary>
/// Writes a Logical Screen Descriptor to the supplied stream.
/// Also writes a global colour table if required.
/// </summary>
/// <param name="outputStream">
/// The stream to write to.
/// </param>
private void WriteLogicalScreenDescriptor(Stream outputStream)
{
bool hasGlobalColourTable = _strategy == ColourTableStrategy.UseGlobal;
int colourResolution = 7; // TODO: parameterise colourResolution?
bool globalColourTableIsSorted = false; // Sorting of colour tables is not currently supported
int backgroundColorIndex = 0; // TODO: parameterise backgroundColourIndex?
int pixelAspectRatio = 0; // TODO: parameterise pixelAspectRatio?
if (_strategy == ColourTableStrategy.UseGlobal)
{
if (_quantizerType == QuantizerType.UseSuppliedPalette)
{
// use supplied palette
_globalColourTable = new ColourTable();
//AddCounter( buildColourTableCounterText,
// _palette.Count );
int paletteIndex = 0;
foreach (Color c in _palette)
{
_globalColourTable.Add(c);
//MyProgressCounters[buildColourTableCounterText].Value
//= paletteIndex;
paletteIndex++;
}
_globalColourTable.Pad();
//RemoveCounter( buildColourTableCounterText );
}
else
{
// Analyse the pixels in all the images to build the
// global colour table.
Collection <Image> images = new Collection <Image>();
foreach (GifFrame thisFrame in _frames)
{
Image thisImage = thisFrame.TheImage;
images.Add(thisImage);
}
_pixelAnalysis = new PixelAnalysis(images);
_pixelAnalysis.ColourQuality = _quality;
_pixelAnalysis.Analyse();
_globalColourTable = _pixelAnalysis.ColourTable;
}
LogicalScreenDescriptor lsd =
new LogicalScreenDescriptor(_logicalScreenSize,
hasGlobalColourTable,
colourResolution,
globalColourTableIsSorted,
_globalColourTable.SizeBits,
backgroundColorIndex,
pixelAspectRatio);
lsd.WriteToStream(outputStream);
_globalColourTable.WriteToStream(outputStream);
}
else
{
LogicalScreenDescriptor lsd =
new LogicalScreenDescriptor(_logicalScreenSize,
hasGlobalColourTable,
colourResolution,
globalColourTableIsSorted,
7,
backgroundColorIndex,
pixelAspectRatio);
lsd.WriteToStream(outputStream);
}
}