/// <summary>
/// See <see cref="BaseColorDitherer.OnProcessPixel"/> for more details.
/// </summary>
protected override Boolean OnProcessPixel(Pixel sourcePixel, Pixel targetPixel)
{
// only process dithering when reducing from truecolor to indexed
if (!TargetBuffer.IsIndexed)
{
return(false);
}
// retrieves the colors
Color sourceColor = SourceBuffer.GetColorFromPixel(sourcePixel);
Color targetColor = TargetBuffer.GetColorFromPixel(targetPixel);
// converts alpha to solid color
sourceColor = QuantizationHelper.ConvertAlpha(sourceColor);
// calculates the difference (error)
Int32 redError = sourceColor.R - targetColor.R;
Int32 greenError = sourceColor.G - targetColor.G;
Int32 blueError = sourceColor.B - targetColor.B;
// only propagate non-zero error
if (redError != 0 || greenError != 0 || blueError != 0)
{
// processes the matrix
for (Int32 shiftY = -MatrixSideHeight; shiftY <= MatrixSideHeight; shiftY++)
{
for (Int32 shiftX = -MatrixSideWidth; shiftX <= MatrixSideWidth; shiftX++)
{
Int32 targetX = sourcePixel.X + shiftX;
Int32 targetY = sourcePixel.Y + shiftY;
Byte coeficient = CachedMatrix[shiftY + MatrixSideHeight, shiftX + MatrixSideWidth];
Single coeficientSummed = CachedSummedMatrix[shiftY + MatrixSideHeight, shiftX + MatrixSideWidth];
if (coeficient != 0 &&
targetX >= 0 && targetX < TargetBuffer.Width &&
targetY >= 0 && targetY < TargetBuffer.Height)
{
ProcessNeighbor(targetPixel, targetX, targetY, coeficientSummed, redError, greenError, blueError);
}
}
}
}
// pixels are not processed, only neighbors are
return(false);
}
/// <summary>
/// See <see cref="BaseColorDitherer.OnProcessPixel"/> for more details.
/// </summary>
protected override Boolean OnProcessPixel(Pixel sourcePixel, Pixel targetPixel)
{
// reads the source pixel
Color oldColor = SourceBuffer.GetColorFromPixel(sourcePixel);
// converts alpha to solid color
oldColor = QuantizationHelper.ConvertAlpha(oldColor);
// retrieves matrix coordinates
Int32 x = targetPixel.X % MatrixWidth;
Int32 y = targetPixel.Y % MatrixHeight;
// determines the threshold
Int32 threshold = Convert.ToInt32(CachedMatrix[x, y]);
// only process dithering if threshold is substantial
if (threshold > 0)
{
Int32 red = GetClampedColorElement(oldColor.R + threshold);
Int32 green = GetClampedColorElement(oldColor.G + threshold);
Int32 blue = GetClampedColorElement(oldColor.B + threshold);
Color newColor = Color.FromArgb(255, red, green, blue);
if (TargetBuffer.IsIndexed)
{
Byte newPixelIndex = (Byte)Quantizer.GetPaletteIndex(newColor, targetPixel.X, targetPixel.Y);
targetPixel.Index = newPixelIndex;
}
else
{
targetPixel.Color = newColor;
}
}
// writes the process pixel
return(true);
}