//Scan-line flood fill, much faster
//https://lodev.org/cgtutor/floodfill.html#Scanline_Floodfill_Algorithm_With_Stack
public static PixelMatrix FloodFillLine(PixelMatrix bmp, int x, int y, Color replacementColor)
{
Point pt = new Point(x, y);
Color targetColor = bmp.GetPixel(pt.x, pt.y);
if (targetColor == replacementColor)
{
return(bmp);
}
Stack <Point> pixels = new Stack <Point>();
pixels.Push(pt);
while (pixels.Count != 0)
{
Point temp = pixels.Pop();
int y1 = temp.y;
while (y1 >= 0 && bmp.GetPixel(temp.x, y1) == targetColor)
{
y1--;
}
y1++;
bool spanLeft = false;
bool spanRight = false;
while (y1 < bmp.height && bmp.GetPixel(temp.x, y1) == targetColor)
{
bmp.SetPixelSafe(temp.x, y1, replacementColor);
Color clm1 = bmp.GetPixel(temp.x - 1, y1);
Color clp1 = bmp.GetPixel(temp.x + 1, y1);
if (!spanLeft && temp.x > 0 && clm1 == targetColor)
{
pixels.Push(new Point(temp.x - 1, y1));
spanLeft = true;
}
else if (spanLeft && temp.x - 1 >= 0 && clm1 != targetColor)
{
spanLeft = false;
}
if (!spanRight && temp.x < bmp.width - 1 && clp1 == targetColor)
{
pixels.Push(new Point(temp.x + 1, y1));
spanRight = true;
}
else if (spanRight && temp.x < bmp.width - 1 && clp1 != targetColor)
{
spanRight = false;
}
y1++;
}
}
return(bmp);
}
/// <summary>
/// Calculates the best-fitting character based on Mean squared error. See <see cref="RenderOption.CalculateCharForMatrix(PixelMatrix)"/> and <see cref="https://en.wikipedia.org/wiki/Mean_squared_error"/> for more information.
/// </summary>
/// <param name="tile">The part of the image to be represented.</param>
/// <returns>The best-fitting character and its corresponding PixelMatrix.</returns>
public override KeyValuePair <char, PixelMatrix> CalculateCharForMatrix(PixelMatrix tile)
{
double minScore = double.MaxValue;
KeyValuePair <char, PixelMatrix> bestFit = Font.Chars.FirstOrDefault();
foreach (var item in Font.Chars)
{
double score = 0;
for (int y = 0; y < Font.CharSize.Height; y++)
{
for (int x = 0; x < Font.CharSize.Width; x += Utils.BytesPerPixel)
{
byte grayChar = Utils.ColorToGray(item.Value.GetPixel(x, y));
byte grayMatrix = Utils.ColorToGray(tile.GetPixel(x, y));
score += (grayMatrix - grayChar) * (grayMatrix - grayChar);
}
}
if (score < minScore)
{
bestFit = item;
minScore = score;
}
}
return(bestFit);
}
/// <summary>
/// Calculates the best-fitting character based on Structural similarity index. See <see cref="RenderOption.CalculateCharForMatrix(PixelMatrix)"/> and <see cref="https://en.wikipedia.org/wiki/Structural_similarity"/> for more information.
/// </summary>
/// <param name="tile">The part of the image to be represented.</param>
/// <returns>The best-fitting character and its corresponding PixelMatrix.</returns>
public override KeyValuePair <char, PixelMatrix> CalculateCharForMatrix(PixelMatrix tile)
{
double maxScore = RenderingMode == RenderingMode.Default ? double.MinValue : double.MaxValue;
KeyValuePair <char, PixelMatrix> bestFit = Font.Chars.FirstOrDefault();
foreach (var item in Font.Chars)
{
double score = 0;
double covariance = 0;
for (int y = 0; y < Font.CharSize.Height; y++)
{
for (int x = 0; x < Font.CharSize.Width; x += Utils.BytesPerPixel)
{
byte grayChar = Utils.ColorToGray(item.Value.GetPixel(x, y));
byte grayMatrix = Utils.ColorToGray(tile.GetPixel(x, y));
covariance += (grayChar - item.Value.Mean) * (grayMatrix - tile.Mean);
}
}
covariance /= Font.CharSize.Height * Font.CharSize.Width;
score = (2 * Math.Sqrt(item.Value.Variance) * Math.Sqrt(tile.Variance) + C1) * (2 * covariance + C2);
score /= (item.Value.Mean * item.Value.Mean + tile.Mean * tile.Mean + C1) * (covariance * covariance + C2);
if (RenderingMode == RenderingMode.Default && score > maxScore)
{
bestFit = item;
maxScore = score;
}
else if (RenderingMode == RenderingMode.Inverted && score < maxScore)
{
bestFit = item;
maxScore = score;
}
}
return(bestFit);
}
/// <summary>
/// Copies the pixel values to the output image. See <see cref="Converter{T}.AddToOutput(KeyValuePair{char, PixelMatrix}, Point, PixelMatrix)"/> for more information.
/// </summary>
/// <param name="character">The character to be drawn.</param>
/// <param name="point">A point that represents the coordinates of the upper left corner to be drawn.</param>
/// <param name="tile">The PixelMatrix representing a tile of the source image.</param>
protected override void AddToOutput(KeyValuePair <char, PixelMatrix> character, Point point, PixelMatrix tile)
{
for (int y = point.Y; y < point.Y + RenderOptions.TileSize.Height; y++)
{
for (int x = point.X * Utils.BytesPerPixel; x < (point.X + RenderOptions.TileSize.Width) * Utils.BytesPerPixel; x += Utils.BytesPerPixel)
{
int index = y * _size.Width * Utils.BytesPerPixel;
System.Drawing.Color c = DrawingMode.CalculateColor(character.Value.GetPixel(x - Utils.BytesPerPixel * point.X, y - point.Y), tile.GetPixel(x - Utils.BytesPerPixel * point.X, y - point.Y));
_pixels[index + x] = c.B; // b
_pixels[index + x + 1] = c.G; // g
_pixels[index + x + 2] = c.R; // r
_pixels[index + x + 3] = c.A; // a
}
}
}