public static void PlotLineSmooth(this IScreenBuffer buffer, int x0, int y0, int x1, int y1, Color baseColor)
{
void Swap(ref int a, ref int b)
{
var temp = a;
a = b;
b = temp;
}
float FractionalPart(float f) => f - (int)f;
float ReciprocalOfFractionalPart(float f) => 1 - FractionalPart(f);
float Gamma(float x, float exp) => (float)Pow(x, 1.0f / exp);
void DrawPixel(int x, int y) => buffer.DrawPixel(x, y, baseColor);
void DrawPixelScale(int x, int y, float intensity) => buffer.AddPixel(x, y, baseColor * Gamma(intensity, GammaExponent));
// Make sure the line runs top to bottom
if (y0 > y1)
{
Swap(ref x0, ref x1);
Swap(ref y0, ref y1);
}
// Draw the initial pixel, which is always exactly intersected by the line and so needs no weighting
DrawPixel(x0, y0);
var deltaX = x1 - x0;
var xDir = 1;
if (deltaX < 0)
{
xDir = -1;
deltaX = -deltaX; // make DeltaX positive
}
var deltaY = y1 - y0; // Guaranteed to be positive since we made sure it goes from top to bottom
// Special cases for horizontal, vertical, and diagonal lines
if (deltaY == 0)
{
while (deltaX-- != 0)
{
x0 += xDir;
DrawPixel(x0, y0);
}
return;
}
if (deltaX == 0)
{
do
{
y0++;
DrawPixel(x0, y0);
} while (--deltaY != 0);
return;
}
if (deltaX == deltaY)
{
do
{
x0 += xDir;
y0++;
DrawPixel(x0, y0);
} while (--deltaY != 0);
return;
}
// line is not horizontal, diagonal, or vertical
float gradient = 0;
float accumulatedError = 0;
bool isYMajorLine = deltaY > deltaX;
if (isYMajorLine)
{
gradient = (float)deltaX / deltaY;
while (--deltaY != 0)
{
accumulatedError += gradient;
y0++;
DrawPixelScale(x0 + xDir * (int)accumulatedError, y0, ReciprocalOfFractionalPart(accumulatedError));
DrawPixelScale(x0 + xDir * (int)accumulatedError + xDir, y0, FractionalPart(accumulatedError));
}
}
else
{
gradient = (float)deltaY / deltaX;
while (--deltaX != 0)
{
accumulatedError += gradient;
x0 += xDir;
DrawPixelScale(x0, y0 + (int)accumulatedError, ReciprocalOfFractionalPart(accumulatedError));
DrawPixelScale(x0, y0 + (int)accumulatedError + 1, FractionalPart(accumulatedError));
}
}
// Draw the final pixel, which is always exactly intersected by the line
// and so needs no weighting
DrawPixel(x1, y1);
}
public static void AddPixel(this IScreenBuffer buffer, Point p, Color c) => buffer.AddPixel(p.X, p.Y, c);
