private void Set4Pixels(Graphics g, Color c, int x, int y)
{
SketchForm.SetPixel(g, c, xc + x, yc + y);
SketchForm.SetPixel(g, c, xc + x, yc - y);
SketchForm.SetPixel(g, c, xc - x, yc + y);
SketchForm.SetPixel(g, c, xc - x, yc - y);
}
private void Set2Pixels(Graphics g, Color C, int x, int y)
{
if (sign == 1)
{
SketchForm.SetPixel(g, C, d_x + x, d_y + y);
SketchForm.SetPixel(g, C, d_x - x, d_y + y);
}
else
{
SketchForm.SetPixel(g, C, d_x + x, -d_y - y);
SketchForm.SetPixel(g, C, d_x - x, -d_y - y);
}
}
protected override void DDARender(Graphics g)
{
int dx = x1 - x0;
int dy = y1 - y0;
int steps = Math.Max(Math.Abs(dx), Math.Abs(dy));
double deltax = dx / (double)steps;
double deltay = dy / (double)steps;
for (int i = 0; i <= steps; ++i)
{
double x_i = x0 + deltax * i;
double y_i = y0 + deltay * i;
SketchForm.SetPixel(g, Color.Red, (int)Math.Round(x_i), (int)Math.Round(y_i));
}
}
protected void XiaolinWuRender(Graphics g)
{
int dx = x1 - x0;
int dy = y1 - y0;
int steps = Math.Max(Math.Abs(dx), Math.Abs(dy));
double deltax = dx / (double)steps;
double deltay = dy / (double)steps;
if (Math.Abs(dx) > Math.Abs(dy))
{
int sign_x = (dx >= 0 ? 1 : -1);
for (int i = 0; i <= steps; ++i)
{
int x_i = x0 + sign_x * i;
double y_i = y0 + deltay * i;
int ry_i = (int)y_i - (y_i > 0 ? 0 : 1);
int p = (int)(255 * (y_i - ry_i));
SketchForm.SetPixel(g, Color.FromArgb(255 - p, 0, 255 - p), x_i, ry_i);
SketchForm.SetPixel(g, Color.FromArgb(p, 0, p), x_i, ry_i + 1);
}
}
else
{
int sign_y = (dy >= 0 ? 1 : -1);
for (int i = 0; i <= steps; ++i)
{
int y_i = y0 + sign_y * i;
double x_i = x0 + deltax * i;
int rx_i = (int)x_i - (x_i > 0 ? 0 : 1);
int p = (int)(255 * (x_i - rx_i));
SketchForm.SetPixel(g, Color.FromArgb(255 - p, 0, 255 - p), rx_i, y_i);
SketchForm.SetPixel(g, Color.FromArgb(p, 0, p), rx_i + 1, y_i);
}
}
}
protected override void BresenhamRender(Graphics g)
{
int dx = x1 - x0, stepx = 1;
if (dx < 0) // Doi xung qua duong thang d = y0
{
dx = -dx;
stepx = -1;
}
int dy = y1 - y0, stepy = 1;
if (dy < 0) // Doi xung qua duong thang d = x0
{
dy = -dy;
stepy = -1;
}
if (dx > dy)
{
int p = 2 * dy - dx;
while (true)
{
SketchForm.SetPixel(g, Color.Blue, x0, y0);
if (x0 == x1 && y0 == y1)
{
break;
}
x0 += stepx;
if (p >= 0)
{
p += 2 * dy - 2 * dx;
y0 += stepy;
}
else
{
p += 2 * dy;
}
}
}
else
{
int p = 2 * dx - dy;
while (true)
{
SketchForm.SetPixel(g, Color.Blue, x0, y0);
if (x0 == x1 && y0 == y1)
{
break;
}
y0 += stepy;
if (p >= 0)
{
p += 2 * dx - 2 * dy;
x0 += stepx;
}
else
{
p += 2 * dx;
}
}
}
}