/// <summary>Renders an arc from the previous point to this one.</summary>
public override void RenderLine(CanvasContext context)
{
// Grab the raw drawing data:
DynamicTexture data = context.ImageData;
// Time to go polar!
// We're going to rotate around the pole drawing one pixel at a time.
// For the best accuracy, we first need to find out how much to rotate through per pixel.
if (Length == 0f)
{
// Nothing to draw anyway.
return;
}
// How much must we rotate through overall?
float angleToRotateThrough = EndAngle - StartAngle;
// So arc length is how many pixels long the arc is.
// Thus to step that many times, our delta angle is..
float deltaAngle = angleToRotateThrough / Length;
// The current angle:
float currentAngle = StartAngle;
// The number of pixels:
int pixelCount = (int)Mathf.Ceil(Length);
if (pixelCount < 0)
{
// Going anti-clockwise. Invert deltaAngle and the pixel count:
deltaAngle = -deltaAngle;
pixelCount = -pixelCount;
}
// Step pixel count times:
for (int i = 0; i < pixelCount; i++)
{
// Map from polar angle to coords:
float x = Radius * (float)Math.Cos(currentAngle);
float y = Radius * (float)Math.Sin(currentAngle);
// Draw the pixel:
data.DrawPixel((int)(CircleCenterX + x), data.Height - (int)(CircleCenterY + y), context.StrokeColour);
// Rotate the angle:
currentAngle += deltaAngle;
}
}
