/// <summary>
/// Clips the <paramref name="line"/> to the <paramref name="container"/>.
/// </summary>
/// <param name="line">The line to be clipped.</param>
/// <param name="container">The container.</param>
/// <param name="borderOverflow">The border (stroke thickness) of the <paramref name="line"/>.</param>
/// <param name="dashPatternLength">The length of the dash pattern of the line stroke.</param>
/// <returns>The clipped line.</returns>
internal static RadLine ClipLine(RadLine line, RadRect container, double borderOverflow, double dashPatternLength)
{
// extend the container with the element border
container.X -= borderOverflow;
container.Y -= borderOverflow;
container.Width += 2 * borderOverflow;
container.Height += 2 * borderOverflow;
bool firstPointInside = container.Contains(line.X1, line.Y1);
bool secondPointInside = container.Contains(line.X2, line.Y2);
if (firstPointInside && secondPointInside)
{
return(line);
}
if (dashPatternLength == 0 || double.IsNaN(dashPatternLength) || double.IsInfinity(dashPatternLength))
{
dashPatternLength = 1;
}
// find intersectionns of the line with the sides of the container
double topIntersectionX = RadMath.CalculateIntersectionX(line.X1, line.Y1, line.X2, line.Y2, container.Y);
double bottomIntersectionX = RadMath.CalculateIntersectionX(line.X1, line.Y1, line.X2, line.Y2, container.Bottom);
double leftIntersectionY = RadMath.CalculateIntersectionY(line.X1, line.Y1, line.X2, line.Y2, container.X);
double rightIntersectionY = RadMath.CalculateIntersectionY(line.X1, line.Y1, line.X2, line.Y2, container.Right);
// slope of the line: angle between the line ant the horizon (-pi/2, pi/2)
var angle = Math.Atan((line.Y1 - line.Y2) / (line.X2 - line.X1));
bool intersectsWithRect = false;
// clip to container sides
intersectsWithRect |= AnnotationHelper.TryClipToContainerTop(ref line, container, topIntersectionX, dashPatternLength, angle > 0 ? angle : Math.PI + angle);
intersectsWithRect |= AnnotationHelper.TryClipToContainerBottom(ref line, container, bottomIntersectionX, dashPatternLength, angle > 0 ? angle : Math.PI + angle);
intersectsWithRect |= AnnotationHelper.TryClipToContainerLeft(ref line, container, leftIntersectionY, dashPatternLength, angle);
intersectsWithRect |= AnnotationHelper.TryClipToContainerRight(ref line, container, rightIntersectionY, dashPatternLength, angle);
if (!intersectsWithRect)
{
line = new RadLine();
}
return(line);
}