Method: HexaPDF::Content::Canvas#line_with_rounded_corner

Defined in:

lib/hexapdf/content/canvas.rb

#line_with_rounded_corner(x0 = , y0 = , x1, y1, x2, y2, in_radius:, out_radius: in_radius) ⇒ Object

:call-seq:

canvas.line_with_rounded_corner(x0 = current_point[0], y0 = current_point[1], x1, y1, x2, y2, in_radius:, out_radius: in_radius)

Appends a line with a rounded corner at (x1, y1) from the current point and returns self. The end point of the rounded corner (i.e. out_radius units from (x1, y1) in the direction of (x2, y2)) becomes the current point. In degraded cases the corner point (x1, y1) becomes the current point.

The corner is specified by (x0, y0) which defaults to the #current_point of the path, (x1, y1) and (x2, y2) - all of which need to be different points. The in_radius specifies the corner radius into the corner and the out_radius the one out of the corner. Degraded cases, like with (x0, y0) == (x1, y1), are handled gracefully.

There has to be a current path when this method is invoked, otherwise an error is raised. For example, the current point could be estabilshed beforehand using #move_to.

Examples:

#>pdf
canvas.move_to(10, 180)   # Both radii are the same
canvas.line_with_rounded_corner(180, 180, 180, 100, in_radius: 20)
canvas.move_to(10, 150)   # Different radii
canvas.line_with_rounded_corner(180, 150, 180, 100, in_radius: 50, out_radius: 20)
canvas.move_to(10, 120)   # One radius is zero, making it just a line
canvas.line_with_rounded_corner(180, 120, 150, 100, in_radius: 0, out_radius: 10)
canvas.stroke

# Special effects when (x0, y0) is not the current point, like when the current
# point would be equal to the corner point. Rounded rectangle use this method
# internally, as high-lighted by the blue segment.
canvas.rectangle(10, 10, 60, 60, radius: 60).stroke
canvas.stroke_color("hp-blue").
  move_to(70, 10). # Start point at the end of the lower-left rounded corner
  line_with_rounded_corner(10, 10, 70, 10, 70, 70, in_radius: 60).stroke
canvas.stroke_color("black").
  rectangle(110, 10, 60, 60, radius: 70).stroke

# File 'lib/hexapdf/content/canvas.rb', line 1435

def line_with_rounded_corner(x0 = current_point[0], y0 = current_point[1], x1, y1, x2, y2,
                             in_radius:, out_radius: in_radius)
  if in_radius == 0 || out_radius == 0
    line_to(x1, y1)
  else
    p0 = point_on_line(x1, y1, x0, y0, distance: in_radius)
    p3 = point_on_line(x1, y1, x2, y2, distance: out_radius)
    p1 = point_on_line(p0[0], p0[1], x1, y1, distance: KAPPA * in_radius)
    p2 = point_on_line(p3[0], p3[1], x1, y1, distance: KAPPA * out_radius)
    if p0[0].finite? && p3[0].finite?
      line_to(*p0)
      curve_to(p3[0], p3[1], p1: p1, p2: p2)
    else
      line_to(x1, y1)
    end
  end
  self
end