#  Strokes.rb

module Tioga

# These are the attributes for doing stroked lines in PDF graphics.
# The methods for strokes include #stroke, stroke_line, stroke_rect, stroke_frame, stroke_circle, stroke_oval, and stroke_polyline.

class Strokes < Doc < FigureMaker

# Calls move_to_point, append_point_to_path, and #stroke.
   def stroke_line(x0, y0, x1, y1)
   end

# :call-seq:
#               miter_limit                                     
#               miter_limit = a_float
#
# Sets a maximum for the ratio of the miter length to the line width (default is 2).  When the limit is
# exceeded, the line join is converted from a miter to a bevel.  This limit
# is needed since when two line segments meet at a sharp angle and mitered joins have been
# specified as the line_join, it is possible for the miter to extend far beyond the
# thickness of the line stroking the path.
   def miter_limit
   end
   
# :call-seq:
#               default_line_scale                                     
#               default_line_scale = a_float
#
# Scaling factor for the width of stroked lines (default is 1).  The #stroke operations produce lines with
# a width determined by the product of the line_width times the default_line_scale.
   def default_line_scale
   end
   
# :call-seq:
#               line_width                                     
#               line_width = a_float
#
# The width of stroked lines.  A line width of 0 denotes the thinnest line that can be rendered at device
# resolution: 1 device pixel wide. However, some devices cannot reproduce 1-pixel lines, and on high-resolution
# devices, they are nearly invisible. Since the results of rendering such "zero-width" lines are device-dependent,
# their use is not recommended.  The actual line width is adjusted according to the current value 
# of the default_line_scale.
   def line_width
   end
   
# :call-seq:
#               stroke_width                                     
#               stroke_width = a_float
#
# Alias for line_width.
   def stroke_width
   end
   
# :call-seq:
#               line_cap                                     
#               line_cap = a_line_cap
#
# The line cap style specifies the shape to be used at the ends of open subpaths (and
# dashes, if any) when they are stroked.   Valid values are the predefined
# constants: +LINE_CAP_BUTT+, +LINE_CAP_ROUND+, and +LINE_CAP_SQUARE+.  For +LINE_CAP_BUTT+, the
# stroke is squared off at the endpoint of the path.  There is no projection beyond the end of the path.
# For +LINE_CAP_ROUND+, a semicircular arc with a diameter equal to the line width is drawn around the endpoint and filled in.
# For +LINE_CAP_SQUARE+, the stroke continues beyond the endpoint of the path for a distance equal to half the
# line width and is then squared off.  See also line_join.
#
# http://theory.kitp.ucsb.edu/~paxton/tioga_jpegs/Caps_and_Joins.jpg
   def line_cap
   end
   
# :call-seq:
#               line_join                                     
#               line_join = a_line_join
#
# The line join style specifies the shape to be used at the corners of paths that are
# stroked.  Join styles are significant only at points where consecutive segments of a
# path connect at an angle; segments that meet or intersect fortuitously receive no special
# treatment.  Valid values are the predefined constants: +LINE_JOIN_MITER+, +LINE_JOIN_ROUND+,
# and +LINE_JOIN_BEVEL+.  For +LINE_JOIN_MITER+, the outer edges of the strokes for the two
# segments are extended until they meet at an angle, as in a picture frame. If the segments
# meet at too sharp an angle (as defined by the miter limit parameter), a bevel join is used
# instead.  For +LINE_JOIN_ROUND+, an arc of a circle with a diameter equal to the line width
# is drawn around the point where the two segments meet, connecting the outer edges of the
# strokes for the two segments. This pieslice-shaped figure is filled in, producing a rounded
# corner.  For +LINE_JOIN_BEVEL+, the two segments are finished with butt caps and the resulting
# notch beyond the ends of the segments is filled with a triangle.  See also line_cap.
   def line_join
   end

# :call-seq:
#               line_type                                     
#               line_type = a_line_type
#
# The line type controls the pattern of dashes and gaps used to stroke paths.
# It is specified by a dash array and a dash phase. The dash array's elements are
# numbers that specify the lengths of alternating dashes and gaps; the dash phase
# specifies the distance into the dash pattern at which to start the dash. The elements
# of both the dash array and the dash phase are expressed in user space units.
# An empty dash array and zero phase can be used to set
# the dash pattern to a solid line.
# 
# Dashed lines wrap around curves and corners just as solid stroked lines do. The
# ends of each dash are treated with the current line cap style, and corners within
# dashes are treated with the current line join style. A stroking operation takes no
# measures to coordinate the dash pattern with features of the path; it simply dispenses
# dashes and gaps along the path in the pattern defined by the dash array.
# 
# When a path consisting of several subpaths is stroked, each subpath is treated independently -- 
# that is, the dash pattern is restarted and the dash phase is reapplied
# to it at the beginning of each subpath.
# http://theory.kitp.ucsb.edu/~paxton/tioga_jpegs/Line_Types.jpg
   def line_type
   end


# Adjust default_line_scale by multiplying it by the given _scale_ and adjust the current line_width accordingly.
   def rescale_lines(scale)
   end
   
# Calls #context, then, inside the new context, changes line_type and stroke_color (if those arguments are not +nil+),
# calls append_points_with_gaps_to_path, calls #stroke, and then saves the legend information (if _legend_
# is not +nil+).  Alias for show_polyline.
    def stroke_polyline(xs, ys, color = nil, legend = nil, type = nil, gaps = nil, close_subpaths = nil)
    end
        


end # class
end # module Tioga