Description
    Assigns styles to the target object, which may be a
    container, shape, text, raster image, or pattern. Styles are
    presentational attributes that define how the object is
    rendered.
    Styles yields to a block if a block is present,
    passing the target object as an argument. This is useful when
    styles is chained to a container constructor
    method such as g or rvg. By default, objects within a
    container get the styles defined on the container.
    Styles returns the target object, so other
    methods can be chained to it.
    Arguments
    The argument is a hash. The hash keys are style name
    symbols. The hash values are the style values. RVG supports the
    following style names.
    
      - :clip_path
- An outline used to clip a shape or collection of shapes.
      The value is an clipping
      path.
- :clip_rule
- If the clip_pathstyle is used, how to
      determine if a point is inside or outside a the clip path.
      The value is a string, either 'nonzero' or 'evenodd'. The
      default is 'nonzero'. See thefill_ruleexample
      below.
- :fill
- The fill color. The value must be a color name or a pattern. The default is
      'black'.
- :fill_opacity
- The opacity of the fill color. A number between 0.0
      (fully transparent) and 1.0 (fully opaque). The default is
      1.0
- :fill_rule
- How to determine if a point is inside or outside a shape.
      The value is a string, either 'nonzero' or 'evenodd'. The
      default is 'nonzero'.
- 
        The following descriptions of 'nonzero' and 'evenodd' are
        from the SVG
        1.1 standard.
        
          - nonzero
- This rule determines the "insideness" of a point on
          the canvas by drawing a ray from that point to infinity
          in any direction and then examining the places where a
          segment of the shape crosses the ray. Starting with a
          count of zero, add one each time a path segment crosses
          the ray from left to right and subtract one each time a
          path segment crosses the ray from right to left. After
          counting the crossings, if the result is zero then the
          point is outside the path. Otherwise, it is inside.
- evenodd
- This rule determines the "insideness" of a point on
          the canvas by drawing a ray from that point to infinity
          in any direction and counting the number of path segments
          from the given shape that the ray crosses. If this number
          is odd, the point is inside; if even, the point is
          outside.
 
- See the examples below.
- :opacity
- Both the stroke and the fill opacity. A number between
      0.0 (fully transparent) and 1.0 (fully opaque). The default
      is 1.0. See below for an example.
- :stroke
- The stroke color. The value must be a color name or a pattern. The default is 'none',
      that is, transparent black ("#000000ff").
- :stroke_dasharray
- An array of numbers that specify the length of the dashes
      and gaps with which to draw a dashed line. If the array
      contains an odd number of values, the values are repeated to
      produce an even number of dashes and gaps. The numbers are in
      user coordinates. By default all lines are drawn as solid
      lines. See below for an example.
- :stroke_dashoffset
- Normally a dashed line is drawn using the first number in
      the stroke_dasharray as the length of the first dash. This
      style can be used to specify a different starting point in
      the array.
- :stroke_linecap
- The shape of the end of a line. The value may be one of
      the strings 'butt', 'round', or 'square'. The default is
      'butt'. See below for an example.
- :stroke_linejoin
- The shape of the corner where two lines are joined. The
      value may be one of the strings 'miter', 'round', or 'bevel'.
      The default is 'miter'. See below for an example.
- :stroke_miterlimit
- If the stroke_linejoinvalue is 'miter', a
      number specifying the ratio of the miter to the thickness of
      the lines being joined. When the limit is exceeded the join
      is converted from a miter to a bevel. The value must be a
      number greater than or equal to 1.0. The default is 4.0.
- :stroke_opacity
- The opacity of the stroke color. A number between 0.0
      (fully transparent) and 1.0 (fully opaque). The default is
      1.0 unless strokehas the default value
      'none'.
- :stroke_width
- The thickness of the stroke. The default is 1 user
      coordinate.
(Text styles are described with the Text class.)
    Examples
    :fill=>'#00ff00', :stroke=>'blue',
    :stroke_width=>8
    :fill_rule=>'nonzero'
    :fill_rule=>'evenodd'
    Three values of :opacity
    :stroke_dasharray=>[10,5]
    Three values of :stroke_linecap
    Three values of :stroke_linejoin
    Returns
    obj