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# Arrows

class `sage.plot.arrow.``Arrow`(xtail, ytail, xhead, yhead, options)

  Bases: `sage.plot.primitive.GraphicPrimitive`

  Primitive class that initializes the (line) arrow graphics type

  EXAMPLES:

  We create an arrow graphics object, then take the 0th entry in it to get the actual Arrow graphics primitive:

      sage: P = arrow((0,1), (2,3))[0]
      sage: type(P)
      <class 'sage.plot.arrow.Arrow'>
      sage: P
      Arrow from (0.0,1.0) to (2.0,3.0)

  `get_minmax_data`()

    Returns a bounding box for this arrow.

    EXAMPLES:

        sage: d = arrow((1,1), (5,5)).get_minmax_data()
        sage: d['xmin']
        1.0
        sage: d['xmax']
        5.0

  `plot3d`(ztail=0, zhead=0, **kwds)

    Takes 2D plot and places it in 3D.

    EXAMPLES:

        sage: A = arrow((0,0),(1,1))[0].plot3d()
        sage: A.jmol_repr(A.testing_render_params())[0]
        'draw line_1 diameter 2 arrow {0.0 0.0 0.0}  {1.0 1.0 0.0} '

    Note that we had to index the arrow to get the Arrow graphics primitive. We can also change the height via the plot3d method of Graphics, but only as a whole:

        sage: A = arrow((0,0),(1,1)).plot3d(3)
        sage: A.jmol_repr(A.testing_render_params())[0][0]
        'draw line_1 diameter 2 arrow {0.0 0.0 3.0}  {1.0 1.0 3.0} '

    Optional arguments place both the head and tail outside the \(xy\)-plane, but at different heights. This must be done on the graphics primitive obtained by indexing:

        sage: A=arrow((0,0),(1,1))[0].plot3d(3,4)
        sage: A.jmol_repr(A.testing_render_params())[0]
        'draw line_1 diameter 2 arrow {0.0 0.0 3.0}  {1.0 1.0 4.0} '

class `sage.plot.arrow.``CurveArrow`(path, options)

  Bases: `sage.plot.primitive.GraphicPrimitive`

  Returns an arrow graphics primitive along the provided path (bezier curve).

  EXAMPLES:

      sage: from sage.plot.arrow import CurveArrow
      sage: b = CurveArrow(path=[[(0,0),(.5,.5),(1,0)],[(.5,1),(0,0)]],options={})
      sage: b
      CurveArrow from (0, 0) to (0, 0)

  `get_minmax_data`()

    Returns a dictionary with the bounding box data.

    EXAMPLES:

        sage: from sage.plot.arrow import CurveArrow
        sage: b = CurveArrow(path=[[(0,0),(.5,.5),(1,0)],[(.5,1),(0,0)]],options={})
        sage: d = b.get_minmax_data()
        sage: d['xmin']
        0.0
        sage: d['xmax']
        1.0

`sage.plot.arrow.``arrow`(tailpoint=None, headpoint=None, **kwds)

  Returns either a 2-dimensional or 3-dimensional arrow depending on value of points.

  For information regarding additional arguments, see either arrow2d? or arrow3d?.

  EXAMPLES:

      sage: arrow((0,0), (1,1))
      Graphics object consisting of 1 graphics primitive
      sage: arrow((0,0,1), (1,1,1))
      Graphics3d Object

`sage.plot.arrow.``arrow2d`(tailpoint=None, headpoint=None, path=None, head=1, linestyle='solid', rgbcolor=(0, 0, 1), width=2, zorder=2, legend_label=None, **options)

  If tailpoint and headpoint are provided, returns an arrow from (xmin, ymin) to (xmax, ymax). If tailpoint or headpoint is None and path is not None, returns an arrow along the path. (See further info on paths in bezier_path).

  INPUT:

  - `tailpoint` - the starting point of the arrow
  - `headpoint` - where the arrow is pointing to
  - `path` - the list of points and control points (see bezier_path for detail) that the arrow will follow from source to destination
  - `head` - 0, 1 or 2, whether to draw the head at the start (0), end (1) or both (2) of the path (using 0 will swap headpoint and tailpoint). This is ignored in 3D plotting.
  - `linestyle` - (default: `'solid'`) The style of the line, which is one of `'dashed'`, `'dotted'`, `'solid'`, `'dashdot'`, or `'--'`, `':'`, `'-'`, `'-.'`, respectively.
  - `width` - (default: 2) the width of the arrow shaft, in points
  - `color` - (default: (0,0,1)) the color of the arrow (as an RGB tuple or a string)
  - `hue` - the color of the arrow (as a number)
  - `arrowsize` - the size of the arrowhead
  - `arrowshorten` - the length in points to shorten the arrow (ignored if using path parameter)
  - `legend_label` - the label for this item in the legend
  - `legend_color` - the color for the legend label
  - `zorder` - the layer level to draw the arrow– note that this is ignored in 3D plotting.

  EXAMPLES:

  A straight, blue arrow:

      sage: arrow2d((1, 1), (3, 3))
      Graphics object consisting of 1 graphics primitive

  Make a red arrow:

      sage: arrow2d((-1, -1), (2, 3), color=(1,0,0))
      Graphics object consisting of 1 graphics primitive
      sage: arrow2d((-1, -1), (2, 3), color='red')
      Graphics object consisting of 1 graphics primitive

  You can change the width of an arrow:

      sage: arrow2d((1, 1), (3, 3), width=5, arrowsize=15)
      Graphics object consisting of 1 graphics primitive

  Use a dashed line instead of a solid one for the arrow:

      sage: arrow2d((1, 1), (3, 3), linestyle='dashed')
      Graphics object consisting of 1 graphics primitive
      sage: arrow2d((1, 1), (3, 3), linestyle='--')
      Graphics object consisting of 1 graphics primitive

  A pretty circle of arrows:

      sage: sum([arrow2d((0,0), (cos(x),sin(x)), hue=x/(2*pi)) for x in [0..2*pi,step=0.1]])
      Graphics object consisting of 63 graphics primitives

  If we want to draw the arrow between objects, for example, the boundaries of two lines, we can use the arrowshorten option to make the arrow shorter by a certain number of points:

      sage: line([(0,0),(1,0)],thickness=10)+line([(0,1),(1,1)], thickness=10)+arrow2d((0.5,0),(0.5,1), arrowshorten=10,rgbcolor=(1,0,0))
      Graphics object consisting of 3 graphics primitives

  If BOTH headpoint and tailpoint are None, then an empty plot is returned:

      sage: arrow2d(headpoint=None, tailpoint=None)
      Graphics object consisting of 0 graphics primitives

  We can also draw an arrow with a legend:

      sage: arrow((0,0), (0,2), legend_label='up', legend_color='purple')
      Graphics object consisting of 1 graphics primitive

  Extra options will get passed on to show(), as long as they are valid:

      sage: arrow2d((-2, 2), (7,1), frame=True)
      Graphics object consisting of 1 graphics primitive
      sage: arrow2d((-2, 2), (7,1)).show(frame=True)

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