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))
sage: arrow((0,0,1), (1,1,1))
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))

Make a red arrow:

sage: arrow2d((-1, -1), (2, 3), color=(1,0,0))
sage: arrow2d((-1, -1), (2, 3), color='red')

You can change the width of an arrow:

sage: arrow2d((1, 1), (3, 3), width=5, arrowsize=15)

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

sage: arrow2d((1, 1), (3, 3), linestyle='dashed')
sage: arrow2d((1, 1), (3, 3), linestyle='--')

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]])

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))

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

sage: arrow2d(headpoint=None, tailpoint=None)

We can also draw an arrow with a legend:

sage: arrow((0,0), (0,2), legend_label='up', legend_color='purple')

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

sage: arrow2d((-2, 2), (7,1), frame=True)
sage: arrow2d((-2, 2), (7,1)).show(frame=True)

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