Arcs of circles and ellipses¶

class sage.plot.arc.Arc(x, y, r1, r2, angle, s1, s2, options)

Primitive class for the Arc graphics type. See arc? for information about actually plotting an arc of a circle or an ellipse.

INPUT:

• x,y - coordinates of the center of the arc
• r1, r2 - lengths of the two radii
• angle - angle of the horizontal with width
• sector - sector of angle
• options - dict of valid plot options to pass to constructor

EXAMPLES:

Note that the construction should be done using arc:

sage: from sage.plot.arc import Arc
sage: print(Arc(0,0,1,1,pi/4,pi/4,pi/2,{}))
Arc with center (0.0,0.0) radii (1.0,1.0) angle 0.78539816339... inside the sector (0.78539816339...,1.5707963267...)
bezier_path()

Return self as a Bezier path.

This is needed to concatenate arcs, in order to create hyperbolic polygons.

EXAMPLES:

sage: from sage.plot.arc import Arc
sage: op = {'alpha':1,'thickness':1,'rgbcolor':'blue','zorder':0,
....:     'linestyle':'--'}
sage: Arc(2,3,2.2,2.2,0,2,3,op).bezier_path()
Graphics object consisting of 1 graphics primitive

sage: a = arc((0,0),2,1,0,(pi/5,pi/2+pi/12), linestyle="--", color="red")
sage: b = a.bezier_path()
sage: b
Bezier path from (1.133..., 0.8237...) to (-0.2655..., 0.9911...)
get_minmax_data()

Return a dictionary with the bounding box data.

The bounding box is computed as minimal as possible.

EXAMPLES:

An example without angle:

sage: p = arc((-2, 3), 1, 2)
sage: d = p.get_minmax_data()
sage: d['xmin']
-3.0
sage: d['xmax']
-1.0
sage: d['ymin']
1.0
sage: d['ymax']
5.0

The same example with a rotation of angle $$\pi/2$$:

sage: p = arc((-2, 3), 1, 2, pi/2)
sage: d = p.get_minmax_data()
sage: d['xmin']
-4.0
sage: d['xmax']
0.0
sage: d['ymin']
2.0
sage: d['ymax']
4.0
plot3d()
sage.plot.arc.arc(center, r1, r2=None, angle=0.0, sector=(0.0, 6.283185307179586), rgbcolor='blue', thickness=1, zorder=5, aspect_ratio=1.0, alpha=1, linestyle='solid', **options)

An arc (that is a portion of a circle or an ellipse)

Type arc.options to see all options.

INPUT:

• center - 2-tuple of real numbers - position of the center.
• r1, r2 - positive real numbers - radii of the ellipse. If only r1 is set, then the two radii are supposed to be equal and this function returns an arc of circle.
• angle - real number - angle between the horizontal and the axis that corresponds to r1.
• sector - 2-tuple (default: (0,2*pi))- angles sector in which the arc will be drawn.

OPTIONS:

• alpha - float (default: 1) - transparency
• thickness - float (default: 1) - thickness of the arc
• color, rgbcolor - string or 2-tuple (default: ‘blue’) - the color of the arc
• linestyle - string (default: 'solid') - The style of the line, which is one of 'dashed', 'dotted', 'solid', 'dashdot', or '--', ':', '-', '-.', respectively.

EXAMPLES:

Plot an arc of circle centered at (0,0) with radius 1 in the sector $$(\pi/4,3*\pi/4)$$:

sage: arc((0,0), 1, sector=(pi/4,3*pi/4))
Graphics object consisting of 1 graphics primitive

Plot an arc of an ellipse between the angles 0 and $$\pi/2$$:

sage: arc((2,3), 2, 1, sector=(0,pi/2))
Graphics object consisting of 1 graphics primitive

Plot an arc of a rotated ellipse between the angles 0 and $$\pi/2$$:

sage: arc((2,3), 2, 1, angle=pi/5, sector=(0,pi/2))
Graphics object consisting of 1 graphics primitive

Plot an arc of an ellipse in red with a dashed linestyle:

sage: arc((0,0), 2, 1, 0, (0,pi/2), linestyle="dashed", color="red")
Graphics object consisting of 1 graphics primitive
sage: arc((0,0), 2, 1, 0, (0,pi/2), linestyle="--", color="red")
Graphics object consisting of 1 graphics primitive

The default aspect ratio for arcs is 1.0:

sage: arc((0,0), 1, sector=(pi/4,3*pi/4)).aspect_ratio()
1.0

It is not possible to draw arcs in 3D:

sage: A = arc((0,0,0), 1)
Traceback (most recent call last):
...
NotImplementedError