matplotlib.patches.Arc — Matplotlib 3.10.1 documentation (original) (raw)
class matplotlib.patches.Arc(xy, width, height, *, angle=0.0, theta1=0.0, theta2=360.0, **kwargs)[source]#
Bases: Ellipse
An elliptical arc, i.e. a segment of an ellipse.
Due to internal optimizations, the arc cannot be filled.
Parameters:
xy(float, float)
The center of the ellipse.
widthfloat
The length of the horizontal axis.
heightfloat
The length of the vertical axis.
anglefloat
Rotation of the ellipse in degrees (counterclockwise).
theta1, theta2float, default: 0, 360
Starting and ending angles of the arc in degrees. These values are relative to angle, e.g. if angle = 45 and theta1 = 90 the absolute starting angle is 135. Default theta1 = 0, theta2 = 360, i.e. a complete ellipse. The arc is drawn in the counterclockwise direction. Angles greater than or equal to 360, or smaller than 0, are represented by an equivalent angle in the range [0, 360), by taking the input value mod 360.
Other Parameters:
**kwargsPatch properties
Most Patch properties are supported as keyword arguments, except fill and facecolor because filling is not supported.
Draw the arc to the given renderer.
Notes
Ellipses are normally drawn using an approximation that uses eight cubic Bezier splines. The error of this approximation is 1.89818e-6, according to this unverified source:
There is a use case where very large ellipses must be drawn with very high accuracy, and it is too expensive to render the entire ellipse with enough segments (either splines or line segments). Therefore, in the case where either radius of the ellipse is large enough that the error of the spline approximation will be visible (greater than one pixel offset from the ideal), a different technique is used.
In that case, only the visible parts of the ellipse are drawn, with each visible arc using a fixed number of spline segments (8). The algorithm proceeds as follows:
- The points where the ellipse intersects the axes (or figure) bounding box are located. (This is done by performing an inverse transformation on the bbox such that it is relative to the unit circle -- this makes the intersection calculation much easier than doing rotated ellipse intersection directly.)
This uses the "line intersecting a circle" algorithm from:Vince, John. Geometry for Computer Graphics: Formulae, Examples & Proofs. London: Springer-Verlag, 2005.
- The angles of each of the intersection points are calculated.
- Proceeding counterclockwise starting in the positive x-direction, each of the visible arc-segments between the pairs of vertices are drawn using the Bezier arc approximation technique implemented in Path.arc.
set(*, agg_filter=, alpha=, angle=, animated=, antialiased=, capstyle=, center=, clip_box=, clip_on=, clip_path=, color=, edgecolor=, facecolor=, fill=, gid=, hatch=, hatch_linewidth=, height=, in_layout=, joinstyle=, label=, linestyle=, linewidth=, mouseover=, path_effects=, picker=, rasterized=, sketch_params=, snap=, transform=, url=, visible=, width=, zorder=)[source]#
Set multiple properties at once.
Supported properties are