expyriment.misc.geometry

The geometry module.

This module contains miscellaneous geometry functions for expyriment.

Classes

expyriment.misc.geometry.XYPoint

Functions

expyriment.misc.geometry.cartesian_to_polar(xy, radians=False)

Convert a cartesian coordinate (x,y) to a polar coordinate (radial, angle[degrees]).

Parameters:

xy(float, float): cartesian coordinate (x,y)
radiansboolean: use radians instead of degrees for the angle

Returns:

polar(float, float): polar coordinate (radial, angle[degrees])

expyriment.misc.geometry.coordinates_to_position(coordinates, surface_size=None)

Convert coordinates on the screen or surface to an Expyriment position.

Parameters:

coordinates(int, int): coordinates (x,y) to convert
surface_size: (int, int), optional: size of the surface one which position is defined if None (default), the position will be calculated relative to the screen

Returns:

position[int, int]

expyriment.misc.geometry.lines_intersect(pa, pb, pc, pd)

Returns true if two line segments are intersecting

Parameters:

pamisc.geometry.XYPoint: point 1 of line 1
pbmisc.geometry.XYPoint: point 2 of line 1
pcmisc.geometry.XYPoint: point 1 of line 2
pbmisc.geometry.XYPoint: point 2 of line 2

Returns:

checkbool: True if lines intersect

expyriment.misc.geometry.lines_intersection_point(pa, pb, pc, pd)

Returns the intersection point of two lines (a-b) and (c-d)

Parameters:

pamisc.geometry.XYPoint: point 1 of line 1
pbmisc.geometry.XYPoint: point 2 of line 1
pcmisc.geometry.XYPoint: point 1 of line 2
pbmisc.geometry.XYPoint: point 2 of line 2

Returns:

intersec_point: misc.geometry.XYPoint: intersection point

expyriment.misc.geometry.points_to_vertices(points)

Returns vertex representation of the points (list of tuples (x,y)).

Parameters:

points(int, int): list of points

Returns:

vtxlist: list of vertices

expyriment.misc.geometry.polar_to_cartesian(polar, radians=False)

Convert a polar coordinate (radial, angle[degrees]) to a polar coordinate (x, y)

Parameters:

polar(float, float): polar coordinate (radial, angle[degrees])
radiansboolean: use radians instead of degrees for the angle

Returns:

xy(float, float): cartesian coordinate (x,y)

expyriment.misc.geometry.position_to_coordinates(position, surface_size=None)

Convert an Expyriment position to coordinates on the screen or surface.

Parameters:

position(int, int): position (x,y) to convert
surface_size: (int, int), optional: size of the surface one which coordinates should be calculated if None (default), the coordinates will be calculated relative to the screen

Returns:

coordinates[int, int]

expyriment.misc.geometry.position_to_visual_angle(position, viewing_distance, monitor_size)

Convert an expyriment position (pixel) to a visual angle from center.

Parameters:

position(int, int): position (x,y) to convert
viewing_distancenumeric: viewing distance in cm
monitor_sizenumeric: physical size of the monitor in cm (x, y)

Returns:

angle(float, float): visual angle for x & y dimension

expyriment.misc.geometry.tuples_to_points(list_of_tuples): Converts a list of tuples (x,y) to a list of misc.XYPoints

expyriment.misc.geometry.vertices_cross(size, line_width)

Returns a list of vertices describing a cross.

Parameters:

size(int, int): xy, length of the horizontal (x) and vertical (y) line
line_widthint: width of the lines

Returns:

vtxlist of vertices

See also

expyriment.stimuli.FixCross

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.vertices_frame(size, frame_thickness)

Returns a list of vertices describing a frame

Parameters:

size(int, int): size (width, height) of the rectangle
frame_thicknessint: the thickness of the frame

Returns:

vtxlist of vertices

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.vertices_parallelogram(angle, length1, length2)

Returns a list of vertices describing a parallelogram A, B, C, D.

   A --- B
  .     .
 .     .
D --- C

Parameters:

anglefloat: the angle between the lines AB and BC in degrees
length1float: the length between AB
length2float: the length between BC

Returns:

vtxlist of vertices

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.vertices_rectangle(size)

Returns a list of vertices describing a rectangle.

Parameters:

size(int, int): size (width, height) of the rectangle

Returns:

vtxlist of vertices

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.vertices_regular_polygon(n_edges, length)

Returns a list of vertices describing a regular polygon.

Parameters:

n_edgesint: the number of edges
lengthfloat: the length of one side of the polygon

Returns:

vtxlist of vertices

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.vertices_trapezoid(width_top, width_bottom, height)

Returns a list of vertices describing a trapezoid

Parameters:

width_top: int: width of the top edge
width_bottom: int: width of the bottom edge
heightint: height of the trapezoid

Returns:

vtxlist of vertices

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.vertices_triangle(angle, length1, length2)

Returns a list of vertices describing a triangle A, B, C.

A --- B
     .
    .
   C

Parameters:

anglefloat: the angle between the lines AB and BC in degrees
length1float: the length between AB
length2float: the length between BC

Returns:

vtxlist of vertices

Notes

The resulting vertices can be plotted with the class stimuli.Shape(vertex_list=…).

expyriment.misc.geometry.visual_angle_to_position(visual_angle, viewing_distance, monitor_size)

Convert an position defined as visual angle from center to expyriment position (pixel).

Parameters:

visual_angle(numeric, numeric): position in visual angle (x,y) to convert
viewing_distancenumeric: viewing distance in cm
monitor_size(numeric, numeric): physical size of the monitor in cm (x, y)

Returns:

position(float, float): position (x,y)