Description

npeuclid is a library that provides vector and matrix classes for 2D and 3D graphics applications.

npeuclid is a port of the https://github.com/ezag/pyeuclid library to numpy. Instead of doing matrix multiplications in native python as euclid is doing, npeuclid is delegating all calculations to numpy.

Differences to pyeuclid

• The base type of all pyeuclid types are numpy ndarrays.
• 2D and 3D geometry is supported. Currenly there is no quaternion support.
• All operaters return their transformed values, i.e. there are no inline operators. E.g. t.scale(sx,sy) will return a scaled version of t, and won't modify t.
• There is no vector point and vector support like in euclid. There is only one type Vec2, which behaves like a point under transformation. To get a vector transformation do t.linear()*p (like in Eigen).

Types

Here are the types defined by npeuclid:

2D

• Vec2 - Holds a 2D vector (or point).
• Vec2Array - Holds a list of points. All operations that can be done on a single Vec2 should be available on a Vec2Array as well. In particular, an Affine2 operation may be applied on a Vec2Array which will transform all the points.
• Affine2 - An 2D affine transformation.

3D

• Vec3 - Holds a 3D vector (or point).
• Vec3Array - Holds a list of points. All operations that can be done on a single Vec3 should be available on a Vec3Array as well. In particular, an Affine3 operation may be applied on a Vec3Array which will transform all the points.
• Affine3 - An 3D affine transformation.

Usage

2D

p = Vec2(2,3)
q = Vec2(5,6)
angle = math.radians(33)
t = Affine2.new_translate(p.x,p.y).rotate(angle).translate(-p.x,-p.y)
print(t*q)
t = Affine2.new_rotate_around(angle, p.x, p.y)
print(t*q)
t = Affine2.rotate_around(angle, p.x, p.y)
print(t*q)
t = Affine2.new_translate(p.x,p.y)
print(t*p, t.linear()*p) 

# Use of Vec2Array is using numpy and is *much* faster than looping.
pp = Vec2Array([[5,6],[7,8],[3,4]])
print (t*pp)[0]

3D

p = Vec2(2,3,4)
q = Vec2(5,6,7)
angle = math.radians(33)
t = Affine2.new_translate(p.x,p.y).rotatex(angle).translate(-p.x,-p.y)
print(t*q)