Transformation¶

This module contains a Matrix class used for our Graphics calculations. We currently support:

rotation, translation and scaling matrices
multiplication matrix
clip matrix (with or without perspective)
transformation matrix for 3d touch

For more information on transformation matrices, please see the OpenGL Matrices Tutorial.

Changed in version 1.6.0: Added Matrix.perspective(), Matrix.look_at() and Matrix.transpose().

class kivy.graphics.transformation.Matrix¶

Bases: builtins.object

Optimized matrix class for OpenGL:

>>> from kivy.graphics.transformation import Matrix
>>> m = Matrix()
>>> print(m)
[[ 1.000000 0.000000 0.000000 0.000000 ]
[ 0.000000 1.000000 0.000000 0.000000 ]
[ 0.000000 0.000000 1.000000 0.000000 ]
[ 0.000000 0.000000 0.000000 1.000000 ]]

[ 0   1   2   3]
[ 4   5   6   7]
[ 8   9  10  11]
[ 12  13  14  15]

get()¶: Retrieve the value of the current as a flat list.

New in version 1.9.1.

identity()¶: Reset the matrix to the identity matrix (inplace).

inverse()¶: Return the inverse of the matrix as a new Matrix.

look_at()¶

Returns a new lookat Matrix (similar to gluLookAt).

Parameters

eyex: float: Eyes X co-ordinate
eyey: float: Eyes Y co-ordinate
eyez: float: Eyes Z co-ordinate
centerx: float: The X position of the reference point
centery: float: The Y position of the reference point
centerz: float: The Z position of the reference point
upx: float: The X value up vector.
upy: float: The Y value up vector.
upz: float: The Z value up vector.

New in version 1.6.0.

multiply()¶

Multiply the given matrix with self (from the left) i.e. we premultiply the given matrix by the current matrix and return the result (not inplace):

m.multiply(n) -> n * m

Parameters

ma: Matrix: The matrix to multiply by

normal_matrix()¶: Computes the normal matrix, which is the inverse transpose of the top left 3x3 modelview matrix used to transform normals into eye/camera space.

New in version 1.6.0.

perspective()¶

Creates a perspective matrix (inplace).

Parameters

fovy: float: “Field Of View” angle
aspect: float: Aspect ratio
zNear: float: Near clipping plane
zFar: float: Far clippin plane

New in version 1.6.0.

project()¶

Project a point from 3d space into a 2d viewport.

Parameters

objx: float: Points X co-ordinate
objy: float: Points Y co-ordinate
objz: float: Points Z co-ordinate
model: Matrix: The model matrix
proj: Matrix: The projection matrix
vx: float: Viewports X co-ordinate
vy: float: Viewports y co-ordinate
vw: float: Viewports width
vh: float: Viewports height

New in version 1.7.0.

rotate()¶

Rotate the matrix through the angle around the axis (x, y, z) (inplace).

Parameters

angle: float: The angle through which to rotate the matrix
x: float: X position of the point
y: float: Y position of the point
z: float: Z position of the point

scale()¶

Scale the current matrix by the specified factors over each dimension (inplace).

Parameters

x: float: The scale factor along the X axis
y: float: The scale factor along the Y axis
z: float: The scale factor along the Z axis

set()¶

Insert custom values into the matrix in a flat list format or 4x4 array format like below:

m.set(array=[
    [1.0, 0.0, 0.0, 0.0],
    [0.0, 1.0, 0.0, 0.0],
    [0.0, 0.0, 1.0, 0.0],
    [0.0, 0.0, 0.0, 1.0]]
)

New in version 1.9.0.

tolist()¶

Retrieve the value of the current matrix in numpy format. for example m.tolist() will return:

[[1.000000, 0.000000, 0.000000, 0.000000],
[0.000000, 1.000000, 0.000000, 0.000000],
[0.000000, 0.000000, 1.000000, 0.000000],
[0.000000, 0.000000, 0.000000, 1.000000]]

you can use this format to plug the result straight into numpy in this way numpy.array(m.tolist())

New in version 1.9.0.

transform_point()¶

Transforms the point by the matrix and returns the transformed point as a (x, y, z) tuple. If the point is a vector v, the returned values is v2 = matrix * v.

If t is provided, it multiplies it with the last column of the matrix and returns the transformed (x, y, z, t).

translate()¶

Translate the matrix.

Parameters

x: float: The translation factor along the X axis
y: float: The translation factor along the Y axis
z: float: The translation factor along the Z axis

transpose()¶: Return the transposed matrix as a new Matrix.

New in version 1.6.0.

view_clip()¶

Create a clip matrix (inplace).

Parameters

left: float: Co-ordinate
right: float: Co-ordinate
bottom: float: Co-ordinate
top: float: Co-ordinate
near: float: Co-ordinate
far: float: Co-ordinate
perpective: int: Co-ordinate

Changed in version 1.6.0: Enable support for perspective parameter.

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Transformation¶