/usr/lib/python3/dist-packages/cairocffi/matrix.py is in python3-cairocffi 0.7.2-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 | # coding: utf8
"""
cairocffi.matrix
~~~~~~~~~~~~~~~~
Transformation matrices.
:copyright: Copyright 2013 by Simon Sapin
:license: BSD, see LICENSE for details.
"""
from . import ffi, cairo, _check_status
class Matrix(object):
"""A 2D transformation matrix.
Matrices are used throughout cairo to convert between
different coordinate spaces.
A :class:`Matrix` holds an affine transformation,
such as a scale, rotation, shear, or a combination of these.
The transformation of a point (x,y) is given by::
x_new = xx * x + xy * y + x0
y_new = yx * x + yy * y + y0
The current transformation matrix of a :class:`Context`,
represented as a :class:`Matrix`,
defines the transformation from user-space coordinates
to device-space coordinates.
See :meth:`Context.get_matrix` and :meth:`Context.set_matrix`.
The default values produce an identity matrix.
Matrices can be compared with ``m1 == m2`` and ``m2 != m2``
as well as multiplied with ``m3 = m1 * m2``.
"""
def __init__(self, xx=1, yx=0, xy=0, yy=1, x0=0, y0=0):
self._pointer = ffi.new('cairo_matrix_t *')
cairo.cairo_matrix_init(self._pointer, xx, yx, xy, yy, x0, y0)
@classmethod
def init_rotate(cls, radians):
"""Return a new :class:`Matrix` for a transformation
that rotates by :obj:`radians`.
:type radians: float
:param radians:
Angle of rotation, in radians.
The direction of rotation is defined such that
positive angles rotate in the direction
from the positive X axis toward the positive Y axis.
With the default axis orientation of cairo,
positive angles rotate in a clockwise direction.
"""
result = cls()
cairo.cairo_matrix_init_rotate(result._pointer, radians)
return result
def as_tuple(self):
"""Return all of the matrix’s components.
:returns: A ``(xx, yx, xy, yy, x0, y0)`` tuple of floats.
"""
ptr = self._pointer
return (ptr.xx, ptr.yx, ptr.xy, ptr.yy, ptr.x0, ptr.y0)
def copy(self):
"""Return a new copy of this matrix."""
return type(self)(*self.as_tuple())
def __getitem__(self, index):
return getattr(
self._pointer, ('xx', 'yx', 'xy', 'yy', 'x0', 'y0')[index])
def __iter__(self):
return iter(self.as_tuple())
def __eq__(self, other):
return self.as_tuple() == other.as_tuple()
def __ne__(self, other):
return self.as_tuple() != other.as_tuple()
def __repr__(self):
class_ = type(self)
return '%s(%g, %g, %g, %g, %g, %g)' % (
(class_.__name__,) + self.as_tuple())
def multiply(self, other):
"""Multiply with another matrix
and return the result as a new :class:`Matrix` object.
Same as ``self * other``.
"""
res = Matrix()
cairo.cairo_matrix_multiply(
res._pointer, self._pointer, other._pointer)
return res
__mul__ = multiply
def translate(self, tx, ty):
"""Applies a translation by :obj:`tx`, :obj:`ty`
to the transformation in this matrix.
The effect of the new transformation is to
first translate the coordinates by :obj:`tx` and :obj:`ty`,
then apply the original transformation to the coordinates.
.. note::
This changes the matrix in-place.
:param tx: Amount to translate in the X direction.
:param ty: Amount to translate in the Y direction.
:type tx: float
:type ty: float
"""
cairo.cairo_matrix_translate(self._pointer, tx, ty)
def scale(self, sx, sy=None):
"""Applies scaling by :obj:`sx`, :obj:`sy`
to the transformation in this matrix.
The effect of the new transformation is to
first scale the coordinates by :obj:`sx` and :obj:`sy`,
then apply the original transformation to the coordinates.
If :obj:`sy` is omitted, it is the same as :obj:`sx`
so that scaling preserves aspect ratios.
.. note::
This changes the matrix in-place.
:param sx: Scale factor in the X direction.
:param sy: Scale factor in the Y direction.
:type sx: float
:type sy: float
"""
if sy is None:
sy = sx
cairo.cairo_matrix_scale(self._pointer, sx, sy)
def rotate(self, radians):
"""Applies a rotation by :obj:`radians`
to the transformation in this matrix.
The effect of the new transformation is to
first rotate the coordinates by :obj:`radians`,
then apply the original transformation to the coordinates.
.. note::
This changes the matrix in-place.
:type radians: float
:param radians:
Angle of rotation, in radians.
The direction of rotation is defined such that positive angles
rotate in the direction from the positive X axis
toward the positive Y axis.
With the default axis orientation of cairo,
positive angles rotate in a clockwise direction.
"""
cairo.cairo_matrix_rotate(self._pointer, radians)
def invert(self):
"""Changes matrix to be the inverse of its original value.
Not all transformation matrices have inverses;
if the matrix collapses points together (it is degenerate),
then it has no inverse and this function will fail.
.. note::
This changes the matrix in-place.
:raises: :exc:`CairoError` on degenerate matrices.
"""
_check_status(cairo.cairo_matrix_invert(self._pointer))
def inverted(self):
"""Return the inverse of this matrix. See :meth:`invert`.
:raises: :exc:`CairoError` on degenerate matrices.
:returns: A new :class:`Matrix` object.
"""
matrix = self.copy()
matrix.invert()
return matrix
def transform_point(self, x, y):
"""Transforms the point ``(x, y)`` by this matrix.
:param x: X position.
:param y: Y position.
:type x: float
:type y: float
:returns: A ``(new_x, new_y)`` tuple of floats.
"""
xy = ffi.new('double[2]', [x, y])
cairo.cairo_matrix_transform_point(self._pointer, xy + 0, xy + 1)
return tuple(xy)
def transform_distance(self, dx, dy):
"""Transforms the distance vector ``(dx, dy)`` by this matrix.
This is similar to :meth:`transform_point`
except that the translation components of the transformation
are ignored.
The calculation of the returned vector is as follows::
dx2 = dx1 * xx + dy1 * xy
dy2 = dx1 * yx + dy1 * yy
Affine transformations are position invariant,
so the same vector always transforms to the same vector.
If ``(x1, y1)`` transforms to ``(x2, y2)``
then ``(x1 + dx1, y1 + dy1)`` will transform
to ``(x1 + dx2, y1 + dy2)`` for all values of ``x1`` and ``x2``.
:param dx: X component of a distance vector.
:param dy: Y component of a distance vector.
:type dx: float
:type dy: float
:returns: A ``(new_dx, new_dy)`` tuple of floats.
"""
xy = ffi.new('double[2]', [dx, dy])
cairo.cairo_matrix_transform_distance(self._pointer, xy + 0, xy + 1)
return tuple(xy)
def _component_property(name):
return property(
lambda self: getattr(self._pointer, name),
lambda self, value: setattr(self._pointer, name, value),
doc='Read-write attribute access to a single float component.')
xx = _component_property('xx')
yx = _component_property('yx')
xy = _component_property('xy')
yy = _component_property('yy')
x0 = _component_property('x0')
y0 = _component_property('y0')
del _component_property
|