File: internals.py

package info (click to toggle)
python-pyqtgraph 0.13.7-6
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 8,072 kB
  • sloc: python: 54,043; makefile: 127; ansic: 40; sh: 2
file content (231 lines) | stat: -rw-r--r-- 8,016 bytes parent folder | download | duplicates (2)
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
import ctypes
import itertools

import numpy as np

from . import QT_LIB, QtCore, QtGui, compat

__all__ = ["get_qpainterpath_element_array"]

if QT_LIB.startswith('PyQt'):
    from . import sip
elif QT_LIB == 'PySide2':
    from PySide2 import __version_info__ as pyside_version_info
elif QT_LIB == 'PySide6':
    from PySide6 import __version_info__ as pyside_version_info

class QArrayDataQt5(ctypes.Structure):
    _fields_ = [
        ("ref", ctypes.c_int),
        ("size", ctypes.c_int),
        ("alloc", ctypes.c_uint, 31),
        ("offset", ctypes.c_ssize_t),
    ]

class QPainterPathPrivateQt5(ctypes.Structure):
    _fields_ = [
        ("ref", ctypes.c_int),
        ("adata", ctypes.POINTER(QArrayDataQt5)),
    ]

class QArrayDataQt6(ctypes.Structure):
    _fields_ = [
        ("ref", ctypes.c_int),
        ("flags", ctypes.c_uint),
        ("alloc", ctypes.c_ssize_t),
    ]

class QPainterPathPrivateQt6(ctypes.Structure):
    _fields_ = [
        ("ref", ctypes.c_int),
        ("adata", ctypes.POINTER(QArrayDataQt6)),
        ("data", ctypes.c_void_p),
        ("size", ctypes.c_ssize_t),
    ]

def get_qpainterpath_element_array(qpath, nelems=None):
    writable = nelems is not None
    if writable:
        qpath.reserve(nelems)

    itemsize = 24
    dtype = dict(names=['x','y','c'], formats=['f8', 'f8', 'i4'], itemsize=itemsize)

    ptr0 = compat.unwrapinstance(qpath)
    pte_cp = ctypes.c_void_p.from_address(ptr0)
    if not pte_cp:
        return np.zeros(0, dtype=dtype)

    # _cp : ctypes pointer
    # _ci : ctypes instance
    if QT_LIB in ['PyQt5', 'PySide2']:
        PTR = ctypes.POINTER(QPainterPathPrivateQt5)
        pte_ci = ctypes.cast(pte_cp, PTR).contents
        size_ci = pte_ci.adata[0]
        eptr = ctypes.addressof(size_ci) + size_ci.offset
    elif QT_LIB in ['PyQt6', 'PySide6']:
        PTR = ctypes.POINTER(QPainterPathPrivateQt6)
        pte_ci = ctypes.cast(pte_cp, PTR).contents
        size_ci = pte_ci
        eptr = pte_ci.data
    else:
        raise NotImplementedError

    if writable:
        size_ci.size = nelems
    else:
        nelems = size_ci.size

    vp = compat.voidptr(eptr, itemsize*nelems, writable)
    return np.frombuffer(vp, dtype=dtype)

class PrimitiveArray:
    # Note: This class is an internal implementation detail and is not part
    #       of the public API.
    #
    # QPainter has a C++ native API that takes an array of objects:
    #   drawPrimitives(const Primitive *array, int count, ...)
    # where "Primitive" is one of QPointF, QLineF, QRectF, PixmapFragment
    #
    # PySide (with the exception of drawPixmapFragments) and older PyQt
    # require a Python list of "Primitive" instances to be provided to
    # the respective "drawPrimitives" method.
    #
    # This is inefficient because:
    # 1) constructing the Python list involves calling wrapinstance multiple times.
    #    - this is mitigated here by reusing the instance pointers
    # 2) The binding will anyway have to repack the instances into a contiguous array,
    #    in order to call the underlying C++ native API.
    #
    # Newer PyQt provides sip.array, which is more efficient.
    #
    # PySide's drawPixmapFragments() takes an instance to the first item of a
    # C array of PixmapFragment(s) _and_ the length of the array.
    # There is no overload that takes a Python list of PixmapFragment(s).

    def __init__(self, Klass, nfields, *, use_array=None):
        self._Klass = Klass
        self._nfields = nfields
        self._capa = -1

        self.use_sip_array = False
        self.use_ptr_to_array = False

        if QT_LIB.startswith('PyQt'):
            if use_array is None:
                use_array = (
                    hasattr(sip, 'array') and
                    (
                        (0x60301 <= QtCore.PYQT_VERSION) or
                        (0x50f07 <= QtCore.PYQT_VERSION < 0x60000)
                    )
                )
            self.use_sip_array = use_array

        if QT_LIB.startswith('PySide'):
            if use_array is None:
                use_array = (
                    Klass is QtGui.QPainter.PixmapFragment
                    or pyside_version_info >= (6, 4, 3)
                )
            self.use_ptr_to_array = use_array

        self.resize(0)

    def resize(self, size):
        if self.use_sip_array:
            # For reference, SIP_VERSION 6.7.8 first arrived
            # in PyQt5_sip 12.11.2 and PyQt6_sip 13.4.2
            if sip.SIP_VERSION >= 0x60708:
                if size <= self._capa:
                    self._size = size
                    return
            else:
                # sip.array prior to SIP_VERSION 6.7.8 had a
                # buggy slicing implementation.
                # so trigger a reallocate for any different size
                if size == self._capa:
                    return

            self._siparray = sip.array(self._Klass, size)

        else:
            if size <= self._capa:
                self._size = size
                return
            self._ndarray = np.empty((size, self._nfields), dtype=np.float64)

            if self.use_ptr_to_array:
                # defer creation
                self._objs = None
            else:
                self._objs = self._wrap_instances(self._ndarray)

        self._capa = size
        self._size = size

    def _wrap_instances(self, array):
        return list(map(compat.wrapinstance,
            itertools.count(array.ctypes.data, array.strides[0]),
            itertools.repeat(self._Klass, array.shape[0])))

    def __len__(self):
        return self._size

    def ndarray(self):
        # ndarray views are cheap to recreate each time
        if self.use_sip_array:
            if (
                sip.SIP_VERSION >= 0x60708 and 
                np.__version__ != "1.22.4"  # TODO: remove me after numpy 1.23+
            ):  # workaround for numpy/sip compatability issue
                # see https://github.com/numpy/numpy/issues/21612
                mv = self._siparray
            else:
                # sip.array prior to SIP_VERSION 6.7.8 had a buggy buffer protocol
                # that set the wrong size.
                # workaround it by going through a sip.voidptr
                mv = sip.voidptr(self._siparray, self._capa*self._nfields*8)
            # note that we perform the slicing by using only _size rows
            nd = np.frombuffer(mv, dtype=np.float64, count=self._size*self._nfields)
            return nd.reshape((-1, self._nfields))
        else:
            return self._ndarray[:self._size]

    def instances(self):
        # this returns an iterable container of Klass instances.
        # for "use_ptr_to_array" mode, such a container may not
        # be required at all, so its creation is deferred
        if self.use_sip_array:
            if self._size == self._capa:
                # avoiding slicing when it's not necessary
                # handles the case where sip.array had a buggy
                # slicing implementation 
                return self._siparray
            else:
                # this is a view
                return self._siparray[:self._size]

        if self._objs is None:
            self._objs = self._wrap_instances(self._ndarray)

        if self._size == self._capa:
            return self._objs
        else:
            # this is a shallow copy
            return self._objs[:self._size]

    def drawargs(self):
        # returns arguments to apply to the respective drawPrimitives() functions
        if self.use_ptr_to_array:
            if self._capa > 0:
                # wrap memory only if it is safe to do so
                ptr = compat.wrapinstance(self._ndarray.ctypes.data, self._Klass)
            else:
                # shiboken translates None <--> nullptr
                # alternatively, we could instantiate a dummy _Klass()
                ptr = None
            return ptr, self._size

        else:
            return self.instances(),