Merge pull request #1936 from pijyoi/empty_qpolygonf

Handle empty QPolygonF

examples/PlotSpeedTest.py

@@ -17,12 +17,10 @@ import pyqtgraph.functions as fn
 import itertools
 import argparse
 
-if QT_LIB == 'PySide2':
-    wrapinstance = pg.Qt.shiboken2.wrapInstance
-elif QT_LIB == 'PySide6':
-    wrapinstance = pg.Qt.shiboken6.wrapInstance
-elif QT_LIB in ['PyQt5', 'PyQt6']:
+if QT_LIB.startswith('PyQt'):
     wrapinstance = pg.Qt.sip.wrapinstance
+else:
+    wrapinstance = pg.Qt.shiboken.wrapInstance
 
 # defaults here result in the same configuration as the original PlotSpeedTest
 parser = argparse.ArgumentParser()

pyqtgraph/Qt/__init__.py

@@ -152,7 +152,12 @@ if QT_LIB == PYQT5:
     _copy_attrs(PyQt5.QtGui, QtGui)
     _copy_attrs(PyQt5.QtWidgets, QtWidgets)
 
-    from PyQt5 import sip, uic
+    try:
+        from PyQt5 import sip
+    except ImportError:
+        # some Linux distros package it this way (e.g. Ubuntu)
+        import sip
+    from PyQt5 import uic
 
     try:
         from PyQt5 import QtSvg
@@ -203,8 +208,7 @@ elif QT_LIB == PYSIDE2:
     except ImportError as err:
         QtTest = FailedImport(err)
 
-    import shiboken2
-    isQObjectAlive = shiboken2.isValid
+    import shiboken2 as shiboken
     import PySide2
     VERSION_INFO = 'PySide2 ' + PySide2.__version__ + ' Qt ' + QtCore.__version__
 elif QT_LIB == PYSIDE6:
@@ -226,8 +230,7 @@ elif QT_LIB == PYSIDE6:
     except ImportError as err:
         QtTest = FailedImport(err)
 
-    import shiboken6
-    isQObjectAlive = shiboken6.isValid
+    import shiboken6 as shiboken
     import PySide6
     VERSION_INFO = 'PySide6 ' + PySide6.__version__ + ' Qt ' + QtCore.__version__
 
@@ -313,6 +316,7 @@ if QT_LIB in [PYQT6, PYSIDE6]:
 if QT_LIB in [PYSIDE2, PYSIDE6]:
     QtVersion = QtCore.__version__
     loadUiType = _loadUiType
+    isQObjectAlive = shiboken.isValid
 
     # PySide does not implement qWait
     if not isinstance(QtTest, FailedImport):

pyqtgraph/exporters/ImageExporter.py

@@ -98,7 +98,7 @@ class ImageExporter(Exporter):
         painter.end()
         
         if self.params['invertValue']:
-            bg = fn.qimage_to_ndarray(self.png)
+            bg = fn.ndarray_from_qimage(self.png)
             if sys.byteorder == 'little':
                 cv = slice(0, 3)
             else:

pyqtgraph/functions.py

@@ -42,7 +42,7 @@ __all__ = [
     'makeRGBA', 'makeARGB',
     # 'try_fastpath_argb', 'ndarray_to_qimage',
     'makeQImage',
-    # 'qimage_to_ndarray',
+    # 'ndarray_from_qimage',
     'imageToArray', 'colorToAlpha',
     'gaussianFilter', 'downsample', 'arrayToQPath',
     # 'ndarray_from_qpolygonf', 'create_qpolygonf', 'arrayToQPolygonF',
@@ -1682,24 +1682,28 @@ def makeQImage(imgData, alpha=None, copy=True, transpose=True):
     return ndarray_to_qimage(imgData, imgFormat)
 
 
-def qimage_to_ndarray(qimg):
+def ndarray_from_qimage(qimg):
     img_ptr = qimg.bits()
 
-    if hasattr(img_ptr, 'setsize'): # PyQt sip.voidptr
+    if img_ptr is None:
+        raise ValueError("Null QImage not supported")
+
+    h, w = qimg.height(), qimg.width()
+    bpl = qimg.bytesPerLine()
+    depth = qimg.depth()
+    logical_bpl = w * depth // 8
+
+    if QT_LIB.startswith('PyQt'):
         # sizeInBytes() was introduced in Qt 5.10
         # however PyQt5 5.12 will fail with:
         #   "TypeError: QImage.sizeInBytes() is a private method"
         # note that sizeInBytes() works fine with:
         #   PyQt5 5.15, PySide2 5.12, PySide2 5.15
-        try:
-            # 64-bits size
-            nbytes = qimg.sizeInBytes()
-        except (TypeError, AttributeError):
-            # 32-bits size
-            nbytes = qimg.byteCount()
-        img_ptr.setsize(nbytes)
+        img_ptr.setsize(h * bpl)
+
+    memory = np.frombuffer(img_ptr, dtype=np.ubyte).reshape((h, bpl))
+    memory = memory[:, :logical_bpl]
 
-    depth = qimg.depth()
     if depth in (8, 24, 32):
         dtype = np.uint8
         nchan = depth // 8
@@ -1708,10 +1712,12 @@ def qimage_to_ndarray(qimg):
         nchan = depth // 16
     else:
         raise ValueError("Unsupported Image Type")
-    shape = qimg.height(), qimg.width()
+
+    shape = h, w
     if nchan != 1:
         shape = shape + (nchan,)
-    return np.frombuffer(img_ptr, dtype=dtype).reshape(shape)
+    arr = memory.view(dtype).reshape(shape)
+    return arr
 
 
 def imageToArray(img, copy=False, transpose=True):
@@ -1721,7 +1727,7 @@ def imageToArray(img, copy=False, transpose=True):
     the QImage is collected before the array, there may be trouble).
     The array will have shape (width, height, (b,g,r,a)).
     """
-    arr = qimage_to_ndarray(img)
+    arr = ndarray_from_qimage(img)
 
     fmt = img.format()
     if fmt == img.Format.Format_RGB32:
@@ -2060,25 +2066,25 @@ def arrayToQPath(x, y, connect='all', finiteCheck=True):
 
 def ndarray_from_qpolygonf(polyline):
     nbytes = 2 * len(polyline) * 8
-    if QT_LIB == "PySide2":
-        buffer = Qt.shiboken2.VoidPtr(polyline.data(), nbytes, True)
-    elif QT_LIB == "PySide6":
-        buffer = Qt.shiboken6.VoidPtr(polyline.data(), nbytes, True)
-    else:
+    if QT_LIB.startswith('PyQt'):
         buffer = polyline.data()
+        if buffer is None:
+            buffer = Qt.sip.voidptr(0)
         buffer.setsize(nbytes)
+    else:
+        ptr = polyline.data()
+        if ptr is None:
+            ptr = 0
+        buffer = Qt.shiboken.VoidPtr(ptr, nbytes, True)
     memory = np.frombuffer(buffer, np.double).reshape((-1, 2))
     return memory
 
 def create_qpolygonf(size):
-    if QtVersion.startswith("5"):
-        polyline = QtGui.QPolygonF(size)
+    polyline = QtGui.QPolygonF()
+    if QT_LIB.startswith('PyQt'):
+        polyline.fill(QtCore.QPointF(), size)
     else:
-        polyline = QtGui.QPolygonF()
-        if QT_LIB == "PySide6":
-            polyline.resize(size)
-        else:
-            polyline.fill(QtCore.QPointF(), size)
+        polyline.resize(size)
     return polyline
 
 def arrayToQPolygonF(x, y):

pyqtgraph/graphicsItems/ROI.py

@@ -1299,7 +1299,7 @@ class ROI(GraphicsObject):
         p.drawPath(shape)
         p.end()
         cidx = 0 if sys.byteorder == 'little' else 3
-        mask = fn.qimage_to_ndarray(im)[...,cidx].T
+        mask = fn.ndarray_from_qimage(im)[...,cidx].T
         return mask.astype(float) / 255
         
     def getGlobalTransform(self, relativeTo=None):

pyqtgraph/graphicsItems/ScatterPlotItem.py

@@ -4,6 +4,7 @@ import itertools
 import math
 import numpy as np
 import weakref
+from .. import Qt
 from ..Qt import QtGui, QtCore, QT_LIB
 from ..Point import Point
 from .. import functions as fn
@@ -13,13 +14,6 @@ from .. import getConfigOption
 from collections import OrderedDict
 from .. import debug
 
-if QT_LIB == 'PySide2':
-    from shiboken2 import wrapInstance
-elif QT_LIB == 'PySide6':
-    from shiboken6 import wrapInstance
-elif QT_LIB in ['PyQt5', 'PyQt6']:
-    from ..Qt import sip
-
 __all__ = ['ScatterPlotItem', 'SpotItem']
 
 
@@ -167,11 +161,11 @@ class PixmapFragments:
         #    instances into a contiguous array, in order to call the underlying C++ native API.
         self.arr = np.empty((size, 10), dtype=np.float64)
         if QT_LIB.startswith('PyQt'):
-            self.ptrs = list(map(sip.wrapinstance,
+            self.ptrs = list(map(Qt.sip.wrapinstance,
                 itertools.count(self.arr.ctypes.data, self.arr.strides[0]),
                 itertools.repeat(QtGui.QPainter.PixmapFragment, self.arr.shape[0])))
         else:
-            self.ptrs = wrapInstance(self.arr.ctypes.data, QtGui.QPainter.PixmapFragment)
+            self.ptrs = Qt.shiboken.wrapInstance(self.arr.ctypes.data, QtGui.QPainter.PixmapFragment)
 
     def array(self, size):
         if size > self.arr.shape[0]:

tests/exporters/test_image.py

@@ -23,6 +23,6 @@ def test_ImageExporter_toBytes():
     exp = ImageExporter(p.getPlotItem())
     qimg = exp.export(toBytes=True)
     qimg = qimg.convertToFormat(QtGui.QImage.Format.Format_RGBA8888)
-    data = fn.qimage_to_ndarray(qimg)
+    data = fn.ndarray_from_qimage(qimg)
     black = (0, 0, 0, 255)
     assert np.all(data == black), "Exported image should be entirely black."

tests/image_testing.py

@@ -77,7 +77,7 @@ def getImageFromWidget(widget):
     painter.end()
 
     qimg = qimg.convertToFormat(QtGui.QImage.Format.Format_RGBA8888)
-    return fn.qimage_to_ndarray(qimg).copy()
+    return fn.ndarray_from_qimage(qimg).copy()
 
 
 def assertImageApproved(image, standardFile, message=None, **kwargs):
@@ -126,7 +126,7 @@ def assertImageApproved(image, standardFile, message=None, **kwargs):
     else:
         qimg = QtGui.QImage(stdFileName)
         qimg = qimg.convertToFormat(QtGui.QImage.Format.Format_RGBA8888)
-        stdImage = fn.qimage_to_ndarray(qimg).copy()
+        stdImage = fn.ndarray_from_qimage(qimg).copy()
         del qimg
 
     # If the test image does not match, then we go to audit if requested.

tests/test_functions.py

@@ -9,6 +9,7 @@ import pytest
 from numpy.testing import assert_array_almost_equal
 
 import pyqtgraph as pg
+from pyqtgraph.Qt import QtGui
 
 np.random.seed(12345)
 
@@ -333,3 +334,31 @@ def test_arrayToQPath(xs, ys, connect, expected):
                 continue
         element = path.elementAt(i)
         assert eq(expected[i], (element.type, element.x, element.y))
+
+
+def test_ndarray_from_qpolygonf():
+    # test that we get an empty ndarray from an empty QPolygonF
+    poly = pg.functions.create_qpolygonf(0)
+    arr = pg.functions.ndarray_from_qpolygonf(poly)
+    assert isinstance(arr, np.ndarray)
+
+
+def test_ndarray_from_qimage():
+    # for QImages created w/o specifying bytesPerLine, Qt will pad
+    # each line to a multiple of 4-bytes.
+    # test that we can handle such QImages.
+    h = 10
+
+    fmt = QtGui.QImage.Format.Format_RGB888
+    for w in [5, 6, 7, 8]:
+        qimg = QtGui.QImage(w, h, fmt)
+        qimg.fill(0)
+        arr = pg.functions.ndarray_from_qimage(qimg)
+        assert arr.shape == (h, w, 3)
+
+    fmt = QtGui.QImage.Format.Format_Grayscale8
+    for w in [5, 6, 7, 8]:
+        qimg = QtGui.QImage(w, h, fmt)
+        qimg.fill(0)
+        arr = pg.functions.ndarray_from_qimage(qimg)
+        assert arr.shape == (h, w)

tests/test_qimage_writethru.py

@@ -0,0 +1,28 @@
+import numpy as np
+import pyqtgraph as pg
+
+def test_qimage_writethrough():
+    w, h = 256, 256
+    backstore = np.ones((h, w), dtype=np.uint8)
+    ptr0 = backstore.ctypes.data
+    fmt = pg.Qt.QtGui.QImage.Format.Format_Grayscale8
+    qimg = pg.functions.ndarray_to_qimage(backstore, fmt)
+
+    def get_pointer(obj):
+        if hasattr(obj, 'setsize'):
+            return int(obj)
+        else:
+            return np.frombuffer(obj, dtype=np.uint8).ctypes.data
+
+    # test that QImage is using the provided buffer (i.e. zero-copy)
+    ptr1 = get_pointer(qimg.constBits())
+    assert ptr0 == ptr1
+
+    # test that QImage is not const (i.e. no COW)
+    # if QImage is const, then bits() returns a copy
+    ptr2 = get_pointer(qimg.bits())
+    assert ptr1 == ptr2
+
+    # test that data gets written through to provided buffer
+    qimg.fill(0)
+    assert np.all(backstore == 0)