benchmark_pyside6_drawlines.py

from PySide6 import QtCore, QtGui
import shiboken6
import numpy as np

import itertools
from time import perf_counter

class LineSegments:
    def __init__(self, use_array):
        self.use_array = use_array
        self.alloc(0)

    def alloc(self, size):
        self.arr = np.empty((size, 4), dtype=np.float64)
        if self.use_array:
            self.objs = shiboken6.wrapInstance(self.arr.ctypes.data, QtCore.QLineF)
        else:
            self.objs = list(map(shiboken6.wrapInstance,
                itertools.count(self.arr.ctypes.data, self.arr.strides[0]),
                itertools.repeat(QtCore.QLineF, self.arr.shape[0])))

    def get(self, size):
        if size != self.arr.shape[0]:
            self.alloc(size)
        return self.objs, self.arr

def generate_pattern(nsegs, size):
    rng = np.random.default_rng()
    x = rng.random(nsegs) * size
    y = rng.random(nsegs) * size
    arr = np.empty((nsegs, 4), dtype=np.float64)
    arr[:, 0] = x
    arr[:, 1] = y
    arr[:, 2] = x + 2
    arr[:, 3] = y + 2
    return arr

nsegs = 10_000
size = 500
nframes = 100
pattern = generate_pattern(nsegs, size)

def run(use_array):
    # generate lines once
    segments = LineSegments(use_array)
    lines, memory = segments.get(nsegs)
    memory[:] = pattern

    # draw multiple frames using the same lines array
    t0 = perf_counter()
    for _ in range(nframes):
        qimg = QtGui.QImage(size, size, QtGui.QImage.Format.Format_RGB32)
        qimg.fill(QtCore.Qt.GlobalColor.transparent)
        painter = QtGui.QPainter(qimg)
        painter.setPen(QtCore.Qt.GlobalColor.cyan)
        if use_array:
            try:
                painter.drawLines(lines, nsegs)
            except TypeError:
                pass
        else:
            painter.drawLines(lines)
        painter.end()
    t1 = perf_counter()
    return t1 - t0

for use_array in [False, True]:
    duration = run(use_array)
    fps = int(nframes / duration)
    print(f'{use_array=} {duration=:.3f} {fps=}')