import importlib
import sys

import numpy as np

import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
from pyqtgraph.examples.utils import FrameCounter

width = 128
pngfile = importlib.resources.files("pyqtgraph.icons.peegee") / f"peegee_{width}px.png"
qimage = QtGui.QImage.fromData(pngfile.read_bytes())
qimage_gray = qimage.convertedTo(QtGui.QImage.Format.Format_Grayscale8)
qimage_alpha = qimage.convertedTo(QtGui.QImage.Format.Format_Alpha8)
z = pg.functions.ndarray_from_qimage(qimage_gray)
a = pg.functions.ndarray_from_qimage(qimage_alpha)

z = z.astype(np.float32)
z[a < 255] = np.nan

Z = z
ny, nx = Z.shape
x = np.linspace(0, nx, nx+1, endpoint=True)
y = np.linspace(0, ny, ny+1, endpoint=True)
X, Y = np.meshgrid(x, y)
X += (ny * 0.025) * np.sin(2*np.pi*2*np.linspace(0, 1, ny+1))[:, np.newaxis]
Y += (nx * 0.025) * np.sin(2*np.pi*2*np.linspace(0, 1, nx+1))

pg.setConfigOptions(useOpenGL=True, enableExperimental=True)
pg.setConfigOption('background', pg.mkColor(0, 0, 100))

pg.mkQApp()
win = pg.PlotWidget()
win.invertY(True)
cmap = pg.colormap.ColorMap(None, [0.0, 1.0])
pcmi = pg.PColorMeshItem(X, Y, Z, colorMap=cmap)
win.addItem(pcmi)
win.setTitle('')
win.show()

cnt = 0
def update():
    global cnt
    cnt = (cnt + 1) % z.shape[1]
    Z = np.roll(z, cnt, axis=1)
    pcmi.setData(None, None, Z)
    framecnt.update()

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start()

framecnt = FrameCounter()
framecnt.sigFpsUpdate.connect(lambda fps: win.setTitle(f'{fps:.1f} fps'))

pg.exec()