### Bug summary Pixel widths appear irregularly in `pcolor(x, y, z, rasterized=True)`, while `x` and `y` are regular. Using `rasterized=False` provides correct (equal size) pixels, but saving the figure to `.png` (instead of `.pdf`) will show the same irregular pixel width bug. It looks like a resampling bug, which messes up precise data visualization completely. ### Code for reproduction ```python import numpy as np import matplotlib.pyplot as plt x, y = np.meshgrid(range(500), range(2)) z = [np.tile([0,1],250), np.tile([0,1],250)] fig, ax = plt.subplots(1,1, figsize=(10,2)) im = ax.pcolor(x, y, z, rasterized=True) ax.set_xticks(np.arange(0,40)) fig.savefig('test.pdf') plt.show() ``` ### Actual outcome In the resulting plot, some pixels are thinner, and some are thicker, than they should be. `rasterize=True` (zoom-in to the lower left corner)  ### Expected outcome `rasterize=False` (zoom-in to the lower left corner)  ### Additional information - This behaviour depends on the number of pixels plotted, for me it becomes visible above `len(x)>100`. - The spread between thicker and thinner lines increases with increasing size of the input array. - If the view is reduced to a lower number of pixels (e.g., `ax.set_xlim(0,10)`), the effect is no longer visible. ### Operating system Windows ### Matplotlib Version 3.5.1 ### Matplotlib Backend inline ### Python version 3.9.6 ### Jupyter version _No response_ ### Installation pip