For #4651

I would assume the advance value only depends on hinting, which should probably run without the FT_LOAD_RENDER flag. In fact, the FreeType docs mention the flag FT_LOAD_BITMAP_METRICS_ONLY which seems appropriate here and conflicts with FT_LOAD_RENDER. https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#ft_load_xxx

While the FT_LOAD_BITMAP_METRICS_ONLY will likely be ignored due to FT_LOAD_NO_BITMAP, it should serve as a reminder for when #891 is resolved properly. (I know the solution, I intend to submit a PR later. Essentially, Pillow should check the bitdepth of the returned bitmap instead of guessing.) Edit: Removed for now as it is not supported on all FreeType versions.

Testing I get the following results (in s) on my Windows 10 laptop with the code below.

    from timeit import repeat

    print(
        'getsize() (x100): ',
        min(repeat(
            'font.getsize("Hello world")',
            'from PIL import ImageFont; font = ImageFont.truetype("Tests/fonts/FreeMono.ttf", 20, layout_engine=ImageFont.LAYOUT_BASIC)',
            number=100, repeat=30
        )),
    )