How to use the pyvips.Image.new_from_buffer function in pyvips

p1 = self.colour.get("icc-profile-data")
            p2 = im.get("icc-profile-data")
            assert p1 == p2

            # add tests for exif, xmp, ipct
            # the exif test will need us to be able to walk the header,
            # we can't just check exif-data

            # we can test that exif changes change the output of webpsave
            # first make sure we have exif support
            z = pyvips.Image.new_from_file(JPEG_FILE)
            if z.get_typeof("exif-ifd0-Orientation") != 0:
                x = self.colour.copy()
                x.set("orientation", 6)
                buf = x.webpsave_buffer()
                y = pyvips.Image.new_from_buffer(buf, "")
                assert y.get("orientation") == 6

def test_load_buffer(self):
        im = pyvips.Image.black(10, 20)
        buf = im.write_to_buffer('.jpg')

        x = pyvips.Image.new_from_buffer(buf, '')
        assert x.width == 10
        assert x.height == 20
        assert x.bands == 1

# first make sure we have exif support
            z = pyvips.Image.new_from_file(JPEG_FILE)
            if z.get_typeof("exif-ifd0-Orientation") != 0:
                x = self.colour.copy()
                x.set("orientation", 6)
                buf = x.webpsave_buffer()
                y = pyvips.Image.new_from_buffer(buf, "")
                assert y.get("orientation") == 6

        # try converting an animated gif to webp ... can't do back to gif
        # again without IM support
        if have("gifload"):
            x1 = pyvips.Image.new_from_file(GIF_ANIM_FILE, n=-1)
            w1 = x1.webpsave_buffer(Q=10)

            x2 = pyvips.Image.new_from_buffer(w1, "", n=-1)
            assert x1.width == x2.width
            assert x1.height == x2.height
            assert x1.get("delay") == x2.get("delay")
            assert x1.get("page-height") == x2.get("page-height")
            assert x1.get("gif-loop") == x2.get("gif-loop")

def test_heifsave(self):
        self.save_load_buffer("heifsave_buffer", "heifload_buffer",
                              self.colour, 80)
        self.save_load("%s.heic", self.colour)

        # test lossless mode
        im = pyvips.Image.new_from_file(HEIC_FILE)
        buf = im.heifsave_buffer(lossless=True)
        im2 = pyvips.Image.new_from_buffer(buf, "")
        # not in fact quite lossless
        assert abs(im.avg() - im2.avg()) < 3

        # higher Q should mean a bigger buffer
        b1 = im.heifsave_buffer(Q=10)
        b2 = im.heifsave_buffer(Q=90)
        assert len(b2) > len(b1)

        # try saving an image with an ICC profile and reading it back 
        # not all libheif have profile support, so put it in an if
        buf = self.colour.heifsave_buffer()
        im = pyvips.Image.new_from_buffer(buf, "")
        p1 = self.colour.get("icc-profile-data")
        if im.get_typeof("icc-profile-data") != 0:
            p2 = im.get("icc-profile-data")
            assert p1 == p2

# to small variations
            assert_almost_equal_objects(a, [71, 166, 236], threshold=2)
            assert im.width == 550
            assert im.height == 368
            assert im.bands == 3

        self.file_loader("webpload", WEBP_FILE, webp_valid)
        self.buffer_loader("webpload_buffer", WEBP_FILE, webp_valid)
        self.save_load_buffer("webpsave_buffer", "webpload_buffer",
                              self.colour, 60)
        self.save_load("%s.webp", self.colour)

        # test lossless mode
        im = pyvips.Image.new_from_file(WEBP_FILE)
        buf = im.webpsave_buffer(lossless=True)
        im2 = pyvips.Image.new_from_buffer(buf, "")
        assert abs(im.avg() - im2.avg()) < 1

        # higher Q should mean a bigger buffer
        b1 = im.webpsave_buffer(Q=10)
        b2 = im.webpsave_buffer(Q=90)
        assert len(b2) > len(b1)

        # try saving an image with an ICC profile and reading it back ... if we
        # can do it, our webp supports metadata load/save
        buf = self.colour.webpsave_buffer()
        im = pyvips.Image.new_from_buffer(buf, "")
        if im.get_typeof("icc-profile-data") != 0:
            # verify that the profile comes back unharmed
            p1 = self.colour.get("icc-profile-data")
            p2 = im.get("icc-profile-data")
            assert p1 == p2

# test lossless mode
        im = pyvips.Image.new_from_file(HEIC_FILE)
        buf = im.heifsave_buffer(lossless=True)
        im2 = pyvips.Image.new_from_buffer(buf, "")
        # not in fact quite lossless
        assert abs(im.avg() - im2.avg()) < 3

        # higher Q should mean a bigger buffer
        b1 = im.heifsave_buffer(Q=10)
        b2 = im.heifsave_buffer(Q=90)
        assert len(b2) > len(b1)

        # try saving an image with an ICC profile and reading it back 
        # not all libheif have profile support, so put it in an if
        buf = self.colour.heifsave_buffer()
        im = pyvips.Image.new_from_buffer(buf, "")
        p1 = self.colour.get("icc-profile-data")
        if im.get_typeof("icc-profile-data") != 0:
            p2 = im.get("icc-profile-data")
            assert p1 == p2

assert x.height == page_height * 15
        assert x(0, 166)[0] == 96
        assert x(0, 167)[0] == 0
        assert x(0, 168)[0] == 1

        # pyr save to buffer added in 8.6
        x = pyvips.Image.new_from_file(TIF_FILE)
        buf = x.tiffsave_buffer(tile=True, pyramid=True)
        filename = temp_filename(self.tempdir, '.tif')
        x.tiffsave(filename, tile=True, pyramid=True)
        with open(filename, 'rb') as f:
            buf2 = f.read()
        assert len(buf) == len(buf2)

        a = pyvips.Image.new_from_buffer(buf, "", page=2)
        b = pyvips.Image.new_from_buffer(buf2, "", page=2)
        assert a.width == b.width
        assert a.height == b.height
        assert a.avg() == b.avg()

        # region-shrink added in 8.7
        x = pyvips.Image.new_from_file(TIF_FILE)
        buf = x.tiffsave_buffer(tile=True, pyramid=True, region_shrink="mean")
        buf = x.tiffsave_buffer(tile=True, pyramid=True, region_shrink="mode")
        buf = x.tiffsave_buffer(tile=True, pyramid=True, region_shrink="median")

x = pyvips.Image.magickload(filename)

        assert self.colour.width == x.width
        assert self.colour.height == x.height
        assert self.colour.bands == x.bands
        max_diff = (self.colour - x).abs().max()
        assert max_diff < 60

        self.save_load_buffer("magicksave_buffer", "magickload_buffer",
                              self.colour, 60, format="JPG")

        # try an animation
        if have("gifload"):
            x1 = pyvips.Image.new_from_file(GIF_ANIM_FILE, n=-1)
            w1 = x1.magicksave_buffer(format="GIF")
            x2 = pyvips.Image.new_from_buffer(w1, "", n=-1)
            assert x1.get("delay") == x2.get("delay")
            assert x1.get("page-height") == x2.get("page-height")
            # magicks vary in how they handle this ... just pray we are close
            assert abs(x1.get("gif-loop") - x2.get("gif-loop")) < 5

assert im.height == height * 2
            page_height = im.get("page-height")
            assert page_height == height

        # should work for dicom
        im = pyvips.Image.magickload(DICOM_FILE)
        assert im.width == 128
        assert im.height == 128
        # some IMs are 3 bands, some are 1, can't really test
        # assert im.bands == 1

        # libvips has its own sniffer for ICO, test that
        with open(ICO_FILE, 'rb') as f:
            buf = f.read()

        im = pyvips.Image.new_from_buffer(buf, "")
        assert im.width == 16
        assert im.height == 16

assert x.width == 439
        assert x.height == page_height * 15
        assert x(0, 166)[0] == 96
        assert x(0, 167)[0] == 0
        assert x(0, 168)[0] == 1

        # pyr save to buffer added in 8.6
        x = pyvips.Image.new_from_file(TIF_FILE)
        buf = x.tiffsave_buffer(tile=True, pyramid=True)
        filename = temp_filename(self.tempdir, '.tif')
        x.tiffsave(filename, tile=True, pyramid=True)
        with open(filename, 'rb') as f:
            buf2 = f.read()
        assert len(buf) == len(buf2)

        a = pyvips.Image.new_from_buffer(buf, "", page=2)
        b = pyvips.Image.new_from_buffer(buf2, "", page=2)
        assert a.width == b.width
        assert a.height == b.height
        assert a.avg() == b.avg()

        # region-shrink added in 8.7
        x = pyvips.Image.new_from_file(TIF_FILE)
        buf = x.tiffsave_buffer(tile=True, pyramid=True, region_shrink="mean")
        buf = x.tiffsave_buffer(tile=True, pyramid=True, region_shrink="mode")
        buf = x.tiffsave_buffer(tile=True, pyramid=True, region_shrink="median")