Pillow/Tests/test_image_access.py

import ctypes
import os
import subprocess
import sys
from distutils import ccompiler, sysconfig

import pytest
from PIL import Image

from .helper import assert_image_equal, hopper, is_win32, on_ci

# CFFI imports pycparser which doesn't support PYTHONOPTIMIZE=2
# https://github.com/eliben/pycparser/pull/198#issuecomment-317001670
if os.environ.get("PYTHONOPTIMIZE") == "2":
    cffi = None
else:
    try:
        from PIL import PyAccess
        import cffi
    except ImportError:
        cffi = None


class AccessTest:
    # initial value
    _init_cffi_access = Image.USE_CFFI_ACCESS
    _need_cffi_access = False

    @classmethod
    def setup_class(cls):
        Image.USE_CFFI_ACCESS = cls._need_cffi_access

    @classmethod
    def teardown_class(cls):
        Image.USE_CFFI_ACCESS = cls._init_cffi_access


class TestImagePutPixel(AccessTest):
    def test_sanity(self):
        im1 = hopper()
        im2 = Image.new(im1.mode, im1.size, 0)

        for y in range(im1.size[1]):
            for x in range(im1.size[0]):
                pos = x, y
                im2.putpixel(pos, im1.getpixel(pos))

        assert_image_equal(im1, im2)

        im2 = Image.new(im1.mode, im1.size, 0)
        im2.readonly = 1

        for y in range(im1.size[1]):
            for x in range(im1.size[0]):
                pos = x, y
                im2.putpixel(pos, im1.getpixel(pos))

        assert not im2.readonly
        assert_image_equal(im1, im2)

        im2 = Image.new(im1.mode, im1.size, 0)

        pix1 = im1.load()
        pix2 = im2.load()

        for y in range(im1.size[1]):
            for x in range(im1.size[0]):
                pix2[x, y] = pix1[x, y]

        assert_image_equal(im1, im2)

    def test_sanity_negative_index(self):
        im1 = hopper()
        im2 = Image.new(im1.mode, im1.size, 0)

        width, height = im1.size
        assert im1.getpixel((0, 0)) == im1.getpixel((-width, -height))
        assert im1.getpixel((-1, -1)) == im1.getpixel((width - 1, height - 1))

        for y in range(-1, -im1.size[1] - 1, -1):
            for x in range(-1, -im1.size[0] - 1, -1):
                pos = x, y
                im2.putpixel(pos, im1.getpixel(pos))

        assert_image_equal(im1, im2)

        im2 = Image.new(im1.mode, im1.size, 0)
        im2.readonly = 1

        for y in range(-1, -im1.size[1] - 1, -1):
            for x in range(-1, -im1.size[0] - 1, -1):
                pos = x, y
                im2.putpixel(pos, im1.getpixel(pos))

        assert not im2.readonly
        assert_image_equal(im1, im2)

        im2 = Image.new(im1.mode, im1.size, 0)

        pix1 = im1.load()
        pix2 = im2.load()

        for y in range(-1, -im1.size[1] - 1, -1):
            for x in range(-1, -im1.size[0] - 1, -1):
                pix2[x, y] = pix1[x, y]

        assert_image_equal(im1, im2)


class TestImageGetPixel(AccessTest):
    @staticmethod
    def color(mode):
        bands = Image.getmodebands(mode)
        if bands == 1:
            return 1
        else:
            return tuple(range(1, bands + 1))

    def check(self, mode, c=None):
        if not c:
            c = self.color(mode)

        # check putpixel
        im = Image.new(mode, (1, 1), None)
        im.putpixel((0, 0), c)
        assert (
            im.getpixel((0, 0)) == c
        ), "put/getpixel roundtrip failed for mode {}, color {}".format(mode, c)

        # check putpixel negative index
        im.putpixel((-1, -1), c)
        assert im.getpixel((-1, -1)) == c, (
            "put/getpixel roundtrip negative index failed for mode %s, color %s"
            % (mode, c)
        )

        # Check 0
        im = Image.new(mode, (0, 0), None)
        with pytest.raises(IndexError):
            im.putpixel((0, 0), c)
        with pytest.raises(IndexError):
            im.getpixel((0, 0))
        # Check 0 negative index
        with pytest.raises(IndexError):
            im.putpixel((-1, -1), c)
        with pytest.raises(IndexError):
            im.getpixel((-1, -1))

        # check initial color
        im = Image.new(mode, (1, 1), c)
        assert (
            im.getpixel((0, 0)) == c
        ), "initial color failed for mode {}, color {} ".format(mode, c)
        # check initial color negative index
        assert (
            im.getpixel((-1, -1)) == c
        ), "initial color failed with negative index for mode %s, color %s " % (mode, c)

        # Check 0
        im = Image.new(mode, (0, 0), c)
        with pytest.raises(IndexError):
            im.getpixel((0, 0))
        # Check 0 negative index
        with pytest.raises(IndexError):
            im.getpixel((-1, -1))

    def test_basic(self):
        for mode in (
            "1",
            "L",
            "LA",
            "I",
            "I;16",
            "I;16B",
            "F",
            "P",
            "PA",
            "RGB",
            "RGBA",
            "RGBX",
            "CMYK",
            "YCbCr",
        ):
            self.check(mode)

    def test_signedness(self):
        # see https://github.com/python-pillow/Pillow/issues/452
        # pixelaccess is using signed int* instead of uint*
        for mode in ("I;16", "I;16B"):
            self.check(mode, 2 ** 15 - 1)
            self.check(mode, 2 ** 15)
            self.check(mode, 2 ** 15 + 1)
            self.check(mode, 2 ** 16 - 1)

    def test_p_putpixel_rgb_rgba(self):
        for color in [(255, 0, 0), (255, 0, 0, 255)]:
            im = Image.new("P", (1, 1), 0)
            im.putpixel((0, 0), color)
            assert im.convert("RGB").getpixel((0, 0)) == (255, 0, 0)


@pytest.mark.skipif(cffi is None, reason="No CFFI")
class TestCffiPutPixel(TestImagePutPixel):
    _need_cffi_access = True


@pytest.mark.skipif(cffi is None, reason="No CFFI")
class TestCffiGetPixel(TestImageGetPixel):
    _need_cffi_access = True


@pytest.mark.skipif(cffi is None, reason="No CFFI")
class TestCffi(AccessTest):
    _need_cffi_access = True

    def _test_get_access(self, im):
        """Do we get the same thing as the old pixel access

        Using private interfaces, forcing a capi access and
        a pyaccess for the same image"""
        caccess = im.im.pixel_access(False)
        access = PyAccess.new(im, False)

        w, h = im.size
        for x in range(0, w, 10):
            for y in range(0, h, 10):
                assert access[(x, y)] == caccess[(x, y)]

        # Access an out-of-range pixel
        with pytest.raises(ValueError):
            access[(access.xsize + 1, access.ysize + 1)]

    def test_get_vs_c(self):
        rgb = hopper("RGB")
        rgb.load()
        self._test_get_access(rgb)
        self._test_get_access(hopper("RGBA"))
        self._test_get_access(hopper("L"))
        self._test_get_access(hopper("LA"))
        self._test_get_access(hopper("1"))
        self._test_get_access(hopper("P"))
        # self._test_get_access(hopper('PA')) # PA -- how do I make a PA image?
        self._test_get_access(hopper("F"))

        im = Image.new("I;16", (10, 10), 40000)
        self._test_get_access(im)
        im = Image.new("I;16L", (10, 10), 40000)
        self._test_get_access(im)
        im = Image.new("I;16B", (10, 10), 40000)
        self._test_get_access(im)

        im = Image.new("I", (10, 10), 40000)
        self._test_get_access(im)
        # These don't actually appear to be modes that I can actually make,
        # as unpack sets them directly into the I mode.
        # im = Image.new('I;32L', (10, 10), -2**10)
        # self._test_get_access(im)
        # im = Image.new('I;32B', (10, 10), 2**10)
        # self._test_get_access(im)

    def _test_set_access(self, im, color):
        """Are we writing the correct bits into the image?

        Using private interfaces, forcing a capi access and
        a pyaccess for the same image"""
        caccess = im.im.pixel_access(False)
        access = PyAccess.new(im, False)

        w, h = im.size
        for x in range(0, w, 10):
            for y in range(0, h, 10):
                access[(x, y)] = color
                assert color == caccess[(x, y)]

        # Attempt to set the value on a read-only image
        access = PyAccess.new(im, True)
        with pytest.raises(ValueError):
            access[(0, 0)] = color

    def test_set_vs_c(self):
        rgb = hopper("RGB")
        rgb.load()
        self._test_set_access(rgb, (255, 128, 0))
        self._test_set_access(hopper("RGBA"), (255, 192, 128, 0))
        self._test_set_access(hopper("L"), 128)
        self._test_set_access(hopper("LA"), (128, 128))
        self._test_set_access(hopper("1"), 255)
        self._test_set_access(hopper("P"), 128)
        # self._test_set_access(i, (128, 128))  #PA  -- undone how to make
        self._test_set_access(hopper("F"), 1024.0)

        im = Image.new("I;16", (10, 10), 40000)
        self._test_set_access(im, 45000)
        im = Image.new("I;16L", (10, 10), 40000)
        self._test_set_access(im, 45000)
        im = Image.new("I;16B", (10, 10), 40000)
        self._test_set_access(im, 45000)

        im = Image.new("I", (10, 10), 40000)
        self._test_set_access(im, 45000)
        # im = Image.new('I;32L', (10, 10), -(2**10))
        # self._test_set_access(im, -(2**13)+1)
        # im = Image.new('I;32B', (10, 10), 2**10)
        # self._test_set_access(im, 2**13-1)

    def test_not_implemented(self):
        assert PyAccess.new(hopper("BGR;15")) is None

    # ref https://github.com/python-pillow/Pillow/pull/2009
    def test_reference_counting(self):
        size = 10

        for _ in range(10):
            # Do not save references to the image, only to the access object
            px = Image.new("L", (size, 1), 0).load()
            for i in range(size):
                # pixels can contain garbage if image is released
                assert px[i, 0] == 0

    def test_p_putpixel_rgb_rgba(self):
        for color in [(255, 0, 0), (255, 0, 0, 255)]:
            im = Image.new("P", (1, 1), 0)
            access = PyAccess.new(im, False)
            access.putpixel((0, 0), color)
            assert im.convert("RGB").getpixel((0, 0)) == (255, 0, 0)


class TestEmbeddable:
    @pytest.mark.skipif(
        not is_win32() or on_ci(),
        reason="Failing on AppVeyor / GitHub Actions when run from subprocess, "
        "not from shell",
    )
    def test_embeddable(self):
        with open("embed_pil.c", "w") as fh:
            fh.write(
                """
#include "Python.h"

int main(int argc, char* argv[])
{
    char *home = "%s";
    wchar_t *whome = Py_DecodeLocale(home, NULL);
    Py_SetPythonHome(whome);

    Py_InitializeEx(0);
    Py_DECREF(PyImport_ImportModule("PIL.Image"));
    Py_Finalize();

    Py_InitializeEx(0);
    Py_DECREF(PyImport_ImportModule("PIL.Image"));
    Py_Finalize();

    PyMem_RawFree(whome);

    return 0;
}
        """
                % sys.prefix.replace("\\", "\\\\")
            )

        compiler = ccompiler.new_compiler()
        compiler.add_include_dir(sysconfig.get_python_inc())

        libdir = sysconfig.get_config_var(
            "LIBDIR"
        ) or sysconfig.get_python_inc().replace("include", "libs")
        print(libdir)
        compiler.add_library_dir(libdir)
        objects = compiler.compile(["embed_pil.c"])
        compiler.link_executable(objects, "embed_pil")

        env = os.environ.copy()
        env["PATH"] = sys.prefix + ";" + env["PATH"]

        # do not display the Windows Error Reporting dialog
        ctypes.windll.kernel32.SetErrorMode(0x0002)

        process = subprocess.Popen(["embed_pil.exe"], env=env)
        process.communicate()
        assert process.returncode == 0