You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
528 lines
19 KiB
Python
528 lines
19 KiB
Python
"""
|
|
Utilities for comparing image results.
|
|
"""
|
|
|
|
import atexit
|
|
import functools
|
|
import hashlib
|
|
import logging
|
|
import os
|
|
from pathlib import Path
|
|
import shutil
|
|
import subprocess
|
|
import sys
|
|
from tempfile import TemporaryDirectory, TemporaryFile
|
|
import weakref
|
|
import re
|
|
|
|
import numpy as np
|
|
from PIL import Image
|
|
|
|
import matplotlib as mpl
|
|
from matplotlib import cbook
|
|
from matplotlib.testing.exceptions import ImageComparisonFailure
|
|
|
|
_log = logging.getLogger(__name__)
|
|
|
|
__all__ = ['calculate_rms', 'comparable_formats', 'compare_images']
|
|
|
|
|
|
def make_test_filename(fname, purpose):
|
|
"""
|
|
Make a new filename by inserting *purpose* before the file's extension.
|
|
"""
|
|
base, ext = os.path.splitext(fname)
|
|
return f'{base}-{purpose}{ext}'
|
|
|
|
|
|
def _get_cache_path():
|
|
cache_dir = Path(mpl.get_cachedir(), 'test_cache')
|
|
cache_dir.mkdir(parents=True, exist_ok=True)
|
|
return cache_dir
|
|
|
|
|
|
def get_cache_dir():
|
|
return str(_get_cache_path())
|
|
|
|
|
|
def get_file_hash(path, block_size=2 ** 20):
|
|
sha256 = hashlib.sha256(usedforsecurity=False)
|
|
with open(path, 'rb') as fd:
|
|
while True:
|
|
data = fd.read(block_size)
|
|
if not data:
|
|
break
|
|
sha256.update(data)
|
|
|
|
if Path(path).suffix == '.pdf':
|
|
sha256.update(str(mpl._get_executable_info("gs").version).encode('utf-8'))
|
|
elif Path(path).suffix == '.svg':
|
|
sha256.update(str(mpl._get_executable_info("inkscape").version).encode('utf-8'))
|
|
|
|
return sha256.hexdigest()
|
|
|
|
|
|
class _ConverterError(Exception):
|
|
pass
|
|
|
|
|
|
class _Converter:
|
|
def __init__(self):
|
|
self._proc = None
|
|
# Explicitly register deletion from an atexit handler because if we
|
|
# wait until the object is GC'd (which occurs later), then some module
|
|
# globals (e.g. signal.SIGKILL) has already been set to None, and
|
|
# kill() doesn't work anymore...
|
|
atexit.register(self.__del__)
|
|
|
|
def __del__(self):
|
|
if self._proc:
|
|
self._proc.kill()
|
|
self._proc.wait()
|
|
for stream in filter(None, [self._proc.stdin,
|
|
self._proc.stdout,
|
|
self._proc.stderr]):
|
|
stream.close()
|
|
self._proc = None
|
|
|
|
def _read_until(self, terminator):
|
|
"""Read until the prompt is reached."""
|
|
buf = bytearray()
|
|
while True:
|
|
c = self._proc.stdout.read(1)
|
|
if not c:
|
|
raise _ConverterError(os.fsdecode(bytes(buf)))
|
|
buf.extend(c)
|
|
if buf.endswith(terminator):
|
|
return bytes(buf)
|
|
|
|
|
|
class _GSConverter(_Converter):
|
|
def __call__(self, orig, dest):
|
|
if not self._proc:
|
|
self._proc = subprocess.Popen(
|
|
[mpl._get_executable_info("gs").executable,
|
|
"-dNOSAFER", "-dNOPAUSE", "-dEPSCrop", "-sDEVICE=png16m"],
|
|
# As far as I can see, ghostscript never outputs to stderr.
|
|
stdin=subprocess.PIPE, stdout=subprocess.PIPE)
|
|
try:
|
|
self._read_until(b"\nGS")
|
|
except _ConverterError as e:
|
|
raise OSError(f"Failed to start Ghostscript:\n\n{e.args[0]}") from None
|
|
|
|
def encode_and_escape(name):
|
|
return (os.fsencode(name)
|
|
.replace(b"\\", b"\\\\")
|
|
.replace(b"(", br"\(")
|
|
.replace(b")", br"\)"))
|
|
|
|
self._proc.stdin.write(
|
|
b"<< /OutputFile ("
|
|
+ encode_and_escape(dest)
|
|
+ b") >> setpagedevice ("
|
|
+ encode_and_escape(orig)
|
|
+ b") run flush\n")
|
|
self._proc.stdin.flush()
|
|
# GS> if nothing left on the stack; GS<n> if n items left on the stack.
|
|
err = self._read_until((b"GS<", b"GS>"))
|
|
stack = self._read_until(b">") if err.endswith(b"GS<") else b""
|
|
if stack or not os.path.exists(dest):
|
|
stack_size = int(stack[:-1]) if stack else 0
|
|
self._proc.stdin.write(b"pop\n" * stack_size)
|
|
# Using the systemencoding should at least get the filenames right.
|
|
raise ImageComparisonFailure(
|
|
(err + stack).decode(sys.getfilesystemencoding(), "replace"))
|
|
|
|
|
|
class _SVGConverter(_Converter):
|
|
def __call__(self, orig, dest):
|
|
old_inkscape = mpl._get_executable_info("inkscape").version.major < 1
|
|
terminator = b"\n>" if old_inkscape else b"> "
|
|
if not hasattr(self, "_tmpdir"):
|
|
self._tmpdir = TemporaryDirectory()
|
|
# On Windows, we must make sure that self._proc has terminated
|
|
# (which __del__ does) before clearing _tmpdir.
|
|
weakref.finalize(self._tmpdir, self.__del__)
|
|
if (not self._proc # First run.
|
|
or self._proc.poll() is not None): # Inkscape terminated.
|
|
if self._proc is not None and self._proc.poll() is not None:
|
|
for stream in filter(None, [self._proc.stdin,
|
|
self._proc.stdout,
|
|
self._proc.stderr]):
|
|
stream.close()
|
|
env = {
|
|
**os.environ,
|
|
# If one passes e.g. a png file to Inkscape, it will try to
|
|
# query the user for conversion options via a GUI (even with
|
|
# `--without-gui`). Unsetting `DISPLAY` prevents this (and
|
|
# causes GTK to crash and Inkscape to terminate, but that'll
|
|
# just be reported as a regular exception below).
|
|
"DISPLAY": "",
|
|
# Do not load any user options.
|
|
"INKSCAPE_PROFILE_DIR": self._tmpdir.name,
|
|
}
|
|
# Old versions of Inkscape (e.g. 0.48.3.1) seem to sometimes
|
|
# deadlock when stderr is redirected to a pipe, so we redirect it
|
|
# to a temporary file instead. This is not necessary anymore as of
|
|
# Inkscape 0.92.1.
|
|
stderr = TemporaryFile()
|
|
self._proc = subprocess.Popen(
|
|
["inkscape", "--without-gui", "--shell"] if old_inkscape else
|
|
["inkscape", "--shell"],
|
|
stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=stderr,
|
|
env=env, cwd=self._tmpdir.name)
|
|
# Slight abuse, but makes shutdown handling easier.
|
|
self._proc.stderr = stderr
|
|
try:
|
|
self._read_until(terminator)
|
|
except _ConverterError as err:
|
|
raise OSError(
|
|
"Failed to start Inkscape in interactive mode:\n\n"
|
|
+ err.args[0]) from err
|
|
|
|
# Inkscape's shell mode does not support escaping metacharacters in the
|
|
# filename ("\n", and ":;" for inkscape>=1). Avoid any problems by
|
|
# running from a temporary directory and using fixed filenames.
|
|
inkscape_orig = Path(self._tmpdir.name, os.fsdecode(b"f.svg"))
|
|
inkscape_dest = Path(self._tmpdir.name, os.fsdecode(b"f.png"))
|
|
try:
|
|
inkscape_orig.symlink_to(Path(orig).resolve())
|
|
except OSError:
|
|
shutil.copyfile(orig, inkscape_orig)
|
|
self._proc.stdin.write(
|
|
b"f.svg --export-png=f.png\n" if old_inkscape else
|
|
b"file-open:f.svg;export-filename:f.png;export-do;file-close\n")
|
|
self._proc.stdin.flush()
|
|
try:
|
|
self._read_until(terminator)
|
|
except _ConverterError as err:
|
|
# Inkscape's output is not localized but gtk's is, so the output
|
|
# stream probably has a mixed encoding. Using the filesystem
|
|
# encoding should at least get the filenames right...
|
|
self._proc.stderr.seek(0)
|
|
raise ImageComparisonFailure(
|
|
self._proc.stderr.read().decode(
|
|
sys.getfilesystemencoding(), "replace")) from err
|
|
os.remove(inkscape_orig)
|
|
shutil.move(inkscape_dest, dest)
|
|
|
|
def __del__(self):
|
|
super().__del__()
|
|
if hasattr(self, "_tmpdir"):
|
|
self._tmpdir.cleanup()
|
|
|
|
|
|
class _SVGWithMatplotlibFontsConverter(_SVGConverter):
|
|
"""
|
|
A SVG converter which explicitly adds the fonts shipped by Matplotlib to
|
|
Inkspace's font search path, to better support `svg.fonttype = "none"`
|
|
(which is in particular used by certain mathtext tests).
|
|
"""
|
|
|
|
def __call__(self, orig, dest):
|
|
if not hasattr(self, "_tmpdir"):
|
|
self._tmpdir = TemporaryDirectory()
|
|
shutil.copytree(cbook._get_data_path("fonts/ttf"),
|
|
Path(self._tmpdir.name, "fonts"))
|
|
return super().__call__(orig, dest)
|
|
|
|
|
|
def _update_converter():
|
|
try:
|
|
mpl._get_executable_info("gs")
|
|
except mpl.ExecutableNotFoundError:
|
|
pass
|
|
else:
|
|
converter['pdf'] = converter['eps'] = _GSConverter()
|
|
try:
|
|
mpl._get_executable_info("inkscape")
|
|
except mpl.ExecutableNotFoundError:
|
|
pass
|
|
else:
|
|
converter['svg'] = _SVGConverter()
|
|
|
|
|
|
#: A dictionary that maps filename extensions to functions which themselves
|
|
#: convert between arguments `old` and `new` (filenames).
|
|
converter = {}
|
|
_update_converter()
|
|
_svg_with_matplotlib_fonts_converter = _SVGWithMatplotlibFontsConverter()
|
|
|
|
|
|
def comparable_formats():
|
|
"""
|
|
Return the list of file formats that `.compare_images` can compare
|
|
on this system.
|
|
|
|
Returns
|
|
-------
|
|
list of str
|
|
E.g. ``['png', 'pdf', 'svg', 'eps']``.
|
|
|
|
"""
|
|
return ['png', *converter]
|
|
|
|
|
|
def convert(filename, cache):
|
|
"""
|
|
Convert the named file to png; return the name of the created file.
|
|
|
|
If *cache* is True, the result of the conversion is cached in
|
|
`matplotlib.get_cachedir() + '/test_cache/'`. The caching is based on a
|
|
hash of the exact contents of the input file. Old cache entries are
|
|
automatically deleted as needed to keep the size of the cache capped to
|
|
twice the size of all baseline images.
|
|
"""
|
|
path = Path(filename)
|
|
if not path.exists():
|
|
raise OSError(f"{path} does not exist")
|
|
if path.suffix[1:] not in converter:
|
|
import pytest
|
|
pytest.skip(f"Don't know how to convert {path.suffix} files to png")
|
|
newpath = path.parent / f"{path.stem}_{path.suffix[1:]}.png"
|
|
|
|
# Only convert the file if the destination doesn't already exist or
|
|
# is out of date.
|
|
if not newpath.exists() or newpath.stat().st_mtime < path.stat().st_mtime:
|
|
cache_dir = _get_cache_path() if cache else None
|
|
|
|
if cache_dir is not None:
|
|
_register_conversion_cache_cleaner_once()
|
|
hash_value = get_file_hash(path)
|
|
cached_path = cache_dir / (hash_value + newpath.suffix)
|
|
if cached_path.exists():
|
|
_log.debug("For %s: reusing cached conversion.", filename)
|
|
shutil.copyfile(cached_path, newpath)
|
|
return str(newpath)
|
|
|
|
_log.debug("For %s: converting to png.", filename)
|
|
convert = converter[path.suffix[1:]]
|
|
if path.suffix == ".svg":
|
|
contents = path.read_text()
|
|
# NOTE: This check should be kept in sync with font styling in
|
|
# `lib/matplotlib/backends/backend_svg.py`. If it changes, then be sure to
|
|
# re-generate any SVG test files using this mode, or else such tests will
|
|
# fail to use the converter for the expected images (but will for the
|
|
# results), and the tests will fail strangely.
|
|
if re.search(
|
|
# searches for attributes :
|
|
# style=[font|font-size|font-weight|
|
|
# font-family|font-variant|font-style]
|
|
# taking care of the possibility of multiple style attributes
|
|
# before the font styling (i.e. opacity)
|
|
r'style="[^"]*font(|-size|-weight|-family|-variant|-style):',
|
|
contents # raw contents of the svg file
|
|
):
|
|
# for svg.fonttype = none, we explicitly patch the font search
|
|
# path so that fonts shipped by Matplotlib are found.
|
|
convert = _svg_with_matplotlib_fonts_converter
|
|
convert(path, newpath)
|
|
|
|
if cache_dir is not None:
|
|
_log.debug("For %s: caching conversion result.", filename)
|
|
shutil.copyfile(newpath, cached_path)
|
|
|
|
return str(newpath)
|
|
|
|
|
|
def _clean_conversion_cache():
|
|
# This will actually ignore mpl_toolkits baseline images, but they're
|
|
# relatively small.
|
|
baseline_images_size = sum(
|
|
path.stat().st_size
|
|
for path in Path(mpl.__file__).parent.glob("**/baseline_images/**/*"))
|
|
# 2x: one full copy of baselines, and one full copy of test results
|
|
# (actually an overestimate: we don't convert png baselines and results).
|
|
max_cache_size = 2 * baseline_images_size
|
|
# Reduce cache until it fits.
|
|
with cbook._lock_path(_get_cache_path()):
|
|
cache_stat = {
|
|
path: path.stat() for path in _get_cache_path().glob("*")}
|
|
cache_size = sum(stat.st_size for stat in cache_stat.values())
|
|
paths_by_atime = sorted( # Oldest at the end.
|
|
cache_stat, key=lambda path: cache_stat[path].st_atime,
|
|
reverse=True)
|
|
while cache_size > max_cache_size:
|
|
path = paths_by_atime.pop()
|
|
cache_size -= cache_stat[path].st_size
|
|
path.unlink()
|
|
|
|
|
|
@functools.cache # Ensure this is only registered once.
|
|
def _register_conversion_cache_cleaner_once():
|
|
atexit.register(_clean_conversion_cache)
|
|
|
|
|
|
def crop_to_same(actual_path, actual_image, expected_path, expected_image):
|
|
# clip the images to the same size -- this is useful only when
|
|
# comparing eps to pdf
|
|
if actual_path[-7:-4] == 'eps' and expected_path[-7:-4] == 'pdf':
|
|
aw, ah, ad = actual_image.shape
|
|
ew, eh, ed = expected_image.shape
|
|
actual_image = actual_image[int(aw / 2 - ew / 2):int(
|
|
aw / 2 + ew / 2), int(ah / 2 - eh / 2):int(ah / 2 + eh / 2)]
|
|
return actual_image, expected_image
|
|
|
|
|
|
def calculate_rms(expected_image, actual_image):
|
|
"""
|
|
Calculate the per-pixel errors, then compute the root mean square error.
|
|
"""
|
|
if expected_image.shape != actual_image.shape:
|
|
raise ImageComparisonFailure(
|
|
f"Image sizes do not match expected size: {expected_image.shape} "
|
|
f"actual size {actual_image.shape}")
|
|
# Convert to float to avoid overflowing finite integer types.
|
|
return np.sqrt(((expected_image - actual_image).astype(float) ** 2).mean())
|
|
|
|
|
|
# NOTE: compare_image and save_diff_image assume that the image does not have
|
|
# 16-bit depth, as Pillow converts these to RGB incorrectly.
|
|
|
|
|
|
def _load_image(path):
|
|
img = Image.open(path)
|
|
# In an RGBA image, if the smallest value in the alpha channel is 255, all
|
|
# values in it must be 255, meaning that the image is opaque. If so,
|
|
# discard the alpha channel so that it may compare equal to an RGB image.
|
|
if img.mode != "RGBA" or img.getextrema()[3][0] == 255:
|
|
img = img.convert("RGB")
|
|
return np.asarray(img)
|
|
|
|
|
|
def compare_images(expected, actual, tol, in_decorator=False):
|
|
"""
|
|
Compare two "image" files checking differences within a tolerance.
|
|
|
|
The two given filenames may point to files which are convertible to
|
|
PNG via the `.converter` dictionary. The underlying RMS is calculated
|
|
with the `.calculate_rms` function.
|
|
|
|
Parameters
|
|
----------
|
|
expected : str
|
|
The filename of the expected image.
|
|
actual : str
|
|
The filename of the actual image.
|
|
tol : float
|
|
The tolerance (a color value difference, where 255 is the
|
|
maximal difference). The test fails if the average pixel
|
|
difference is greater than this value.
|
|
in_decorator : bool
|
|
Determines the output format. If called from image_comparison
|
|
decorator, this should be True. (default=False)
|
|
|
|
Returns
|
|
-------
|
|
None or dict or str
|
|
Return *None* if the images are equal within the given tolerance.
|
|
|
|
If the images differ, the return value depends on *in_decorator*.
|
|
If *in_decorator* is true, a dict with the following entries is
|
|
returned:
|
|
|
|
- *rms*: The RMS of the image difference.
|
|
- *expected*: The filename of the expected image.
|
|
- *actual*: The filename of the actual image.
|
|
- *diff_image*: The filename of the difference image.
|
|
- *tol*: The comparison tolerance.
|
|
|
|
Otherwise, a human-readable multi-line string representation of this
|
|
information is returned.
|
|
|
|
Examples
|
|
--------
|
|
::
|
|
|
|
img1 = "./baseline/plot.png"
|
|
img2 = "./output/plot.png"
|
|
compare_images(img1, img2, 0.001)
|
|
|
|
"""
|
|
actual = os.fspath(actual)
|
|
if not os.path.exists(actual):
|
|
raise Exception(f"Output image {actual} does not exist.")
|
|
if os.stat(actual).st_size == 0:
|
|
raise Exception(f"Output image file {actual} is empty.")
|
|
|
|
# Convert the image to png
|
|
expected = os.fspath(expected)
|
|
if not os.path.exists(expected):
|
|
raise OSError(f'Baseline image {expected!r} does not exist.')
|
|
extension = expected.split('.')[-1]
|
|
if extension != 'png':
|
|
actual = convert(actual, cache=True)
|
|
expected = convert(expected, cache=True)
|
|
|
|
# open the image files
|
|
expected_image = _load_image(expected)
|
|
actual_image = _load_image(actual)
|
|
|
|
actual_image, expected_image = crop_to_same(
|
|
actual, actual_image, expected, expected_image)
|
|
|
|
diff_image = make_test_filename(actual, 'failed-diff')
|
|
|
|
if tol <= 0:
|
|
if np.array_equal(expected_image, actual_image):
|
|
return None
|
|
|
|
# convert to signed integers, so that the images can be subtracted without
|
|
# overflow
|
|
expected_image = expected_image.astype(np.int16)
|
|
actual_image = actual_image.astype(np.int16)
|
|
|
|
rms = calculate_rms(expected_image, actual_image)
|
|
|
|
if rms <= tol:
|
|
return None
|
|
|
|
save_diff_image(expected, actual, diff_image)
|
|
|
|
results = dict(rms=rms, expected=str(expected),
|
|
actual=str(actual), diff=str(diff_image), tol=tol)
|
|
|
|
if not in_decorator:
|
|
# Then the results should be a string suitable for stdout.
|
|
template = ['Error: Image files did not match.',
|
|
'RMS Value: {rms}',
|
|
'Expected: \n {expected}',
|
|
'Actual: \n {actual}',
|
|
'Difference:\n {diff}',
|
|
'Tolerance: \n {tol}', ]
|
|
results = '\n '.join([line.format(**results) for line in template])
|
|
return results
|
|
|
|
|
|
def save_diff_image(expected, actual, output):
|
|
"""
|
|
Parameters
|
|
----------
|
|
expected : str
|
|
File path of expected image.
|
|
actual : str
|
|
File path of actual image.
|
|
output : str
|
|
File path to save difference image to.
|
|
"""
|
|
expected_image = _load_image(expected)
|
|
actual_image = _load_image(actual)
|
|
actual_image, expected_image = crop_to_same(
|
|
actual, actual_image, expected, expected_image)
|
|
expected_image = np.array(expected_image, float)
|
|
actual_image = np.array(actual_image, float)
|
|
if expected_image.shape != actual_image.shape:
|
|
raise ImageComparisonFailure(
|
|
f"Image sizes do not match expected size: {expected_image.shape} "
|
|
f"actual size {actual_image.shape}")
|
|
abs_diff = np.abs(expected_image - actual_image)
|
|
|
|
# expand differences in luminance domain
|
|
abs_diff *= 10
|
|
abs_diff = np.clip(abs_diff, 0, 255).astype(np.uint8)
|
|
|
|
if abs_diff.shape[2] == 4: # Hard-code the alpha channel to fully solid
|
|
abs_diff[:, :, 3] = 255
|
|
|
|
Image.fromarray(abs_diff).save(output, format="png")
|