Pillow/selftest.py
Jon Dufresne 4cd4adddc3 Improve handling of file resources
Follow Python's file object semantics. User code is responsible for
closing resources (usually through a context manager) in a deterministic
way.

To achieve this, remove __del__ functions. These functions used to
closed open file handlers in an attempt to silence Python
ResourceWarnings. However, using __del__ has the following drawbacks:

- __del__ isn't called until the object's reference count reaches 0.
  Therefore, resource handlers remain open or in use longer than
  necessary.

- The __del__ method isn't guaranteed to execute on system exit. See the
  Python documentation:

  https://docs.python.org/3/reference/datamodel.html#object.__del__

  > It is not guaranteed that __del__() methods are called for objects
  > that still exist when the interpreter exits.

- Exceptions that occur inside __del__ are ignored instead of raised.
  This has the potential of hiding bugs. This is also in the Python
  documentation:

  > Warning: Due to the precarious circumstances under which __del__()
  > methods are invoked, exceptions that occur during their execution
  > are ignored, and a warning is printed to sys.stderr instead.

Instead, always close resource handlers when they are no longer in use.
This will close the file handler at a specified point in the user's code
and not wait until the interpreter chooses to. It is always guaranteed
to run. And, if an exception occurs while closing the file handler, the
bug will not be ignored.

Now, when code receives a ResourceWarning, it will highlight an area
that is mishandling resources. It should not simply be silenced, but
fixed by closing resources with a context manager.

All warnings that were emitted during tests have been cleaned up. To
enable warnings, I passed the `-Wa` CLI option to Python. This exposed
some mishandling of resources in ImageFile.__init__() and
SpiderImagePlugin.loadImageSeries(), they too were fixed.
2019-10-12 08:27:17 -07:00

204 lines
5.6 KiB
Python
Executable File

#!/usr/bin/env python
# minimal sanity check
from __future__ import print_function
import os
import sys
from PIL import Image, features
try:
Image.core.ping
except ImportError as v:
print("***", v)
sys.exit()
except AttributeError:
pass
def _info(im):
im.load()
return im.format, im.mode, im.size
def testimage():
"""
PIL lets you create in-memory images with various pixel types:
>>> from PIL import Image, ImageDraw, ImageFilter, ImageMath
>>> im = Image.new("1", (128, 128)) # monochrome
>>> _info(im)
(None, '1', (128, 128))
>>> _info(Image.new("L", (128, 128))) # grayscale (luminance)
(None, 'L', (128, 128))
>>> _info(Image.new("P", (128, 128))) # palette
(None, 'P', (128, 128))
>>> _info(Image.new("RGB", (128, 128))) # truecolor
(None, 'RGB', (128, 128))
>>> _info(Image.new("I", (128, 128))) # 32-bit integer
(None, 'I', (128, 128))
>>> _info(Image.new("F", (128, 128))) # 32-bit floating point
(None, 'F', (128, 128))
Or open existing files:
>>> with Image.open("Tests/images/hopper.gif") as im:
... _info(im)
('GIF', 'P', (128, 128))
>>> _info(Image.open("Tests/images/hopper.ppm"))
('PPM', 'RGB', (128, 128))
>>> try:
... _info(Image.open("Tests/images/hopper.jpg"))
... except IOError as v:
... print(v)
('JPEG', 'RGB', (128, 128))
PIL doesn't actually load the image data until it's needed,
or you call the "load" method:
>>> im = Image.open("Tests/images/hopper.ppm")
>>> print(im.im) # internal image attribute
None
>>> a = im.load()
>>> type(im.im) # doctest: +ELLIPSIS
<... '...ImagingCore'>
You can apply many different operations on images. Most
operations return a new image:
>>> im = Image.open("Tests/images/hopper.ppm")
>>> _info(im.convert("L"))
(None, 'L', (128, 128))
>>> _info(im.copy())
(None, 'RGB', (128, 128))
>>> _info(im.crop((32, 32, 96, 96)))
(None, 'RGB', (64, 64))
>>> _info(im.filter(ImageFilter.BLUR))
(None, 'RGB', (128, 128))
>>> im.getbands()
('R', 'G', 'B')
>>> im.getbbox()
(0, 0, 128, 128)
>>> len(im.getdata())
16384
>>> im.getextrema()
((0, 255), (0, 255), (0, 255))
>>> im.getpixel((0, 0))
(20, 20, 70)
>>> len(im.getprojection())
2
>>> len(im.histogram())
768
>>> '%.7f' % im.entropy()
'8.8212866'
>>> _info(im.point(list(range(256))*3))
(None, 'RGB', (128, 128))
>>> _info(im.resize((64, 64)))
(None, 'RGB', (64, 64))
>>> _info(im.rotate(45))
(None, 'RGB', (128, 128))
>>> [_info(ch) for ch in im.split()]
[(None, 'L', (128, 128)), (None, 'L', (128, 128)), (None, 'L', (128, 128))]
>>> len(im.convert("1").tobitmap())
10456
>>> len(im.tobytes())
49152
>>> _info(im.transform((512, 512), Image.AFFINE, (1,0,0,0,1,0)))
(None, 'RGB', (512, 512))
>>> _info(im.transform((512, 512), Image.EXTENT, (32,32,96,96)))
(None, 'RGB', (512, 512))
The ImageDraw module lets you draw stuff in raster images:
>>> im = Image.new("L", (128, 128), 64)
>>> d = ImageDraw.ImageDraw(im)
>>> d.line((0, 0, 128, 128), fill=128)
>>> d.line((0, 128, 128, 0), fill=128)
>>> im.getextrema()
(64, 128)
In 1.1.4, you can specify colors in a number of ways:
>>> xy = 0, 0, 128, 128
>>> im = Image.new("RGB", (128, 128), 0)
>>> d = ImageDraw.ImageDraw(im)
>>> d.rectangle(xy, "#f00")
>>> im.getpixel((0, 0))
(255, 0, 0)
>>> d.rectangle(xy, "#ff0000")
>>> im.getpixel((0, 0))
(255, 0, 0)
>>> d.rectangle(xy, "rgb(255,0,0)")
>>> im.getpixel((0, 0))
(255, 0, 0)
>>> d.rectangle(xy, "rgb(100%,0%,0%)")
>>> im.getpixel((0, 0))
(255, 0, 0)
>>> d.rectangle(xy, "hsl(0, 100%, 50%)")
>>> im.getpixel((0, 0))
(255, 0, 0)
>>> d.rectangle(xy, "red")
>>> im.getpixel((0, 0))
(255, 0, 0)
In 1.1.6, you can use the ImageMath module to do image
calculations.
>>> im = ImageMath.eval("float(im + 20)", im=im.convert("L"))
>>> im.mode, im.size
('F', (128, 128))
PIL can do many other things, but I'll leave that for another
day. If you're curious, check the handbook, available from:
http://www.pythonware.com
Cheers /F
"""
if __name__ == "__main__":
# check build sanity
exit_status = 0
print("-" * 68)
print("Pillow", Image.__version__, "TEST SUMMARY ")
print("-" * 68)
print("Python modules loaded from", os.path.dirname(Image.__file__))
print("Binary modules loaded from", os.path.dirname(Image.core.__file__))
print("-" * 68)
for name, feature in [
("pil", "PIL CORE"),
("tkinter", "TKINTER"),
("freetype2", "FREETYPE2"),
("littlecms2", "LITTLECMS2"),
("webp", "WEBP"),
("transp_webp", "WEBP Transparency"),
("webp_mux", "WEBPMUX"),
("webp_anim", "WEBP Animation"),
("jpg", "JPEG"),
("jpg_2000", "OPENJPEG (JPEG2000)"),
("zlib", "ZLIB (PNG/ZIP)"),
("libtiff", "LIBTIFF"),
("raqm", "RAQM (Bidirectional Text)"),
]:
if features.check(name):
print("---", feature, "support ok")
else:
print("***", feature, "support not installed")
print("-" * 68)
# use doctest to make sure the test program behaves as documented!
import doctest
print("Running selftest:")
status = doctest.testmod(sys.modules[__name__])
if status[0]:
print("*** %s tests of %d failed." % status)
exit_status = 1
else:
print("--- %s tests passed." % status[1])
sys.exit(exit_status)