Image plugin fails despite correct tile settings #7536
Description
What did you do?
I created a working function to read FLIR FFF files.
Then I started a new plugin based off that function, using the handbook instructions.
What did you expect to happen?
I expected the plugin to succeed in opening the image.
What actually happened?
Pillow tried to open it twice, and then failed with a generic error.
PIL.UnidentifiedImageError: cannot identify image file 'Snap-000014.img
What are your OS, Python and Pillow versions?
- OS: Windows 10
- Python: Python 3.10.10
- Pillow: 9.4.0
from PIL import Image, ImageFile, ImageStat
def _accept(prefix):
return prefix[:3] == b"FFF"
def u16(arr, index):
return int.from_bytes(arr[index:index+2], 'little')
class FFFImageFile(ImageFile.ImageFile):
format = "FFF"
format_description = "Raw image exported by FLIR ResearchIR"
def _open(self):
h = self.fp.read(2780)
print(h[:16]) #To verify that this is called
s = u16(h,0x6c)
self._size = (
u16(h,s+2),
u16(h,s+4),
)
self._mode = 'I;16L'
self.tile = [('raw', (0,0) + self.size, s+32, (self.mode, 0, 1))]
print(self.mode)
Image.register_open(FFFImageFile.format, FFFImageFile, _accept)
Image.register_extensions(
FFFImageFile.format,
[
".img", #Single image
".seq", #Series of images
],
)
def read(fname):
d = []
with open(fname, 'rb') as f:
d = f.read()
s = u16(d,0x6c)
size = (
u16(d,s+2),
u16(d,s+4),
)
mode = 'I;16L'
im = Image.frombytes(mode,size,d[s+32:],decoder_name='raw')
im = im.convert(mode='F')
return(im)
def max_contrast(im, debug=False):
pmin, pmax = im.getextrema()
if debug:
print(f'{pmin}, {pmax}')
m = 255 / (pmax - pmin)
b = m * pmin
im = im.point(lambda x: m*x-b)
im = im.convert(mode='L')
if debug:
stat = ImageStat.Stat(im)
print(f'min/max: {stat.extrema}')
print(f'mean: {stat.mean} stddev: {stat.stddev}')
return im
if __name__ == '__main__':
fname = "Snap-000014.img"
#im = read(fname)
im = Image.open(fname)
im = max_contrast(im, True)
im.show()