This is very helpful indeed, thank you. Awe-inspiring.
It occurred to me that I could edit the PIL/ImageShow.py, replacing ‘xv’
(in five places) with the utility of my choice and using ‘executable’ as
the command.
Or, is this just not done?
On 26/05/2018 19:11, Peter Otten wrote:
Paul St George wrote:
Thank you.
You are very right. The show() method is intended for debugging purposes
and is useful for that, but what method should I be using and is PIL the
best imaging library for my purposes? I do not want to manipulate
images, I only want to show images (full screen) on an external display.
I want to use Python to control the timing of the images.
And, out of curiosity, as I will probably use a different method - how
do I find out what commands can be used as parameters for show()? I read
the docs at
<https://pillow.readthedocs.io/en/5.1.x/reference/Image.html
#PIL.Image.Image.show>,
but I am none the wiser.
If you look into the source code
https://github.com/python-pillow/Pillow/blob/master/src/PIL/Image.py#L1967
after a few indirections
show --> _show --> _showxv --> ImageShow.show
you will end up in the file
https://github.com/python-pillow/Pillow/blob/master/src/PIL/ImageShow.py
which is short enough to read completely ;)
At first glance it looks like the command argument is silently discarded, so
here's plan B:
It turns out that you can register() Viewer instances, and the pre-
registered viewers for unixoids -- and thus probably the Pi are
DisplayViewer and XVViewer.
Using these as a template I came up with the following simple viewer that
shows an image with firefox:
#!/usr/bin/env python3
import os
import sys
from PIL import Image, ImageShow
class Firefox(ImageShow.UnixViewer):
# store the image in a format understood by the browser
format = "jpeg"
def get_command_ex(self, file, **options):
return ("firefox",) * 2
def show_file(self, file, **options):
quote = ImageShow.quote
command, executable = self.get_command_ex(file, **options)
# firefox returns immediately, so let's sleep a few seconds
# to give it time to actually open the image file
command = "(%s %s; sleep 10; rm -f %s)&" % (
command, quote("file://" + file), quote(file)
)
os.system(command)
return 1
# the -1 means our viewer will be inserted before the others
# and thus become the default
ImageShow.register(Firefox(), -1)
if __name__ == "__main__":
try:
file = sys.argv[1]
except IndexError:
print("Please provide an image file", file=sys.stderr)
else:
image = Image.open(file)
image.show()
Here's another, even simpler one:
class Gwenview(ImageShow.UnixViewer):
def get_command_ex(self, file, **options):
return ("gwenview",) * 2
--
Paul St George
http://www.paulstgeorge.com
http://www.devices-of-wonder.com
+44(0)7595 37 1302
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