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image to blob to file ::then:: file to blob to image :: is this possible? why so hard to figure out?

Posted: 2019-09-14T15:28:05-07:00
by ss.private
Hi,
Old hand at development here, but newbie to image-magick.
Just BTW, right now I am in strawberry perl (v28) on Win10.

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use strict;
use warnings;
use Image::Magick;
magick -version
Version: ImageMagick 7.0.8-59 Q16 x64 2019-08-04 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2018 ImageMagick Studio LLC
License: http://www.imagemagick.org/script/license.php
Visual C++: 180040629
Features: Cipher DPC Modules OpenCL OpenMP(2.0)
Delegates (built-in): bzlib cairo flif freetype gslib heic jng jp2 jpeg lcms lqr lzma openexr pangocairo png ps raw rsvg tiff webp xml zlib
All that said, what I need to do is store images in an relatively unreadable or at least serious pain-in-the-neck form -- without encryption. I am figuring so far that IM blobs ought to fit the bill.(I have not yet started fighting with "authentic pixels", though I guess that's my next, unpromising, step.)

So far I can create the images I need. They look fine. I can write them out as PNG files. Those are fine too. And in pursuit of my real goal, I use ImageToBlob to get at the insides, and then I write that out to yaddayada.blob. No prob.

When I read the blob files back in and try to convert them back to PNG images that I could display or send them over the wire for somebody else's code to display, or even persist to disk somewhere, I find my self in MAGICK HELL. (cue drums and booga booga noises, bwa hah hah etc.)

I haven't included a code sample here because I've done just about every permutation of

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new, read, blobtoimage
and whatnot that I can think of, and I keep getting:
Exception 410: no images defined `Image::Magick' @ error/Magick.xs/unknown/14276] from image->Write to somedumbfilename.png
A few lines of working code or even a good hint where to find an answer will get you my most profound and lasting gratitude -- and free beer if you're ever in my neighborhood.

In any case, Thank you for reading this far.

Best,
SS

Re: image to blob to file ::then:: file to blob to image :: is this possible? why so hard to figure out?

Posted: 2019-09-14T15:32:02-07:00
by fmw42
Have you considered using MIFF format, which only ImageMagick uses. Or INLINE: format, which is base64 text. See https://imagemagick.org/Usage/files/#special_formats

Re: image to blob to file ::then:: file to blob to image :: is this possible? why so hard to figure out?

Posted: 2019-09-14T15:37:36-07:00
by ss.private
Oh, just another bit of diabolical torment, IrfanView can figure out that my .blob files are PNG's with the wrong extension and display them. BUT if I concatenate my blobs into a single file, and then later read those chunks back out and record them as single files, Irfanview has no idea what they are, nor gimp, nor DarkTable.

This is double-dang confusticating!

Re: image to blob to file ::then:: file to blob to image :: is this possible? why so hard to figure out?

Posted: 2019-09-14T15:39:44-07:00
by ss.private
@ fmw42 THX a million. will try that rright now,
fingers crossed.
SS