ImageMagick getimagesize in perl???

[LocoPollo]

How do I get the original size of the image in perl?? I have tired this and alot of other things:

#!/usr/bin/perl -w
print "Content-type: text/html\n\n";
use Image::Magick;

my $workimage = Image::Magick->new;

$workimage->Read("./test.jpg");
my @imginfo = getimagesize($workimage);
print"$imginfo[0] x $imginfo[1]";

undef($workimage);

---------

Thanks again!
Peter

 

[duncdude]

Hi

I can only help with this (must use BACKTICKS not single speech marks):-

$result = `identify test.jpg`;
print $result;

... as i don't have PerlMagick installed

You can split up the result as it always consistent

Cheers
Duncan


Kind Regards
Duncan

 

[LocoPollo]

Cool! And thanks alot, from ZERO, you got me 95% happy. A oneliner would have brought me to 110% ;-)
I get a string like this:

test.jpg JPEG 242x337+0+0 DirectClass 8-bit 7kb 0.000u 0:01

I'm working on it, and it gets a bit clumbsy, but it DOES works!.. First I have to split where there are spaces, then replace the +0+0, then split again where there is a X.

So if someone knows a spiffy way to get the height and weight in just one line, it would be even greater. Cant find much documentation on it!?

Once again thanks Duncan.

BTW: what does the backtips do?? I never read about those before? Do they execute commandline things?

 

[duncdude]

thanks LocoPollo

just off to bed (UK)

this does the trick:-

[b]#!/usr/bin/perl[/b]

$_ = 'test.jpg JPEG 242x337+0+0 DirectClass 8-bit 7kb 0.000u 0:01';

m/^[^.]+\.[^ ]+ [A-Z]+ ([^x]+)x([^+]+).*$/;

print $1; # 1st dimension
print "\n";
print $2; # 2nd dimension

Kind Regards
Duncan

 

[LocoPollo]

You tricked some keywords here, and I found this solution...

#!/usr/bin/perl -w
print "Content-type: text/html\n\n";
use Image::Magick;

my $image = Image::Magick->new;
$image->Read("./test.jpg");
$width = $image->Get('columns');
$height = $image->Get('rows');
print "$width x $height";
undef($image);

Incase someone else can use it, I found it here:

http://www.imagemagick.org/script/perl-magick.php

Wauw! your oneliner is hardcore!?
I have 100 questions to that one, but here are two if you dont mind, and I know it's basic, but I'm still using "my $something", for everything.

$_ when does that one contain any data, and for how long? until first { or }

..the same question with $1 and $2??

Thanks alot once again. )

 

[KevinADC]

there is also:

my $dims = `imgsize test.jpg`;
print $dims;

 

[duncdude]

Hi LocoPollo

Thank you for your kind comments

This is a breakdown of the regex - I hope it is of use!?

my $something = 'test.jpg JPEG 242x337+0+0 DirectClass 8-bit 7kb 0.000u 0:01';

$something =~ m/^[^.]+\.[^ ]+ [A-Z]+ ([^x]+)x([^+]+).*$/;

( note - i have used hashes to denote spaces for visibility )

m/                --- start of match ---
^                 FORCES REGEX TO START MATCHING AT BEGINNING OF LINE
[^.]+             1 or more chars that aren't a dot
\.                a dot
[^#]+             1 or more chars that aren't a space 
#                 a space
[A-Z]+            1 or more uppercase chars
#                 a space
([^x]+)           1 or more chars that aren't an 'x' - capture as $1
x                 an 'x'
([^+]+)           1 or more chars that aren't an '+' - capture as $2
.*                zero or more characters (be careful as this is greedy)
$                 FORCES REGEX TO MATCH TO END OF LINE
/                 --- end of match ---

Kind Regards
Duncan

 

[duncdude]

Hi LocoPollo

Regarding the $_

For example you might write a loop as follows:-

[b]#!/usr/bin/perl[/b]

@names = ( 'name1',
           'name1',
           'name3' );

foreach $name (@names) {
  print "$name\n";
}

but you could omit the $name as follows:-

[b]#!/usr/bin/perl[/b]

@names = ( 'name1',
           'name1',
           'name3' );

foreach (@names) {
  print "[b]$_[/b]\n";
}

Be careful with this - it can be quite dangerous

Basically it is a predifined variable - if you have not been EXPLICIT (i.e. specifying the variable to hold the individual values of the array in this instance) then it IMPLICITLY Perl knows. A good example would be if you wre in a room with one other person and they said 'Do you have the time please' - then you would assume they meant you! The example explains it better!


Kind Regards
Duncan

 

[ishnid]

There's also the Image::Size module.

 

[LocoPollo]

Sorry, didn't see the additions until now!

Thanks alot, it was all very useful, now I know more about regex, it has always been a big mysterious!? Thanks for carving it out for me.

And that temp-thingy: $_ ... I dont know, I might start using it, but it sounds a like a dangerous little thing.

You didn't gave any examples of when it can go wrong, but I guess thats it will if I use one of them inside another one. (e.g. for/foreach) I will only use it in small foreach's.

$1 and $2 thats only for matches as far as I can see elsewhere on the net, or can I use it in other case?

Anyway, I will start playing with all of it! hehe

Thanks again everyone, this made my day! )

 

[duncdude]

Hi LocoPollo

Thanks again for your kind comments - and i'm really glad you are enjoying learning!

You are quite right about the $_ variable - with nested loops this implied method won't work. And you are also correct about the $1 $2 etc. - these are the captures within the regular expression. These are populated on a match if the regex contains braces - i.e. just before and after the 'x' - giving you a separate capture for both the horizontal and vertical dimensions of the image

Sorry i did not explain fully in an earlier post

Carry on having fun!


Kind Regards
Duncan

 

[ishnid]

Technically, you *can* use $1, $2, $3 etc and $a, $b anywhere you want. You probably *shouldn't* though, as Perl will take them over when it needs them as special variables.

 

[youradds]

Wouldn't Image::Size be better? =)

Cheers

Andy

 

[duncdude]

Would it not seem a shame to have to install a module just to find this out? Please tell me if this is so as I have yet to install a single module after using Perl for many years. Maybe i am being very naiive. Thanks.


Kind Regards
Duncan

 

[KevinADC]

considering `identify test.jpg` and `imgsize test.jpg' are OS specific (unix), using Image::Size should be more portable. Part of the power of perl is it's portability, so many will say it's best to use perl and perl modules as often as possible.