[SOLVED] Bash: Image dimensions

graphicsmanx1 · 11-01-2012, 09:38 AM

Ive been trying to figure out a way to write some bash script that will record to a .txt file images over a certain amount of pixels. Ive been reading on ImageMagick but I was wanting to know if there is a better way to just code it out in bash?? I can write an if statement based on file size but I need it by dimensions. Can this be done and if so how??

gnashley · 11-01-2012, 10:09 AM

Depending on what type of image they are, using 'file' may return the dimensions of the image.

druuna · 11-01-2012, 10:12 AM

There are command line tools that can do this. Here's one that comes to mind:

Code:

$ identify image.jpg 
image.jpg JPEG 2000x2917 2000x2917+0+0 8-bit DirectClass 526KB 0.000u 0:00.000

# or more tailored to your demands:
$ identify -format "%w %h"  image.jpg
2000 2917

The format option is flexible, use the man page for other details.

graphicsmanx1 · 11-01-2012, 10:49 AM

Quote:

Originally Posted by druuna

There are command line tools that can do this. Here's one that comes to mind:

Code:

$ identify image.jpg 
image.jpg JPEG 2000x2917 2000x2917+0+0 8-bit DirectClass 526KB 0.000u 0:00.000

# or more tailored to your demands:
$ identify -format "%w %h"  image.jpg
2000 2917

The format option is flexible, use the man page for other details.

my apologies but its only my third week in bash and Linux but if I want to check the dimension of all jpegs would it be:

Code:

$ identify -format "%w %h"  /*.jpg >>results.txt

>> to print to .txt

druuna · 11-01-2012, 11:17 AM

This should work:

Code:

identify -format "%f %w %h\n" *jpg > results.txt

# or if you want to append to the results.txt file:

identify -format "%f %w %h\n" *jpg >> results.txt

i've used 2 extra format options: %f reflect the full file name, \n makes sure every entry is on its own line (newline).

Have a look here for all the format options: http://www.imagemagick.org/script/escape.php

graphicsmanx1 · 11-01-2012, 11:40 AM

If i wanted to write in a loop for the sizes is this printing them as variables or integers??

millgates · 11-01-2012, 11:52 AM

Quote:

Originally Posted by graphicsmanx1

If i wanted to write in a loop for the sizes is this printing them as variables or integers??

What do you mean by "printing as variables"? identify outputs the results as text.

graphicsmanx1 · 11-01-2012, 12:07 PM

Quote:

Originally Posted by millgates

What do you mean by "printing as variables"? identify outputs the results as text.

yes I wanted to write a loop and echo the results if the images are more than a total number of pixels. When I research about loops it shows me two different options with either integers or strings

What Im trying to do is figure out how to use imageMagick to write bash script to tell me what images are to large based on pixels. I know how to do this with size but that's why I asked the question how to tell what the dimension is and if you echo what is it echoing an integer or string.

My idea is pull the height and width if they can be echoed as integers and times the integers. Run an >= on the size i want to flag.

millgates · 11-01-2012, 12:20 PM

Quote:

Originally Posted by graphicsmanx1

My idea is pull the height and width if they can be echoed as integers and times the integers. Run an >= on the size i want to flag.

bash does not differentiate between integers and strings. Every variable is treated as a string, unless in math context. You can't make any program to output values "as integers". stdout is a character stream.

example:

Code:

#!/bin/bash

maxsize="2000000"
while read -r width height fname; do 
    ((width*height>maxsize)) && echo "$fname";
done < <(identify -format "%w %h %f\n" *jpg)

schneidz · 11-01-2012, 12:51 PM

what i do is resize the images regardless of size because it is easier than identifying those that are too big then going back and selectively resize certain files:

Code:

[schneidz@hyper ~]$ cat /var/www/html/estella-farm/pic-import.ksh 
#!/bin/bash

mkdir photos/bak; cp photos/*.* photos/bak
mogrify -resize 400x300 photos/*.* 

cp index.html index.bak
head -n 15 index.bak  > index.html

i=0
for pic in photos/*.*
do
 echo \<li\>\<img src=$pic width=500 height=300 alt=$pic /\>\</li\> >> index.html
 i=`expr $i + 1`
done

echo 			\</ul\> >> index.html
echo		\</div\> >> index.html
echo		\<div class=\"sliderbutton\"\>\<img src=\"images/right.gif\" width=\"32\" height=\"38\" alt=\"Next\" onclick=\"slideshow.move\(1\)\" /\>\</div\> >> index.html
echo	\</div\> >> index.html
echo	\<ul id=\"pagination\" class=\"pagination\"\> >> index.html

x=0
while [ $x -le $i ]
do
 echo  \<li onclick=\"slideshow.pos\($x\)\"\>`expr $x + 1`\</li\> >> index.html
 x=`expr $x + 1`
done

echo	\</ul\> >> index.html
echo \</div\> >> index.html
echo \<script type=\"text/javascript\"\> >> index.html
echo var slideshow=new TINY.slider.slide\(\'slideshow\',\{ >> index.html
echo	id:\'slider\', >> index.html
echo	auto:3, >> index.html
echo	resume:true, >> index.html
echo	vertical:false, >> index.html
echo	navid:\'pagination\', >> index.html
echo	activeclass:\'current\', >> index.html
echo	position:0 >> index.html
echo \}\)\; >> index.html
echo \</script\> >> index.html
echo \</body\> >> index.html
echo \</html\> >> index.html

graphicsmanx1 · 11-01-2012, 01:33 PM

Quote:

Originally Posted by schneidz

what i do is resize the images regardless of size because it is easier than identifying those that are too big then going back and selectively resize certain files:

Code:

[schneidz@hyper ~]$ cat /var/www/html/estella-farm/pic-import.ksh 
#!/bin/bash

mkdir photos/bak; cp photos/*.* photos/bak
mogrify -resize 400x300 photos/*.* 

cp index.html index.bak
head -n 15 index.bak  > index.html

i=0
for pic in photos/*.*
do
 echo \<li\>\<img src=$pic width=500 height=300 alt=$pic /\>\</li\> >> index.html
 i=`expr $i + 1`
done

echo 			\</ul\> >> index.html
echo		\</div\> >> index.html
echo		\<div class=\"sliderbutton\"\>\<img src=\"images/right.gif\" width=\"32\" height=\"38\" alt=\"Next\" onclick=\"slideshow.move\(1\)\" /\>\</div\> >> index.html
echo	\</div\> >> index.html
echo	\<ul id=\"pagination\" class=\"pagination\"\> >> index.html

x=0
while [ $x -le $i ]
do
 echo  \<li onclick=\"slideshow.pos\($x\)\"\>`expr $x + 1`\</li\> >> index.html
 x=`expr $x + 1`
done

echo	\</ul\> >> index.html
echo \</div\> >> index.html
echo \<script type=\"text/javascript\"\> >> index.html
echo var slideshow=new TINY.slider.slide\(\'slideshow\',\{ >> index.html
echo	id:\'slider\', >> index.html
echo	auto:3, >> index.html
echo	resume:true, >> index.html
echo	vertical:false, >> index.html
echo	navid:\'pagination\', >> index.html
echo	activeclass:\'current\', >> index.html
echo	position:0 >> index.html
echo \}\)\; >> index.html
echo \</script\> >> index.html
echo \</body\> >> index.html
echo \</html\> >> index.html

um wow.. I guess I need to research what you are doing. Way out from what Ive learned yet

schneidz · 11-01-2012, 01:41 PM

the significant line is highlighted in red.

the rest of it basically automatedly creates an index.html file for my webserver updating links to the new photo names.

graphicsmanx1 · 11-01-2012, 01:48 PM

Quote:

Originally Posted by schneidz

the significant line is highlighted in red.

the rest of it basically automatedly creates an index.html file for my webserver updating links to the new photo names.

but I dont want to resize I want to detect and print to file or as they call it echo

schneidz · 11-01-2012, 02:15 PM

ok, i misunderstood, druunas/ millgates advice seems appropriate.

graphicsmanx1 · 11-01-2012, 02:21 PM

Quote:

Originally Posted by schneidz

ok, i misunderstood, druuna's advice seems appropriate.

yes druuna and mills work great. Mills is exactly what I was looking for. Now I need to understand whats going on so I can learn from it.