ImageMagick change image width and height -

ImageMagick change image width and height -

i using imagemagick resize image resolution using below command-line option

convert abc.png -set units pixelsperinch -density 75 abc_a.png

i in need of this: if images has more 300 width or more 100 height, want convert width 300 width , 100 height, changing above dpi (i.e. 75dpi).

can 1 help me on this?

if on linux/osx, can image dimensions this:

identify -format "%w %h" input.jpg

so, if want width , height in variables w , h, this:

read w h < <(identify -format "%w %h" input.jpg)

now can test width , height , farther processing if necessary:

[ $w -gt 300 -o $h -gt 100 ] && convert input.jpg -set units ...

or, if want more verbose:

if [ $w -gt 300 -o $h -gt 100 ]; convert ... fi

so, total solution proposing looks this:

#!/usr/bin/bash read w h < <(identify -format "%w %h" input.jpg) [ $w -gt 300 -o $h -gt 100 ] && convert input.jpg -set units ...

jpeg or png makes no difference, replace jpg png if format of choice.

updated windows

ok, no-one else helping out (very) rusty windows skills. image width under windows:

identify -format "%w" input.png > w.txt set /p w=<w.txt

now height:

identify -format "%h" input.png > h.txt set /p h=<h.txt

you should have width , height of image input.png in 2 variables, w , h, check typing

echo %w% echo %h%

now need if statements:

if %w% leq 300 goto skip if %h% leq 100 goto skip convert .... :skip

note:: may need ^ in front end of percent sign in windows.

note: may need double @ signs in scripts because windows illogical.

image imagemagick imagemagick-convert