GD library to resize images.

csull

Hey everyone. I hope someone can help me out.

Hey guys. I have read a lot of different option to resize images.

What about a script that will resize an image, constrain proportions, and add a background color to whatever is left.

For example, I have a picture that is 600 (width) by 300 (height) and I want to constrain proportions, and resize this to 300 by 400 (width by height). There would be an extra 250 pixels left in the height, so now that gets filled in with some background color.

This way, the people that have to make any image fit in a certain location can keep the same aspect ratio, and not have to have an 'out of place' image.

Can anybody help me out?

Thanks,
-Chris

jayant

open the manual page for all gd related functions.

and start writing code.

<?php
# open ur existing image
# resize it using formula below
# a x b is original size
# c x d is target size
# 
#  calculate y,z
#  where
#  y = a/c
#  z = b/d
#
#  if(y>z)
#     resize to a/y x b/y
#  else
#     resize to a/z x b/z
#
# create a blank image
# copy it there
# close

# NOTE to center the new image:
#
#    if(y>z)
#         leave (d-b/y)/2 pixels on top and 
#         then copy to new blank image
#     else
#         leave (c-a/z)/2 pixels on left and 
#         then copy to new blank image
#

?>

csull

Hye. I appreciate you laying out the general know how for me.....I don't really work with the GD functions too often though, and I'm afraid I don't know how to copy the image, and center it and so on.

I understand if you don't want to write out the code...but maybe you can point me in the direction of a tutorial site for working with the GD library?

Thanks
-Chris

jayant

u didnt look at the functions page
http://in2.php.net/manual/en/ref.image.php
see this and read the whole page. the descriptions of functions are gud enough.

also when u will click afunction name. more detailed help will come with examples. 🙂

also
hotwired had a article on this, search there.