resizing all the images in a directory?

sneakyimp

ok...i know how to list the contents of a directory and get all the files, etc. what i need to know is how to resize a single image.

basically, what i'd like to do is determine how large the image is...i can use getimagesize() for this. happily, this will also tell me what the image type is.

then how do i resize it? i've seen a whole slew of image functions in the php documentation, but they seem to deal with image resources (kind of like a query resource??) and i'm not familiar with those.

i reckon i could figure this out on my own eventually, but was hoping for a quick tip from someone who has experience dealing with images.

i'm also curious about all those little meta data bits generated by digital cameras.

any help would be much appreciated.

Weedpacket

Originally posted by sneakyimp
they seem to deal with image resources (kind of like a query resource??) and i'm not familiar with those.

Then the thing to do would be to start at the first page of the manual chapter on [man]image[/man] functions and learn. You load the image, create a new image of the new size, copy the original image data to the new image, then save the new image. You put that in a loop that iterates over each of the image files in the directory.

sneakyimp

thanks.

i had been reading that and had been through half a dozen pages of it without having any inkling of how to export an image resource to a file. still looking.

will report back when i find out.

Weedpacket

Originally posted by sneakyimp
thanks.

i had been reading that and had been through half a dozen pages of it without having any inkling of how to export an image resource to a file. still looking.

So you haven't got as far as the function listing on the [man]image[/man] page then, yet?

[man]imagegif[/man] -- Output image to browser or file
[man]imagejpeg[/man] -- Output image to browser or file
[man]imagepng[/man] -- Output a PNG image to either the browser or a file
...

sneakyimp

i got there last night. i'm currently using imagejpeg() for the output.

the other functions looked so promising! And there were so many of them! thanks for the additional help.

so most of these functions create and/or manipulate an image resource. and only those precious few create a file on the hard drive. can you manually create a file and write the image things to it as binary?

MikeSnead

Originally posted by sneakyimp
i got there last night. i'm currently using imagejpeg() for the output.

the other functions looked so promising! And there were so many of them! thanks for the additional help.

so most of these functions create and/or manipulate an image resource. and only those precious few create a file on the hard drive. can you manually create a file and write the image things to it as binary?

Well you use the imagecreatefromXXXX() functions to turn a stored image into a resource, then you can play with it via the long list of functions, and finally you can convert it back into a jpeg/png/gif as a file when you're done.

Weedpacket

Originally posted by sneakyimp
the other functions looked so promising! And there were so many of them! thanks for the additional help.

To be honest, that's one of the reasons I was so insistent about reading through them. It seems every time I do so there have been new ones added. "Oooo ... that sounds like fun...!"

so most of these functions create and/or manipulate an image resource. and only those precious few create a file on the hard drive. can you manually create a file and write the image things to it as binary?

You certainly can, but you'd need to be intimately familiar with the format specification of the image you're creating. And generally the resulting program would be pretty inefficient compared to writing the same in something like C.

sneakyimp

weedpacket, you sneaky bastard. i suppose i can't really complain...you've helped me so many times.

i reckon maybe i'll try and see if you can write directly from an image resource to a binary file...not in the next few minutes tho.