Resizing Images before uploading

carlo2343

I know the GD library is capable of doing this, but I don't recall how I would resize an image to a certain filesize. The filesize limit is 200kb. However, if a user uploads a 2mb file I would like it to be resized to something <= 200kb in filesize and in perfect proportion automatically before it is saved on the server.

It's no problem if it saves temporarily just to resize, but how would I go about doing this? Like I said, I'm used to the GD(2) library and I used to use it a lot, but I haven't in about 1-2 years.

Currently, I know that cardomain.com allows users to upload any file size, (I uploaded a 2mb photo) and it auto resizes it to less than 200kb and keeps it in proportion. This is what I need!

Thanks!

samudasu

This is what the php manual is for.
http://www.php.net/manual/en/function.imagecopyresampled.php

carlo2343

samudasu wrote:
This is what the php manual is for.
http://www.php.net/manual/en/function.imagecopyresampled.php

Yeah, but I want to use that code inside a page with output. How would I get around the header()?

discostudio

It is really hard work resizing images by filesize, by demensions is reletively easy. There may be a math equasion that can calculate a sum of the pixels/in (web is 72) and dimensions & Jpg quality.

There must be some way of doing it, this way you can do the equasion backwards and find out how small you need to shrink it to get it below 200Kb.

I don't think you will find your answer here though, try looking at graphic design forums.

samudasu

Do you mean you want to resize the photo and display it resized on the same page? If that's the case then you know where you're saving the newly resized photo and it's name right? After the image resize part runs then just add something like this:

$newimage = "newimage.jpg";
print "<img src=\"http://yourhost.com/images/$newimage\" />";

carlo2343

Okay, the last problem I have is pretty minute, I think. I can't think of how to functionize this code I've written. It's fairly adaptable to all sorts of images and since I only need them to be scaled down to a max width, and height is irrelevant, I wrote a nice and simple resizing program in it as well.

Here is my code:

function resize($filename)

$type = preg_replace('#.*?\.(.+)$#i', '\\1', $filename);

if ($type == 'jpg') {
 $type = 'jpeg';
}

$func = 'imagecreatefrom' . $type;

// Content type
//header('Content-type: image/' . $type);

// Get new dimensions
list($width, $height) = getimagesize($filename);
$new_width = $width * $percent;
$new_height = $height * $percent;

$max_width = 200;

# Calculate percent
$per = $width/$max_width;

$new_width = $width / $per;
$new_height = $height / $per;


// Resample
$image_p = imagecreatetruecolor($new_width, $new_height);
$image = $func($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

// Output
imagejpeg($image_p, 'template.jpeg', 100);

}

resize('template.gif') or die ('Could not execute');

Well, the file template.gif worked before, but now it won't since I put it in a function, and none of the files will. Without the function it was working fine; however, I still never reached the Could not execute error message, so it seems a bit odd the function isn't performing as it should but it isn't dying.

Perhaps I should slap a "return false;" for some circumstances in there? Oh well, could you guys see waht's wrong with this function and tell me how to make it into one?

carlo2343

anyone?