please excuse the intrussion and the petty post above. 10 minutes later and I found the sollution.

If it's of any help to any one trying to get square crops here's the trick: the scale ratio between normal height and normal width ( ex: 768*1024) is about 1.3.

Use that value to disproportionate the photo's newheight/newwidth (depending on a portrait or landscape photo)

Ex: for a landscape photo the fix is:
$newheight = ($dimensions[1] * 1.3) / 2;

Hope this helps anyone.

And here's some code to do padded resizes (forces the exact width/height specified even if the image is skewed. It takes width and height as the first two arguments and the third is a RRGGBB colour like you'd use in CSS.

Some notes:
- $this->gd is an object which contains a GD class - in this case it's the original image that we're doing a resize of (hence why the original image's filename etc isn't ever passed - it's in $this->gd. Feel free to make your own class or just replace this with whatever works for you.

This is the web2gd method:
static function color_web2gd($image, $webColor) {
if(substr($webColor,0,1) == "#") $webColor = substr($webColor,1);
$r = hexdec(substr($webColor,0,2));
$g = hexdec(substr($webColor,2,2));
$b = hexdec(substr($webColor,2,2));

return imagecolorallocate($image, $r, $g, $b);

}

And the paddedResize method:
function paddedResize($width, $height, $backgroundColor = "FFFFFF") {
if(!$this->gd) return;

$width = round($width);
$height = round($height);


$newGD = imagecreatetruecolor($width, $height);
$bg = GD::color_web2gd($newGD, $backgroundColor);
imagefilledrectangle($newGD, 0, 0, $width, $height, $bg);

$destAR = $width / $height;
if ($this->width > 0 && $this->height > 0) {
// We can't divide by zero theres something wrong.

$srcAR = $this->width / $this->height;

// Destination narrower than the source
if($destAR > $srcAR) {
$destY = 0;
$destHeight = $height;

$destWidth = $height * $srcAR;
$destX = ($width - $destWidth) / 2;

// Destination shorter than the source
} else {
$destX = 0;
$destWidth = $width;

$destHeight = $width / $srcAR;
$destY = ($height - $destHeight) / 2;
}

imagecopyresampled($newGD, $this->gd, $destX, $destY, 0, 0, $destWidth, $destHeight, $this->width, $this->height);
}
$output = new GD();
$output->setGD($newGD);
return $output;
}

Hope the base code at least helps someone who sucks at Maths like I do :P

Hi.

Great tutorial!

I'm still a big n00b when it comes to php (although I'm trying to learn... unsuccessfully), anyway I was wondering how you would combine this with a simple upload form? Ive tried several things but they never seem to work :(

Thanks.

why is it double posting?

If you replace:
$newwidth = $dimensions[0] / 2;
$newheight = $dimensions[1] / 2;

With:
$newwidth = (($dimensions[0]-$width) / 3)*2;
$newheight = (($dimensions[1]-$height) / 3)*2;

It means it that (as long as teh original image is larger than the thumbnail size) the image won't scale itself down to a smaller size than the thumbnail size.

Its a bit better...

Just a thought I had, but as an addition to this, if you set an input type as "image" (<input type="image" .... >) with the src being the path to the image, when you click the image, it submits the form, but also throws in two more form variables--the x and y coords of where the click was performed (relative to the image). This could be useful for a thumbnail creation script by centering the box about the click origin rather than the center of the image.

H, come back to us in #surpass. We miss you.

This helped me get started with image manipulation, but it's not quite getting where I want.

I have a 480 x 480 image. I want to resize it o 240 x 240 and then crop out the middle "portrait" shaped rectangle 150px wide by 200px high. I've tried different combinations of numbers for the offsets, but I can't seem to get that rectangle without stretching the image.

Many thanks in advance!

oh and the line 51 is

if (imagejpeg($canvas ,'images/thumbs',90 )) {