Image cropping with fixed aspect ratio - php

Question

I'm trying to take in two sets of x-y co-ordinates from an image in a 7:9 aspect ratio and replace the original image with the cropped section in a 280x360 image, but it's not working. It's not throwing up any errors but the image replacement after cropping doesn't seem to work. Echoing data tells me it takes in everything up to the imagecopyresampled code.
$formDatax1=$_POST["x1"];
$formDatax2=$_POST["x2"];
$formDatay1=$_POST["y1"];
$formDatay2=$_POST["y2"];
$filename='http://pathtofiles/path/photo/'.$a_photo;
$image_info = getimagesize($filename);
switch(strtolower($image_info['mime'])){
case 'image/png' : $image = imagecreatefrompng($filename); $imgtype='png'; break;
case 'image/jpeg': $image = imagecreatefromjpeg($filename); $imgtype='jpg'; break;
case 'image/gif' : $image = imagecreatefromgif($filename); $imgtype='gif'; break;
default: die();
}
$resized_width = ((int)$formDatax2) - ((int)$formDatax1);
$resized_height = ((int)$formDatay2) - ((int)$formDatay1);
$resized_image = imagecreatetruecolor(280, 360);
imagecopyresampled($resized_image, $image, 0, 0, (int)$formDatax1, (int)$formDatay1, 280, 360, $resized_width, $resized_height);
if ($imgtype=='png') {
imagepng($resized_image, $filename);
}
if ($imgtype=='jpg') {
imagejpeg($resized_image, $filename);
}
if ($imgtype=='gif') {
imagejpeg($resized_image, $filename);
}
echo '<script type="text/javascript">alert("Image cropped!"); </script>';
exit();

Answer 1

You're not specifying a new value for $filename. The http[s] URL wrappers can retrieve a file, but not write. You'll need to specify a local filesystem location to save the image to.

Answer 2

This solution is from PHP cookbook 3rd edition
Use the ImageCopyResampled() function, scaling the image as needed.
To shrink proportionally:
$filename = __DIR__ . '/php.png';
$scale = 0.5; // Scale
// Images
$image = ImageCreateFromPNG($filename);
$thumbnail = ImageCreateTrueColor(
ImageSX($image) * $scale,
ImageSY($image) * $scale);
// Preserve Transparency
ImageColorTransparent($thumbnail,
ImageColorAllocateAlpha($thumbnail, 0, 0, 0, 127));
ImageAlphaBlending($thumbnail, false);
ImageSaveAlpha($thumbnail, true);
// Scale & Copy
ImageCopyResampled($thumbnail, $image, 0, 0, 0, 0,
ImageSX($thumbnail), ImageSY($thumbnail),
ImageSX($image), ImageSY($image));
// Send
header('Content-type: image/png');
ImagePNG($thumbnail);
ImageDestroy($image);
ImageDestroy($thumbnail);
To shrink to a fixed-size rectangle:
// Rectangle Version
$filename = __DIR__ . '/php.png';
// Thumbnail Dimentions
$w = 50; $h = 20;
// Images
$original = ImageCreateFromPNG($filename);
$thumbnail = ImageCreateTrueColor($w, $h);
// Preserve Transparency
ImageColorTransparent($thumbnail,
ImageColorAllocateAlpha($thumbnail, 0, 0, 0, 127));
ImageAlphaBlending($thumbnail, false);
ImageSaveAlpha($thumbnail, true);
// Scale & Copy
$x = ImageSX($original);
$y = ImageSY($original);
$scale = min($x / $w, $y / $h);
ImageCopyResampled($thumbnail, $original,
0, 0, ($x - ($w * $scale)) / 2, ($y - ($h * $scale)) / 2,
$w, $h, $w * $scale, $h * $scale);
// Send
header('Content-type: image/png');
ImagePNG($thumbnail);
ImageDestroy($original);
ImageDestroy($thumbnail);