PHP imagecopyresampled() function cutting in the wrong place

Question

I already reversed the parameters several times to check if I was passing them erroneously, but I was not successful. What is happening is that Crop is performed in a different location than specified. I am using jQuery and jCrop plugin to find the coordinates. On the client side everything works normal.

As in the image below:

I selected the area that is in the print above and it cropped in a totally different location:

Initialization of Jcrop

$('#target').Jcrop({
     onSelect: showCoords,
     onChange: showCoords,
     aspectRatio: 960/720,
     boxWidth: 600,
     boxHeight: 400,
     bgColor: '#674323'
 });

Jsfiddle

This is PHP script where I do Crop on Server-side:

  if ($_SERVER['REQUEST_METHOD'] == 'POST') {

        $dst_x = 0;
        $dst_y = 0;
        $src_x = ceil($_POST['x']); // x1 da imagem de origem
        $src_y = ceil($_POST['y']); // y1 da imagem de origem
        $dst_w = ceil($_POST['w']); // largura da imagem de destino
        $dst_h = ceil($_POST['h']); // altura da imagem de destino
        $src_w = ceil($_POST['x2']); // x2 da imagem de origem
        $src_h = ceil($_POST['y2']); // y2 da imagem de origem

        $jpeg_quality = 100;

        $src = 'css/images/luitame.jpg';
        $img_r = imagecreatefromjpeg($src);
        $dst_r = imagecreatetruecolor($_POST['w'], $_POST['h']);
        $imageName = "css/images/thumbs/".time().'.jpg';
        imagecopyresampled($dst_r, $img_r, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
        imagejpeg($dst_r, $imageName, $jpeg_quality);

        header("location: result.php?img=$imageName");
        exit;
    }

Answer 1

^{I think my comments above did not proceed, Jcrop already automatically handles the scale, according to documentation. I removed the comments (and soon remove this notice as well).}

---

I think you’re passing the wrong dimensions of the cutting area, which are obtained here:

$src_w = ceil($_POST['x2']); // x2 da imagem de origem
$src_h = ceil($_POST['y2']); // y2 da imagem de origem

It was necessary to subtract the original position to have the height and width. Or use the height and width that Jcrop has already calculated for you by changing the last two parameters passed to $dst_w and $dst_h:

imagecopyresampled($dst_r, $img_r, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $dst_w, $dst_h);

Answer 2

Observing the code in crop.php in the jCrop plugin examples, we have the code executed when the user gives a POST:

$targ_w = $targ_h = 150;
$jpeg_quality = 90;

$src = 'demo_files/pool.jpg';
$img_r = imagecreatefromjpeg($src);
$dst_r = ImageCreateTrueColor( $targ_w, $targ_h );

imagecopyresampled($dst_r,$img_r,
//destino x_y           src x_y
0,          0,          $_POST['x'],    $_POST['y'],
//destino w_h           src w_h
$targ_w,     $targ_h,     $_POST['w'],    $_POST['h']);  

Below we have the graphic example of what happens in the code of imagecopyresampled of the example code:

What you must change is the $src_h and the $src_w for the values $_POST['h'] and $_POST['w'] respectively.