Crop image without stretching it, inside PHP

Question

I am making a upload form inside PHP. Though I want the form to upload a thumbnail that is exactly, lets say, 100px high and 100px width. The form has to rescale the tumbnail without stretching the image, but by removing a part from the image. I prefer to do this with 100% php and the most simple script. I already have made my upload form and I only want to know how to make this auto-crop system with my tumbnails.

I really hope you can help me out and I want to thank you in advance.

My script already uploads a image with a thumbnail:

if( $imgtype == 'image/jpeg' ){ $filetype= '.jpg'; }else{ $filetype= str_replace ( 'image/', '', $imgtype ); }

$path= 'images/' . md5( rand( 0, 1000 ) . rand( 0, 1000 ) . rand( 0, 1000 ) . rand( 0, 1000 ) ) . '.jpg';
$thumb_path= 'images/thumb_' . md5( rand( 0, 1000 ) . rand( 0, 1000 ) . rand( 0, 1000 ) . rand( 0, 1000 ) ) . '.jpg';
$imgsize2= getimagesize( $imgtemp );
$width= $imgsize2[0];
$height= $imgsize2[1];

$maxwidth= 1281;
$maxheight= 721;
$allowed= array( 'image/png', 'image/jpeg', 'image/gif', );

if( in_array( $imgtype, $allowed ) ){

    if( $width < $maxwidth && $height < $maxheight ){

    if( $imgsize < 5242880 ){

        if( $width == $height ){ $case=1; }
        if( $width > $height ){ $case=2; }
        if( $width < $height ){ $case=3; }

        switch( $case ){

            case 1:

            $newwidth= 100;
            $newheight= 100;

            break;

            case 2:

            $newheight= 100;
            $ratio= $newheight / $height;
            $newwidth= round( $width * $ratio );

            break;

            case 3:

            $newwidth= 100;
            $ratio= $newwidth / $width;
            $newheight= $height * $ratio;

            break;

            }

            switch( $imgtype ){

                case 'image/jpeg';

                $img= imagecreatefromjpeg( $imgtemp );
                $thumb= imagecreatetruecolor( $newwidth, $newheight );
                imagecopyresized( $thumb, $img, 0,0,0,0, $newwidth, $newheight, $width, $height );
                imagejpeg( $thumb, $thumb_path );  

                break;

                case 'image/png';

                $img= imagecreatefrompng( $imgtemp );
                $thumb= imagecreatetruecolor( $newwidth, $newheight );
                imagecopyresized( $thumb, $img, 0,0,0,0, $newwidth, $newheight, $width, $height );
                imagepng( $thumb, $thumb_path ); 

                break;

                case 'image/gif';

                $img= imagecreatefromgif( $imgtemp );
                $thumb= imagecreatetruecolor( $newwidth, $newheight );
                imagecopyresized( $thumb, $img, 0,0,0,0, $newwidth, $newheight, $width, $height );
                imagegif( $thumb, $thumb_path ); 

                break;

                } if(empty($errors))  {

        move_uploaded_file( $imgtemp, $path );
        $upimage = "Image is successfully uploaded.";
                }
        } else{
        $errors[9] = "The image you just uploaded does not meet the requirements. Your picture is too large. ";
        }

        } else{
        $errors[10] = "The image you just uploaded does not meet the requirements. It is a forbidden extension.";
        }

    } else{
        $errors[11] = "The image you just uploaded does not meet the requirements. It is a forbidden extension. Type: $imgtype,  $image, $imgsize, $imgtemp, $name";
        }
if(empty($errors))  {
move_uploaded_file( $imgtemp, $path );
}
     }

Answer 1

I believe you need to set the x and y coordinates to crop an image. Try something like this. You might have to play with the top and left numbers until you get it where you want. Take note of the imagecopyresized line. Also here is a similar post with an identical answer PHP - cropping image with imagecopyresampled()? You need to set the x and y parameters as noted below. BTW the answer was really easy to find. SO even provides related questions on the right hand side of the page where I found that other example for you. Cheers.

          switch( $case ){

        case 1:
        $top = 50;
        $left = 50;   
        $newwidth= 100;
        $newheight= 100;

        break;

        case 2:

        $newheight= 100;
        $ratio= $newheight / $height;
        $newwidth= round( $width * $ratio );

        break;

        case 3:

        $newwidth= 100;
        $ratio= $newwidth / $width;
        $newheight= $height * $ratio;

        break;

        }

        switch( $imgtype ){

            case 'image/jpeg';

            $img= imagecreatefromjpeg( $imgtemp );
            $thumb= imagecreatetruecolor( $newwidth, $newheight );
            imagecopyresized( $thumb, $img, 0,0,$left,$top, $newwidth, $newheight, $width, $height );
            imagejpeg( $thumb, $thumb_path );  

            break;

            case 'image/png';

            $img= imagecreatefrompng( $imgtemp );
            $thumb= imagecreatetruecolor( $newwidth, $newheight );
            imagecopyresized( $thumb, $img, 0,0,0,0, $newwidth, $newheight, $width, $height );
            imagepng( $thumb, $thumb_path ); 

            break;

            case 'image/gif';

            $img= imagecreatefromgif( $imgtemp );
            $thumb= imagecreatetruecolor( $newwidth, $newheight );
            imagecopyresized( $thumb, $img, 0,0,0,0, $newwidth, $newheight, $width, $height );
            imagegif( $thumb, $thumb_path ); 

            break;