在 PHP 中裁剪图像而不拉伸它[关闭]

Question

我正在 PHP 中制作上传表单。虽然我希望表单上传一个精确的缩略图，比如说，100px 高和 100px 宽。表单必须在不拉伸图像的情况下重新缩放缩略图，而是从图像中删除一部分。我更喜欢用 100% php 和最简单的脚本来做这件事。我已经制作了上传表单，我只想知道如何用我的缩略图制作这个自动裁剪系统。

我真的希望你能帮助我，我想提前感谢你。

我的脚本已经上传了一张带有缩略图的图片：

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

我相信您需要设置 x 和 y 坐标来裁剪图像。尝试这样的事情。您可能不得不使用top 和left 数字，直到您将它放在您想要的位置。记下imagecopyresized 行。 这里还有一个类似的帖子，答案相同PHP - cropping image with imagecopyresampled()? 您需要设置 x 和 y 参数，如下所述。顺便说一句，答案真的很容易找到。 SO 甚至在我为您找到另一个示例的页面右侧提供了相关问题。干杯。

          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;