修剪图像中的空白，然后使用“填充”调整图像大小

I don't mind if this is done via a PHP script (ideally Codeigniter but any is fine) or via a Photoshop action.

Essentially I want to get an image which I can do the following:

1. Trim all the 'boring' whitespace around the image
2. Resize to a maximum of 380px (height & width)
3. Finally pad the image out to 400px x 400px (e.g put my own 'white' padding around the modified image)

Can anyone give me any tips on how to do this using GD/ImageMagick or any suitable PHP script/library?

I have tried the following so far...

  $gd = imagecreatefromjpeg('./assets/temp/whitespace-img.jpg');
  imagetrim($gd, '#ffffff', null);

    function imagetrim($im, $bg, $pad=null, $output=null){

    // Calculate padding for each side.
    if (isset($pad)){
        $pp = explode(' ', $pad);
        if (isset($pp[3])){
            $p = array((int) $pp[0], (int) $pp[1], (int) $pp[2], (int) $pp[3]);
        }else if (isset($pp[2])){
            $p = array((int) $pp[0], (int) $pp[1], (int) $pp[2], (int) $pp[1]);
        }else if (isset($pp[1])){
            $p = array((int) $pp[0], (int) $pp[1], (int) $pp[0], (int) $pp[1]);
        }else{
            $p = array_fill(0, 4, (int) $pp[0]);
        }
    }else{
        $p = array_fill(0, 4, 0);
    }

    // Get the image width and height.
    $imw = imagesx($im);
    $imh = imagesy($im);

    // Set the X variables.
    $xmin = $imw;
    $xmax = 0;

    // Start scanning for the edges.
    for ($iy=0; $iy<$imh; $iy++){
        $first = true;
        for ($ix=0; $ix<$imw; $ix++){
            $ndx = imagecolorat($im, $ix, $iy);
            if ($ndx != $bg){
                if ($xmin > $ix){ $xmin = $ix; }
                if ($xmax < $ix){ $xmax = $ix; }
                if (!isset($ymin)){ $ymin = $iy; }
                $ymax = $iy;
                if ($first){ $ix = $xmax; $first = false; }
            }
        }
    }

    // The new width and height of the image. (not including padding)
    $imw = 1+$xmax-$xmin; // Image width in pixels
    $imh = 1+$ymax-$ymin; // Image height in pixels

    // Make another image to place the trimmed version in.
    $im2 = imagecreatetruecolor($imw+$p[1]+$p[3], $imh+$p[0]+$p[2]);

    // Make the background of the new image the same as the background of the old one.
    $bg2 = imagecolorallocate($im2, ($bg >> 16) & 0xFF, ($bg >> 8) & 0xFF, $bg & 0xFF);
    imagefill($im2, 0, 0, $bg2);

    // Copy it over to the new image.
    imagecopy($im2, $im, $p[3], $p[0], $xmin, $ymin, $imw, $imh);

    if ($output)
    {
        imagejpeg($im2, $output);           
    }

    // To finish up, we replace the old image which is referenced.
    $im = $im2;
}

This Photoshop script will do what you want. Pleas bear in mind that the trim function only works of the bottom right or top left pixel colour. This won't work if that border area is "dirty"

var srcDoc = app.activeDocument;

//trim image to transparent width
srcDoc.trim(TrimType.TOPLEFT, true, true, true, true);

var w = srcDoc.width.value;
var h = srcDoc.height.value;

if (w<h)
  {
    var imageWidth = 380;
    var imageHeight = Math.floor(w*(380/h))
  }
else
  {
    var imageHeight = 380;
    var imageWidth = Math.floor(h*(380/w))
  }

var resizeRes = 72
var resizeMethod = ResampleMethod.BICUBIC;

//resize
srcDoc.resizeImage(imageWidth, imageHeight, resizeRes, resizeMethod)

// adjust canvas size
srcDoc.resizeCanvas(400, 400, AnchorPosition.MIDDLECENTER);