从中心裁剪并在PHP中调整大小（功能）

Question

我希望有一个功能可以调整到特定高度和图像的重量而不会丢失纵横比。所以首先我要裁剪它，然后再调整它。

这是我到目前为止所得到的：

function image_resize($src, $dst, $width, $height, $crop=1){

  if(!list($w, $h) = getimagesize($src)) return "Unsupported picture type!";

  $type = strtolower(substr(strrchr($src,"."),1));
  if($type == 'jpeg') $type = 'jpg';
  switch($type){
    case 'bmp': $img = imagecreatefromwbmp($src); break;
    case 'gif': $img = imagecreatefromgif($src); break;
    case 'jpg': $img = imagecreatefromjpeg($src); break;
    case 'png': $img = imagecreatefrompng($src); break;
    default : return "Unsupported picture type!";
  }

  // resize
    $originalW = $w;
    $originalH = $h;

  if($crop){
    if($w < $width or $h < $height) return "Picture is too small!";
    $ratio = max($width/$w, $height/$h);
    $h = $height / $ratio;
    $x = ($w - $width / $ratio) / 2;
    $w = $width / $ratio;
  }
  else{
    if($w < $width and $h < $height) return "Picture is too small!";
    $ratio = min($width/$w, $height/$h);
    $width = $w * $ratio;
    $height = $h * $ratio;
    $x = 0;
  }

  $new = imagecreatetruecolor($width, $height);

  // preserve transparency
  if($type == "gif" or $type == "png"){
    imagecolortransparent($new, imagecolorallocatealpha($new, 0, 0, 0, 127));
    imagealphablending($new, false);
    imagesavealpha($new, true);
  }

  imagecopyresampled($new, $img, 0, 0, ($originalW - $width)/2, ($originalH - $height)/2, $width, $height, $w, $h);


  switch($type){
    case 'bmp': imagewbmp($new, $dst); break;
    case 'gif': imagegif($new, $dst); break;
    case 'jpg': imagejpeg($new, $dst); break;
    case 'png': imagepng($new, $dst); break;
  }
  return true;
}       

功能正常。但我还是有问题。例如：当我调整肖像图像（300×450）到（260 x 140）时，我会得到一个我不想要的黑色边栏。

以下是2张图片：

Answer 1

可以正常使用：

imagecopyresampled($new, $img, 0, 0, 0, 0, $width, $height, $w, $h);

Answer 2

它对我有用。你可以尝试：

$x=288; $y=202; // my final thumb
$ratio_thumb=$x/$y; // ratio thumb

list($xx, $yy) = getimagesize($image); // original size
$ratio_original=$xx/$yy; // ratio original

if ($ratio_original>=$ratio_thumb) {
    $yo=$yy; 
    $xo=ceil(($yo*$x)/$y);
    $xo_ini=ceil(($xx-$xo)/2);
    $xy_ini=0;
} else {
    $xo=$xx; 
    $yo=ceil(($xo*$y)/$x);
    $xy_ini=ceil(($yy-$yo)/2);
    $xo_ini=0;
}

imagecopyresampled($thumb, $source, 0, 0, $xo_ini, $xy_ini, $x, $y, $xo, $yo);