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
  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, $x, 0, $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，但它的作物来自左上角。我想让它从中心裁剪。

Answer 1

您必须为imagecopyresampled（）计算裁剪的图像偏移：

在计算新内容之前保持原始尺寸：

// resize
$originalW = $w;
$originalH = $h;
if ($crop) {
...

并替换您的imagecopyresampled：

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

您可以查看手册here。

Answer 2

我解决了图像中的黑色区域。现在这个脚本调整大小，裁剪和居中。最终的代码在这里：

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

// resize
$originalW = $w;
$originalH = $h;
if($crop){
    if ($w < $width or $h < $height) return array(false,"Picture is too small! Min size $width px X $height px");
    $ratio = max($width/$w, $height/$h);
    $h = $height / $ratio;
    $x = ($w - $width / $ratio) / 2;
    $w = $width / $ratio;
} else {
    if($w < $width and $h < $height) return array(false,"Picture is too small! Min size $width px X $height px");
    $ratio = min($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, $img, 0, 0, ($w - $width)/2, ($h - $height)/2,  $width,  $height, $w - (($w - $width)/2), $h - (($h - $height)/2) );

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

从中心裁剪并在PHP中调整大小

2 个答案: