在 PHP 中将图像裁剪为正方形，而不是调整为相同的纵横比

Posted 2023-02-25

【中文标题】在 PHP 中将图像裁剪为正方形，而不是调整为相同的纵横比

【英文标题】：Crop image to square in PHP instead of resizing to same aspect ratio

【发布时间】：2015-02-13 11:49:50

【问题描述】：

我正在使用 Joomla 中的一个函数来调整上传图像的大小。但是，该函数使用输入 max-width 和 max-height 将图像大小调整为与开始时相同的宽高比......即插件将图像大小调整为最大高度或最大宽度（取决于上传的图片中哪个是最大的）。

但是，我希望能够裁剪图像以填充最大高度/最大宽度，并从中心裁剪边缘（以最大者为准）。

有人可以提供任何帮助吗？

这是我当前的功能...谢谢！！！

<?php
/**
 * easy image resize function
 * @param  $file - file name to resize
 * @param  $string - The image data, as a string
 * @param  $width - new image width
 * @param  $height - new image height
 * @param  $proportional - keep image proportional, default is no
 * @param  $output - name of the new file (include path if needed)
 * @param  $delete_original - if true the original image will be deleted
 * @param  $use_linux_commands - if set to true will use "rm" to delete the image, if false will use PHP unlink
 * @param  $quality - enter 1-100 (100 is best quality) default is 100
 * @return boolean|resource
 */
  function smart_resize_image($file,

                          $string             = null,
                          $width              = 0, 
                          $height             = 0, 
                          $proportional       = false, 
                          $output             = 'file', 
                          $delete_original    = true, 
                          $use_linux_commands = false,
                          $quality = 100
     ) 

if ( $height <= 0 && $width <= 0 ) return false;
if ( $file === null && $string === null ) return false;

# Setting defaults and meta
$info                         = $file !== null ? getimagesize($file) : getimagesizefromstring($string);
$image                        = '';
$final_width                  = 0;
$final_height                 = 0;
list($width_old, $height_old) = $info;
$cropHeight = $cropWidth = 0;

# Calculating proportionality
if ($proportional) 
  if      ($width  == 0)  $factor = $height/$height_old;
  elseif  ($height == 0)  $factor = $width/$width_old;
  else                    $factor = min( $width / $width_old, $height / $height_old );

  $final_width  = round( $width_old * $factor );
  $final_height = round( $height_old * $factor );

else 
  $final_width = ( $width <= 0 ) ? $width_old : $width;
  $final_height = ( $height <= 0 ) ? $height_old : $height;
  $widthX = $width_old / $width;
  $heightX = $height_old / $height;

  $x = min($widthX, $heightX);
  $cropWidth = ($width_old - $width * $x) / 2;
  $cropHeight = ($height_old - $height * $x) / 2;


# Loading image to memory according to type
switch ( $info[2] ) 
  case IMAGETYPE_JPEG:  $file !== null ? $image = imagecreatefromjpeg($file) : $image = imagecreatefromstring($string);  break;
  case IMAGETYPE_GIF:   $file !== null ? $image = imagecreatefromgif($file)  : $image = imagecreatefromstring($string);  break;
  case IMAGETYPE_PNG:   $file !== null ? $image = imagecreatefrompng($file)  : $image = imagecreatefromstring($string);  break;
  default: return false;



# This is the resizing/resampling/transparency-preserving magic
$image_resized = imagecreatetruecolor( $final_width, $final_height );
if ( ($info[2] == IMAGETYPE_GIF) || ($info[2] == IMAGETYPE_PNG) ) 
  $transparency = imagecolortransparent($image);
  $palletsize = imagecolorstotal($image);

  if ($transparency >= 0 && $transparency < $palletsize) 
    $transparent_color  = imagecolorsforindex($image, $transparency);
    $transparency       = imagecolorallocate($image_resized, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);
    imagefill($image_resized, 0, 0, $transparency);
    imagecolortransparent($image_resized, $transparency);
  
  elseif ($info[2] == IMAGETYPE_PNG) 
    imagealphablending($image_resized, false);
    $color = imagecolorallocatealpha($image_resized, 0, 0, 0, 127);
    imagefill($image_resized, 0, 0, $color);
    imagesavealpha($image_resized, true);
  

imagecopyresampled($image_resized, $image, 0, 0, $cropWidth, $cropHeight, $final_width, $final_height, $width_old - 2 * $cropWidth, $height_old - 2 * $cropHeight);


# Taking care of original, if needed
if ( $delete_original ) 
  if ( $use_linux_commands ) exec('rm '.$file);
  else @unlink($file);


# Preparing a method of providing result
switch ( strtolower($output) ) 
  case 'browser':
    $mime = image_type_to_mime_type($info[2]);
    header("Content-type: $mime");
    $output = NULL;
  break;
  case 'file':
    $output = $file;
  break;
  case 'return':
    return $image_resized;
  break;
  default:
  break;


# Writing image according to type to the output destination and image quality
switch ( $info[2] ) 
  case IMAGETYPE_GIF:   imagegif($image_resized, $output);    break;
  case IMAGETYPE_JPEG:  imagejpeg($image_resized, $output, $quality);   break;
  case IMAGETYPE_PNG:
    $quality = 9 - (int)((0.9*$quality)/10.0);
    imagepng($image_resized, $output, $quality);
    break;
  default: return false;


return true;
  

【问题讨论】：

您需要取最小的宽度和高度，将其缩放到目标尺寸，然后再计算正确的值以用于src_x/src_y ...

【参考方案1】：

你试过 phpthumb 吗？它是一个包含，您可以使用它来调整图像大小（并创建所述图像的缩略图）。您还可以裁剪和缩放裁剪以使图像成为您想要的形状。

http://phpthumb.sourceforge.net/

【讨论】：

嗨，是的，我已经看到了，但理想情况下需要坚持我在这里所拥有的，因为它只是更广泛插件的一小部分......这个插件已经完美地调整大小并集成到任何地方它是需要的......只是我无法工作的作物......谢谢！