PHP image scaling and cutting functions-PHP Tutorial-php.cn

PHP image scaling and cutting functions

墨辰丷

Release： 2023-03-29 19:08:01

Original

1165 people have browsed it

This article mainly introduces the PHP image scaling and cutting functions. Interested friends can refer to it. I hope it will be helpful to everyone.

The code is as follows:

/**
 * 图片缩放函数（可设置高度固定，宽度固定或者最大宽高，支持gif/jpg/png三种类型）
 * Author : Specs
 *
 * @param string $source_path 源图片
 * @param int $target_width 目标宽度
 * @param int $target_height 目标高度
 * @param string $fixed_orig 锁定宽高（可选参数 width、height或者空值）
 * @return string
 */
function myImageResize($source_path, $target_width = 200, $target_height = 200, $fixed_orig = ''){
  $source_info = getimagesize($source_path);
  $source_width = $source_info[0];
  $source_height = $source_info[1];
  $source_mime = $source_info['mime'];
  $ratio_orig = $source_width / $source_height;
  if ($fixed_orig == 'width'){
    //宽度固定
    $target_height = $target_width / $ratio_orig;
  }elseif ($fixed_orig == 'height'){
    //高度固定
    $target_width = $target_height * $ratio_orig;
  }else{
    //最大宽或最大高
    if ($target_width / $target_height > $ratio_orig){
      $target_width = $target_height * $ratio_orig;
    }else{
      $target_height = $target_width / $ratio_orig;
    }
  }
  switch ($source_mime){
    case 'image/gif':
      $source_image = imagecreatefromgif($source_path);
      break;
    
    case 'image/jpeg':
      $source_image = imagecreatefromjpeg($source_path);
      break;
    
    case 'image/png':
      $source_image = imagecreatefrompng($source_path);
      break;
    
    default:
      return false;
      break;
  }
  $target_image = imagecreatetruecolor($target_width, $target_height);
  imagecopyresampled($target_image, $source_image, 0, 0, 0, 0, $target_width, $target_height, $source_width, $source_height);
  //header('Content-type: image/jpeg');
  $imgArr = explode('.', $source_path);
  $target_path = $imgArr[0] . '_new.' . $imgArr[1];
  imagejpeg($target_image, $target_path, 100);
}

Copy after login

Usage:

myImageResize($filename, 200, 200 ); //Maximum width and height
myImageResize($filename, 200, 200, 'width'); //Fixed width
myImageResize ($filename, 200, 200, 'height'); //Fixed height

##Cut the picture to a fixed size:

function imagecropper($source_path, $target_width, $target_height){
  $source_info = getimagesize($source_path);
  $source_width = $source_info[0];
  $source_height = $source_info[1];
  $source_mime = $source_info['mime'];
  $source_ratio = $source_height / $source_width;
  $target_ratio = $target_height / $target_width;
  
  // 源图过高
  if ($source_ratio > $target_ratio){
    $cropped_width = $source_width;
    $cropped_height = $source_width * $target_ratio;
    $source_x = 0;
    $source_y = ($source_height - $cropped_height) / 2;
  }elseif ($source_ratio < $target_ratio){ // 源图过宽
    $cropped_width = $source_height / $target_ratio;
    $cropped_height = $source_height;
    $source_x = ($source_width - $cropped_width) / 2;
    $source_y = 0;
  }else{ // 源图适中
    $cropped_width = $source_width;
    $cropped_height = $source_height;
    $source_x = 0;
    $source_y = 0;
  }
  
  switch ($source_mime){
    case 'image/gif':
      $source_image = imagecreatefromgif($source_path);
      break;
    
    case 'image/jpeg':
      $source_image = imagecreatefromjpeg($source_path);
      break;
    
    case 'image/png':
      $source_image = imagecreatefrompng($source_path);
      break;
    
    default:
      return false;
      break;
  }
  
  $target_image = imagecreatetruecolor($target_width, $target_height);
  $cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);
  
  // 裁剪
  imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);
  // 缩放
  imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);
  $dotpos = strrpos($source_path, '.');
  $imgName = substr($source_path, 0, $dotpos);
  $suffix = substr($source_path, $dotpos);
  $imgNew = $imgName . '_small' . $suffix;
  imagejpeg($target_image, $imgNew, 100);
  imagedestroy($source_image);
  imagedestroy($target_image);
  imagedestroy($cropped_image);
}

Copy after login

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

Related recommendations:

Header usage and basic functions in PHP

##PHP Analysis of concepts and usage examples of abstract classes and abstract methods in PHP

Detailed explanation of inheritance and usage examples of classes in PHP

The above is the detailed content of PHP image scaling and cutting functions. For more information, please follow other related articles on the PHP Chinese website!