php等比例缩放图片及剪切图片代码分享

/** * 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);}

用法：

  1. myImageResize($filename, 200, 200); //最大宽高
  2. myImageResize($filename, 200, 200, "width"); //宽度固定
  3. myImageResize($filename, 200, 200, "height"); //高度固定

剪切图片为固定大小：

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);}