/**
 * 获取图片的Base64编码(不支持url)
 * @param $img_file 传入本地图片地址
 * @return string
 */
function imgToBase64($img_file) {
 $img_base64 = '';
 if (file_exists($img_file)) {
  $app_img_file = $img_file; // 图片路径
  $img_info = getimagesize($app_img_file); // 取得图片的大小，类型等
  //echo '<pre>' . print_r($img_info, true) . '</pre><br>';
  list($width, $height, $type, $attr) = getimagesize($app_img_file);
  $fp = fopen($app_img_file, "r"); // 图片是否可读权限
  if ($fp) {
   $filesize = filesize($app_img_file);
   $content = fread($fp, $filesize);
   $file_content = chunk_split(base64_encode($content)); // base64编码
   switch ($type) {   //判读图片类型
    case 1: $img_type = "gif";
     break;
    case 2: $img_type = "jpg";
     break;
    case 3: $img_type = "png";
     break;
   }
   $img_base64 = 'data:image/png;base64,' . $file_content;//合成图片的base64编码
  }
  fclose($fp);
 }else{
  return $img_file;
 }
 return $img_base64; //返回图片的base64
}

/**
 * 图片旋转
 * @param $src 图片地址
 * @param $direction 1顺时针90 2 逆时针90
 * @return string
 */
function imgturn($src, $direction = 1){
 $ext = pathinfo($src)['extension'];
 switch ($ext) {
  case 'gif':
   $img = imagecreatefromgif($src);
   break;
  case 'jpg':
  case 'jpeg':
   $img = imagecreatefromjpeg($src);
   break;
  case 'png':
   $img = imagecreatefrompng($src);
   break;
  default:
   die('图片格式错误!');
   break;
 }
 $width = imagesx($img);
 $height = imagesy($img);
 $img2 = imagecreatetruecolor($height, $width);
 //顺时针旋转90度
 if($direction == 1){
  for ($x = 0; $x < $width; $x++) {
   for($y=0; $y<$height; $y++) {
    imagecopy($img2, $img, $height - 1 - $y, $x, $x, $y, 1, 1);
   }
  }
 }else if($direction == 2) {
  //逆时针旋转90度
  for ($x = 0; $x < $height; $x++) {
   for($y = 0; $y < $width; $y++) {
    imagecopy($img2, $img, $x, $y, $width - 1 - $y, $x, 1, 1);
   }
  }
 }
 switch ($ext) {
  case 'jpg':
  case "jpeg":
   imagejpeg($img2, $src, 100);
   break;
  case "gif":
   imagegif($img2, $src, 100);
   break;
  case "png":
   imagepng($img2, $src, 100);
   break;
  default:
   die('图片格式错误!');
   break;
 }
 imagedestroy($img);
 imagedestroy($img2);
}

/**
* 图片压缩处理
* @param string $sFile 源图片路径
* @param int $iWidth 自定义图片宽度
* @param int $iHeight 自定义图片高度
* @return string 压缩后的图片路径
*/
function getThumb($sFile, $iWidth, $iHeight){
 //图片公共路径
 $public_path = '';
 //判断该图片是否存在
 if(!file_exists($public_path . $sFile)) return $sFile;
 list($width, $height, $type, $attr) = getimagesize($sFile);
 if($width < $height){
  imgturn($sFile, 2);
 }
 //判断图片格式(图片文件后缀)
 $extend = explode("." , $sFile);
 $attach_fileext = strtolower($extend[count($extend) - 1]);
 if (!in_array($attach_fileext, array('jpg','png','jpeg'))){
  return '';
 }
 //压缩图片文件名称
 $sFileNameS = str_replace("." . $attach_fileext, "_" . $iWidth . '_' . $iHeight . '.' . $attach_fileext, $sFile);
 //判断是否已压缩图片，若是则返回压缩图片路径
 if(file_exists($public_path . $sFileNameS)){
  return $sFileNameS;
 }
 //生成压缩图片，并存储到原图同路径下
 resizeImage($public_path . $sFile, $public_path . $sFileNameS, $iWidth, $iHeight);
 if(!file_exists($public_path . $sFileNameS)){
  return $sFile;
 }
 return $sFileNameS;
}

/**
 * 生成图片
 * @param string $im 源图片路径
 * @param string $dest 目标图片路径
 * @param int $maxwidth 生成图片宽
 * @param int $maxheight 生成图片高
 */
function resizeImage($im, $dest, $maxwidth, $maxheight) {
 $img = getimagesize($im);
 switch ($img[2]) {
  case 1:
   $im = @imagecreatefromgif($im);
  break;
  case 2:
   $im = @imagecreatefromjpeg($im);
  break;
  case 3:
   $im = @imagecreatefrompng($im);
  break;
 }
 $pic_width = imagesx($im);
 $pic_height = imagesy($im);
 $resizewidth_tag = false;
 $resizeheight_tag = false;
 if (($maxwidth && $pic_width > $maxwidth) || ($maxheight && $pic_height > $maxheight)) {
  if ($maxwidth && $pic_width > $maxwidth) {
   $widthratio = $maxwidth / $pic_width;
   $resizewidth_tag = true;
  }
  if ($maxheight && $pic_height > $maxheight) {
   $heightratio = $maxheight / $pic_height;
   $resizeheight_tag = true;
  }
  if ($resizewidth_tag && $resizeheight_tag) {
   if ($widthratio < $heightratio){
    $ratio = $widthratio;
   }else{
    $ratio = $heightratio;
   }
  }
  if ($resizewidth_tag && !$resizeheight_tag){
   $ratio = $widthratio;
  }
  if ($resizeheight_tag && !$resizewidth_tag){
   $ratio = $heightratio;
  }
  $newwidth = $pic_width * $ratio;
  $newheight = $pic_height * $ratio;
  if (function_exists("imagecopyresampled")) {
   $newim = imagecreatetruecolor($newwidth, $newheight);
   imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $pic_width, $pic_height);
  } else {
   $newim = imagecreate($newwidth, $newheight);
   imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $pic_width, $pic_height);
  }
  imagejpeg($newim, $dest);
  imagedestroy($newim);
 } else {
  imagejpeg($im, $dest);
 }
}