作者:花非花红非红 | 来源:互联网 | 2020-08-15 06:09
php图片压缩成指定大小的方法:1、使用图像处理函数“imagecopyresampled”将图片压缩为指定大小。2、使用“imagecopy”函数将图片裁剪为指定大小。
1、按照指定的尺寸压缩图片
/**
* 按照指定的尺寸压缩图片
* @param $source_path 原图路径
* @param $target_path 保存路径
* @param $imgWidth 目标宽度
* @param $imgHeight 目标高度
* @return bool|string
*/
function resize_image($source_path,$target_path,$imgWidth,$imgHeight)
{
$source_info = getimagesize($source_path);
$source_mime = $source_info['mime'];
switch ($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;
}
$target_image = imagecreatetruecolor($imgWidth, $imgHeight); //创建一个彩色的底图
imagecopyresampled($target_image, $source_image, 0, 0, 0, 0, $imgWidth, $imgHeight, $source_info[0], $source_info[1]);
//保存图片到本地
$dir = '../'.$target_path. '/'. date("Ymd") . '/';
if (!is_dir($dir)) {
mkdir($dir, 0777);
}
$fileName = $dir.date("YmdHis").uniqid().'.jpg';
if(!imagejpeg($target_image,'./'.$fileName)){
$fileName = '';
}
imagedestroy($target_image);
return $fileName;
}
2、按照比例裁剪图片
/**
* 图像裁剪
* @param $title string 原图路径
* @param $content string 需要裁剪的宽
* @param $encode string 需要裁剪的高
* @param $target_path string 需要保存的路径
*/
function image_cropper($source_path, $target_width, $target_height, $target_path)
{
$source_info = getimagesize($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 / $target_width;
if ($source_ratio > $target_ratio) // 源图过高
{
$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 &#39;image/gif&#39;:
$source_image = imagecreatefromgif($source_path);
break;
case &#39;image/jpeg&#39;:
$source_image = imagecreatefromjpeg($source_path);
break;
case &#39;image/png&#39;:
$source_image = imagecreatefrompng($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);
//保存图片到本地(两者选一)
$dir = &#39;../../&#39;.$target_path. &#39;/&#39;. date("Ymd") . &#39;/&#39;;
if (!is_dir($dir)) {
mkdir($dir, 0777);
}
$fileName = $dir.date("YmdHis").uniqid().&#39;.jpg&#39;;
if(!imagejpeg($target_image,&#39;./&#39;.$fileName)){
$fileName = &#39;&#39;;
}
imagedestroy($target_image);
return $fileName;
}
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