将base64转换为图像调整大小并在php中编码

Question

我使用html5文件api在浏览器中预览图像，然后使用ajax将其保存到数据库中作为base64字符串。

我需要降低质量以调整图像大小。

<?php 

$img = $_POST['img']; 
$i = explode(",",$img); 

$img = $i[1]; 
$img = imagecreatefromstring[$img]; 
$rimg = imagejpeg($img,XXXXXXX, 60); 

?> 

xxx=> how could I turned it back to base64? 

在此先感谢。

Answer 1

http://php.net/manual/en/function.imagejpeg.php从

/* 
* imageXXX() only has two options, save as a file, or send to the browser. 
* It does not provide you the oppurtunity to manipulate the final GIF/JPG/PNG file stream 
* So I start the output buffering, use imageXXX() to output the data stream to the browser, 
* get the contents of the stream, and use clean to silently discard the buffered contents. 
*/ 
ob_start(); 

switch ($image_type) 
{ 
    case 1: imagegif($tmp); break; 
    case 2: imagejpeg($tmp, NULL, 100); break; // best quality 
    case 3: imagepng($tmp, NULL, 0); break; // no compression 
    default: echo ''; break; 
} 

$final_image = ob_get_contents(); 

ob_end_clean(); 

return $final_image; 

或保存到文件中，然后加载该文件作为二进制流，基部64的二进制和删除文件