将base64转换为图像大小调整和php编码 - Convert base64 to image resize and encode in php

Convert base64 to image resize and encode in php

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

我需要降低质量以便调整图像大小。

<?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?

提前谢谢。

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

 /*
 * 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;

或者保存到文件中，然后将文件加载为二进制流，以64为基础的二进制文件并删除文件