我正在尝试使用以下代码(源代码)将 pngquant 与 PHP 一起使用:
<?php
function compress_png($path_to_png_file, $max_quality = 90)
{
if (!file_exists($path_to_png_file)) {
throw new Exception("File does not exist: $path_to_png_file");
}
// guarantee that quality won't be worse than that.
$min_quality = 60;
// '-' makes it use stdout, required to save to $compressed_png_content variable
// '<' makes it read from the given file path
// escapeshellarg() makes this safe to use with any path
// maybe with more memory ?
ini_set("memory_limit", "128M");
// The command should look like: pngquant --quality=60-90 - < "image-original.png"
$comm = "pngquant --quality=$min_quality-$max_quality - < ".escapeshellarg( $path_to_png_file);
$compressed_png_content = shell_exec($comm);
var_dump($compressed_png_content);
if (!$compressed_png_content) {
throw new Exception("Conversion to compressed PNG failed. Is pngquant 1.8+ installed on the server?");
}
return $compressed_png_content;
}
echo compress_png("image-original.png");
该函数应该检索 shell_exec 函数的输出。使用输出我应该能够创建一个新的 png 文件,但是shell_exec
浏览器中的输出已损坏:�PNG
.
注意:该命令的执行是在没有PHP的控制台中成功执行的(pngquant --quality=60-90 - < "image-original.png"
)
如果我从控制台执行 php 代码,我会收到以下消息:
错误:将图像写入标准输出失败 (16)
我到处搜索都没有任何解决方案,有人可以帮助我或知道可能导致问题的原因吗?