我想造成图像模糊,需要一个更快的解决方案。
I am trying to blur an image and need a faster solution.
这是我当前的尝试是多的大型影像太慢了,我不希望使用imagick。
This is my current attempt which is much too slow for large images and I do not want to use imagick.
public function blur($filename, $extension, $factor = 20){
if (strtolower($extension) === "jpg" || strtolower($extension) === "jpeg") $image = imagecreatefromjpeg($filename);
if (strtolower($extension) === "png") $image = imagecreatefrompng($filename);
for ($x=1; $x<=$factor; $x++)
imagefilter($image, IMG_FILTER_GAUSSIAN_BLUR);
imagejpeg($image, "$filename.blur.$extension");
imagedestroy($image);
}
有一个PHP实现stackblur或其它快速算法可用?
Is there a PHP implementation of stackblur or another fast algorithm available?
最简单的解决方案是应用模糊滤镜前缩放图像了。下面是一些例子:
The simple solution is to scale the image down before you apply the blur filter. Here are some examples:
原图:
20×高斯模糊(2.160秒):
{
$start = microtime(true);
for ($x=0; $x<20; $x++) {
imagefilter($image, IMG_FILTER_GAUSSIAN_BLUR);
}
$end = microtime(true);
$howlong = $end - $start;
}
组合比例和高斯模糊(0.237秒)的:
{
$start = microtime(true);
/* Scale by 25% and apply Gaussian blur */
$s_img1 = imagecreatetruecolor(160,120);
imagecopyresampled($s_img1, $image, 0, 0, 0, 0, 160, 120, 640, 480);
imagefilter($s_img1, IMG_FILTER_GAUSSIAN_BLUR);
/* Scale result by 200% and blur again */
$s_img2 = imagecreatetruecolor(320,240);
imagecopyresampled($s_img2, $s_img1, 0, 0, 0, 0, 320, 240, 160, 120);
imagedestroy($s_img1);
imagefilter($s_img2, IMG_FILTER_GAUSSIAN_BLUR);
/* Scale result back to original size and blur one more time */
imagecopyresampled($image, $s_img2, 0, 0, 0, 0, 640, 480, 320, 240);
imagedestroy($s_img2);
imagefilter($image, IMG_FILTER_GAUSSIAN_BLUR);
$end = microtime(true);
$howlong = $end - $start;
}