PHP图像像素化？

Question

我需要用php制作这个效果.我知道PHP图像过滤器中有IMG_FILTER_PIXELATE.但我需要它更流畅和浮雕？像在这张图片中:

此效果将使用户上传的任何图像变为像素化,并且图片的边缘变为红色(我知道IMG_FILTER_EDGEDETECT但我不知道如何使用它来更改边缘颜色).

我不知道该怎么做.

Answer 1

由于最后一个答案是理论上的并且似乎还不够,我已经创建了一个实际的例子:
注意:这远非"理想"和完美的像素化效果函数,但它确实起到了作用.您可以根据自己的需要随意编辑.

<?php
/* Function to make pixelated images
* Supported input: .png .jpg .jpeg .gif
* 
*
* Created on 24.01.2011 by Henrik Peinar
*/


/*
* image - the location of the image to pixelate 
* pixelate_x - the size of "pixelate" effect on X axis (default 10)
* pixelate_y - the size of "pixelate" effect on Y axis (default 10)
* output - the name of the output file (extension will be added)
*/
function pixelate($image, $output, $pixelate_x = 20, $pixelate_y = 20)
{
    // check if the input file exists
    if(!file_exists($image))
        echo 'File "'. $image .'" not found';

    // get the input file extension and create a GD resource from it
    $ext = pathinfo($image, PATHINFO_EXTENSION);
    if($ext == "jpg" || $ext == "jpeg")
        $img = imagecreatefromjpeg($image);
    elseif($ext == "png")
        $img = imagecreatefrompng($image);
    elseif($ext == "gif")
        $img = imagecreatefromgif($image);
    else
        echo 'Unsupported file extension';

    // now we have the image loaded up and ready for the effect to be applied
    // get the image size
    $size = getimagesize($image);
    $height = $size[1];
    $width = $size[0];

    // start from the top-left pixel and keep looping until we have the desired effect
    for($y = 0;$y < $height;$y += $pixelate_y+1)
    {

        for($x = 0;$x < $width;$x += $pixelate_x+1)
        {
            // get the color for current pixel
            $rgb = imagecolorsforindex($img, imagecolorat($img, $x, $y));

            // get the closest color from palette
            $color = imagecolorclosest($img, $rgb['red'], $rgb['green'], $rgb['blue']);
            imagefilledrectangle($img, $x, $y, $x+$pixelate_x, $y+$pixelate_y, $color);

        }       
    }

    // save the image
    $output_name = $output .'_'. time() .'.jpg';

    imagejpeg($img, $output_name);
    imagedestroy($img); 
}


pixelate("test.jpg", "testing");


?>

这是在图像上创建像素化效果的示例函数.以下是使用此功能的示例结果:
原始:

像素化5px:

像素化10px:

像素化20px: