Question

我有一幅画面,把照片翻一番,所有照片都用得很美,但我希望能够把颜色从照片中抹掉,留下黑白的图像(各种灰尘基本上)。我肯定了如何实现这一目标?

增编

Answer 1

2. 遵循这些思路:

<?php 
$source_file = "test_image.jpg";

$im = ImageCreateFromJpeg($source_file); 

$imgw = imagesx($im);
$imgh = imagesy($im);

for ($i=0; $i<$imgw; $i++)
{
        for ($j=0; $j<$imgh; $j++)
        {

                // get the rgb value for current pixel

                $rgb = ImageColorAt($im, $i, $j); 

                // extract each value for r, g, b

                $rr = ($rgb >> 16) & 0xFF;
                $gg = ($rgb >> 8) & 0xFF;
                $bb = $rgb & 0xFF;

                // get the Value from the RGB value

                $g = round(($rr + $gg + $bb) / 3);

                // grayscale values have r=g=b=g

                $val = imagecolorallocate($im, $g, $g, $g);

                // set the gray value

                imagesetpixel ($im, $i, $j, $val);
        }
}

header( Content-type: image/jpeg );
imagejpeg($im);
?>

通知说,我无耻地从上渗入了这条,我发现该条使用了“ogle”搜索术语: php形象改为“graycal <>。

[ edit ] And from the comments, if you use PHP5, you could also use:

imagefilter($im, IMG_FILTER_GRAYSCALE);

Answer 2

The easiest solution is to use imagefilter($im, IMG_FILTER_GRAYSCALE); But every single method mentioned here is not working for 100%. All of them is counting on color palette of the image, but the shades of gray might be missing and another color from the palette is used.

我的解决办法是用图像col器替换彩色盒。

$colorsCount = imagecolorstotal($img->getImageResource());
for($i=0;$i<$colorsCount;$i++){
    $colors = imagecolorsforindex( $img->getImageResource() , $i );
    $g = round(($colors[ red ] + $colors[ green ] + $colors[ blue ]) / 3);
    imagecolorset($img->getImageResource(), $i, $g, $g, $g);
}

Answer 3

It s better to use command tool to convert such type of image.

While animated gif is also support.

例如:

$file =  image.jpg ;
$file =  image.gif ;
$file =  image.png ;
$image_type = getimagesize($file);

switch (strtolower($image_type[ mime ])) {
    case  image/png :
       exec("convert $file -colorspace Gray dummy.png");
        break;
    case  image/jpeg :
       exec("convert $file -colorspace Gray dummy.jpeg");
        break;
    case  image/gif :
       exec("convert $file -colorspace Gray dummy.gif");
        break;
    default:
        die;
}

It s better to use command tool to convert such type of image.

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