Imagick setColor not working with php - php

Question

I've tried setting all pixels to black. But it isn't working. I am getting the same image as original.
Here is my code:
$image = new Imagick(__DIR__."/image_new.jpg");
$i=0;
$j=0;
while ($i < 100)
{
$j=0;
while($j < 100)
{
$pixel = $image->getImagePixelColor($i, $j);
$pixel->setColor("#000000");
$j++;
}
$i++;
}
header("content-type:image/jpeg");
echo $image;
Image size is 100x100.
Any ideas?

Answer 1

The Imagick::getImagePixelColor will return an ImagickPixel object; which, would have copied data from the originating Imagick object. After altering the pixel's data/state, you would need to "sync" the pixel back to the image. To help with this process, a ImagickPixelIterator object has been provided -- see Imagick::getPixelIterator. Here's a quick example
$image = new Imagick(__DIR__."/image_new.jpg");
$pixel_iterator = $image->getPixelIterator();
foreach($pixel_iterator as $i => $pixels)
{
if( $i < 100 )
{
foreach($pixels as $j => $pixel)
{
if( $j < 100 )
{
$pixel->setColor("#000000");
}
}
}
$pixel_iterator->syncIterator();
}
header("content-type:image/jpeg");
echo $image;