PHP Image Change to Silhouette - php

Question

I'm displaying an image where the URL is kept in the database, now i want to display it completely black if a condition isn't met
The URL
$url = '/images/'.$row['sprite'].'.png';
its then displayed in a normal image tag
What i want is if $row['normal'] == 0 then black the image, making it a silhouette, otherwise display the normal image
After some searching I've found about imagefilter but am not sure how to apply it, as the examples i've found don't show how to apply it when there is other content on the page
Or would it be better to make the silhouettes in photoshop, given that there is over 800 of them, though only a maximum of two on the page

Answer 1

Firstly you need to load GD Image Library to your server.
Define your image path and create an image object by using imagecreatefrompng if your image types are different choose correct one.
$image_path = $_SERVER['DOCUMENT_ROOT']."/assets/img/horse1.png";
$image_obj = imagecreatefrompng($image_path);
Now, we need to apply a filter, if your conditions provided. Using the imagefilter function to apply any filter to your image. In this example IMG_FILTER_GRAYSCALE is fair enough or you can change it by using the manual of function.
if($row['normal'] == 0) {
$op_result = imagefilter($image_obj,IMG_FILTER_GRAYSCALE);
}
Finally, we need save the image to server using by imagepng function.
imagepng($image_obj,$_SERVER['DOCUMENT_ROOT']."/assets/img/horse1_black.png");
Check the full code below beacuse I strongly suggest that, you shouldn't create black image for every single user. If your image is already exist in your server just show it without any creation.
$image_path = $_SERVER['DOCUMENT_ROOT']."/assets/img/horse.png";
$black_image_path = $_SERVER['DOCUMENT_ROOT']."/assets/img/horse_black.png";
if($row['normal'] == 0) {
if(file_exists($black_image_path)){
return $black_image_path; //if your black image is already exist just return and use it.
}
else {
$image_obj = imagecreatefrompng($image_path); //create a image object from a path
$op_result = imagefilter($image_obj,IMG_FILTER_GRAYSCALE); //applying grayscale filter to your image object.
if($op_result) {
imagepng($image_obj,$black_image_path); //save the image to defined path.
return $black_image_path;
}
else {
return "Error Occured.";
}
}
}