Replace a color in intervention image

Question

I want to convert a user-uploaded image to a page background, by merging it with the background color.

To do that effect, I wanted to set the image to grayscale, then replacing the colors to match my background color (which is orange), so I wanted to replace the colorss (black matching my background's color, then each gray level faded to another clearer value).

The grescale() method is OK, but I don't know how to make the replacement. I tried the colorize function, but it only seems to brighten the image too much, even if I darken the image before with contrast(). LimitColors() didn't work neither.

How could I get the effect I want ?

Answer 1

I managed to get the display I wanted, using this method :

• create an image the size of my main image, filled with the color I want
• use my main image as a mask for the first image
• save as PNG (I put the emphasis here because my tests didn't work because I was using the default JPEG export).

Using intervention's filters to make it easier to use elsewhere, here's my result :

<?php

namespace App\ImageFilters;

use Intervention\Image\Filters\FilterInterface;
use Intervention\Image\Image;
use Intervention\Image\ImageManager;

class MyFilter implements FilterInterface
{
    /** @var ImageManager */
    private $imageManager;

    const BACKGROUND_COLOR = '#FCB65B';

    public function __construct()
    {
        $this->imageManager = new ImageManager();
    }

    public function applyFilter(Image $image)
    {
        $height = $image->getHeight();
        $width = $image->getWidth();

        return $this->imageManager
            ->canvas($width, $height)
            ->fill(self::BACKGROUND_COLOR)
            ->mask($image, false);
    }

}

It's used like this in my image management script:

$image = $image->filter(New MyFilter());

Edit before posting:

• I was trying to convert the main image to black&white with greyscale()but after omitting it it happens that there is no impact with the mask function.

• I brighten a little the main image before applying it as a mask, I think it works best for my purposes.

  /* replace the mask call with this one */ ->mask($image->brightness(25), false);