Add the ability to pass params through to the underlying ImageService

[chrispymm]

I've been really enjoying using Twill Image - it's made managing images within a site so much easier!

However while using it I came a cross a couple of things that couldn't be achieved with Twill Image due to the inability to pass parameters to the ImageService.

In one instance instance I wanted to greyscale an image and the the other, possibly more common use case would be to amend the quality of the image. When handling large banner images and high-density screens I tend to adjust the image quality down on the larger images for hiDPI screens as the density covers up the lower quality and it means a much smaller image can be delivered. reference

This PR adds the ability to pass a params array through the Image model to the ImageService

TwillImage::make($object, 'crop', null, ['q' => 50]);

$image = TwillImage::make($object, 'crop');

$image->params('filt' => 'sepia');

You can also add the params array into the preset array in twill-image.php

'presets' => [
    'art_directed' => [
        'crop' => 'desktop',
        'width' => 700,
        'params' => ['q' => 75],
    ]
],

It is also possible to pass the params via the sources array too - this allows for different params (quality settings) per media query.

'presets' => [
    'art_directed' => [
        'crop' => 'desktop',
        'width' => 700,
        'params' => ['q' => 75],
        'sizes' => '(max-width: 767px) 25vw, (min-width: 767px) and (max-width: 1023px) 50vw, 33vw',
        'srcSetWidths' => [350, 700, 1400],
        'sources' => [
                [
                    'crop' => 'mobile',
                    'media_query' => '(max-width: 767px)',
                    'srcSetWidths' => [100, 200, 400],
                ],
                [
                    'crop' => 'desktop',
                    'media_query' => '(min-width: 769px) and (-webkit-min-device-pixel-ratio: 1.5)',
                    'params' => ['q' => 40],
                    'srcSetWidths' => [1600, 2400],
                ],
            ]
    ]
],

This is tested as far as my use case goes - so this may not be feature-complete, and I expect it may require further work. But this was just a quickly put-together PR to see whether this is something you'd want in the library.

[ptrckvzn]

Hey @chrispymm, thanks for submitting a PR for this feature. I see some benefit of adding the eloquent ->params([...]) to the Image model and having the ability to add params to the preset. The only thing I am not sure is to add the option to the make method. I feel passing params doesn't belong to the make methods, but only has an option in preset or with a method params. Does it makes sense?