Include all ImageSizer options in image variation filename suffix

[Toutouwai]

Short description of the enhancement

ImageSizer options are:

$config->imageSizerOptions = array(
	'upscaling' => true, // upscale if necessary to reach target size?
	'cropping' => true, // crop if necessary to reach target size?
	'autoRotation' => true, // automatically correct orientation?
	'sharpening' => 'soft', // sharpening: none | soft | medium | strong
	'quality' => 90, // quality: 1-100 where higher is better but bigger
	'hidpiQuality' => 60, // Same as above quality setting, but specific to hidpi images
	'defaultGamma' => 2.0, // defaultGamma: 0.5 to 4.0 or -1 to disable gamma correction (default=2.0)
	);

All of these affect the variation, yet only some of the options are included in the variation filename suffix, meaning the wrong variation can be served if there is an existing variation of the same filename.

For example, this results in the same varation being served twice, when it should be two different variations:

<img src="<?= $image->width(300, ['quality' => 90])->url ?>" alt="">
<img src="<?= $image->width(300, ['quality' => 10])->url ?>" alt="">

This request is that every change to an ImageSizer option produces a unique variation filename.

Related forum topic (old): https://processwire.com/talk/topic/10706-include-image-config-settings-in-image-variation-filenames/

Current vs. suggested behavior

Currently only some ImageSizer options affect the variation filename suffix. Suggestion is that all ImageSizer options affect the variation filename suffix.

Why would the enhancement be useful to users?

Ensures the wrong variation is never served when an ImageSizer option is changed.

[ryancramerdesign]

Options that change the image filename are those that actually change the physical dimensions or subject of the image (width, height, crop). While changing the filename for a change in any option sounds useful, it can be quite problematic on existing installations, especially like some I work on having hundreds of thousands of photos. A change to an option (or addition of an option, like the interlace option added this week) could force all images to be re-created. That's a very expensive process that could slow down or halt the server (potentially for hours or days, on a large site). Maybe that's what the developer wanted, to re-create everything, but chances are it's not. So if you want to ensure a change to an image, add your own suffix to indicate that intention, like this (where "high" and "low" are the words I've chosen as suffixes):

<img src="<?= $image->width(300, ['quality' => 90, 'suffix' => 'high'])->url ?>" alt="">
<img src="<?= $image->width(300, ['quality' => 10, 'suffix' => 'low'])->url ?>" alt="">

[Toutouwai]

A change to an option (or addition of an option, like the interlace option added this week) could force all images to be re-created.

When I first read this I didn't get it, but now I see what you mean. You're saying if a user changes the global imageSizerOptions in /site/config.php it will affect images sitewide. In this request I was actually thinking primarily of options passed in as an argument to an ImageSizer method.

Do you think there could be some way to distinguish between options coming from these two different sources? Because I think if someone is passing in options to an ImageSizer method these should just work - you shouldn't have to think about whether it is necessary to add some custom suffix. This is a source of confusion that regularly comes up in the forums:
https://processwire.com/talk/topic/9021-upscaling-false-is-ignored/
https://processwire.com/talk/topic/14776-image-sizer-options-setting-quality-of-image/
https://processwire.com/talk/topic/261-where-to-set-image-resizing-quality-and-how-to-re-resize-images/?do=findComment&comment=102599

Options that change the image filename are those that actually change the physical dimensions or subject of the image (width, height, crop).

In this case, one option that should be reflected in the filename is the upscaling option, as this does result in different physical dimensions. It would be good if the filename suffix reflected the actual resized dimensions when upscaling is false (related issue: processwire/processwire-issues#454). I think changing the upscaling setting in /site/config.php is one case where I would want variations to be regenerated sitewide.

[horst-n]

Once I had a module written to do exactly what you described here. But due to changes on the filename scheme, it was obsolete after PW 2.6. If you like, I can give you the old code, if you want create a new third party module for PW 3

[Toutouwai]

If you like, I can give you the old code, if you want create a new third party module for PW 3

Yes please :)

[Toutouwai]

Once I had a module written to do exactly what you described here. But due to changes on the filename scheme, it was obsolete after PW 2.6. If you like, I can give you the old code, if you want create a new third party module for PW 3

I found your module, thanks.

I wouldn't want to be maintaining a replacement method for Pageimage::size, but I can see a much simpler solution. Will release a module soon.

[ryancramerdesign]

It doesn't really matter if the options are coming from a global config or from arguments to the method, as the problem is the same (though to a lesser extent, depending on the site). Say for instance we start using those $options to the size() method for the filename. All of a sudden, existing installations will re-create any images that happen to be using an $options argument, so that the filename reflects whatever options they've used. In my case, this would kill a couple of the sites I work on just as easily as a global setting (since I often use the options argument). I think what would be necessary is for there to be an option that specifies that you DO want verbose image filenames that reflect all the options. Something like a "verbose_filename" option that you set to true (or to an array of option names that should affect the filename). From there, you could opt to specify that in any size() call, or in the global imageSizerOptions config setting, if you wanted verbose filenames throughout. How does this sound?

[Toutouwai]

Something like a "verbose_filename" option that you set to true (or to an array of option names that should affect the filename). From there, you could opt to specify that in any size() call, or in the global imageSizerOptions config setting, if you wanted verbose filenames throughout. How does this sound?

Sounds good, thanks.

Although if you decide you'd rather not include this in the core I was able to achieve the desired result in a module (UniqueImageVariations) via a hook to Pageimage::size.

Maybe the format of the settings string would be of interest if you decide to add a similar feature to the core. I also included a public method to decode the settings string in a variation filename back to the original ImageSizer options, but this was just for fun and not really necessary.

[apeisa]

Just came to say that all clients feel "focus doesn't work at all" because of browser cache. UniqueImageVariations saves this, but I do have a feeling that this should be handled in core.