Re: [gentoo-user] faded images with Gwenview

[Philip Webb]

210909 Michael wrote:
> On Thursday, 9 September 2021 00:25:41 BST Philip Webb wrote:
>> I have cropped some  .png  images using Gwenview & the reduced versions
>> are faded with Gwenview, but fully colored with Feh.
>> I've tried using 'convert' to create  .jpg  versions,
>> but while they're much smaller in Kbytes (good),
>> they're also faded when viewed with Gwenview (Feh ok).
> I think the gwenview faded display phenomenon you describe here
> is unlikely to be the result of your conversion,
> since feh displays it without any fading.
> It may be caused by gwenview scaling the image to a different size,
> to make it fit in the gwenview window,
> unlike feh, which will open it in its original size
> whether its full size dimensions fit in your PC monitor or not.
> You can check the gwenview % reduction/increase shown at the bottom
> right hand corner and change this to 100% to see if it makes any odds.

Gwenview says it's showing it at  100 % .
Both viewers show it at the same size on my monitor.

> In the gwenview settings you can select what the default 'Zoom Mode' is,
> if indeed this is the cause of the faded image display.
> Another thing perhaps related could be the anti-aliasing gwenview applies
> to fit the image in the window aperture and how this interacts
> with the image elements and the resolution of your monitor
> - you should be able to check this if you change the zoom level.
> https://photo.stackexchange.com/questions/24512/what-is-aliasing-and-anti-aliasing

The problem doesn't seem to have anything to do with aliasing,
which corrects jagged lines etc.

> On the same PC/monitor with the same display dimensions for an image
> gwenview (with its default settings) and feh
> ought to produce the same output - at least they do so here.
> "... but fully *colored* with Feh" :
> this is probably related to the colour gamut settings of gwenview.
> In the gwenview settings, on the Advanced tab,
> there are settings for "Rendering intent" and "Colour profile".
> Change these and see if it makes a difference.

I've tried changing all the various settings in Gwenview config separately,
but nothing changes.

NB this happens only with images which I've cropped using Gwenview,
ie simply removed some outer parts of a larger original.
In itself, that shouldn't change the colors in the new version.

I have made screenshots of the different images via Imagemagick,
which each show the same image in both Gwenview + Feh
-- ie Gwenview shows the Feh test as vivid & Feh shows the other as faded --
& display how the former is faded, while the latter is vivid.
I'll attach them to a separate e-mail to your address off the list.

It remains a puzzle.  Any further comments from anyone are most welcome.

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