[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #23 from Nate Graham  ---
Oh! How nice.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Toby Fox]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #22 from Toby Fox  ---
Yo @Nate Graham you should claim your bounty on
https://www.bountysource.com/issues/78105774-make-it-possible-to-adjust-jpeg-quality-compression-settings-when-saving

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #21 from DrSlony  ---
As can be seen in the sample images, using chroma subsampling where pixel-level
detail exists leads to glaring differences when comparing to the original. If
these were screenshots (which usually have pixel-wide lines such as frames,
outlines, text, etc) they would look ugly after compression with any chroma
subsampling.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

 Resolution|--- |FIXED
 Status|REOPENED|RESOLVED

--- Comment #20 from Nate Graham  ---
We can re-open Bug 333733.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #19 from Nate Graham  ---
Not sure if QImageWriter supports that

https://doc.qt.io/qt-5/qimagewriter.html

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #18 from DrSlony  ---
Created attachment 122373
  --> https://bugs.kde.org/attachment.cgi?id=122373=edit
Chroma subsampling 4:4:4

Quality 90, chroma subsampling 4:4:4 - no chroma subsampling.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #17 from DrSlony  ---
Created attachment 122372
  --> https://bugs.kde.org/attachment.cgi?id=122372=edit
Chroma subsampling 4:2:2

Quality 90, chroma subsampling 4:2:2 - chroma information was halved
horizontally.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #16 from DrSlony  ---
Created attachment 122371
  --> https://bugs.kde.org/attachment.cgi?id=122371=edit
Chroma subsampling 4:2:0

Quality 90, chroma subsampling 4:2:0 - chroma information was quartered (halved
horizontally and vertically).

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #15 from DrSlony  ---
Created attachment 122370
  --> https://bugs.kde.org/attachment.cgi?id=122370=edit
PNG test image

The same pattern repeated several times over varying background and angles.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

DrSlony  changed:

   What|Removed |Added

 Status|RESOLVED|REOPENED
 Resolution|FIXED   |---

--- Comment #14 from DrSlony  ---
Sure.

The unfortunate thing about the JPEG "quality" parameter's name is that it
makes it sound as if this is all there is to the actual image quality, but that
is not the case.

The chroma subsampling parameter lets you control the precision at which color
information (as opposed to luma) is recorded. At worst, 3/4 of the color info
is discarded. More information here:
https://en.wikipedia.org/wiki/Chroma_subsampling

Of all the parameters that JPEG compression involves, both quality and chroma
subsampling should be exposed to the user.

When dealing with full-sized real-world photographs, the pixel-level level of
chroma detail is generally low - the lens, sensor and post-processing result in
blurriness at the 100% zoom level, and it's near impossible to see a difference
between an image with no subsampling vs one where the chroma was halved.
However, when dealing with screenshots or downscaled real-world photographs,
there is usually meaningful information at the pixel level which will be
glaringly obvious if it's lost in the JPEG compression process.

Examples to follow.

My original issue 333733 was marked as a duplicate of this one, and then this
one was closed without solving the original issue, so I'm re-opening this one.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #13 from Nate Graham  ---
Can you explain what that is and how it's relevant here?

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #12 from DrSlony  ---
What about chroma subsampling?

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Pepe]

https://bugs.kde.org/show_bug.cgi?id=277996

Pepe  changed:

   What|Removed |Added

 CC||mr-pei...@web.de

--- Comment #11 from Pepe  ---
Spectacle 19.08.0 has a different look and feel for that option. Is there a
reason why this is implemented in two different ways? It increases
inconsistency between KDE apps in my opinion.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

 Resolution|--- |FIXED
   Version Fixed In||19.12.0
 Status|CONFIRMED   |RESOLVED
  Latest Commit||https://commits.kde.org/gwe
   ||nview/24cd548e1f7fb85319706
   ||134980c5354efb5053d

--- Comment #10 from Nate Graham  ---
Git commit 24cd548e1f7fb85319706134980c5354efb5053d by Nate Graham.
Committed on 24/08/2019 at 17:37.
Pushed by ngraham into branch 'master'.

Allow the user to select the JPEG save/compression quality

Summary:
Currently, anytime Gwenview is used to save a non-JPEG file as a JPEG, or
anytime JPEG file is saved or re-saved after performing a lossy edit (e.g. crop
or red eye, but not rotation), the new file is saved with 75% quality level,
resulting in a noticeable degradation in appearance.

This patch implements a user-selectable JPEG save/compression quality setting,
which can be temporarily overridden in the {nav Save As} dialog when saving a
file as a JPEG. The new default quality level is 90% -- same as Spectacle. This
should prevent people from accdientally destroying their JPEGs.

As before, when saving an existing JPEG file with a new name or after
performing a non-lossy edit (e.g. rotation, which only changes the EXIF
rotation tag), the appearance of the file is not changed because no actual
image manipulation is done.
FIXED-IN: 19.12.0

Test Plan:
{F7205336}

{F7208763}

Set JPEG quality to 5% in the config file and test the following use cases:
- Non-JPEG image: do {nav Save} or {nav Save As} in non-JPEG formats -> No
changes or regressions.
- JPEG image: do {nav Save} or {nav Save As} without changing the image format
or the image's pixels at all -> No changes; quality level not taken into
consideration because these are lossless operations that do not re-compress the
image (which is good)
- JPEG image: do {nav Save} or {nav Save As} after changing the image's pixels
in some way (e.g. a crop operation) -> Image is saved with the user-specified
5% quality level and looks terrible
- JPEG image: do {nav Save As} into a non-JPEG file format after changing the
image image's pixels in some way, or not -> No changes or regressions (in
particular, lossless images like PNG are not hugely ballooned in file size)

Set JPEG quality to 90% in the config file and test the following use cases:
- Non-JPEG image: do {nav Save As} in non-JPEG formats -> No changes or
regressions; dialog box does not show quality spinbox
- Non-JPEG image: do {nav Save As} into a JPEG and in the {nav Save As] dialog,
change the quality from 90% to 5%-> Image is saved with the user-specified 5%
quality level and looks terrible
- JPEG image: do {nav Save As} into a non-JPEG file format -> No changes or
regressions; dialog box does not show quality spinbox
- JPEG image: do {nav Save As} after changing the image's pixels in some way
(e.g. a crop operation), and in the {nav Save As] dialog, change the quality
from 90% to 5%-> Image is saved with the user-specified 5% quality level and
looks terrible

Reviewers: #gwenview, #vdg

Subscribers: filipf, pino

Tags: #gwenview

Differential Revision: https://phabricator.kde.org/D23106

M  +40   -4app/generalconfigpage.ui
M  +68   -10   app/gvcore.cpp
M  +5-0lib/document/documentloadedimpl.cpp
M  +4-0lib/gwenviewconfig.kcfg
M  +1-0lib/jpegcontent.cpp

https://commits.kde.org/gwenview/24cd548e1f7fb85319706134980c5354efb5053d

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #9 from Nate Graham  ---
I've submitted a patch to implement this feature:
https://phabricator.kde.org/D23106.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Toby Fox]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #8 from Toby Fox  ---
This seems like a good opportunity for me to try out Bountysource!
https://www.bountysource.com/issues/78105774-make-it-possible-to-adjust-jpeg-quality-compression-settings-when-saving

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

   Assignee|gwenview-bugs-n...@kde.org  |n...@kde.org

--- Comment #7 from Nate Graham  ---
Oh jeez, I need to just finally do this...

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Toby Fox]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #6 from Toby Fox  ---
Small note that ideally there could be a default setting accessible in
preferences, because if you're doing a regular Save (instead of Save As) then
there's no dialog with which to give the user the opportunity to change this
value.

Also, my two cents that this is pretty important! The default value of 75%
(what I've seen reported elsewhere, can't confirm that's the current value) is
low - any enthusiast using Gwenview to make changes is inadvertently mangling
their collection a little bit.

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Toby Fox]

https://bugs.kde.org/show_bug.cgi?id=277996

Toby Fox  changed:

   What|Removed |Added

 CC||toby...@gmail.com

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

   Priority|NOR |HI

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Patrick Silva]

https://bugs.kde.org/show_bug.cgi?id=277996

Patrick Silva  changed:

   What|Removed |Added

 CC||bugsefor...@gmx.com

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

 CC||vladimir.b...@gmail.com

--- Comment #5 from Nate Graham  ---
*** Bug 294594 has been marked as a duplicate of this bug. ***

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

   Keywords||usability

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[DrSlony]

https://bugs.kde.org/show_bug.cgi?id=277996

--- Comment #4 from DrSlony  ---
Not only JPEG quality but also chroma subsampling, please.

Ref: https://bugs.kde.org/show_bug.cgi?id=294594#c20

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

 CC||b...@londonlight.org

--- Comment #3 from Nate Graham  ---
*** Bug 333733 has been marked as a duplicate of this bug. ***

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[gwenview] [Bug 277996] Make it possible to adjust JPEG quality/compression settings when saving

[Nate Graham]

https://bugs.kde.org/show_bug.cgi?id=277996

Nate Graham  changed:

   What|Removed |Added

Summary|Make it possible to adjust  |Make it possible to adjust
   |advanced properties when|JPEG quality/compression
   |saving file |settings when saving
 CC||pointedst...@zoho.com

--- Comment #2 from Nate Graham  ---
Gonna use this to track just JPEG quality for now; can do more later.

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