Add Compression Quality slider for lossy formats

Authored by nrother on Mar 7 2019, 8:27 PM.


Add Compression Quality slider for lossy formats

FEATURE: 63151
FIXED-IN: 19.04.0

This adds a slider to set the compression quality for lossy file formats
to the settings page, so users can set it themselves instead of having
to just accept the (in my opinion too low) default value.
The slider defaults to a quality level of 90.

A couple of notes:

-When adding the slider to the 'Save'-page layout I noticed that the
 bottom of the help text for the filename chooser got cut off because
 the window was too small. I tried to figure out how to get the settings
 page to scroll but couldn't quite get it working. Instead I resorted to
 simply increasing the default size of the settings window just enough to make it
 fit. If someone with more experience in Qt than me can get the page to scroll OR
 can suggest a better way to display the formatting help text (which I feel
 takes up too much of the page), that would be marvelous.

-When saving an image at full (100) quality it still looks a bit washed out and
 fuzzy, when compared to, for example, saving the image as png and converting it
 to JPG in gimp at full quality. This might be an issue with QImageWriter unless
 this is the desired behaviour? I haven't looked into it too much, just something
 I've noticed when testing

Test Plan:
This setting can be found under
Configure -> Save -> Compression Quality

Set the default file type to JPG, adjust the slider and export to an image-viewer
of your choosing (eg. feh) to see how it affects image quality.

Reviewers: VDG, Spectacle, davidre, ngraham

Reviewed By: VDG, Spectacle, davidre, ngraham

Subscribers: ngraham, davidre, Spectacle

Tags: Spectacle

Differential Revision:


ngrahamMar 7 2019, 8:36 PM
Differential Revision
D19591: Add Compression Quality slider for lossy formats
R166:996adc7cc27a: Update docs for the new 'Accept on click-and-release' option