---- Reported by adam@yorba.org 2010-07-29 11:14:00 -0700 ----

Original Redmine bug id: 2339
Original URL: http://redmine.yorba.org/issues/2339
Searchable id: yorba-bug-2339
Original author: Adam Dingle
Original description:

Josh Freeman <yorba@twilightedge.com> has proposed an improvement to our tint
and temperature adjustments:

I've attached a Shotwell patch with some improvements to the Tint &
Temperature color adjustments, along with some before & after screenshots for
comparison.

    
    The trunk's current method of adjusting Tint & Temperature is to  shift (offset) the color values. The drawback is that shifted values at  the top or bottom of the table (depending on the direction) are  truncated, so the image loses detail in its highlights or shadows.
    
    The patched version adds a scaling factor to shrink the full range of  the color table into the smaller, shifted color space. This way,  information is lost evenly across the table instead of a big chunk at  one end. This gives the adjustment a more realistic & subtle effect  that preserves image detail, and I hope you'll find it's more useful for  color correction.
    
    The patch also includes another change (which perhaps could have been  separate) to the way the Temperature adjustment is done:
    
    The current method shifts the Green channel by the same amount as the  Red channel, but the linear Temperature adjustments I've seen have  always left the Green channel untouched, shifting only the Red &  Blue channels.
    
    I looked at F-Spot, Picasa, & iPhoto for comparison, and they all  leave the Green channel in place. (Although Picasa does perform a small  Green shift at the extreme Blue end of the temperature range – it could  possibly be unintended or just a histogram roundoff glitch). The patch  updates the Temperature adjustment to shift only the Red & Blue  channels.
    
    Finally, there were a few lines near the other changes that had 5-space tabs instead of 4-, so those were updated as well.
    
    Hope this patch is helpful – please let me know if there's any problems with it or if you have questions.



---- Additional Comments From shotwell-maint@gnome.bugs 2011-03-28 09:52:00 -0700 ----

### History

####

#1

Updated by Lucas Beeler over 3 years ago

  * **Priority** set to _High_

####

#2

Updated by Adam Dingle about 3 years ago

  * **Priority** deleted (<strike>_High_</strike>)

Will not make 0.8, but still a strong candidate for 0.9. Dropping to medium.

####

#3

Updated by Adam Dingle almost 3 years ago

  * **Priority** set to _High_

####

#4

Updated by Adam Dingle over 2 years ago

  * **Status** changed from _Open_ to _Review_
  * **Assignee** changed from _Lucas Beeler_ to _Anonymous_
  * **Subject** changed from _improve tint & temperature color adjustments_ to _[patch] improve tint & temperature color adjustments_



--- Bug imported by chaz@yorba.org 2013-11-25 21:46 UTC  ---

This bug was previously known as _bug_ 2339 at http://redmine.yorba.org/show_bug.cgi?id=2339
Imported an attachment (id=261756)

Unknown Component 
   Using default product and component set in Parameters 
Unknown version " in product shotwell. 
   Setting version to "!unspecified".
Unknown milestone "unknown in product shotwell. 
   Setting to default milestone for this product, "---".
Setting qa contact to the default for this product.
   This bug either had no qa contact or an invalid one.
Resolution set on an open status.
   Dropping resolution