Make the histogram (dialog, Levels, Curves, etc) default to show RGB instead of Value
Submitted by Elle Stone
Created attachment 305244 Patch to make the histogram dialog default to RGB instead of Value
My preference is to see the RGB histogram in the histogram dialog. But the histogram dialog resets to the Value histogram just about every time anything is done to the image.
The Value histogram is not terribly useful. Even seeing the Luminance histogram (https://bugzilla.gnome.org/show_bug.cgi?id=109161) is not as useful for photographic editing as seeing the RGB histogram, because the Luminance histogram doesn't show individual channel values, and so adjustments using the Luminance histogram can easily cause unintended channel clipping.
The attached patch makes the RGB histogram the default histogram for the histogram dialog.
An alternative (or nice addition) to making the RGB histogram the default histogram would be if the user could choose the default histogram in the Preferences dialog (or even in the histogram dialog UI itself, which might be more convenient to change if the user's editing needs change from one image to the next).
This patch has the unanticipated but very nice side-effect of making the initially displayed histogram for the Levels dialog be RGB instead of Value, thus allowing to set the end-points while seeing exactly which channels might be clipped. Unfortunately the Levels RGB histogram is replaced with the Value histogram as soon as the user goes to, say, the Red channel, and then back to the Value channel. And even more unfortunately the Curves dialog still shows the Value channel instead of the RGB channels.
It would be most helpful to be able to see all three channels, perhaps with a Luminance backdrop (when the Luminance channel is added to the histogram), while making Levels and Curves changes.
Patch 305244, "Patch to make the histogram dialog default to RGB instead of Value":
Version: git master