[Gimp-user] Masking for Contrast Control - Can this be done in Gimp?

[Alec Burgess]

Thanks Saul. (Leaving text below in case this s/b the basis for a 
bugreport ...)
a) I can drag and drop in the Layers dialog - but never see the '+'-sign 
in the cursor.
b) In your video (I stepped through it frame by frame so I'm pretty sure 
I have this correct) as soon as you grabbed the layer and moved it up to 
the channels icon to open the channels dialog the '+' sign appeared and 
(I think(?)] was visible until you dropped it "below the line - below 
the components section - into the channels section.

When I do it (again Windows XP, same in both GIMP 2.6.6 and GIMP 2.7 
r28070) the '+' sign never appears while dragging in the image dialog 
and only appears when dragging in the channels dialog if I position my 
cursor to the right of where a fairly short channel name would appear - 
or if none yet, to the right of where it would be. (If description is 10 
characters (say) "background copy" the "+" sign appears when cursor is 
over the 'c' in "copy" or further right - otherwise it is not shown). 
When '+' displayed drop will be successful otherwise it fails.
.
When I was first trying to follow your description I didn't have my 
cursor far enough right and first time I managed to do it had confused 
myself into thinking it was a matter of how close cursor was to the 
separator line :-(

For improved discoverablity suggest that the '+' sign s/b added to 
drag-drop anywhere its legal to drop and in particular only be removed 
in the Channels dialog when cursor is over the components section but 
reappear when cursor is *anywhere* below the line. I *think* but not 
sure about this, that '+' sign should appear when cursor is over the 
"Channels " icon allowing drop there - which should automatically drop 
it in the same place that a new channel would be created if user keyed 
Shift+[New] button.

can anyone confirm/refute above using Linux/Mac/Windows build?

btw: Once I got the above straight your "recipe" worked great on the 
sample image.

saulgoode at flashingtwelve.brickfilms.com wrote:
> Quoting Alec Burgess <buralex at gmail.com>:
>
>> Saul:
>> You said
>>> 1. Drag your original layer over to the Channels Dialog and drop  
>>> it,  creating a new channel.
>> In your video, when you drag the image from the layer dock up to the
>> channels dock your cursor has a '+' sign inside the
>> _
>> |+ ... when I do it I have no plus sign and when the channels dock
>> opens and I drop the dragged item just disappears without raising a new
>> channel.
>
> Just to be clear, after the Channels Dialog is raised (this feature 
> thanks to Michael Natterer :) ), you must move the pointer down to the 
> "channels" section of the dialog (as opposed to the "components" part 
> at the top with the red, green, and blue components). The "+" symbol 
> should appear when the pointer is hovered in the droppable region -- 
> if you had some channels already there then the "+" would only appear 
> when you are between channels (there would also be a horizontal line 
> similar to what appears when dropping layers in the Layers Dialog).
>
>> I'm using 2.6.6 on Windows XP. I tried modifier keys Shift and Ctrl and
>> Shift+Ctrl just in case but can't get the '+' sign to appear in the
>> cursor and more importantly can't get the auto-creation of a new
>> channel.
>
> I do not use Windows so I doubt I can be of much help. You should 
> check to see if you can drag-n-drop layers in the Layers Dialog to 
> reorder your layerstack (instead of a "+" symbol, you will see an 
> arrow because you are not copying the layer, but moving it).
>
> You should also see if, in the Channels Dialog, you can drag one of 
> the components (red, green, or blue) down from the top and drop it in 
> the channels list. If you have problems doing either of these then it 
> is possibly owing to a bug in the Windows version of GIMP.
>
>
>
>
>