Sun Jun 15, 2014 9:10 pm
Sun Jun 15, 2014 11:36 pm
gramp wrote:GIMP Version: 2.8.10
Operating System: Linux
OS Version: Ubuntu 10.04 LTS
GIMP Experience: Intermediate Level
Hi, all you gooduns.
I want to "intersect" one grayscale layer with another one. That is (that is, I think) where the two layers overlap physically and where their grayscales share overlapped values, I want to create a path that follows the intersection of their gray values.
There's an old problem in drafting to find and draw such an intersection for two cylinders of different diameters crossing at a non-perpendicular angle and with centers offset. A simpler example is lines painted with gradients composed of the same grayscale range: what does the path of their intersection look like. (If they are identical, the path of intersection is a perfect 45-degrees, but non-identical cases are more interesting.)
I was expecting that I'd be able to open a selection tool of some type and just type in the range of gray scales I wanted, and do the same for the other layer, and then work with the two selections to delete some of one or the other.
Sorry. Another Crazy Scheme. As I was writing this, I went back to the threshold tool to create a B&W (Kodalith? anyone? :^) ) boundary, thinking that I could use them--or an intersection or union of them--as Layer Masks, which I rush headlong to confess I have avoided like latter-day whooping cough.
But JUST as I was about to make a breakthrough my brains fell out on the floor.
I suspect this might be easy, but I could be persuaded that it is quite impossible too. Anyway, I know you like--scratch that--you respond politely to conundra sometimes. And I am Conundrum, the Contrarian.
Thank you.
Sun Jun 15, 2014 11:40 pm
Mon Jun 16, 2014 2:36 am
Mon Jun 16, 2014 5:50 am
Mon Jun 16, 2014 7:19 am
Mon Jun 16, 2014 7:58 am
Mon Jun 16, 2014 8:04 am
Mon Jun 16, 2014 8:12 am
Mon Jun 16, 2014 10:07 am
gramp wrote:First of all, thank you, all, for your replies.
Second of all, LOOK AT THE POSTING TIMES! I posted at 10:10--exactly 40 min. after my bedtime... but all of you stayed up late to offer advice.
Mon Jun 16, 2014 10:26 am
Gino D wrote:Once you have picked out the first of the two layers, you have to create a layer mask having the same appearance of the related layer by checking the "Grayscale copy of layer" radio button in the "Add Layer mask" dialog. Then you can run the "Mask to Selection" command and save the resulting selection to a new channel by means of the "Save to Channel" command.
Mon Jun 16, 2014 11:29 am
Tue Oct 11, 2022 10:06 pm
Wed Oct 12, 2022 3:05 am
Wed Oct 12, 2022 5:35 am
Wed Oct 12, 2022 6:38 am
Wed Oct 12, 2022 6:50 am
ofnuts wrote:In 2.10, unless you have a very good reason not to (and if you find one it will usually not be, it will just be that you are trying to solve the wrong problem), you should use the default "linear" modes.