On Mon, 2003-06-02 at 22:03, Joao S. O. Bueno wrote:

Therefore, one could, for instance,ina single work use a "combine 50% blue as green" mode, and on his next image, the artist could make an "add red to alpha" combine mode. The differene is that the option is up to the user, and there will be no need for him to patch the Gimp to get the desired effects.

Another cool thing to have would be conditional layer mode statements like 'if [luminosity] of [background layers] is [higher than] [50%] paint [foreground] in [normal] mode' (something similar to the UI when defining mail filters in Evoilution).

So, I would like to know if you think this could be an itneresting feature. What could and could not be done here. If we get to an interesting final idea here, I think I can write, with ocasional questions to you, the necessary code to make it work.

I love the idea, as long as one doesn't need to be an uberhacker to be able to construct a blending mode with that sort of thing ;)

good luck! hope to see some code soon.

Hi,

"Joao S. O. Bueno" writes:

I wrote yesterday that I was writting a XOR layer combine mode.

[snip]

So, it ocurred to me that with something more elaborated than what I did, there could be implemented a "custom layer combine" mode. Them, one "custom" option would be added in the layer mode/paint options,a nd the actual pixel operations for this would be defined in a dialog box somewhere else, maybe even as a plugin.

I like the idea of pluggable paint-modes since the API would probably be relatively simple. This makes it an ideal candidate for providing a GimpModule interface to it:

http://developer.gimp.org/api/1.3/libgimpmodule/index.html

For an example have a look at the GimpColorDisplay API:

http://developer.gimp.org/api/1.3/libgimpwidgets/GimpColorDisplay.html

and a simple impplementation:

http://cvs.gnome.org/lxr/source/gimp/modules/cdisplay_gamma.c

So, I would like to know if you think this could be an itneresting feature. What could and could not be done here. If we get to an interesting final idea here, I think I can write, with ocasional questions to you, the necessary code to make it work.

First of all, we are of course interested in your patch that implements XOR as a new layer mode. It might be a little late to integrate pluggable paint-modes now since we really need to get a release done soon. So we might want to include your new layer mode now and develop pluggable paint-modes in parallel. It could then be merged when the code is branched after the release.

Sven

On Tue, Jun 03, 2003 at 12:52:39AM +0200, Sven Neumann wrote:

First of all, we are of course interested in your patch that implements XOR as a new layer mode.

Just a question: If one is to move to floating point layers (ie. GIMP 2.0), how would XOR work between two such layers?

/* Steinar */

* Steinar H. Gunderson [030603 14:21]:

Just a question: If one is to move to floating point layers (ie. GIMP 2.0), how would XOR work between two such layers?

In a system supporting both floating point and integer fata types for the image samples, some operations are natural to restrict. XOR would perhaps be restricted to 16bpc and 8bpc, the neccesary conversion would have to be done for the input/output of the filter.

In the same manner it is common to merge brightness/contrast/color adjustments into a series of operations on floating point values, even when the working space is 8bit or 16bit.

/pippin