Hi Maciej, On Wed, Sep 24, 2008 at 3:47 PM, Maciej Pilichowski <[EMAIL PROTECTED]> wrote: > Hello, > >> From: bgw <[EMAIL PROTECTED]> >> How does "draw with transparency" differ from using eraser tool >> with x% opacity? > > Pencil and eraser are counterparts of course, but I wished for > transparent color, not just transparent pencil (yes, it exists, and > it is eraser). > >> From: Chris Moller <[EMAIL PROTECTED]> >> Doesn't the Eraser Tool do what you need? > > Yes and no, see above. > >> (Though maybe some >> interesting effects could be gotten with an erasing airbrush that >> accumulated in the alpha channel. > > Exactly! Because once you have transparency as your color you could > use any tool which works with colors. > >> From: Simon Budig <[EMAIL PROTECTED]> >> Well, historically new stuff always had to proove that it is better >> than the old stuff and I personally don't think that is a bad >> thing. > > Of course. > >> So how do you want to work with transparency? What should happen if >> you have a semi-transparent red and you paint on top of blue? > > Good example, because it shows how natural transparent color is. The > answer: you should get exactly the same effect if you have blue color > and paint on top of semi-transparent red. It depends on mode and used > tool. > >> Currently it gets blended on top of the blue resulting in some kind >> of violet and that is a widely used feature to do natural looking >> paintings. I understand your proposal, that you actually want to >> have a semi-transparent red in the image after painting? > > Both answers are really correct -- see above. > >> How is your new feature supposed to interact with tablets with >> varying pressure devices like tablets? Right now you can map the >> pressure information pretty naturally to the opacity. Your >> "replacement" approach for alphacolors would directly influence the >> images alpha channel, making it pretty tricky to lift off the pen >> without leaving a transparent spot (tablets tend to add some events >> at the end et the stroke with very low pressure). > > I don't understand that paragraph: > a) the transparent color is not a replacement, I clearly stated this > in original post, it is addition to the color palette > b) don't pick the transparent color if you don't need it > >> How is your "replacement" approach supposed to work with multiple >> layers? > > Again, it is not a replacement. There is no way to achieve the effect you describe without it being a replacement effect. This is because it violates the normal behaviour of alpha, which is a specifier of opacity for a particular color; without a color, an alpha value is meaningless.
Also, the 'semitransparent color' usage and the 'erasing' usage are directly contradictory. Semitransparent color could work in a fairly normal way, erasing would have to replace the underlying pixel values rather than blending them. If you want to develop this idea further -- personally I think it's an interesting idea -- I believe it will be necessary to discard the notion of a 'color' which is fully transparent, ie. the notion of being able to erase just by 'color' adjustment. David _______________________________________________ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer