<div class="gmail_quote">On Sat, Sep 26, 2009 at 11:49 PM, Cyrille Berger <span dir="ltr"><<a href="mailto:cberger@cberger.net">cberger@cberger.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Saturday 26 September 2009, Sven Langkamp wrote:<br>
> At the moment there is a fundamental difference between Gimp/Photoshop and<br>
> Krita in the way we see masks. In both cases we have and (8-bit) one<br>
> channel paint device, so not a technical difference.<br>
> The actual difference is how these channel is interpreted: In<br>
> Gimp/Photoshop is a grayscale representation while in Krita it's an alpha<br>
> representation.<br>
><br>
> The grayscale way is probably what most artists are used too, even if the<br>
> meaning of black and white is arbitary. The advantage is that it match good<br>
> with gradient and fill.<br>
><br>
> The way Krita uses is closer to the physical representation either there is<br>
> something (color) or you can look through it. The problem that Dmitry<br>
> descibes is that the only way to "paint" transparency is the eraser tool in<br>
> Krita, which might be unusual for users form other editors. The bigger<br>
> problem is that you e.g. can't use a transparent color in the fill tool.<br>
><br>
> I hope that's the correctly summarizes it.<br>
Ok now I get the problem.<br>
<br>
First, I will restate that I don't like the use of color for transparancy:<br>
<br>
> I can't remember which color is used usually (e.g. in a "well known<br>
> graphical editor"). I guess, when we paint with white paint the image<br>
> becomes opaque, when we paint with black paint - becomes transparent, with<br>
> gray color - becomes semi-transparent.<br>
<br>
That's exatly my problem with using color. From a technical point of view, it<br>
makes sense to have black==transparent == 0, white == opaque == 255. But I<br>
don't see how it can have sense for an user (and from my point of view,<br>
because photoshop does it isn't a valid answer, we are not aiming at cloning<br>
all its broken behaviour, if it's good lets use it, otherwise lets innovate).<br>
<br>
Maybe we should reinvestigate the whole transparancy with the color selector<br>
thing. We had that debate see [1] and [2] (around 18:38 in the log).<br>
<br>
In our previous discutions on the subject we considered that the choice<br>
between transparancy and opacity was wether to put the choice in the tool or<br>
in the color selector. But what if, actually, we need both. Because currently,<br>
the opacity is mainly used to control how much of the color is mixed. While<br>
the transparancy in the color selector could be used to paint with transparent<br>
color, either on a layer (either for filling or not), or on a selection.<br>
<br>
I am trying to think about the math for that, and also about wether it would<br>
make sense for an user, and we would probably have to rethink about the<br>
"opacity" label, to make it have more sense.<br>
<br>
[1]<br>
<a href="http://wiki.koffice.org/index.php?title=Colordialogs#Opacity_as_part_of_color" target="_blank">http://wiki.koffice.org/index.php?title=Colordialogs#Opacity_as_part_of_color</a><br>
[2] <a href="http://lists.kde.org/?l=koffice-devel&m=123060912408849&w=2" target="_blank">http://lists.kde.org/?l=koffice-devel&m=123060912408849&w=2</a><font color="#888888"><br></font></blockquote></div>
<br>There is another potential flaw I see when you paint with transparency vs grayscale (from user point of view):<br><br>If you have a completey white/opaque mask in the Gimp system and paint with black color over it you will get black.<br>
<br>In the Krita system that would mean that you have an opaque mask and paint with a transparent color over it you would get transparency.<br>Does that make sense? With the opacity label it would get even more weird: What is e.g. a transparent color painted with 50% opacity?<br>