Tool overlay and cursor shapes

[LukasT.dev@gmail.com]

On Friday 04 September 2009 10:52:20 Cyrille Berger wrote:
> Hi,
>
> On Friday 04 September 2009, LukasT.dev at gmail.com wrote:
> > I'm waiting whether somebody approve my commit which uses QImage as
> > buffer in canvas although we have many buffers in the render chain...
>
> That is still a concern.

Any chance to test this patch through beta stages and revert if it shows 
performance problems?

>
> > At least my
> > patch would help me to fix some issues (I could use various compositing
> > modes, e.g. XOR, without fear that some platform or X11 would not work
> > correctly)
>
> What's wrong with the black&white lines solution ?

I really think that some composite operation is better because it can help you 
identify e.g. the borders of some area you paint. You can see on the outline 
where is different colour. Black and white just covers part of the image.

Second argument is pure subjective -- it is ugly :)

>
> > Related bugs:
> > * When you change the cursor shape in Krita, it is changed after you
> > change the tool from freehand to some other tool and back to freehand.
> >
> > * Brush outlines are invisible on black surfaces. Solution is composition
> > mode ala XOR or black-and-white outline of the tool. This was discussed
> > on IRC with boemann and Cyrille and I tested various approaches for this
> > so just document your opinion here please.
>
> I wonder if a solution to that wouldn't be to use the current color for the
> brush outline.

I disagree. See previous argument.

>
> > I would prefer some intelligent XOR instead of black&white versions. When
> > the under-laying pixel has brightness less then 50 use black pixel, white
> > otherwise...
>
> Yes but we don't have that in Qt, do we ?

Yep, we don't. It is possible to have own code for that outside Qt? E.g. some 
method that would raster line on QImage according bresensham algorithm and 
would take pixels in QImage into account? Then just use value from QColor as 
the limit for black&white? Would be that usable?

Lukas