Iterator requirements

[Cyrille Berger]

> * Iterators
>
> 	Iterators offer random and linear read/write access to channels, pixels
> and 2 dimensional arrays of pixels.


> 	Iterators return pixel data as a vector/array (whatever, but preferably
> not a pointer to a amorphous chunk of bytes*) of bytes which can be
> interpreted by the colour strategy as a colour.
> 	Iterators can skip pixels according to selection status, with a degree of
> 	fuzziness.

I have already made a change (not commited yet), that will help : I have add 
an "=" operator that will make the convert to QUANTUM* operator deprecated.

> 	Iterators and single pixel values are passed to the colour strategies for
> 	colour model specific handling.
I was planning to work on that specific part during this week. And I was 
planning to implement a second type of iterrator that will return a class 
representing a pixel.

> 	Colour strategies can render their pixels to display RGB format (i.e. a
>    QImage).
or better a QPixmap.
When writting the grayscale strategy, I noticed that there was a lot of 
unnecessary call to the render function of the strategies, I wonder if it 
wouldn't be faster to have a tile manager of pixmap. This way, we only have 
to compute the transformation if the tile has been changed.

-- 
--- Cyrille Berger ---