Re: [Rosegarden-devel] pb with SnapGrid.snapX() ?

[Guillaume L. <gla...@te...>]

On Saturday 26 February 2005 13:38, Chris Cannam wrote:
> On Friday 25 Feb 2005 23:57, Guillaume Laurent wrote:
> > what difference
> > does it make that I'd convert the timeT to x coord in the View as you
> > suggest, or in the Model as I currently do ?
>
> I gave an example of where it makes a difference: drawing repeating
> trails.  For these, what you currently do is store the width of a
> repeat in graphical coordinates (converting in the Model) and then in
> the View you draw rectangles at multiples of that repeat width.  This
> results in incremental rounding errors unless the repeat width is
> exactly expressible in graphical coordinates: as you scroll right, the
> repeat rectangles will gradually drift away from the bar lines.

OK, I understand. Plus the computation is repeat rects is broken as it is 
anyway (plenty of refresh problems).

> If you're going to maintain that separation, then you need to be doing
> things like passing the exact positions of the individual visible
> repeat boundaries from the Model to the View in display x coordinates,
> not just passing a value that the View can use to approximate them.

That's what I intend to do.

> By the way -- I should probably say that I do think the CompositionView
> design is a big improvement, regardless of the details I'm arguing
> about.

Thanks :-). I don't claim it to be perfect either.

-- 
      Guillaume.
      http://www.telegraph-road.org