Re: [Rosegarden-devel] segmentcanvas_rework branch

[Chris C. <ca...@al...>]

On Tuesday 09 Mar 2004 4:53 pm, Richard Bown wrote:
> Ok, I've worked out how to get untransformed text onto the right
> place on the QCanvasView (hence the Segment labels text looks
> better) but how do we allow for the transformation matrix in
> QFontMetric so that the label is correctly truncated or extended? 
> Any ideas G or C?  segmentcanvas.cpp:800 is the comment.

Hm.  Troublesome.  I know you can query a font metrics object from a 
painter (presumably once you've set the font on the painter) and I 
suppose that might take into account any transformation you've set on 
the painter.  (Or it might not -- I really don't know.)  We haven't 
actually got a painter in the function that does that calculation, 
but I suppose it shouldn't be hard to get one.

But I don't quite get why we need to do that -- why can't we just 
query the existing font metrics and then divide by the scale ratio, 
or whatever?

That apart -- and things like the pointer stuff -- this is looking 
pretty good.  It's much faster for very large canvases but it does 
seem slightly clunkier when compressing a lot of previews onto a 
small canvas (at minimum zoom) -- it seems to paint everything once 
and then blip! refresh, whereas previously it only painted and was 
then done.

I'm inclined to think this is probably a post-release merge rather 
than something to go into 0.9.7, as it inevitably won't get all that 
much testing until it's merged.


Chris