On Monday 08 April 2002 9:07 pm, Herbert Voss wrote:
> Angus Leeming wrote:
> > modify the bounding box of your graphic file from say:
> > %%BoundingBox: 0 0 200 180
> > to
> > %%BoundingBox: 30 30 200 180
> >
> > (Big enough to see the effect anyway...)
> >
> > Display the file. Fine. Clip it fine. (Not changed the bounds, so it
> > isn't clipped).
> >
> > Change xl to 31 in the graphics dialog (change by 1). Now clip it...
> >
> > Lose 30 from the top and the right :-(
> >
> > What's the solution to this then?
>
> what does the unit of the bb says?? always bp?
>
> Herbert
Yes.
I think that the problem is quite subtle.
rose.eps had a bounding box of (xl yb xr yt), but had no pixels outside this
range, so the width of the loaded image was (xr-xl) and it's height was
(yt-yb).
If I modify the bounding box by hand, the image width, height of the
original, unclipped image is unchanged by my modification and is greater than
(xr-xl), (yt-yb).
If I now clip, I take those 30 pixels of the top right, so:
int const xoffset_r = image_->w - params.bb.xr);
int const yoffset_t = image_->h - params.bb.yt);
rather than off the bottom left.
I'm not sure what the solution to this is.
Angus
