Re: Extents under rotation
Donn <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <[email protected]> |
On 06/12/2013 17:13, Bill Spitzak wrote: > The matrices are multiplied before this is done, so this error does not > accumulate. For instance if you rotate by 45 degrees and then back by 45 > degrees, it will act like a rotation of 0 and produce your expected > bounding box, rather than enlarging the bounding box twice. I'm sure I will face these things soon when I institute picking beyond a basic bbox hit approach. Bill, Do you have a way to draw a tight bbox in user-space around a path? I have tried various things like getting the extents in device space (by doing a identity_matrix call before extents) and then using device_to_user on each returned x,y coordinate -- in order to try get those corners *in user space* and I just can't get it right. I'd like to draw an X shape over my original path: At first I have a complex shape - so I want to measure extents and thereafter substitute a simple X shape [*] that can be drawn quickly(into user/local space) and re-measured by extents in the future. [*] X from top-left to bottom-right and reverse. Or just a rect, or just four dots in the bbox corners. \d -- cairo mailing list [email protected] http://lists.cairographics.org/mailman/listinfo/cairo