So it comes down to this: given a projective transformation T from a rectangle (your form) to a quad Q (what you want to draw on screen), how can you express the same transformation in terms of mapping a quad to a rectangle (what WarpBlt needs)?
One possible plan is: 1) determine the transformation's parameters 2) take the bounding box of Q (a rectangle R) and transform it by the inverse of T, giving you a quad Q' 3) use WarpBlt to transform pixels in Q' (should be a superset of your form) to R 4) mask the result with your original quad Q, using pixel-by-pixel operations on Forms I think all you need in terms of mathematics for this is in http://www.cs.cmu.edu/~ph/869/www/notes/proj/proj.pdf Hope this helps, feel free to ask about the details, Matthias On Tue, Jul 22, 2008 at 9:31 PM, Iulian Wande Radu <[EMAIL PROTECTED]> wrote: > Back to the question... > Yes WarpBlt is available in v2, but I can't seem to be able to use it for > this purpose, because it maps a quad to a rectangle (not a rectangle to a > quad). > There must be a way to do this... > > > On Tue, Jul 22, 2008 at 3:27 PM, Brad Fuller <[EMAIL PROTECTED]> > wrote: >> >> what is Squeak V2? >> >> On Tue, Jul 22, 2008 at 12:02 PM, Matthias Berth >> <[EMAIL PROTECTED]> wrote: >> > Hi, >> > >> > is WarpBlt available in Squeak V2? >> > >> > On Tue, Jul 22, 2008 at 7:53 PM, Iulian Wande Radu >> > <[EMAIL PROTECTED]> wrote: >> >> Hi, I'd like to skew the graphics of a Form, is there an easy way to do >> >> this >> >> in v2 ? >> >> >> >> What I want is to take the rectangle from a normal form, transform it >> >> into >> >> an arbitrarily-defined quadrilateral, and then paint on the screen. I >> >> saw >> >> that WarpBlt does something like this.. but it maps a quadrilateral >> >> section >> >> of a form onto a rectangle. >> >> >> >> >> >> _______________________________________________ >> >> Beginners mailing list >> >> Beginners@lists.squeakfoundation.org >> >> http://lists.squeakfoundation.org/mailman/listinfo/beginners >> >> >> >> >> > _______________________________________________ >> > Beginners mailing list >> > Beginners@lists.squeakfoundation.org >> > http://lists.squeakfoundation.org/mailman/listinfo/beginners >> > >> >> >> >> -- >> Brad Fuller >> www.bradfuller.com >> _______________________________________________ >> Beginners mailing list >> Beginners@lists.squeakfoundation.org >> http://lists.squeakfoundation.org/mailman/listinfo/beginners > > > _______________________________________________ > Beginners mailing list > Beginners@lists.squeakfoundation.org > http://lists.squeakfoundation.org/mailman/listinfo/beginners > > _______________________________________________ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
