Oh, sorry. Robby
On Thu, May 10, 2012 at 10:04 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote: > Although pixel alignment can be confusing, I think this one is just a > bug. > > The `draw-rectangle' method tries to adjust the width of an outline so > that in the simple case --- a width 0 or 1 pen in unsmoothed or aligned > mode with a bitmap target --- the rectangle outline is the given width > and height, instead of extending an extra pixel. That adjustment isn't > implemented correctly, and the problem is particularly clear with a > large scaling factor. > > You can work around the problem by creating a rectangle `dc-path%' and > drawing it with `draw-path'. Meanwhile, I'll fix `draw-rectangle'. > > At Thu, 10 May 2012 09:57:26 -0500, Robby Findler wrote: >> The problem is that the coordinates are "between" the pixels. There is an >> explanation of this in the context of another library, but the issues are >> the same: >> >> >> http://docs.racket-lang.org/teachpack/2htdpimage.html?q=2htdp/image#%28part._nitty-g >> ritty%29 >> >> hth, >> Robby >> >> On Thu, May 10, 2012 at 8:29 AM, Garrett Mitchener < >> garrett.mitche...@gmail.com> wrote: >> >> > Hi, I'm learning the racket GUI package, and I ran into something that >> > doesn't make sense to me: >> > >> > #lang racket/gui >> > >> > (define black-pen >> > (new pen% >> > [width 1] >> > [color "black"])) >> > >> > (define blue-brush >> > (new brush% >> > [color "blue"])) >> > >> > (define (draw-test-2 dc) >> > (send dc scale 10 10) >> > (send dc set-pen black-pen) >> > (send dc set-brush blue-brush) >> > (send dc draw-rectangle 7 2 4 4)) >> > >> > (define pic (make-bitmap 200 100)) >> > >> > (define dc (new bitmap-dc% [bitmap pic])) >> > >> > (draw-test-2 dc) >> > >> > And at the end, pic looks like this: >> > >> > [image: Inline image 1] >> > The outline and the filling don't line up. What am I doing wrong? This >> > is with DrRacket 5.2.1 on linux. >> > >> > Thanks, >> > -- Garrett Mitchener >> > >> > ____________________ >> > Racket Users list: >> > http://lists.racket-lang.org/users >> > >> > >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
