[racket-dev] [plt] Push #26344: master branch updated

From: Sam Tobin-Hochstadt (samth at ccs.neu.edu)
Date: Fri Feb 22 16:56:15 EST 2013

Ok, that makes sense.

I think you should maybe add the word "floor" in the nitty-gritty
documentation.  You might also link from that discussion in the docs
to the Cairo docs here: http://cairographics.org/operators/ .
However, I can't find anything where they say they round down rather
than to nearest.  Grrr. Makes me glad for the Racket documentation
(such as all the nitty-gritty sections you've written).

On Fri, Feb 22, 2013 at 4:49 PM, Robby Findler
<robby at eecs.northwestern.edu> wrote:
> No, I don't think it does. The drawing operation is called "over" and it
> takes two colors (rgb, say), and an alpha and produces a color (rgb). So you
> always start with some solid color in the background and draw the shape on
> top of it, resulting in another color that some other shape can be drawn on
> top of.
> On Fri, Feb 22, 2013 at 3:45 PM, Sam Tobin-Hochstadt <samth at ccs.neu.edu>
> wrote:
>> On Fri, Feb 22, 2013 at 4:40 PM,  <robby at racket-lang.org> wrote:
>> >
>> > +  The list of colors is obtained by drawing the image on a white
>> > +  background and then reading off the colors of the pixels that were
>> > drawn.
>> Is there a particular reason to choose white, as opposed to clear, for
>> the background in this test?  Does drawing on a "clear" background
>> even make any sense in this case?
>> Sam

Posted on the dev mailing list.