From fa0809eb4d9bc6e339c60b58996368bfb82e67fa Mon Sep 17 00:00:00 2001 From: Matthias Felleisen Date: Wed, 12 Oct 2011 09:36:39 -0400 Subject: [PATCH] document unexpected mouse event reporting; Closes PR 12278 (cherry picked from commit 8cdbd3285b5acc34df301545df26144159e13b83) --- collects/teachpack/2htdp/scribblings/universe.scrbl | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/collects/teachpack/2htdp/scribblings/universe.scrbl b/collects/teachpack/2htdp/scribblings/universe.scrbl index 31f45bb72a..a3d1f5a4e7 100644 --- a/collects/teachpack/2htdp/scribblings/universe.scrbl +++ b/collects/teachpack/2htdp/scribblings/universe.scrbl @@ -442,10 +442,16 @@ All @tech{MouseEvent}s are represented via strings: coordinates may be negative or larger than the (implicitly) specified width and height. - Note: the computer's software doesn't really notice every single movement + @bold{Note 1}: the operating system doesn't really notice every single movement of the mouse (across the mouse pad). Instead it samples the movements and signals most of them.} -} + + @bold{Note 2}: while mouse events are usually reported in the expected + manner, the operating system doesn't necessarily report them in the + expected order. For example, the Windows operating system insists on + signaling a @racket["move"] event immediately after a @racket["button-up"] + event is discovered. Programmers must design the @racket[on-mouse] + handler to handle any possible mouse event at any moment. } @item{