Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!keith From: keith@Apple.COM (Keith Rollin) Newsgroups: comp.sys.mac.system Subject: Re: ScrollBar design question Message-ID: <54415@apple.Apple.COM> Date: 27 Jun 91 23:19:45 GMT References: <1991Jun25.124247.11023@cbnews.cb.att.com> <54349@apple.Apple.COM> Organization: Apple Computer Inc., Cupertino, CA Lines: 26 In article shores@fergvax.unl.edu (Shores) writes: >In <54349@apple.Apple.COM> keith@Apple.COM (Keith Rollin) writes: >>You are correct that changing it now would cause problems. In order to >>show a proportional thumb, you have know know the size of the view >>you are scrolling, which isn't currently supported in the scrollbar >>control interface. > >But you do know the size of the view most of the time. Why couldn't the >scrollbar CDEF look at contrlMin, contrlMax, and contrlValue fields of >the control it's mangling? I suppose that many applications are lazy >and don't update these fields as they should. Yes, you could make a guess at the size of the view in pixels. You could also look at contrlMin, Max, and Value. However, you don't know what units are being used for the control values. Are they in pixels? Are they in lines of text? Are they in units of 10 pixels? Are they in something else? Unless you can make that determination, you can't get a proportional thumb to be aesthetically correct. I've seen and used INITs that implement proportional thumbs, but they never work uniformly well. -- ------------------------------------------------------------------------------ Keith Rollin --- Apple Computer, Inc. INTERNET: keith@apple.com UUCP: {decwrl, hoptoad, nsc, sun, amdahl}!apple!keith "But where the senses fail us, reason must step in." - Galileo