XOR support for mouse cursors
ben at swartzlander.org
Sat Nov 10 14:45:44 PST 2007
Didn't Microsoft Windows 3.0 have XOR cursors? How is it possible to
patent something that already existed in a shipping product at the time?
SDL currently has XOR cursors -- why haven't they been sued?
Just so I understand, is it the case that the X.org team has considered
implementing XOR cursors, and opted not to purely out of legal fears? Or
has it never seriously been considered?
Russell Sears wrote:
> There's also a relevant patent (5,359,347) from 1994.
> Ben Swartzlander wrote:
>> Are you talking about patent 4,197,590? That one appears to have been
>> issued in 1980. It must have expired 10 years ago!
>> -Ben Swartzlander
>> Marco wrote:
>>> Ben Swartzlander escreveu:
>>>> As far as I can tell, X does not support mouse cursors that invert
>>>> the pixels underneath them (like Windows mouse cursors). This
>>>> causes a number of problems. First, it makes it impossible to use a
>>>> 1-pixel wide "I" style cursor for text editing, because the cursor
>>>> will completely disappear over a black background (or a white
>>>> background, if you use a white cursor). The only usable "I" style
>>>> cursors I've seen are 3 pixels wide, such as a black "I" with a
>>>> white outline to prevent it from vanishing. This would not be so
>>>> bad, but then certain applications like rdesktop (and possibly
>>>> Wine) need to use actual Windows cursors, so they convert the
>>>> Windows cursors bitmap to a valid X cursor by discarding most of
>>>> the data, which in the case of the 1-pixel wide "I" cursor is
>>>> mostly useless.
>>>> A apologize if this issue has been discussed before but I want to
>>>> know (1) if there are any extensions or options I can use to fix
>>>> this behavior (2) if not, is there a good reason why X has this
>>>> limitation and (3) what can I do to fix this? I am a long time
>>>> Windows and Linux use and as much as I would like to replace my
>>>> Windows desktop with Linux, the poor mouse cursor support is one
>>>> issue holding me back. I'm willing to code an extension to X if
>>>> that's what it takes (and obviously write the patch for rdesktop)
>>>> but I'd like to know how others have dealt with this problem and if
>>>> anyone has some suggestions.
>>>> -Ben Swartzlander
>>> Because It is patented?
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