alan@rnms1.paradyne.com (0000-Alan Lovejoy(0000)) (04/02/89)
In article <141200011@cdp> sklein@cdp.UUCP writes: >For example, one company patented >the process of ORing the pixels of a character display, and EVERYONE >who uses inverse text has to pay them royalties! Do you mean XORing (exclusive-orring) the destination pixels with a source all of whose bits are 1s? What if one simply uses bitwise NOT? I find it hard to believe that bitmap graphics could have existed longer than 5 minutes (well, maybe 5 weeks) before someone used either NOT or XOR to produce text in inverse video. This patent doesn't sound very enforceable to me. Alan Lovejoy; alan@pdn; 813-530-2211; AT&T Paradyne: 8550 Ulmerton, Largo, FL. Disclaimer: I do not speak for AT&T Paradyne. They do not speak for me. __American Investment Deficiency Syndrome => No resistance to foreign invasion. Motto: If nanomachines will be able to reconstruct you, YOU AREN'T DEAD YET.
barmar@think.COM (Barry Margolin) (04/03/89)
Actually, I believe that what was patented was the use of XOR to
display a movable cursor on a raster display. This technique allows a
cursor to be displayed over existing portions of the display without
requiring additional storage for the old contents of the overlaid
area. When the cursor moves you simply XOR it again in the old
location to restore the original contents.
It may also cover things like blinking block cursors. I suspect it
DOESN'T cover the standard Macintosh arrow mouse cursor, since that
displays a black arrow, rather than an inverted arrow. However, it
inverts the border, so that the arrow is still visible on a black
background; I don't know whether this hybrid scheme is covered by the
patent.
Barry Margolin
Thinking Machines Corp.
barmar@think.com
{uunet,harvard}!think!barmarcarlson@hpindda.HP.COM (Bob Carlson) (04/03/89)
In about 1973 someone taught me the trick of XOR A,B XOR B,A XOR A,B in order to do a swap. It's hardly a new idea, nor is it limited to graphics. Cheers
sklein@cdp.UUCP (04/06/89)
In message <blah blah blah> carlson at hpindda.HP.COM writes: >In about 1973 someone taught me the trick of XOR A,B XOR B,A XOR A,B >in order to do a swap. It's hardly a new idea, nor is it limited to >graphics. It's not a new idea *now*, but it may have been patented in 1972, or earlier. Keep in mind, that the patent office has routinely issued patents that didn't seem to conflict with existing patents. They usually do *not* rule as to whether or not something is patentable-- they issue the patent and let you fight it out in the courts. Also, if the license fee was $500, it would cost you more to challenge this patent then to license it. So even though the patent holder may not have patented a legitimately original idea, no one wants to make a big deal over it. You can argue all you want, fact is, the patent is real! -shabtai
kent@lloyd.camex.uucp (Kent Borg) (04/07/89)
In article <38395@think.UUCP> barmar@kulla.think.com.UUCP (Barry Margolin) writes: [talking about whether x-oring a cursor is patented] >It may also cover things like blinking block cursors. I suspect it >DOESN'T cover the standard Macintosh arrow mouse cursor, since that >displays a black arrow, rather than an inverted arrow. However, it >inverts the border, so that the arrow is still visible on a black >background; I don't know whether this hybrid scheme is covered by the >patent. When I move my cursor it looks like the pixels under the arrow itself are set black and bits under the the 1-pixel wide border are set white. I don't see any x-oring going on. I have heard that, if as a programmer, you want to animate between windows (like the Finder does with draging icons between folders or open/close zooming rectangles) you are supposed to do everything with paired x-ors as a way to be sure to put all the bits back the way you found them before letting anybody else have the CPU. (Before calling SystemTask, GetNextEvent, etc.) Kent Borg kent@lloyd.uucp or ...!hscfvax!lloyd!kent