Minimizing damage to a canvas

Article View: comp.windows.interviews

Article #1280

Back to comp.windows.interviews Previous Next

#1280

From: The Political Crony
Date: Tue, 17 Nov 1992 18:52

17 lines
1225 bytes

I'm involved in a monitoring application where a number of meter-style
display glyphs will be updated from a comm channel coming in through
some Dispatch methods. All the updating per se seems to be fine. My
question pertains to update of the various displays as required.

It is possible for more than one meter to be updated at a time.  The
natural mechanism for forcing a display update would be to put a patch
around the meter and call the redraw() method. However, if more than
one such redraw() occurs on spots widely separated on the canvas, the
damage area will be the rectangle that contains all the damages,
causing unchanged areas to be redisplayed.

Is there some way to avoid the extra drawing without kludging in the
checking?

Jim Grier
grier@world.std.com

Technical Details

Message-ID: <BxvJ3n.AI3@world.std.com>

Path:

arc1-ca.pugleaf.net!sparky!uunet!charon.amdahl.com!pacbell.com!ames!agate!spool.mu.edu!wupost!gumby!yale!yale.edu!qt.cs.utexas.edu!news.Brown.EDU!noc.near.net!mv!world!grier

Show Full Headers

Complete Article Headers

Newsgroups: comp.windows.interviews
Path: arc1-ca.pugleaf.net!sparky!uunet!charon.amdahl.com!pacbell.com!ames!agate!spool.mu.edu!wupost!gumby!yale!yale.edu!qt.cs.utexas.edu!news.Brown.EDU!noc.near.net!mv!world!grier
From: grier@world.std.com (The Political Crony)
Subject: Minimizing damage to a canvas
Message-ID: <BxvJ3n.AI3@world.std.com>
Organization: The World Public Access UNIX, Brookline, MA
Date: Tue, 17 Nov 1992 18:52:35 GMT
Lines: 17