Article View: borland.public.cppbuilder.nativeapi
Article #13600Re: Thread synchronisation - Question
From: Bob Gonder
Date: Tue, 07 Oct 2003 01:42
Date: Tue, 07 Oct 2003 01:42
19 lines
2155 bytes
2155 bytes
Remy Lebeau (TeamB) wrote: >"Matt Heling" <heli@nospamheling.de> wrote in message >> But I've read, especially TCanvas-Objects were "lockable" >> using the method Lock() to avoid other running threads's >> access until Unlock() is called after having painted to the >> Canvas directly. > >That does not mean that the underlying drawing is going to be thread-safe >even with locking. It depends on the actual device being drawn to whether >multithread-drawing to it is supported. In my experience, drawing to a >Canvas from multiple threads doesn't usually work correctly. Probably best to use 3 canvases. Thread draws on #1 while GUI displays #3. Thread finishes with #1, posts message to GUI telling it to use #1. Thread starts drawing #2. (Gui likely hasn't finished with #3 yet, but will shortly, when it get the posted message). Cycle endlessly through the 3 canvases.
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10cc67,20b65b563d927a2d X-Google-Attributes: gid10cc67,public X-Google-ArrivalTime: 2003-10-06 19:10:11 PST From: Bob Gonder <notbg@notmindspring.invalid> Newsgroups: borland.public.cppbuilder.nativeapi Subject: Re: Thread synchronisation - Question Date: Mon, 06 Oct 2003 18:42:01 -0700 Organization: MindSpring Enterprises, Inc. Reply-To: notbg@notmindspring.invalid Message-ID: <b764ovs48k5s6v9r3n5q093pq498ej8dvt@4ax.com> References: <3f704989@newsgroups.borland.com> <3f750c0d$2@newsgroups.borland.com> <3f818e8c@newsgroups.borland.com> <3f8198e0$1@newsgroups.borland.com> X-Newsreader: Forte Agent 1.91/32.564 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit NNTP-Posting-Host: 67.31.176.44 X-Trace: newsgroups.borland.com 1065490923 67.31.176.44 (6 Oct 2003 18:42:03 -0700) Lines: 21 Path: arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!sn-xit-03!sn-xit-01!sn-xit-09!supernews.com!news-xfer2.atl.newshosting.com!63.218.45.10.MISMATCH!newshosting.com!news-xfer1.atl.newshosting.com!newsfeed.icl.net!newsfeed.fjserv.net!news-FFM2.ecrc.net!newsfeed00.sul.t-online.de!newsfeed01.sul.t-online.de!t-online.de!newsgroups.borland.com!not-for-mail