BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  StretchDraw() in TThread causes Memory Leak          BorlandTalk.com Forum Index -> C++ Builder (Graphics) View previous topic :: View next topic   Author Message Phuoc Guest Posted: Sat Jul 30, 2005 2:58 pm    Post subject: StretchDraw() in TThread causes Memory Leak In my program, I'm using StretchDraw() in a thread which is causing memory leak. When I use Synchronize() and move the execution of StretchDraw() into the main thread, the memory problem is gone. The access of the canvas in the threads are surrounded by lock/unlock. There are some OTHER canvases in the main threads which are not locked/unlocked. Is that the reason? When I lock a canvas do I have to lock before everything, also changing color, fonts etc.? or only before modification of the bitmap, i.e. Draw, Copy etc? thanks Phuoc Can HUA -- =============================== I'm using BCB5 on XP Home Back to top Remy Lebeau (TeamB) Guest Posted: Sat Jul 30, 2005 7:16 pm    Post subject: Re: StretchDraw() in TThread causes Memory Leak "Phuoc" <xyz.home (AT) xyz (DOT) huaonline.com.xyz> wrote Quote: In my program, I'm using StretchDraw() in a thread which is causing memory leak. How do you know that? How are you measuring it? How do you know that your own code isn't leaking the memory? What does your actual code look like? Quote: When I lock a canvas do I have to lock before everything, also changing color, fonts etc.? or only before modification of the bitmap, i.e. Draw, Copy etc? All work done in a separate thread has to be locked. Otherwise, the Canvas is not protected at all. Fortunately, the VCL does most of the locking internally for you. But there are times when you should still lock manually. Gambit Back to top PC HUA Guest Posted: Sun Jul 31, 2005 12:46 pm    Post subject: Re: StretchDraw() in TThread causes Memory Leak On Sat, 30 Jul 2005 12:16:40 -0700, Remy Lebeau (TeamB) <no.spam (AT) no (DOT) spam.com> wrote: Quote: "Phuoc" <xyz.home (AT) xyz (DOT) huaonline.com.xyz> wrote in message news:op.suqejhkpewlac1 (AT) centrino (DOT) .. In my program, I'm using StretchDraw() in a thread which is causing memory leak. How do you know that? How are you measuring it? I found that when I noticed that the system became very slow after my program has been running for a while. Then I checked the Performance in Windows Task Manager. I can see 'Page File Usage History' increasing and the available Physical Memory getting down. Quote: How do you know that your own code isn't leaking the memory? When I comment that line of code with StretchDraw() (one single line) the available memory gets up and down within a range. I also replaced it with Draw() it's fine as well. When I move that one line into main thread with a Synchronize routine it's okay. Quote: What does your actual code look like? Basically, it's a slide show which loads JPEG images and stretches/shrinks it for display. One TJPEGImage is used repeatly and the image is StretchDraw() in 2 TBitmap's alternatively. StretchDraw() was written in the main thread originally. But when the image is too large the StretchDraw() interrupts the background (MIDI) music (although the music routine is running on a seperate thread). It was better when I increased the priority of the music thread temporary before the StretchDraw(). But I thought it's better to put the StretchDraw() into the same thread as the image is loaded and I set the priority of that thread to very low. Apart from the memory problem the music is running smoothly. Quote: All work done in a separate thread has to be locked. So, you mean also setting colors etc. If I have more than one thread using Canvas should I always use lock/unlock wherever I can regardless whether it's required, just for safty? thanks Phuoc Can HUA -- ============================== I'm using BCB5 on XP Hpme Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> C++ Builder (Graphics) All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.