DARenderPageToDC() slowing down form processing.

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   I am using QuickPDF's DARenderPageToDC() function in a background thread in a form-based application.  I have tried setting the background thread to ThreadPriority.Lowest.  Despite that, when QuickPDF is rendering (to an HDC that is never displayed) processing events on the form becomes very sluggish, often taking over a second to register things like button clicks or moving the form to a new location on the screen.

I am on an Intel i5 750 (2.67 GHz quad-core) and there are no other background threads running.  If I disable the single DARenderPageToDC() line (and leave in the rest of what happens in the background thread such as opening the PDF, retrieving the number of pages, saving the image via a custom function, etc.) the form registers events as quickly as you would expect.

Any ideas as to how to use DARenderPageToDC() in a way that is more friendly in a multi-threaded application?  I'm assuming that function must be multi-threaded?  Can someone confirm that and, if so, what priority are its child threads?

- Roulette

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Roulette Members Profile Find Members Posts Beginner Joined: 26 Mar 10 Status: Offline Points: 6	Post Options Post Reply Quote Roulette Report Post Thanks(0) Quote Reply Topic: DARenderPageToDC() slowing down form processing. Posted: 06 Jun 10 at 11:47PM
	I am using QuickPDF's DARenderPageToDC() function in a background thread in a form-based application. I have tried setting the background thread to ThreadPriority.Lowest. Despite that, when QuickPDF is rendering (to an HDC that is never displayed) processing events on the form becomes very sluggish, often taking over a second to register things like button clicks or moving the form to a new location on the screen. I am on an Intel i5 750 (2.67 GHz quad-core) and there are no other background threads running. If I disable the single DARenderPageToDC() line (and leave in the rest of what happens in the background thread such as opening the PDF, retrieving the number of pages, saving the image via a custom function, etc.) the form registers events as quickly as you would expect. Any ideas as to how to use DARenderPageToDC() in a way that is more friendly in a multi-threaded application? I'm assuming that function must be multi-threaded? Can someone confirm that and, if so, what priority are its child threads? - Roulette