I need help - I can help - page rendering is quite slow.

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page rendering is quite slow.

Printed From: Debenu Quick PDF Library - PDF SDK Community Forum
Category: For Users of the Library
Forum Name: I need help - I can help
Forum Description: Problems and solutions while programming with the Debenu Quick PDF Library and Debenu PDF Viewer SDK
URL: http://www.quickpdf.org/forum/forum_posts.asp?TID=1569
Printed Date: 06 May 25 at 3:57PM
Software Version: Web Wiz Forums 11.01 - http://www.webwizforums.com

Topic: page rendering is quite slow.

Posted By: giantjupiter
Subject: page rendering is quite slow.
Date Posted: 13 Sep 10 at 4:47PM

Hi,

I am trying version 7.21, and I noticed that DARenderPageToDC(...) is quite slow. I call DARenderPageToDC(...) in OnDraw event, so that repainting has a delay, which is quite annoying.

I called these functions:

DAOpenFile(...),

DAFindPage(...)

DARenderPageToDC(...)

and no other function is called. The Quick Pdf Library Demo seems to be fast.

So I'd like to ask what is the best way to render a page?

Thx

michael

Replies:

Posted By: Ingo
Date Posted: 13 Sep 10 at 7:37PM

Hi Michael!

Is it slow with all pdf-documents or only few (very special)?
What about ...
LoadFromFile...
SelectPage...
RenderPageToDC...
Is it faster?

Cheers and welcome here,
Ingo

Posted By: giantjupiter
Date Posted: 13 Sep 10 at 11:44PM

Hi, Ingo,

It is much obvious when there is an large image in the page, and it seems only RenderPageToDC() is slow and other functions are ok. The pause of rendering text is short but still noticable.

Should I render it to a bitmap first, then every time repaint the bitmap. I am also trying mupdf, but it don't have this problem.

By the way, I am trying them with wxWidgets, and I put RenderPageToDC() and mupdf's winblit() in the inherited function of wxWindow::OnDraw(), which is invoked to repaint the DC.

Thx,

Michael

Posted By: pavsej
Date Posted: 22 Sep 10 at 8:59AM

I have the same Problem with one large image on a PDF page.

I kind of solved it by changing PrinterResolution. For preveiw I use lower Resolution, for real printing job I use higher Resolution.

In my case rendering of one PDF page with one image takes (RenderPageToDC):

2.3 sec - 300 DPI

6.5 sec - 600 DPI

Anyway, any performace improvement would be welcome.

Posted By: Ingo
Date Posted: 22 Sep 10 at 2:27PM

Hi!

And 900 dpi perhaps 15 sec...
But 72 dpi (the standard) immediately.
It depends on what you wanna do ... like always ;-)
The dev-team has already done a lot in case of speed
but if you want a lot then ... ;-)

Cheers, Ingo