General Discussion - Documentation: OnProgress

Documentation: OnProgress

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Forum Name: General Discussion
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URL: http://www.quickpdf.org/forum/forum_posts.asp?TID=1465
Printed Date: 23 Nov 24 at 7:43AM
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Topic: Documentation: OnProgress

Posted By: IanK
Subject: Documentation: OnProgress
Date Posted: 01 Jun 10 at 11:45AM

I'm currently updating old iSEDQuickPDF code, and in the course of looking at the QuickPDF library's MergeFileList[Fast] code stumbled across lines that looked very like they were doing progress tracking and callbacks.

With a bit more tracing I found the TQuickPDF.OnProgress event handler property, and the associated TQuickPDFProgressEvent type.

From context this handler's called periodically as file merges (and other operations?) take place, passing an integer in the range 1-100 out so external code can update a progress bar or similar.

However, checking the Reference Guide that went out with the library (v7.19) there's no mention of OnProgress, or TQuickPDFProgressEvent, and short of checking library code (or maybe noticing it on a code completion dropdown) there's be no way of telling this facility existed. It is very useful if you're doing a large merge, so it's probably worth adding it to the documentation in some future release.

Replies:

Posted By: Rowan
Date Posted: 01 Jun 10 at 12:08PM

Hi Ian,

There are a few internal functions that are not exposed in the public API for Quick PDF Library and can only been seen in the source code version.

Generally the only reason that these internal functions are not exposed is that they are basic utility functions which are only useful behind the scenes or that they are functions which are too complex for most people to use, unless they have extensive knowledge of the PDF specification.

I'll chat with the development team about the functions you've mentioned and see if there's any reason why we can't expose these functions in the public API for the next release.

Cheers,

- Rowan.

P.S. We're also considering exposing more of the low-level functions that would allow users with a decent knowledge of the PDF specification to really get inside of PDF files at a very low level.

Posted By: IanK
Date Posted: 01 Jun 10 at 12:15PM

Thanks for the feedback Rowan.

It's probably worth mentioning that while the internal setup for the calling of OnProgress is (naturally) deep within the code, the OnProgress property itself is public, as is the TQuickPDFProgressEvent (in QuickPDFStructure.pas).

It looks very like it's there to be used, in as simple a way as any other Delphi event handler, just not documented.