A clarification re: PDFTron WebPublisher ToXod() converter options

[Support]

Q:

A have a few questions re: PDFTron WebPublisher (ToXod()) converter options:

 

·         SetRenderPages (true)

o    Will the setting change render a section of the page (special blend modes) or the whole page?

o    Will this influence the file size?

o    Is there an adverse effect on the system (i.e. Content being effected) because of the setting change?

·         Set Element Limit()

o    What is the function of Set Element Limit()?

o    Why wouldn’t we want complicated pages to be rendered as they would have blend modes as well?

o    We are unsure of what value to set, if we had 10 elements and we set it to 1,000,000 what would happen?

o    What does an element refer to? Only Images or effects contained in the PDF?

·         Set Opacity Mask (True)

o    Would there be any issues if we were to set the Opacity Mask True at all times?

o    Would this influence the File Size or System Performance?

 

 

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 A:

 

>         SetRenderPages (true)

>  >     Will the setting change render a section of the page (special blend modes) or the whole page?

 

The short answer is a section of the page. The longer answer is that if special blend modes are the reason for rendering an image containing only the incorrect portion of the page is overlayed on top of the page to fix any errors.

 

> o    Will this influence the file size?

 

Yes, it could be larger, but necessary to maintain the correctness. Generally only small portions of the page are affected so the file size increase isn't too large.

 

> o    Is there an adverse effect on the system (i.e. Content being effected) because of the setting change?

 

Anything that is affected will already be incorrect, so that shouldn't be a problem. One thing you may notice if you use a low dpi value is that text in the affected area may appear blurry.

 

>·         Set Element Limit()

> o    What is the function of Set Element Limit()?

The SetElementLimit option is used to determine when pages containing a large number of elements should be rendered as images. The idea is to avoid really slow rendering on the viewer side on these documents. 

> o    Why wouldn’t we want complicated pages to be rendered as they would have blend modes as well?

 

The page would still be partially rendered if it had special blend modes.

> o    We are unsure of what value to set, if we had 10 elements and we set it to 1,000,000 what would happen?

I suggested 1000000 elements as the limit only if you want to entirely avoid rendering because of page complexity, but you may want to consider a smaller value for performance reasons. (the default is 10,000) If there were 10 elements no rendering would occur because of page complexity. (but could occur because of special blend modes)

> o    What does an element refer to? Only Images or effects contained in the PDF?

Paths, (lines, rectangles, shapes etc.) Text, Images, Shadings etc. are all Elements in PDFNet. Elements are mostly just used as a measure of PDF page complexity in this case.

> ·         Set Opacity Mask (True)

>   o    Would there be any issues if we were to set the Opacity Mask True at all times?

Note: This parameter is only relevant to Silvelright. If you are primarily targeting HTML5/Flash it would increase the file size for no reason. When the option is specified the pages containing OpacityMasks would be entirely rendered. The output should look correct, but quality will depend on the DPI parameter.

 

> o    Would this influence the File Size or System Performance?

On those pages the file size could increase and the loading speed can be affected. (whether it is faster or slower depends on the complexity of the page and the dpi of the image) If the page is complex enough it is even possible for rendering to create smaller output.

Keep in mind that any rendering option whatsoever uses the value passed into SetDPI to determine what output quality it should be using. A larger dpi value will increase the quality of the rendered output but increase the file size of the image.