[poppler] /SMask support

Leonard Rosenthol leonardr at pdfsages.com
Wed Dec 14 15:38:31 PST 2005

At 02:06 PM 12/14/2005, jyotirmoy bhattacharya wrote:
>I have been trying to get draw alpha gradients using /SMask
>and /XObjects but it does not seem to work with current


>Are there plans to include such support in the future


         It's on the list for future Xpdf development, but it's a 
complex problem to implement fully and correctly - and Derek hasn't 
gotten enough real-world documents to justify it.  I've been pushing 
him on it, however.

>or is there a workaround that I can use?

         Yes, but it sucks.  Draw a gradiant the old fashioned way (a 
series of lines) with each line having varying opacity levels.

>I must admit that Abobe's PDF Reference is very vague on how
>all this is supposed to work.

         How so?

         There are aspects of transparency not well documented, and 
there is a forthcoming technote from Adobe on the topic.

Leonard Rosenthol                            <mailto:leonardr at pdfsages.com>
Chief Technical Officer                      <http://www.pdfsages.com>
PDF Sages, Inc.                              215-938-7080 (voice)
                                              215-938-0880 (fax)

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