# Pdf::Writer and "Replacement Tags" **URL:** \ **Category:** Rails\ **Created:** [December 15, 2005, 1:10am UTC](https://www.ruby-forum.com/t/pdf-writer-and-replacement-tags/50309 "2005-12-15T01:10:32Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![jshow](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/977dab/32.png) [@jshow](https://www.ruby-forum.com/u/jshow)\ **Post date:** [December 15, 2005, 1:10am UTC](https://www.ruby-forum.com/t/pdf-writer-and-replacement-tags/50309/1 "2005-12-15T01:10:32Z")
Having read over the ruby pdf generation (simple reporting) options, I think Pdf::Writer will do just fine… …if the following is possible On page 13 of (the really expansive) ::Writer manual, Replacement Tags are detailed. Before I jump into this tomorrow, I’m hoping for some triage sage advice. Finally, the question : “Would utilizing Replacement Tags be a suitable solution for injecting ActiveRecord contents (datafields, etc) ?” From the aforementioned page " Replacement tags will replace the tag with a value computed by the callback. It may perform additional processing, but no location information is provided to the callback. The return from this callback must be the string that will replace the tag. A replacement tag looks like this in text: \ " If so, then the PWD format would be a reasonable solution for generating database driven reports; Injecting row level data on each callback - this implies that I can retain a static reference to a row. There are no code samples (that I could see) to help out, but on the demo page there is a ominous note: ([http://ruby-pdf.rubyforge.org/pdf-writer/demos/index.html](http://ruby-pdf.rubyforge.org/pdf-writer/demos/index.html)): “code.rb: An example of a custom text formatting tag. Note that this tag doesnâ??t quite work as it should because of an as-yet unidentified bug in PDF::Writerâ??s tag handling code.” Will I encounter this bug? Any takers? Thank you for any suggestions or lookouts. Austin, if you’re out there I’d appreciate your thoughts. cheers, Jodi ---
**Author:** ![jshow](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/977dab/32.png) [@jshow](https://www.ruby-forum.com/u/jshow)\ **Post date:** [December 15, 2005, 2:45am UTC](https://www.ruby-forum.com/t/pdf-writer-and-replacement-tags/50309/2 "2005-12-15T02:45:49Z")
On 14/12/05, Jodi S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Having read over the ruby pdf generation (simple reporting) options, I > think Pdf::Writer will do just fine… > > …if the following is possible > > On page 13 of (the really expansive) ::Writer manual, Replacement Tags > are detailed. Replacement tags are simply ways to programmatically insert text or other tags. I am using this in the manual code (PDF::TechBook) to replace \ tags with internal link tags (\). That way, I can just put something like: \ which will be replaced with: \Embedding Fonts\ It’s not really what you want for writing reports or injecting ActiveRecord contents unless you’re entirely working with a template, which isn’t really something that is built-in for PDF::Writer at this point. Tags are specifically meant to replace text within PDF::Writer#text calls, which is essentially what PDF::TechBook uses. It’s a callback, not a general text insertion method. ## -austin Austin Z. \* removed\_email\_address@domain.invalid \* Alternate: removed\_email\_address@domain.invalid ---
**Author:** ![jshow](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/977dab/32.png) [@jshow](https://www.ruby-forum.com/u/jshow)\ **Post date:** [December 15, 2005, 2:24pm UTC](https://www.ruby-forum.com/t/pdf-writer-and-replacement-tags/50309/3 "2005-12-15T14:24:19Z")
On 14/12/05, Jodi S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > It’s not really what you want for writing reports or injecting > > ActiveRecord contents unless you’re entirely working with a template, > > which isn’t really something that is built-in for PDF::Writer at this > > point. > > > > Tags are specifically meant to replace text within PDF::Writer#text > > calls, which is essentially what PDF::TechBook uses. It’s a callback, > > not a general text insertion method. > > Why do you say that it’s not a general text insertion method? > It seems to me (perhaps why I’m asking the question) that essentially > a PWD could be considered a “template” - A. layout considerations > which when utlized with B. \ tags could function as a rudimentary > pdf template. Right. And that’s certainly a good way to handle it, but to do that you need the interpreter for that, which is PDF::TechBook. I think that the way that most people use PDF::Writer right now is to dynamically generate all of the text and formatting using custom code similar to what you see in the demo programs. If you’re doing that, or even the partial generation technique detailed in my Ruby Code & Style article (where you generate most of the format first and then fill things in later when you need it), then using a \ tag makes no sense, since you’re able to insert whatever text you want in whatever way you want. I would be surprised, myself, if people are using the TechBook formatter/interpreter, because it does make a few assumptions on how things are supposed to work. 😉 > I think the callback could be leveraged to provide powerful insertion > functionality. It could. > Is there a good reason (like speed, or some limit on functionality) > why your tool shouldn’t be used in this manner? It’s just not something that I would have imagined that it would be that useful. If it works for you, it shouldn’t be that differentt. > In the past I commited patches to iText - and found it’s html-\>pdf > worked very well - where my custom tags mapped to our persistance > mapper. Your solution caught my eye as I figured I could build > templates to render pdf rather quickly. Cool. Like I said, I think you could do it, it’s just not the way that I would do it simply because I haven’t got a true “html-\>pdf” converter at this point. ## -austin Austin Z. \* removed\_email\_address@domain.invalid \* Alternate: removed\_email\_address@domain.invalid ---
**Author:** ![jshow](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/977dab/32.png) [@jshow](https://www.ruby-forum.com/u/jshow)\ **Post date:** [December 15, 2005, 5:47am UTC](https://www.ruby-forum.com/t/pdf-writer-and-replacement-tags/50309/4 "2005-12-15T05:47:08Z")
Thanx Austin. > It’s not really what you want for writing reports or injecting > ActiveRecord contents unless you’re entirely working with a template, > which isn’t really something that is built-in for PDF::Writer at this > point. > > Tags are specifically meant to replace text within PDF::Writer#text > calls, which is essentially what PDF::TechBook uses. It’s a callback, > not a general text insertion method. Why do you say that it’s not a general text insertion method? It seems to me (perhaps why I’m asking the question) that essentially a PWD could be considered a “template” - A. layout considerations which when utlized with B. \ tags could function as a rudimentary pdf template. I think the callback could be leveraged to provide powerful insertion functionality. Is there a good reason (like speed, or some limit on functionality) why your tool shouldn’t be used in this manner? In the past I commited patches to iText - and found it’s html-\>pdf worked very well - where my custom tags mapped to our persistance mapper. Your solution caught my eye as I figured I could build templates to render pdf rather quickly. Thanx for your thoughts. Jodi > ## -austin > > Austin Z. \* removed\_email\_address@domain.invalid > \* Alternate: removed\_email\_address@domain.invalid