Adobe XFDF

Adobe Xml Forms Data Format is an xml format that allows you to fill PDF forms.  I used this in my D&D character generator to allow for easy creation of a printable character sheet in PDF form.

I started with an editable PDF form.  Each field in an editable form has a name of some sort, and if you have access to Adobe LiveCycle Designer, you can view the fields as XML.  All you have to do is open the editable PDF in LiveCycle Designer and click View->XML Source.  This will give you a long XML list detailing all the fields in your form.

UPDATE 2008-11-13: I got an email from someone recently who was creating his editable form using LiveCycle Designer.  It turns out that if you use LiveCycle Designer to build your form, it won't work with XFDF.  If you want to use XFDF, you have to create the form using Acrobat.  LiveCycle Designer forms require that you use XDP (which I have never used).  You can read a bit more about the incompatibilities here.

To specify the values to go into an editable PDF, you create an XFDF file.  The basic format is this:

<?xml version="1.0" encoding="UTF-8"?>

<xfdf xmlns="http://ns.adobe.com/xfdf/" xml:space="preserve">

<f href="http://www.lukerymarz.com/files/CharacterSheet.pdf"/>

<fields>

  <field name="name">

    <value>null</value>

  </field>

  <field name="level">

    <value>1</value>

  </field>

  <field name="class">

    <value>Warlock</value>

  </field>

  <field name="race">

    <value>Tiefling</value>

  </field>

   ...

   ...

   ...

</fields>

</xfdf>

You put this in a text file with an xfdf extension and when you open it, it will reference the pdf in the <f> field and fill in the specified fields.  

So how do you get from the XML LiveCycle Designer gives you to the actual xfdf data.  Well, I didn't want to type a bunch of repetitive lines for each field in the form, so I wrote a little tool to take the LiveCycle xml and spit out ActionScript.  My tool opens the LiveCycle XML, parses each field, and provides a listing with the field type.  It then converts each field to ActionScript code that will append to a string in a my output function.  All I did then was copy the ActionScript code, fill in the specific piece of data for each field (for example, currentCharacter.name for the "name" field), and the output was done.  

There are two caveats I ran into, and the first has to do with spaces.  For each field, the name of that field in the LiveCycle XML has an underscore where a space is.  In the XFDF XML you generate, those underscores need to be replaced with an actual space, otherwise your field won't get filled in.  

The second caveat has to do with arrays.  For example, a part of the ActionScript code my tool generated looks like this:

xfdf += '<field name="class_feature.0"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.1"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.2"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.3"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.4"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.5"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.6"><value>' + Database.Data.currentCharacter. + '</value></field>';

This is an array of class features.  You'd think you could just go through the list, creating:

  <field name="class feature.0">

    <value>sample feature 1</value>

  </field>

  <field name="class feature.1">

    <value>sample feature 2</value>

  </field>

But that is incorrect.  Since this is an array, you have to represent it as one in the xfdf.  The actual output would look like this:

  <field name="class feature">

    <field name="0">

      <value>Eldritch Blast:</value>

    </field>

    <field name="1">

      <value>Edlritch Pact: Choose Fey Pact, Infernal Pact, or Star Pact.</value>

    </field>

    <field name="2">

      <value>Prime Shot: If you are closest to your target, +1 to attack rolls</value>

    </field>

  </field>

And that's it.  If you reference a pdf on a website, you can send only the xfdf to your user, and as long as they have access to your website, when they open the xfdf, Adobe will take care of the rest.  Pretty neat, once you get past the catches.

XML schemas, Excel, and getting what you want

In my character generator, there is a lot of data.  There's races, classes, skill, feats, and powers.  On top of that, they're not static lists.  Wizards of the Coast (and other people) are always adding and expanding on everything.  With that in mind, I knew I needed to have all that data extensible in my character generator.  XML is the obvious choice, especially since Flex is so good at parsing it.

But how was I to get the data in the PHB into XML in the easiest way possible?  Microsoft Excel and XML Schemas is the answer.  The basic idea is that you enter all your data into Microsoft Excel as a big list.  Then you tell Excel to export it as XML.  That XML is then fed into the Flex app.  

XML schemas tell Excel how to format the XML you export.  With an XML schema, you're defining the basic format of your XML (in XML, ironically).  There's an article here that gives a good way to create a simple Xml Schema Definition (XSD) using Excel (see step 6, specifically).  That will give you the schema, and then you can attach that to your Excel spreadsheet and have Excel export XML for you.

But there's a HUGE caveat.  Excel cannot handle (that is, export, import, deal with at all) XML with a list of lists.  This looks something like this:

<feats>

  <feat name="a">

    <prerequisites>

      <prerequisite name="x"/>

      <prerequisite name="y"/>

    </prerequisites>

  </feat>

  <feat name="b">

    <prerequisites>

      <prerequisite name="p"/>

      <prerequisite name="q"/>

    </prerequisites>

  </feat>

</feats>

We've got a list of feats, each containing a list of prerequisites.  The issue, specifically, is that we have many elements.  Now, if you think about this, it makes sense.  Excel allows you to easily edit a two dimensional array of data.  More than that and it gets complicated.

The solution I went with to get around this (because I require being able to add and remove from various lists of data, and it makes the XML easier to read) is to make use of the really good XML functionality in Flex.  My solution works like this:

1.  enter you data in Excel.  any time you have a list of things, enter them as a single cell and separate each "thing" with a comma.

2.  export to a simple xml format.

3.  feed the xml into a Flex app that takes the XML and converts any comma separated lists to a proper XML list.

A sample of this is here.  My flex app takes a list of feats I exported from Excel (shown on the left side), and then prints the proper XML for me to save to a file (shown on the right side).  There's now an extra step if I update my Excel spreadsheet, but it's better than having to edit XML all day long.

Unfortunately, I don't know of a way to get Flex to do magic things with XML schemas, so the dream app of being able to give one XML format and export another is still off my radar.  Also, you are effectively writing your XML schema in Flex code, so if you need to make a schema change, it's instead a Flex code change.  This is not necessarily bad.  I feel more comfortable making changes in code instead of in fancy XML schema editors.

Now, I've heard that Altova makes a really nice application that can handle lists of lists, but I haven't tried it (and the price is outside my budget).  Something for next time, I suppose.  For now, I've got a "good enough" solution for tricky XML, and it will be easy to update in the future if I need to.

Character Generator update

I've updated the Character Builder. I added a changelog that tracks the changes I've made. It's accessible from the About box (click the top right button in the app).

I made a fix for the healing surges not showing up, and I fixed a bug that was keeping humans from getting their bonus skill, feat, and power.

bugs in Generator

There seems to be a bug in the healing surges calculations on the character sheet. I'll take a look sometime this weekend. I'll also look at the character sheet and see if I can get, for example, the damage and attack workspaces to show blank instead of Zero so they can be filled in with a pencil.

D&D Character Generator

Ok. I've FINALLY finished a project I've been working on for the last couple months. I've been giving it about two 4 hour sessions a week, and [AT LAST!] I'm satisfied enough with it to post it.

It's a character generator for Dungeons and Dragons 4th edition. I got the books in July when they released the set, and I thought it would be fun to put together a character generator that made it a bit easier to parse the whole thing.

This bad boy is written in Flex, so you can run it from any web browser with Flash 9. The general idea is that you build your character through the flex interface, and when you're done, click the "View as PDF" button and out pops a nice PDF for you to print out. It DOES NOT replace the Player's Handbook in any way. It's more of an easing function on the whole ordeal.

Use the app here. You'll need Flash 9. Don't forget that you can drag and drop your stat numbers in the Standard Array and Roll entry types. I haven't yet figured out a good way to indicate that they're draggable, as the Flex "useHandCursor" flag doesn't see to work.

Here's a list of caveats / known flaws / things that aren't implemented:

- THIS DOES NOT REPLACE THE PLAYERS HANDBOOK.

- choosing of equipment is not implemented. You'll need to use the PHB after you print your PDF.

- Half-Elf: after creating the PDF, be sure to choose an at-will power from another class for the dilettante race feature.
- Ranger: After creating the PDF, choose Dungeoneering or Nature as a skill. This will affect your modifier for the skill by 5 points, so don't forget!
- There appears to be an error in the class listings in the Player's Handbook. When a skill is automatically given (listed as "free" in my UI), it is also listed as a choice. In my code, I automatically remove the free skills from the choice list.
- I have not implemented languages. choose them on the PDF.
- Human: you get +2 to an ability of your choice. Do this on the PDF.
- The PDF has some fields that automatically fill as Zero. If there are certain ones you think should not be filled at all, let me know and I'll fix them.
- certain class and race features require you to choose between two things. In cases where this is not implemented, it is listed on the character sheet as a "choose x or y" listing under the class/race features sections.

UI bugs:
- there's a minor glitch in the positioning of the strength stat when you drag a number on top of it (only seen in the Roll entry type).
- Powers have no descriptions. They're intended to not have power descriptions, but they're supposed to say "See Player's Handbook".

Note that I got the character sheet pdf I'm currently using from here.

This was a very fun little project. I enjoy writing apps in Flex. In working on this, I learned about XML schemas, XFDF (a pdf format), and some Perl tricks I'm currently using on my server. I'll make some posts soon about all that stuff. I wrote some helper Flex apps that I'll post as well.

On Other Projects

I haven't made a post in the last two weeks because I've been working on another top secret project. I'm guessing it will take another two weeks of my time, and then I'll start posting some more stuff here. 'Til then...

A Custom MFC Control to Display Guitar Chords

Recently, I've tasked myself with learning a bit more about custom MFC controls. For a hands on project, I chose to create a custom MFC control for displaying guitar chords. The basic steps of creating custom MFC controls are this:

1. Create a class for your control, and inherit from a control similar to what you want to make. If nothing is similar, inherit from CStatic.
2. Override the OnPaint function to do your custom drawing.

Everything else is just MFC, although you have to be careful about redrawing. If you're constantly redrawing, you could get a bit of flicker.

To show your control in a dialog, you have do the following:

1. Add a Custom Control to the dialog.
2. Set the "Class" property of the custom control to the name of your custom class.
3. Make sure you register your custom class using the AfxRegisterClass() function. An example of this is in ChordDisplay.cpp.

In making this control, I learned something very important. If you can draw something with the CDC drawing functions, then do it that way. Bitmaps are easy enough to blit onto the Device Context, but if you need transparency or any fancy stuff, you're gonna be spending a good bit of time figuring it out (or searching for code that does what you want). I used 100% CDC drawing functions for my guitar control.

Here's a screenshot:


And, as always, my source code is here. The control can be told to draw a chord by filling a struct with some data. See ChordDatabase.cpp for more how to do that. An expansion of this would be to get a full database of chords that could be loaded from an xml file. I've only got a few chords here because it's just a sample to show the control.