Definition: Transforms are the modules we use in RPM to pre-process your print job data.
- text search and replace
- convert from one form to another
- extract pages from the print job
- insert a file or a string of bytes
Pre-processing happens before we print, archive, email, etc.
Each transform has an input and an output, and most have some setup as well. For instance, there are no setup options for removing null characters from a data stream, but there are over a dozen for converting to PDF.
How transforms work
The important thing to know about transforms is that they are run in order. However you have set up the order in your queue, that's how RPM does it. Note that this is a change from version 5.0 prior to 5.1, when we moved the insert transforms to be the beginning and the append transforms to the end. We changed that because it was too difficult to do useful things such as removing a sequence of bytes and inserting another sequence (more than you could do with the string translator, and something you wanted to do only once not throughout the print job).
Here is the processing scheme:
- RPM reads the print job data file
- It passes data in chunks to the input of the first transform
- It takes the output of that transform and passes it to the input of the next transform
- RPM repeats this process until the entire print job has been read and passed to each of the transforms
The final output is written to a temporary file. Then this file is given to each of the actions.
Note that RPM never overwrites the original print job. That is kept until the job is removed.
Click on the category to go directly to the list of transforms in that category.
|Editing the data or changing to another data type
|Eliminating data by number or by search
|Insert / append
|Insert data ahead of your print job, or append
|Convert to an intermediary format, or run your own program
|Convert from the intermediary format to PDF, PCL, HTML