How to Use the Command 'grap' (with Examples)
Grap is a powerful charting preprocessor used with the groff (GNU Troff) document formatting system, which aids in generating high-quality textual and graphical representations in documents. It primarily processes files containing graph descriptions and translates them into a format compatible with groff using pic, a language for describing diagrams. This tool is essential for users who require precise and customizable plotting capabilities in their text documents.
Use case 1: Process a grap File and Save the Output for Future Processing
Code:
grap path/to/input.grap > path/to/output.pic
Motivation:
In many document preparation or publishing workflows, you may need to first process data independently before incorporating it into a comprehensive document. Processing a grap file and saving the output for further manipulation allows users to separate the chart generation phase from the document generation phase. This approach provides flexibility, enabling you to review, refine, or include additional processing steps before integrating charts into the final document.
Explanation:
grap: Invokes the grap command-line tool to start processing.path/to/input.grap: Specifies the path to the input file that contains the grap script, which describes a graph or chart.>: Redirects the standard output (which would typically be to the console) to a file.path/to/output.pic: Indicates the target file where the processed output from the grap command, in pic format, is saved. This file can later be fed into other utilities like pic and groff for actual rendering.
Example Output:
Assuming the input file describes a simple bar chart, the output is a .pic file containing pic commands that describe the chart’s graphical elements. This file serves as an intermediary stage where you have a textual representation of the graphical elements ready for further processing.
Use case 2: Typeset a grap File to PDF Using the [me] Macro Package
Code:
grap path/to/input.grap | pic -T pdf | groff -me -T pdf > path/to/output.pdf
Motivation:
This use case addresses the workflow for generating a complete, typeset PDF document directly from a grap file. By integrating grap with pic and groff, users can leverage the full power of these utilities to produce polished documents that include sophisticated charts and typesetting. This integrated approach is invaluable in scenarios where precision and quality of both text and graphics are critical, such as academic publications or professional presentations.
Explanation:
grap: Initiates the processing of the grap file into pic format.path/to/input.grap: Specifies the grap script containing the graph description.|: Pipes the output from one command to be used as input to the next, facilitating a seamless workflow from grap to pic to groff.pic -T pdf: Processes the pic-format data to a form suitable for PDF output.-T pdf: Specifies that the target output format is PDF, ensuring compatibility in the final document format.
groff -me -T pdf: Typesets the document using groff with the [me] macro package, outputting to a PDF file.-me: Applies the [me] macro package, which provides numerous features for document formatting such as headers, footers, and structured text.-T pdf: Indicates that the output should be in PDF format, ensuring the document is produced with all the precision and typographical features supported by groff.
>: Redirects the final output, which is a PDF document, to the specified file path.path/to/output.pdf: Specifies the location where the resultant PDF document will be saved, ready for viewing or distribution.
Example Output:
The result is a fully-formed PDF document that incorporates the graphical data processed by grap, formatted text provided by groff, and structured using the [me] macro package. This PDF document could, for instance, feature a detailed chart embedded within a comprehensively formatted research article, demonstrating the effectiveness of grap in conjunction with other tools.
Conclusion:
Using grap in tandem with pic and groff provides powerful capabilities for generating and typesetting documents that contain detailed graphs and charts. This approach aligns with workflows that demand high-quality outputs with intricate format control, making it an indispensable process for technical writing, academic reports, and professional documentation. Through this article, you can now understand and utilize grap for efficient graph processing, intermediate storage, and typesetting into polished PDF documents.
