9.4 The functions in libplot: A detailed listing

In the current release of GNU libplot, any Plotter supports 97 distinct operations. A language binding for libplot necessarily includes 97 functions that correspond to these operations. In the C binding, these 97 functions belong to the C API (application programming interface). The name of each function begins with the prefix "pl_" and ends with the suffix "_r". In the C++ binding, the 97 functions are implemented as public members of the Plotter class. No prefix or suffix is used.

A language binding may also include functions for creating, selecting, and deleting Plotters. For example, the C binding includes the additional functions pl_newpl_r and pl_deletepl_r. See The C API.

The 97 functions that operate on a specified Plotter are divided into the four sets tabulated below.

Many functions come in two versions: integer and double precision floating point. Internally, libplot uses double precision floating point. The integer versions are provided for backward compatibility. If there are two versions of a function, the name of the floating point version begins with the letter ‘f’.

Many functions come in both absolute and relative versions, also. The latter use relative coordinates (i.e., coordinates relative to the current position of the graphics cursor), and their names end in ‘rel’.

Currently, only a few of the 97 functions have meaningful return values.

• Control Functions: Functions that open, initialize or close a Plotter
• Drawing Functions: Functions that draw objects
• Attribute Functions: Functions that affect drawing attributes
• Mapping Functions: Functions affecting the user -> device coordinate map