VAXstation Native Graphics Procedures

This document, "VAXstation Native Graphics Procedures" (June 1984), describes five core native graphics procedures within the VAXstation Display Management Library (VSTA). These procedures provide direct access to the VAXstation Display System's hardware and firmware for fundamental output operations:

1. Copying an Area (VSTA$COPY_AREA): Moves a source image to a destination, allowing for source masks, offsets, and mapping functions.
2. Drawing a Curve (VSTA$DRAW_CURVE): Paints a source image along a sequence of points, forming straight or curved lines, with options for patterns and secondary sources.
3. Printing Text (VSTA$PRINT_TEXT): Outputs character strings using fonts, allowing for text formatting, control commands, and padding.
4. Filling an Area (VSTA$FILL_AREA): Fills one or more closed shapes with a constant color or halftone.
5. Flooding an Area (VSTA$FLOOD_AREA): Floods bounded areas of a destination image with a color or halftone, determining the area based on a seed point and a boundary map.

The document details how the display processor operates using a source, a destination, and an optional map to modify pixels. These procedures work with virtual displays (referenced by channel numbers) and program-controlled bitmaps (referenced by bitmap descriptors), rather than directly modifying the frame buffer.

Intended for graphics application programmers, the manual provides detailed parameters for each procedure, covering aspects like source/destination types, offsets, masks, map functions, clipping rectangles, and specific elements like paths or fonts. It also outlines VAX/VMS I/O synchronization mechanisms.

Key Caution: The document emphasizes that this interface is newly developed and its specifications (defined in loadable firmware) may change in future releases. Users are advised to limit and isolate their use of these native graphics procedures to minimize future migration efforts.