Back to Volume
Paper: Public Access Programming: Opening The Black Box That Hides Internal Data
Volume: 61, Astronomical Data Analysis Software and Systems III
Page: 507
Authors: Mandel, E.; Swick, R.
Abstract: Data analysis and display programs typically are written as ``black boxes'' with only a limited specification of input and output data. Often additional data are associated with the analysis or with the presentation that are internal to the program and therefore are not available for direct access by external means. As analysis and visualization tools become more sophisticated, there are important cases where it is desirable to read or even modify a program's ``internal'' data through external means. The SAOimage image display program is a good example: over the years there have been numerous requests by users and developers to be able to access SAOimage's image data, region information, colormaps, etc . In this paper we describe a simple and effective use of the X Toolkit (Xt) selection mechanism by which data in an Xt program can be tagged with string identifiers and then accessed externally by other programs. We will discuss our design goals, the technical challenges we faced -- including extensions to the Xt selection implementation -- and the user interface and application programming interface that we developed to meet these challenges. We also will discuss the important implications that our scheme has for programs such as SAOimage.
Back to Volume