Principles of interactive computer graphics (2nd ed.)
Principles of interactive computer graphics (2nd ed.)
ACM SIGGRAPH Computer Graphics
SIGGRAPH '75 Proceedings of the 2nd annual conference on Computer graphics and interactive techniques
Aplanar, two-dimensional geometry in APL
ACM SIGAPL APL Quote Quad
A segmented transformed display file for APL GRAPH-II
APL '75 Proceedings of seventh international conference on APL
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A context dependent graphics system for APL users is described. The system is divided into environmental and functional routines. The environmental routines set the current graphics environment, such as the units of reference on the display device, window definitions, rotation and scale parameters, etc. Functional routines perform actions on the display, for instance drawing a line through a series of points, according to the current environmental definitions. The system is implemented in such a manner as to allow the various graphic commands to be simply understood at a glance. For example, one can type: DRAW HOUSE AT 1 3 The environment for this operation could have been specified by writing: USING INCHES SET ROTATION TO 45, SCALE TO 3 .5 This would cause the graphic object HOUSE to be drawn in inches, at a rotation of 45° with an X-scale factor of 3 and a Y-scale factor of .5. The use of context dependent graphics allows the user to program in a more natural manner. Objects may be defined in one context and then utilized in many others. Context dependency should be particularly attractive to the APL user, who thereby has available the means for facile interactive manipulation of graphic entities.