Gr_Active, Gr_Other; Graphing - Texas Instruments TI-89 Developer's Manual

Appendix B: Global Variables — Graphing

gr_active, gr_other

Declaration: GR_WIN_VARS * gr_active
GR_WIN_VARS * gr_other
Category:

Graphing

Description: Pointers to GR_WIN_VARS structs that contain most of the data used by
the Graph application and other graph related apps. gr_active points to the
GR_WIN_VARS struct containing all the information for the active graph.
gr_other points to the information for the second graph in two graph mode.
As the calculator user switches between the two windows in two graph
mode, the pointers in gr_active and gr_other are swapped so that
gr_active is always referring to the active graph. The members of a
GR_WIN_VARS struct are shown below along with an explanation of the
contents of each. None of the data should be changed directly by an app or
ASM but can be accessed for use. System routines may be called to
change many items (for example, VarStore may be used to change the
graph system variables), but some data is for internal use only and should
only be changed by the appropriate system app.
Struct Members and their Contents:
BCD16 flt_xcursor
BCD16 flt_ycursor
BCD16 flt_zcursor
BCD16 flt_tcursor
BCD16 flt_rcursor
BCD16 flt_thetacursor
BCD16 flt_ncursor
BCD16 recip_delx
BCD16 recip_dely
BCD16 orgxmin
BCD16 orgxmax
BCD16 panshift
TI-89 / TI-92 Plus Developer Guide
— Graph system variable xc.
— Graph system variable yc.
— Graph system variable zc.
— Graph system variable tc.
— Graph system variable rc.
— Graph system variable c.
— Graph system variable nc.
— 1/ x rounded to 6 significant digits.
— 1/ y rounded to 6 significant digits.
— Original xmin, before any panning has
occurred.
— Original xmax, before any panning has
occurred.
— Number of columns panned from
orgxmin.
(continued)
Not for Distribution
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Beta Version January 26, 2001