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cmd_drawparm |
Function (ROM Call 0x343) |
Executes TI-Basic 'DrawParm' command.
cmd_drawparm displays the Graph Screen and draws a parametric graph, using
"t" as the independent variable. This function expects one of the following
eight layouts on the expression stack:
The parameter ExprList should point to the tag of the last item.
x_expr and y_expr are the expressions for "x(t)" and "y(t)",
which define the curve. tmin, tmax and tstep are
floating point items which determine the starting value, the ending
value, and the increment of the independent variable "t" which will be used
for drawing. For example, to draw the curve defined by x=cos(t)
and y=sin(t)
where t varies from 0 to 2*pi in steps of 0.1, you
can use the following code fragment:
push_Float (0.1);
push_Float (2. * PI);
push_Float (0);
push_parse_text ("cos(t)");
push_parse_text ("sin(t)");
cmd_drawparm (top_estack);
If the current graphing mode is not parametric, only the first layout is
valid. Otherwise, the omitted expressions will be picked from the current
settings of the "tmin", "tmax", and "tstep" system variables, which can be
set using the "Window Editor" application.
Uses: ER_catch, ER_success, ER_throwVar, next_expression_index, push_expression, push_Float, push_quantum, top_estack, gr_active, StepCk, OSCheckBreak, is_transfinite, CptIndep, ForceFloat, GraphActivate, GrLineFlt, QSkipGraphErr
See also: cmd_drawpol, cmd_drawfunc