Grclipline - Texas Instruments TI-89 Developer's Manual

Appendix A: System Routines — Graphing

GrClipLine

Declaration: BYTE GrClipLine (BCD16 x1 , BCD16 y1 , BCD16 x2 , BCD16 y2 ,
BCD16 * nx1 , BCD16 * ny1 , BCD16 * nx2 , BCD16 * ny2 ,
GR_WIN_VARS * grPtr )
Category(ies): Graphing
Description: Clip a line to the given graph window.
Inputs: x1, y1, x2, y2 — End-points of line to clip.
grPtr
Outputs: Return 1 if output line ( nx1 , ny1 , nx2 , ny2 ) is valid and x2 , y2 was on
screen.
Return a value > 1 if output line was valid and x2 , y2 was off screen.
Return 0 if the line is outside the specified window region.
nx1, ny1, nx2, ny2 — End-points of the line after it has been clipped to
Assumptions: Assumes an x, y coordinate system, even in 3D mode so should not be
used for 3D graphing.
Side Effects: None
Availability: All versions of the TI-89 / TI-92 Plus.
TI-89 / TI-92 Plus
Differences: None
See Also: GrLineFlt
TI-89 / TI-92 Plus Developer Guide
— Graph window structure (gr_active, gr_other) defining
window to clip to.
the given graph window.
(continued)
Not for Distribution
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Beta Version January 26, 2001