GpiPointArc
This function creates an arc, using the current arc parameters, through three points, starting at the current position.
Syntax
GpiPointArc(hps, pptl2)
Parameters
- hps (HPS) - input
- Presentation-space handle.
- pptl2 (PPOINTL) - input
- Intermediate and end points.
- Pointer to an array containing the intermediate and end points.
Return Value
- lHits (LONG) - returns
- Correlation and error indicators.
- GPI_OK
- Successful
- GPI_HITS
- Correlate hits
- GPI_ERROR
- Error.
Remarks
The first element of the pptl2 array defines an intermediate point along the arc, and the second element identifies the end point of the arc. Upon completion, current position is set to the end point of the arc.
Errors
Possible returns from WinGetLastError:
- PMERR_INV_HPS (0x207F)
- An invalid presentation-space handle was specified.
- PMERR_PS_BUSY (0x20F4)
- An attempt was made to access the presentation space from more than one thread simultaneously.
- PMERR_INV_COORDINATE (0x205B)
- An invalid coordinate value was specified.
- PMERR_INV_NESTED_FIGURES (0x20A8)
- Nested figures have been detected within a path definition.
Graphic Elements and Orders
- Element Type
- OCODE_GCARC
Order: Arc at Current Position
Example Code
#define INCL_GPIPRIMITIVES /* Or use INCL_GPI, INCL_PM, */ #include <os2.h> HPS hps; /* Presentation-space handle. */ PPOINTL pptl2; /* Intermediate and end points. */ LONG lHits; /* Correlation and error indicators. */ lHits = GpiPointArc(hps, pptl2);
This example uses the GpiPointArc function to draw an arc through the three points of a triangle. The GpiPolyLine function then draws the triangle.
#define INCL_GPIPRIMITIVES /* GPI primitive functions */
#include <os2.h>
HPS hps; /* presentation space handle */
POINTL ptlTriangle[] = { 0, 0, 100, 100, 200, 0 };
GpiMove(hps, &ptlTriangle[0]); /* moves to start point (0, 0)*/
GpiPointArc(hps, &ptlTriangle[1]);/* draws the arc */
GpiMove(hps, &ptlTriangle[0]); /* moves to start point (0, 0)*/
/* draws the triangle */
GpiPolyLine(hps, 3L, &ptlTriangle[1]);