GreEndArea

Simulation support: This function is simulated by a handling routine in the graphics engine.

GreEndArea indicates the end of a set of drawing functions that define the boundary of an area. If the final (X,Y) position is not the same as the starting position of the last figure in the area, the handling routine must close the figure by drawing a line from the current position to the start of the final figure. Upon completion, the current (X,Y) position is the last (X,Y) position specified in the area boundary unless a closure line was drawn. In this case, the start of the last figure in the area definition becomes the current (X,Y) position.

The area fill can be built up in memory or on devices that have hardware assistance for area fill in the device. For convex figures, performance gain can be increased by recording the start and end pel positions across each scan line. Whatever algorithm is used to fill the area, the interior fill must be identical in each occurrence. If it is not identical, bit-map operations can fail to join correctly when copied to the screen.

This function can be hooked by the presentation driver.

Note: If the flOptions bit BA_EXCL (specified on the GreBeginArea call) was set on and the driver is calling the engine with fill path for simulation, the fill path flOptions parameter must have the FPATH_EXCL bit set.

Syntax

rc = GreEndArea(hdc, flCancel, pInstance, lFunction);

Parameters

hdc (HDC) - input: Device context handle.

flCancel (ULONG) - input: The value of this flag specifies whether this call cancels the area definition:

EA_DRAW Draw the area. This flag is the default.
EA_CANCEL Cancel the area definition. Otherwise, draw the area.

Note: When GreBeginArea is not called and EA_CANCEL is set, GreEndArea is valid but has no effect, thus allowing the handling routine to reset an area bracket to a known state when it has no knowledge of the actual current state.

pInstance (PVOID) - input: Pointer to instance data.

lFunction (ULONG) - input: High-order WORD=flags; low-order WORD=NGreEndArea.

Return Code

rc (LONG) - returns: Return codes.

This function returns an integer (cHits) indicating, where appropriate, whether correlation hits were detected:

GPI_OK Successful
GPI_HITS Successful with correlation hit (returned by display drivers when the correlation flag is ON, and a hit is detected) on any part of the interior, regardless of mix
GPI_ERROR Error

Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:

PMERR_BASE_ERROR
PMERR_BITMAP_NOT_SELECTED
PMERR_COORDINATE_OVERFLOW
PMERR_DEV_FUNC_NOT_INSTALLED
PMERR_EXCEEDS_MAX_SEG_LENGTH
PMERR_HDC_BUSY
PMERR_HRGN_BUSY
PMERR_HUGE_FONTS_NOT_SUPPORTED
PMERR_INSUFFICIENT_MEMORY
PMERR_INV_AREA_CONTROL
PMERR_INV_BACKGROUND_COL_ATTR
PMERR_INV_BACKGROUND_MIX_ATTR
PMERR_INV_CHAR_DIRECTION_ATTR
PMERR_INV_CHAR_MODE_ATTR
PMERR_INV_CODEPAGE
PMERR_INV_COLOR_ATTR
PMERR_INV_COLOR_DATA
PMERR_INV_COLOR_INDEX
PMERR_INV_COORD_SPACE
PMERR_INV_COORDINATE
PMERR_INV_HDC
PMERR_INV_HRGN
PMERR_INV_IN_AREA
PMERR_INV_IN_PATH
PMERR_INV_LENGTH_OR_COUNT
PMERR_INV_LINE_TYPE_ATTR
PMERR_INV_MIX_ATTR
PMERR_INV_PATTERN_REF_PT_ATTR
PMERR_INV_PATTERN_SET_ATTR
PMERR_INV_PATTERN_SET_FONT
PMERR_INV_PICK_APERTURE_POSN
PMERR_INV_RECT
PMERR_INV_REGION_CONTROL
PMERR_NOT_IN_AREA
PMERR_PATH_LIMIT_EXCEEDED
PMERR_REGION_IS_CLIP_REGION.

Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.

Example Code

#define INCL_GRE_PATHS
#include <os2.h>

HDC      hdc;        /*  Device context handle. */
ULONG    flCancel;
PVOID    pInstance;  /*  Pointer to instance data. */
ULONG    lFunction;  /*  High-order WORD=flags; low-order WORD=NGreEndArea. */
LONG     rc;         /*  Return codes. */

rc = GreEndArea(hdc, flCancel, pInstance, lFunction);