GreGetClipBox: Difference between revisions

Latest revision as of 12:20, 20 January 2020

GreGetClipBox determines the dimensions of the tightest rectangle around the DC region in world coordinates. The DC region is defined as the intersection of the visible region, clip region, viewing limits, graphics field, and clip path. The bounding rectangle is inclusive. Points on its boundary are deemed to be inside it. If COM_TRANSFORM is not set, the rectangle points are returned in screen coordinates.

This function can be hooked by the presentation driver.

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

Syntax

GreGetClipBox(hdc, prclRect, pInstance, lFunction)

Parameters

hdc (HDC) - input: Device context handle.
prclRect (PRECTL) - input: Pointer to rectangle in world or screen coordinates.
pInstance (PVOID) - input: Pointer to instance data.
lFunction (ULONG) - input: High-order WORD=flags; low-order WORD=NGreGetClipBox.

Returns

rc (LONG) - returns

Return codes.

This function returns an integer (lComplexity) indicating the complexity of the resultant "clipping region", which is defined as the intersection of all clipping (that is, the clip path, viewing limits, graphics field, clip region, and visible region).

RGN_ERROR Error
RGN_NULL Null region
RGN_RECT Rectangular region
RGN_COMPLEX Complex region (more than 1 rectangle)

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_COORDINATE_OVERFLOW
PMERR_DEV_FUNC_NOT_INSTALLED
PMERR_HDC_BUSY
PMERR_INV_COORD_SPACE
PMERR_INV_HDC
PMERR_INV_LENGTH_OR_COUNT
PMERR_INV_RECT

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

@@ Line 1: / Line 1: @@
 GreGetClipBox determines the dimensions of the tightest rectangle around the DC region in world coordinates. The DC region is defined as the intersection of the visible region, clip region, viewing limits, graphics field, and clip path. The bounding rectangle is inclusive. Points on its boundary are deemed to be inside it. If COM_TRANSFORM is not set, the rectangle points are returned in screen coordinates.
 This function can be hooked by the presentation driver.
 ;Simulation support: This function is simulated by a handling routine in the graphics engine.
 == Syntax ==
-  GreGetClipBox(hdc, prclRect, pInstance, lFunction);
+  GreGetClipBox(hdc, prclRect, pInstance, lFunction)
 == Parameters ==
-;hdc (HDC) - input
+;hdc (HDC) - input:Device context handle.
-:Device context handle.
+;prclRect ([[PRECTL]]) - input:Pointer to rectangle in world or screen coordinates.
+;pInstance (PVOID) - input:Pointer to instance data.
-;prclRect (PRECTL) - input
+;lFunction (ULONG) - input:High-order WORD=flags; low-order WORD=NGreGetClipBox.
-:Pointer to rectangle in world or screen coordinates.
-:RECTL structure:
-::xLeft Minimum x-coordinate of rectangle
-::yBottom Minimum y-coordinate
-::xRight Maximum x-coordinate of rectangle
-::yTop Maximum y-coordinate
-:The prclRect parameter is a NULL rectangle when the value of xRight is less than xLeft, and yTop is less than yBottom.
-;pInstance (PVOID) - input
-:Pointer to instance data.
-;lFunction (ULONG) - input
-:High-order WORD=flags; low-order WORD=NGreGetClipBox.
 == Returns ==
-;rc (LONG) - returns
+;rc (LONG) - returns:Return codes.
-:Return codes.
+:This function returns an integer (lComplexity) indicating the complexity of the resultant "clipping region", which is defined as the intersection of all clipping (that is, the clip path, viewing limits, graphics field, clip region, and visible region).
+:*RGN_ERROR Error
-:This function returns an integer (lComplexity) indicating the complexity of the resultant "clipping region", which is defined as the intersection of all clipping (that is, the clip path, viewing limits, graphics field, clip region, and visible region).
+:*RGN_NULL Null region
+:*RGN_RECT Rectangular region
-:*RGN_ERROR Error
+:*RGN_COMPLEX Complex region (more than 1 rectangle)
-:*RGN_NULL Null region
+: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:
-:*RGN_RECT Rectangular region
+:*PMERR_COORDINATE_OVERFLOW
-:*RGN_COMPLEX Complex region (more than 1 rectangle)
+:*PMERR_DEV_FUNC_NOT_INSTALLED
+:*PMERR_HDC_BUSY
-: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_INV_COORD_SPACE
+:*PMERR_INV_HDC
-:*PMERR_COORDINATE_OVERFLOW
+:*PMERR_INV_LENGTH_OR_COUNT
-:*PMERR_DEV_FUNC_NOT_INSTALLED
+:*PMERR_INV_RECT
-:*PMERR_HDC_BUSY
+:Refer to the "Error Explanations" section in the ''Presentation Manager Programming Reference'' for further explanation.
-:*PMERR_INV_COORD_SPACE
-:*PMERR_INV_HDC
-:*PMERR_INV_LENGTH_OR_COUNT
-:*PMERR_INV_RECT
-:Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.
-== Sample ==
-<pre>
-#define INCL_GRE_CLIP
-#include <os2.h>
-HDC       hdc;        /*  Device context handle. */
-PRECTL    prclRect;   /*  Pointer to rectangle in world or screen coordinates. */
-PVOID     pInstance;  /*  Pointer to instance data. */
-ULONG     lFunction;  /*  High-order WORD=flags; low-order WORD=NGreGetClipBox. */
-LONG      rc;         /*  Return codes. */
-rc = GreGetClipBox(hdc, prclRect, pInstance,
-       lFunction);
-</pre>
 [[Category:Gre]]