GreQueryColorData
GreQueryColorData stores an array of information about the currently available logical color table and device colors at the location addressed by pArray.
This function must be supported by the presentation driver. GreQueryColorData is called by GpiQueryColorData in response to an application's request for the currently selected color table data for the device context. This function can be handled by bit-map simulation.
- Simulation support
- None. This function is mandatory for all drivers.
Syntax
GreQueryColorData(hdc, cArray, pArray, pInstance, lFunction)
Parameters
- hdc (HDC) - input
- Device context handle.
- cArray (LONG) - input
- Number of elements supplied in Array.
- pArray (PLONG) - input
- Pointer to Array.
- On return, this array contains:
- lArray[QCD_LCT_FORMAT]
- Format of loaded color table (if any):
- LCOLF_DEFAULT
- Default color table is in force.
- LCOLF_INDRGB
- Color table loaded, which provides translation from index to RGB.
- LCOLF_RGB
- Color index = RGB.
- LCOLF_PALETTE
- DC has a palette selected.
- lArray[QCD_LCT_LOINDEX]
- Smallest color index loaded (always 0).
- lArray[QCD_LCT_HIINDEX]
- Largest color index loaded (never less than 15).
- Information is only returned for the number of elements supplied. Any extra elements supplied must be zeroed by the handling routine.
- pInstance (PVOID) - input
- Pointer to instance data.
- lFunction (ULONG) - input
- High-order WORD=flags; low-order WORD=NGreQueryColorData.
Returns
- rc (BOOL) - returns
- Return Code.
- On completion, the handling routine must return a BOOLEAN value to indicate success or an error.
- TRUE Successful
- FALSE 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_DEV_FUNC_NOT_INSTALLED
- PMERR_INV_HDC
- PMERR_INV_LENGTH_OR_COUNT
Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.
Sample
#define INCL_GRE_COLORTABLE #include <os2.h> HDC hdc; /* Device context handle. */ LONG cArray; /* Number of elements supplied in Array. */ PLONG pArray; /* Pointer to Array. */ PVOID pInstance; /* Pointer to instance data. */ ULONG lFunction; /* High-order WORD=flags; low-order WORD=NGreQueryColorData. */ BOOL rc; /* Return Code. */ rc = GreQueryColorData(hdc, cArray, pArray, pInstance, lFunction);
Remarks
When the current table is the default logical color table, presentation drivers that support less than 16 colors return the device colors to which the 16 colors from 0 (CLR_BACKGROUND) through 15 (CLR_PALEGRAY) have been mapped.