WORD FAR PASCAL CBFilterGraphics(LPBYTE lpdv, LPSTR lpBuf, WORD wLen)
Alters the format of raster graphic data before sending the data to the output device. This is useful if a specific device addresses pins on the print head in an unusual way (such as older Okidata dot matrix printers), or if the device requires raster graphics data in an unusual format (such as the "24 raster bits in 4 bytes" format common among Toshiba dot matrix printers).
·Returns the number of bytes of processed raster data.The number of bytes may be the same as wLen, but not necessarily.
lpdv
Address of private data used by RasDD. The CBFilterGraphics function should not change this data.
lpBuf
Address of a buffer that holds raster graphic data.
wLen
Size, in bytes, of the buffer specified by lpBuf.
After CBFilterGraphics has finished changing the raster graphic data, it should call the WriteSpoolBuf function to pass the data to RasDD.
To implement this function, you must:
1.Set the RES_BO_OEMGRXFILTER bit flag in fBlockOut dialog box that is accessible through the RESOLUTION dialog box.
2.Export the CBFilterGraphics function as ordinal 300 in the EXPORTS section of the module definition (.DEF) file for your minidriver.
3.Import the WriteSpoolBuf function as ordinal 300 in the IMPORTS section of the module definition (.DEF) file for your minidriver.
4.In the drvname.C file for your minidriver, add the function to perform the changes upon the raster data needed by the device. Define this function as described under “WriteSpoolBuf.”