Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!think.com!snorkelwacker.mit.edu!bloom-beacon!dont-send-mail-to-path-lines
From: Nagesh_Pabbisetty.Henr801C@xerox.COM
Newsgroups: comp.windows.x
Subject: Re: white and black colors in the X server
Message-ID: <".5-Jun-91.14:22:03.EDT".*.Nagesh_Pabbisetty.Henr801C@Xerox.com>
Date: 5 Jun 91 18:22:03 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 56


Bob & keith,

Thanks for responding to my query. Sorry for taking so much of your time, but I
am a little confused about what you said in your message:

On the Sun, 0 is white and 1 is black (set in sunBW2.c). But you mentioned the
following in your message:
	"White" in the mfb code simply means "1" not white,
	"Black" simply means "0" not black.
Does the "ddx/sun" portion of the server have a different notion of white and
black than the "ddx/mfb" portion of the server? Doesn't seem probable!


In your message, you said: "Don't just read the function names, read and
understand the code". I am unable to find the segment of code which makes
mfbTEGlyphBltWhite paint 1's if white is defined as 1 in sunBW2.c, and makes it
paint 0's if white is so defined there... Any help you can provide will be
appreciated.


Also, on the Sun, mfb.h defines the following
	#define RROP_BLACK	GXclear
	#define RROP_WHITE	GXset

	#define fnCLEAR(src, dst)	(0)
	#define fnSET(src, dst)		(~0)
Doesn't GXclear/fnCLEAR means setting to 0? If it does, then how can RROP_BLACK
be synonymous with GXclear on a Sun?



mfbPaintWindow procedure in mfbpntwin.c has the following segment of code:
	case BackgroundPixel:
	    if (pWin->background.pixel)
		mfbSolidWhiteArea(pWin, REGION_NUM_RECTS(pRegion),
				  REGION_RECTS(pRegion), GXset, NullPixmap);
	    else
		mfbSolidBlackArea(pWin, REGION_NUM_RECTS(pRegion),
				  REGION_RECTS(pRegion), GXclear, NullPixmap);
	    return;
On the Sun, if 1 is Black, and 0 is white, then how come WhiteArea is called
when the background pixel is not equal to 0...



Overall Question:
	Where, if any, is the magic segment of code which communicates
	the values of black and white from sunBW2.c to the mfb routines
	so that the correct drawing effect with 0's and 1's is achieved
	(irrespective of the name of the functions)


Thanks...

Nagesh Pabbisetty