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From: rws@EXPO.LCS.MIT.EDU (Bob Scheifler)
Newsgroups: comp.windows.x
Subject: Re: XDrawRectangle and stipples in GC.
Message-ID: <9005291251.AA11790@expire.lcs.mit.edu>
Date: 29 May 90 12:51:18 GMT
Article-I.D.: expire.9005291251.AA11790
References: <351@echbull.bull.fr>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
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    So, what are the members of the GC which are meaningfull to XDrawRectangle
    as far as the line style is concerned ?

Such questions are answered in the standard Xlib and Protocol manuals.  From
the MIT Xlib manual, section 6.3.3, on XDrawRectangle and XDrawRectangles:

Both functions use these GC components: 
function, plane-mask, line-width, line-style, join-style, fill-style, 
subwindow-mode, clip-x-origin, clip-y-origin, and clip-mask.
They also use these GC mode-dependent components: 
foreground, background, tile, stipple, tile-stipple-x-origin, 
tile-stipple-y-origin, dash-offset, and dash-list.

This information also appears in O'Reilly Volume 2 (at least the new
addition I have).

    Another question by the way, was is the diffrence between a thin line
    (gc.line_width == 0) and a wide line (gc.line_width == 1) ?

What pixels they affect.  The semantics of thin lines are not contrained
very much by the protocol, but there are specific semantics for wide lines.
(We've seen several product servers that drew width 1 lines the same as
width 0, but they're broken.)  See the MIT Xlib manual, section 5.3
(pages 98 and 99 in the Digital Press book).  Or see O'Reilly Volume 1
section 5.5.1 (at least in the edition I have).