77 lines
2.3 KiB
Plaintext
77 lines
2.3 KiB
Plaintext
'\"! eqn | mmdoc
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'\"macro stdmacro
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.ds Vn Version 1.2
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.ds Dt 6 March 1997
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.ds Re Release 1.2.0
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.ds Dp Feb 16 02:57
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.ds Dm Feb 10 17:2
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.ds Xs 55673 5 xusexfont.gl
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.TH GLXUSEXFONT 3
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.SH NAME
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glXUseXFont
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\- create bitmap display lists from an X font
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.SH C SPECIFICATION
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void \f3glXUseXFont\fP(
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Font \fIfont\fP,
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.nf
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.ta \w'\f3void \fPglXUseXFont( 'u
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int \fIfirst\fP,
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int \fIcount\fP,
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int \fIlistBase\fP )
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.fi
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.EQ
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delim $$
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.EN
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.SH PARAMETERS
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.TP \w'\fIlistBase\fP\ \ 'u
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\f2font\fP
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Specifies the font from which character glyphs are to be taken.
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.TP
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\f2first\fP
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Specifies the index of the first glyph to be taken.
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.TP
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\f2count\fP
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Specifies the number of glyphs to be taken.
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.TP
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\f2listBase\fP
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Specifies the index of the first display list to be generated.
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.SH DESCRIPTION
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\f3glXUseXFont\fP generates \f2count\fP display lists,
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named \f2listBase\fP through \f2listBase\fP\&+\&\f2count\fP\&\-\&1,
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each containing a single \f3glBitmap\fP command.
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The parameters of the \f3glBitmap\fP command of display list \f2listBase\fP\&+\f2i\fP
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are derived from glyph \f2first\fP\&+\f2i\fP.
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Bitmap parameters \f2xorig, yorig, width,\fP and \f2height\fP
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are computed from font metrics as
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\f2descent\-1, \-lbearing,\fP
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\f2rbearing\-lbearing,\fP and \f2ascent+descent\fP, respectively.
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\f2xmove\fP is taken from the glyph's \f2width\fP metric,
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and \f2ymove\fP is set to zero.
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Finally,
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the glyph's image is converted to the appropriate format for \f3glBitmap\fP.
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.P
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Using \f3glXUseXFont\fP may be more efficient than accessing the X font and generating
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the display lists explicitly,
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both because the display lists are created on the server without requiring
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a round trip of the glyph data,
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and because the server may choose to delay the creation of each
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bitmap until it is accessed.
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.P
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Empty display lists are created for all glyphs that are requested and
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are not defined in \f2font\fP.
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\f3glXUseXFont\fP is ignored if there is no current GLX context.
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.SH ERRORS
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\f3BadFont\fP is generated if \f2font\fP is not a valid font.
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.P
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\f3GLXBadContextState\fP is generated if the current GLX context is
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in display-list construction mode.
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.P
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\f3GLXBadCurrentWindow\fP is generated if the drawable associated
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with the current context of the calling thread is a window, and that
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window is no longer valid.
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.SH SEE ALSO
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\f3glBitmap\fP,
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\f3glXMakeCurrent\fP
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