glcRenderChar(3G) OpenGL Character Renderer glcRenderChar(3G)
NAME
glcRenderChar - render a character
C SPECIFICATION
void glcRenderChar( GLint inCode )
PARAMETERS
inCode Specifies the character to render.
DESCRIPTION
glcRenderChar renders the character that inCode is mapped to.
GLC finds a font that maps inCode to a character such as LATIN CAPITAL
LETTER A, then uses one or more glyphs from the font to create a
graphical layout that represents the character. Finally, GLC issues a
sequence of GL commands to draw the layout. Glyph coordinates are defined
in em units and are transformed during rendering to produce the desired
mapping of the glyph shape into the GL window coordinate system.
Except where otherwise specified, every character code used in GLC is an
element of the Universal Multiple-Octet Coded Character Set (UCS) defined
by the standards ISO/IEC 10646-1:1993 and Unicode 2.0. A UCS code is
denoted as U+hexcode, where hexcode is a sequence of hexadecimal digits.
Each UCS code corresponds to a character that has a unique name string.
For example, the code U+41 corresponds to the character LATIN CAPITAL
LETTER A.
If glcRenderChar cannot find a font in the list GLCCURRENTFONTLIST
that maps inCode, it attempts to produce an alternate rendering. If the
value of the boolean variable GLCAUTOFONT is GLTRUE, glcRenderChar
finds a font that has the character that maps inCode, giving preference
to Courier and Helvetica. If the search succeeds, glcRenderChar appends
the font's ID to GLCCURRENTFONTLIST and renders the character.
If there are fonts in the list GLCCURRENTFONTLIST, but a match for
inCode cannot be found in any of those fonts, glcRenderChar goes through
these steps:
1. If the value of the variable GLCREPLACEMENTCODE is nonzero,
glcRenderChar finds a font that maps the replacement code, and
renders the character that the replacement code is mapped to.
2. If the variable GLCREPLACEMENTCODE is zero, or if the replacement
code does not result in a match, glcRenderChar checks whether a
callback function is defined. If a callback function is defined for
GLCOPglcUnmappedCode, glcRenderChar calls the function. The
callback function provides inCode to the user and allows loading of
the appropriate font. After the callback returns, glcRenderChar
tries to render inCode again.
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glcRenderChar(3G) OpenGL Character Renderer glcRenderChar(3G)
3. If no match is found, nothing is rendered.
ERRORS
GLCSTATEERROR is generated if the issuing thread has no current GLC
context.
SEE ALSO
glcRenderCountedString, glcRenderString
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