143 lines
3.8 KiB
Plaintext
143 lines
3.8 KiB
Plaintext
'\" t
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'\"! tbl | mmdoc
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'\"macro stdmacro
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.ds Vn Version 1.2
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.ds Dt 24 September 1999
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.ds Re Release 1.2.1
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.ds Dp Jan 14 18:30
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.ds Dm 01 gethistog
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.ds Xs 52081 6 gethistogram.gl
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.TH GLGETHISTOGRAM 3G
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.SH NAME
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.B "glGetHistogram
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\- get histogram table
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.SH C SPECIFICATION
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void \f3glGetHistogram\fP(
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GLenum \fItarget\fP,
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.nf
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.ta \w'\f3void \fPglGetHistogram( 'u
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GLboolean \fIreset\fP,
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GLenum \fIformat\fP,
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GLenum \fItype\fP,
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GLvoid \fI*values\fP )
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.fi
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.SH PARAMETERS
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.TP \w'\f2target\fP\ \ 'u
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\f2target\fP
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Must be
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\%\f3GL_HISTOGRAM\fP.
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.TP
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\f2reset\fP
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If \%\f3GL_TRUE\fP, each component counter that is actually returned
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is reset to zero. (Other counters are unaffected.)
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If \%\f3GL_FALSE\fP, none of the counters in the histogram table is modified.
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.TP
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\f2format\fP
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The of values to be returned in \f2values\fP.
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Must be one of
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\%\f3GL_RED\fP,
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\%\f3GL_GREEN\fP,
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\%\f3GL_BLUE\fP,
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\%\f3GL_ALPHA\fP,
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\%\f3GL_RGB\fP,
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\%\f3GL_BGR\fP,
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\%\f3GL_RGBA\fP,
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\%\f3GL_BGRA\fP,
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\%\f3GL_LUMINANCE\fP, or
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\%\f3GL_LUMINANCE_ALPHA\fP.
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.TP
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\f2type\fP
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The type of values to be returned in \f2values\fP.
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Symbolic constants
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\%\f3GL_UNSIGNED_BYTE\fP,
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\%\f3GL_BYTE\fP,
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\%\f3GL_BITMAP\fP,
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\%\f3GL_UNSIGNED_SHORT\fP,
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\%\f3GL_SHORT\fP,
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\%\f3GL_UNSIGNED_INT\fP,
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\%\f3GL_INT\fP,
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\%\f3GL_FLOAT\fP,
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\%\f3GL_UNSIGNED_BYTE_3_3_2\fP,
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\%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP,
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\%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP,
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\%\f3GL_UNSIGNED_INT_10_10_10_2\fP, and
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\%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP
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are accepted.
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.TP
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\f2values\fP
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A pointer to storage for the returned histogram table.
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.SH DESCRIPTION
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\%\f3glGetHistogram\fP returns the current histogram table as a one-dimensional image
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with the same width as the histogram.
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No pixel transfer operations are performed on this image, but pixel storage
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modes that are applicable to 1D images are honored.
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.PP
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Color components that are requested in the specified \f2format\fP, but which
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are not included in the internal of the histogram, are returned as
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zero.
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.bp
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The assignments of internal color components to the components
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requested by \f2format\fP are:
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.TS
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center;
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lb lb
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l l.
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_
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Internal Component Resulting Component
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_
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Red Red
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Green Green
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Blue Blue
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Alpha Alpha
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Luminance Red
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_
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.TE
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.SH NOTES
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\%\f3glGetHistogram\fP is present only if \%\f3GL_ARB_imaging\fP is returned when \%\f3glGetString\fP
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is called with an argument of \%\f3GL_EXTENSIONS\fP.
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.SH ERRORS
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\%\f3GL_INVALID_ENUM\fP is generated if \f2target\fP is not \%\f3GL_HISTOGRAM\fP.
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.P
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\%\f3GL_INVALID_ENUM\fP is generated if \f2format\fP is not one of the allowable
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values.
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.P
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\%\f3GL_INVALID_ENUM\fP is generated if \f2type\fP is not one of the allowable
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values.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glGetHistogram\fP is executed
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between the execution of \%\f3glBegin\fP and the corresponding
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execution of \%\f3glEnd\fP.
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.P
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \f2type\fP is one of
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\%\f3GL_UNSIGNED_BYTE_3_3_2\fP,
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\%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5\fP, or
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\%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP
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and \f2format\fP is not \%\f3GL_RGB\fP.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \f2type\fP is one of
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP,
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\%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP,
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\%\f3GL_UNSIGNED_INT_10_10_10_2\fP, or
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\%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP
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and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP.
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.SH SEE ALSO
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\%\f3glHistogram(3G)\fP,
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\%\f3glResetHistogram(3G)\fP,
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\%\f3glGetHistogramParameter(3G)\fP
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