'\" te
.\" Copyright (c) 2007, Sun Microsystems, Inc.  All Rights Reserved 
.TH mlib_ImageColorOrderedDitherMxN 3MLIB "2 Mar 2007" "SunOS 5.11" "mediaLib Library Functions"
.SH NAME
mlib_ImageColorOrderedDitherMxN \- true-color to indexed-color or grayscale to black-white conversion, using ordered dithering
.SH SYNOPSIS
.LP
.nf
cc [ \fIflag\fR... ] \fIfile\fR... \fB-lmlib\fR [ \fIlibrary\fR... ]
#include <mlib.h>

\fBmlib_status\fR \fBmlib_ImageColorOrderedDitherMxN\fR(\fBmlib_image *\fR\fIdst\fR,
     \fBconst mlib_image *\fR\fIsrc\fR, \fBconst mlib_s32 **\fR\fIdmask\fR, \fBmlib_s32\fR \fIm\fR,
     \fBmlib_s32\fR \fIn\fR, \fBmlib_s32\fR \fIscale\fR, \fBconst void *\fR\fIcolormap\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBmlib_ImageColorOrderedDitherMxN()\fR function converts a 3-channel image to a 1-channel indexed image, or converts a 1-channel grayscale image to a 1-channel \fBMLIB_BIT\fR image, with the method of ordered dithering.
.sp
.LP
The \fIsrc\fR can be an \fBMLIB_BYTE\fR image with 1 or 3 channels. The \fIdst\fR must be a 1-channel \fBMLIB_BIT\fR or \fBMLIB_BYTE\fR image.
.sp
.LP
The \fIcolormap\fR must be created by \fBmlib_ImageColorDitherInit()\fR, and it must have a colorcube included.
.sp
.LP
The dither masks are required to have the following property:
.sp
.in +2
.nf
0 \(<= dmask[i][j] < 2**scale; scale > 0
.fi
.in -2

.SH PARAMETERS
.sp
.LP
The function takes the following arguments:
.sp
.ne 2
.mk
.na
\fB\fIdst\fR\fR
.ad
.RS 12n
.rt  
Pointer to destination image.
.RE

.sp
.ne 2
.mk
.na
\fB\fIsrc\fR\fR
.ad
.RS 12n
.rt  
Pointer to source image.
.RE

.sp
.ne 2
.mk
.na
\fB\fIdmask\fR\fR
.ad
.RS 12n
.rt  
Pointer to the dither masks, one per channel, in row major order.
.RE

.sp
.ne 2
.mk
.na
\fB\fIm\fR\fR
.ad
.RS 12n
.rt  
Mask width. \fBm > 1\fR.
.RE

.sp
.ne 2
.mk
.na
\fB\fIn\fR\fR
.ad
.RS 12n
.rt  
Mask height. \fBn > 1\fR.
.RE

.sp
.ne 2
.mk
.na
\fB\fIscale\fR\fR
.ad
.RS 12n
.rt  
Scaling factor for dmask to convert the input integer coefficients into floating-point coefficients:
.sp
.in +2
.nf
floating-point coefficient = integer coefficient * \e
2**(-scale)
.fi
.in -2

.RE

.sp
.ne 2
.mk
.na
\fB\fIcolormap\fR\fR
.ad
.RS 12n
.rt  
Internal data structure for image dithering.
.RE

.SH RETURN VALUES
.sp
.LP
The function returns \fBMLIB_SUCCESS\fR if successful. Otherwise it returns \fBMLIB_FAILURE\fR.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityCommitted
_
MT-LevelMT-Safe
.TE

.SH SEE ALSO
.sp
.LP
\fBmlib_ImageColorDitherInit\fR(3MLIB), \fBmlib_ImageColorDitherFree\fR(3MLIB), \fBmlib_ImageColorErrorDiffusion3x3\fR(3MLIB), \fBmlib_ImageColorErrorDiffusionMxN\fR(3MLIB), \fBmlib_ImageColorOrderedDither8x8\fR(3MLIB), \fBattributes\fR(5)