mlib_ImagePolynomialWarpTable(3mlib)

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NAME

6       mlib_ImagePolynomialWarpTable - polynomial-based image warp with table-
7       driven interpolation
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SYNOPSIS

10       cc [ flag... ] file... -lmlib [ library... ]
11       #include <mlib.h>
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13       mlib_status mlib_ImagePolynomialWarpTable(mlib_image *dst,
14            const mlib_image *src, const mlib_d64 *xCoeffs,
15            const mlib_d64 *yCoeffs, mlib_s32 n, mlib_d64 preShiftX,
16            mlib_d64 preShiftY, mlib_d64 postShiftX, mlib_d64 postShiftY,
17            mlib_d64 preScaleX, mlib_d64 preScaleY, mlib_d64 postScaleX,
18            mlib_d64 postScaleY, const void *interp_table, mlib_edge edge);
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DESCRIPTION

22       The mlib_ImagePolynomialWarpTable()  function  performs  a  polynomial-
23       based image warp with table-driven interpolation.
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26       The  images  must  have the same type, and the same number of channels.
27       The images can have 1, 2, 3, or 4 channels. The data type of the images
28       can  be MLIB_BYTE, MLIB_SHORT, MLIB_USHORT, or MLIB_INT. The source and
29       destination images may have different sizes.
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32       The xCoeffs and yCoeffs parameters must  contain  the  same  number  of
33       coefficients  of  the  form (n + 1)(n + 2)/2 for some n, where n is the
34       degree power of the polynomial. The coefficients, in order, are associ‐
35       ated with the terms:
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37         1, x, y, x**2, x*y, y**2, ...,
38         x**n, x**(n-1)*y, ..., x*y**(n-1), y**n
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42       and coefficients of value 0 cannot be omitted.
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45       The image pixels are assumed to be centered at .5 coordinate points. In
46       other words, the upper-left corner pixel of  an  image  is  located  at
47       (0.5, 0.5).
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50       For each pixel in the destination image, its center point D is backward
51       mapped to a point S in the source image. Then the  source  pixels  with
52       their  centers surrounding point S are selected to do the interpolation
53       specified by interp_table to generate the pixel value for point D.
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56       The mapping is defined by the two bivariate polynomial  functions  X(x,
57       y)  and Y(x, y) that map destination (x, y) coordinates to source X and
58       Y positions respectively.
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61       The functions X(x, y) and Y(x, y) are:
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63         preX = (x + preShiftX)*preScaleX
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65         preY = (y + preShiftY)*preScaleY
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67                    n    i
68         warpedX = SUM {SUM {xCoeffs_ij * preX**(i-j) * preY**j}}
69                   i=0  j=0
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71                    n    i
72         warpedY = SUM {SUM {yCoeffs_ij * preX**(i-j) * preY**j}}
73                   i=0  j=0
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75         X(x, y) = warpedX*postScaleX - postShiftX
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77         Y(x, y) = warpedY*postScaleY - postShiftY
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81       The destination (x,  y)  coordinates  are  pre-shifted  by  (preShiftX,
82       preShiftY)  and pre-scaled by the factors preScaleX and preScaleY prior
83       to the evaluation of the polynomial.  The  results  of  the  polynomial
84       evaluations  are  scaled by postScaleX and postScaleY, and then shifted
85       by (-postShiftX, -postShiftY) to produce the source pixel  coordinates.
86       This  process  allows  for better precision of the results and supports
87       tiled images.
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PARAMETERS

90       The function takes the following arguments:
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92       dst             Pointer to destination image.
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95       src             Pointer to source image.
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98       xCoeffs         Destination to source transform coefficients for the  X
99                       coordinate.
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102       yCoeffs         Destination  to source transform coefficients for the Y
103                       coordinate.
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106       n               Degree power of the polynomial.
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109       preShiftX       Displacement to apply to destination X positions.
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112       preShiftY       Displacement to apply to destination Y positions.
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115       postShiftX      Displacement to apply to source X positions.
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118       postShiftY      Displacement to apply to source Y positions.
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121       preScaleX       Scale factor to apply to destination X positions.
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124       preScaleY       Scale factor to apply to destination Y positions.
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127       postScaleX      Scale factor to apply to source X positions.
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130       postScaleY      Scale factor to apply to source Y positions.
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133       interp_table    Pointer to an interpolation table. The table is created
134                       by the mlib_ImageInterpTableCreate() function.
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137       edge            Type of edge condition. It can be one of the following:
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139                         MLIB_EDGE_DST_NO_WRITE
140                         MLIB_EDGE_SRC_PADDED
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RETURN VALUES

145       The  function  returns MLIB_SUCCESS if successful. Otherwise it returns
146       MLIB_FAILURE.
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ATTRIBUTES

149       See attributes(5) for descriptions of the following attributes:
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154       ┌─────────────────────────────┬─────────────────────────────┐
155       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
156       ├─────────────────────────────┼─────────────────────────────┤
157       │Interface Stability          │Committed                    │
158       ├─────────────────────────────┼─────────────────────────────┤
159       │MT-Level                     │MT-Safe                      │
160       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

PARAMETERS

RETURN VALUES

ATTRIBUTES

SEE ALSO