mlib_ImagePolynomialWarp(3mlib)

1mlib_ImagePolynomialWarp(3MmLeIdBi)aLib Library Functmiloinbs_ImagePolynomialWarp(3MLIB)
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NAME

6       mlib_ImagePolynomialWarp - polynomial-based image warp
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SYNOPSIS

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

21       The  mlib_ImagePolynomialWarp()  function  performs  a polynomial-based
22       image warp.
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25       The images must have the same type, and the same  number  of  channels.
26       The images can have 1, 2, 3, or 4 channels. The data type of the images
27       can be MLIB_BYTE, MLIB_SHORT, MLIB_USHORT, or MLIB_INT. The source  and
28       destination images may have different sizes.
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31       The  xCoeffs  and  yCoeffs  parameters  must contain the same number of
32       coefficients of the form (n + 1)(n + 2)/2 for some n, where  n  is  the
33       degree power of the polynomial. The coefficients, in order, are associ‐
34       ated with the terms:
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36         1, x, y, x**2, x*y, y**2, ...,
37         x**n, x**(n-1)*y, ..., x*y**(n-1), y**n
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41       and coefficients of value 0 cannot be omitted.
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44       The image pixels are assumed to be centered at .5 coordinate points. In
45       other  words,  the  upper-left  corner  pixel of an image is located at
46       (0.5, 0.5).
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49       For each pixel in the destination image, its center point D is backward
50       mapped  to  a  point S in the source image. Then the source pixels with
51       their centers surrounding point S are selected to do one of the  inter‐
52       polations specified by the filter parameter to generate the pixel value
53       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       filter        Type of resampling filter. It can be one of  the  follow‐
134                     ing:
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136                       MLIB_NEAREST
137                       MLIB_BILINEAR
138                       MLIB_BICUBIC
139                       MLIB_BICUBIC2
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143       edge          Type of edge condition. It can be one of the following:
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145                       MLIB_EDGE_DST_NO_WRITE
146                       MLIB_EDGE_SRC_PADDED
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RETURN VALUES

151       The  function  returns MLIB_SUCCESS if successful. Otherwise it returns
152       MLIB_FAILURE.
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ATTRIBUTES

155       See attributes(5) for descriptions of the following attributes:
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160       ┌─────────────────────────────┬─────────────────────────────┐
161       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
162       ├─────────────────────────────┼─────────────────────────────┤
163       │Interface Stability          │Committed                    │
164       ├─────────────────────────────┼─────────────────────────────┤
165       │MT-Level                     │MT-Safe                      │
166       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

PARAMETERS

RETURN VALUES

ATTRIBUTES

SEE ALSO