mlib_ImagePolynomialWarpTable_Fp(3mlib)

1mlib_ImagePolynomialWarpTabmleed_iFapL(i3bMLLIiBb)ramrlyibF_uInmcatgieoPnoslynomialWarpTable_Fp(3MLIB)
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NAME

6       mlib_ImagePolynomialWarpTable_Fp - polynomial-based image warp with ta‐
7       ble-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_Fp(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_Fp() function performs a  polynomial-
23       based image warp on a floating-point image with table-driven interpola‐
24       tion.
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27       The images must have the same type, and the same  number  of  channels.
28       The images can have 1, 2, 3, or 4 channels. The data type of the images
29       can be MLIB_FLOAT or MLIB_DOUBLE. The source and destination images may
30       have different sizes.
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33       The  xCoeffs  and  yCoeffs  parameters  must contain the same number of
34       coefficients of the form (n + 1)(n + 2)/2 for some n, where  n  is  the
35       degree power of the polynomial. The coefficients, in order, are associ‐
36       ated with the terms:
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38         1, x, y, x**2, x*y, y**2, ...,
39         x**n, x**(n-1)*y, ..., x*y**(n-1), y**n
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43       and coefficients of value 0 cannot be omitted.
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46       The image pixels are assumed to be centered at .5 coordinate points. In
47       other  words,  the  upper-left  corner  pixel of an image is located at
48       (0.5, 0.5).
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51       For each pixel in the destination image, its center point D is backward
52       mapped  to  a  point S in the source image. Then the source pixels with
53       their centers surrounding point S are selected to do the  interpolation
54       specified by interp_table to generate the pixel value for point D.
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57       The  mapping  is defined by the two bivariate polynomial functions X(x,
58       y) and Y(x, y) that map destination (x, y) coordinates to source X  and
59       Y positions respectively.
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62       The functions X(x, y) and Y(x, y) are:
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64         preX = (x + preShiftX)*preScaleX
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66         preY = (y + preShiftY)*preScaleY
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68                    n    i
69         warpedX = SUM {SUM {xCoeffs_ij * preX**(i-j) * preY**j}}
70                   i=0  j=0
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72                    n    i
73         warpedY = SUM {SUM {yCoeffs_ij * preX**(i-j) * preY**j}}
74                   i=0  j=0
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76         X(x, y) = warpedX*postScaleX - postShiftX
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78         Y(x, y) = warpedY*postScaleY - postShiftY
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82       The  destination  (x,  y)  coordinates  are  pre-shifted by (preShiftX,
83       preShiftY) and pre-scaled by the factors preScaleX and preScaleY  prior
84       to  the  evaluation  of  the  polynomial. The results of the polynomial
85       evaluations are scaled by postScaleX and postScaleY, and  then  shifted
86       by  (-postShiftX, -postShiftY) to produce the source pixel coordinates.
87       This process allows for better precision of the  results  and  supports
88       tiled images.
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PARAMETERS

91       The function takes the following arguments:
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93       dst             Pointer to destination image.
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96       src             Pointer to source image.
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99       xCoeffs         Destination  to source transform coefficients for the X
100                       coordinate.
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103       yCoeffs         Destination to source transform coefficients for the  Y
104                       coordinate.
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107       n               Degree power of the polynomial.
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110       preShiftX       Displacement to apply to destination X positions.
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113       preShiftY       Displacement to apply to destination Y positions.
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116       postShiftX      Displacement to apply to source X positions.
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119       postShiftY      Displacement to apply to source Y positions.
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122       preScaleX       Scale factor to apply to destination X positions.
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125       preScaleY       Scale factor to apply to destination Y positions.
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128       postScaleX      Scale factor to apply to source X positions.
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131       postScaleY      Scale factor to apply to source Y positions.
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134       interp_table    Pointer to an interpolation table. The table is created
135                       by the mlib_ImageInterpTableCreate() function.
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138       edge            Type of edge condition. It can be one of the following:
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140                         MLIB_EDGE_DST_NO_WRITE
141                         MLIB_EDGE_SRC_PADDED
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RETURN VALUES

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

150       See attributes(5) for descriptions of the following attributes:
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155       ┌─────────────────────────────┬─────────────────────────────┐
156       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
157       ├─────────────────────────────┼─────────────────────────────┤
158       │Interface Stability          │Committed                    │
159       ├─────────────────────────────┼─────────────────────────────┤
160       │MT-Level                     │MT-Safe                      │
161       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

PARAMETERS

RETURN VALUES

ATTRIBUTES

SEE ALSO