Manual Pages for UNIX Operating System command usage for man mlib_ImagePolynomialWarp

mediaLib Library Functions        mlib_ImagePolynomialWarp(3MLIB)



NAME
     mlib_ImagePolynomialWarp - polynomial-based image warp

SYNOPSIS
     cc [ flag... ] file... -lmlib [ library... ]
     #include 

     mlib_status mlib_ImagePolynomialWarp(mlib_image *dst,
          const mlib_image *src, const mlib_d64 *xCoeffs,
          const mlib_d64 *yCoeffs, mlib_s32 n, mlib_d64 preShiftX,
          mlib_d64 preShiftY, mlib_d64 postShiftX, mlib_d64 postShiftY,
          mlib_d64 preScaleX, mlib_d64 preScaleY, mlib_d64 postScaleX,
          mlib_d64 postScaleY, mlib_filter filter, mlib_edge edge);


DESCRIPTION
     The   mlib_ImagePolynomialWarp()   function    performs    a
     polynomial-based image warp.


     The images must have the same type, and the same  number  of
     channels.  The  images  can have 1, 2, 3, or 4 channels. The
     data type  of  the  images  can  be  MLIB_BYTE,  MLIB_SHORT,
     MLIB_USHORT,  or MLIB_INT. The source and destination images
     may have different sizes.


     The xCoeffs and yCoeffs parameters  must  contain  the  same
     number of coefficients of the form (n + 1)(n + 2)/2 for some
     n, where n is the degree power of the polynomial. The  coef-
     ficients, in order, are associated with the terms:

       1, x, y, x**2, x*y, y**2, ...,
       x**n, x**(n-1)*y, ..., x*y**(n-1), y**n



     and coefficients of value 0 cannot be omitted.


     The image pixels are assumed to be centered at .5 coordinate
     points.  In  other  words, the upper-left corner pixel of an
     image is located at (0.5, 0.5).


     For each pixel in the destination image, its center point  D
     is  backward  mapped  to a point S in the source image. Then
     the source pixels with their centers surrounding point S are
     selected  to  do  one of the interpolations specified by the
     filter parameter to generate the pixel value for point D.





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mediaLib Library Functions        mlib_ImagePolynomialWarp(3MLIB)



     The mapping is defined by the two bivariate polynomial func-
     tions  X(x, y) and Y(x, y) that map destination (x, y) coor-
     dinates to source X and Y positions respectively.


     The functions X(x, y) and Y(x, y) are:

       preX = (x + preShiftX)*preScaleX

       preY = (y + preShiftY)*preScaleY

                  n    i
       warpedX = SUM {SUM {xCoeffs_ij * preX**(i-j) * preY**j}}
                 i=0  j=0

                  n    i
       warpedY = SUM {SUM {yCoeffs_ij * preX**(i-j) * preY**j}}
                 i=0  j=0

       X(x, y) = warpedX*postScaleX - postShiftX

       Y(x, y) = warpedY*postScaleY - postShiftY



     The  destination  (x,  y)  coordinates  are  pre-shifted  by
     (preShiftX,  preShiftY)  and pre-scaled by the factors preS-
     caleX and preScaleY prior to the evaluation of  the  polyno-
     mial.  The  results of the polynomial evaluations are scaled
     by  postScaleX  and  postScaleY,  and  then  shifted  by  (-
     postShiftX, -postShiftY) to produce the source pixel coordi-
     nates. This process  allows  for  better  precision  of  the
     results and supports tiled images.

PARAMETERS
     The function takes the following arguments:

     dst           Pointer to destination image.


     src           Pointer to source image.


     xCoeffs       Destination to source  transform  coefficients
                   for the X coordinate.


     yCoeffs       Destination to source  transform  coefficients
                   for the Y coordinate.






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mediaLib Library Functions        mlib_ImagePolynomialWarp(3MLIB)



     n             Degree power of the polynomial.


     preShiftX     Displacement to apply to destination  X  posi-
                   tions.


     preShiftY     Displacement to apply to destination  Y  posi-
                   tions.


     postShiftX    Displacement to apply to source X positions.


     postShiftY    Displacement to apply to source Y positions.


     preScaleX     Scale factor to apply to destination  X  posi-
                   tions.


     preScaleY     Scale factor to apply to destination  Y  posi-
                   tions.


     postScaleX    Scale factor to apply to source X positions.


     postScaleY    Scale factor to apply to source Y positions.


     filter        Type of resampling filter. It can  be  one  of
                   the following:

                     MLIB_NEAREST
                     MLIB_BILINEAR
                     MLIB_BICUBIC
                     MLIB_BICUBIC2



     edge          Type of edge condition. It can be one  of  the
                   following:

                     MLIB_EDGE_DST_NO_WRITE
                     MLIB_EDGE_SRC_PADDED



RETURN VALUES
     The function returns MLIB_SUCCESS if  successful.  Otherwise
     it returns MLIB_FAILURE.



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mediaLib Library Functions        mlib_ImagePolynomialWarp(3MLIB)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     mlib_ImagePolynomialWarp_Fp(3MLIB),
     mlib_ImagePolynomialWarpTable(3MLIB),
     mlib_ImagePolynomialWarpTable_Fp(3MLIB), attributes(5)




































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