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include "qpio.h"
# QPIO_LOADWCS -- Load the WCS, if any, from the QPOE file associated with the
# given QPIO descriptor, into an open MWCS descriptor. This is equivalent to
# QP_LOADWCS except that the Lterm is updated to reflect the current blocking
# factor and rect (if any) used for rasterization. In the resultant WCS, the
# logical coordinate system gives the pixel coordinates of the sampled rect.
pointer procedure qpio_loadwcs (io)
pointer io #I QPIO descriptor
pointer qp, mw
int ndim, i, j
double ltv_1[NDIM], ltv_2[NDIM], ltm[NDIM,NDIM]
pointer qp_loadwcs()
errchk qp_loadwcs
begin
qp = IO_QP(io)
mw = qp_loadwcs (qp)
ndim = NDIM
# Formalize the transformation.
ltv_1[1] = IO_VSDEF(io,1) - 1
ltv_1[2] = IO_VSDEF(io,2) - 1
# L(i) :== LTM=(1 / block) * P(i) + Vx
# At pixel {P(i) :== (block + 1) / 2} L(i) is 1.0.
# Solve for Vx :== 1.0 - (1 / block) * ((block + 1) / 2)
# --> 0.5 - 1 / (2 * block)
ltv_2[1] = 0.5d0 - 1.0d0 / double (max (1.0, IO_XBLOCK(io))) / 2.0d0
ltv_2[2] = 0.5d0 - 1.0d0 / double (max (1.0, IO_YBLOCK(io))) / 2.0d0
do j = 1, ndim
do i = 1, ndim
if (i == j) {
if (i == 1)
ltm[i,j] = 1.0D0 / max (1.0, IO_XBLOCK(io))
else
ltm[i,j] = 1.0D0 / max (1.0, IO_YBLOCK(io))
} else
ltm[i,j] = 0
# Apply the transformation.
call mw_translated (mw, ltv_1, ltm, ltv_2, ndim)
return (mw)
end
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