/*!
* pixBilinearPtaGray()
*
* Input: pixs (8 bpp)
* ptad (4 pts of final coordinate space)
* ptas (4 pts of initial coordinate space)
* grayval (0 to bring in BLACK, 255 for WHITE)
* Return: pixd, or null on error
*/
PIX *
pixBilinearPtaGray(PIX *pixs,
PTA *ptad,
PTA *ptas,
l_uint8 grayval)
{
l_float32 *vc;
PIX *pixd;
PROCNAME("pixBilinearPtaGray");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (!ptas)
return (PIX *)ERROR_PTR("ptas not defined", procName, NULL);
if (!ptad)
return (PIX *)ERROR_PTR("ptad not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs must be 8 bpp", procName, NULL);
if (ptaGetCount(ptas) != 4)
return (PIX *)ERROR_PTR("ptas count not 4", procName, NULL);
if (ptaGetCount(ptad) != 4)
return (PIX *)ERROR_PTR("ptad count not 4", procName, NULL);
/* Get backwards transform from dest to src, and apply it */
getBilinearXformCoeffs(ptad, ptas, &vc);
pixd = pixBilinearGray(pixs, vc, grayval);
FREE(vc);
return pixd;
}
/*!
* pixBilinearSampledPta()
*
* Input: pixs (all depths)
* ptad (4 pts of final coordinate space)
* ptas (4 pts of initial coordinate space)
* incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
* Return: pixd, or null on error
*
* Notes:
* (1) Brings in either black or white pixels from the boundary.
* (2) Retains colormap, which you can do for a sampled transform..
* (3) No 3 of the 4 points may be collinear.
* (4) For 8 and 32 bpp pix, better quality is obtained by the
* somewhat slower pixBilinearPta(). See that
* function for relative timings between sampled and interpolated.
*/
PIX *
pixBilinearSampledPta(PIX *pixs,
PTA *ptad,
PTA *ptas,
l_int32 incolor)
{
l_float32 *vc;
PIX *pixd;
PROCNAME("pixBilinearSampledPta");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (!ptas)
return (PIX *)ERROR_PTR("ptas not defined", procName, NULL);
if (!ptad)
return (PIX *)ERROR_PTR("ptad not defined", procName, NULL);
if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);
if (ptaGetCount(ptas) != 4)
return (PIX *)ERROR_PTR("ptas count not 4", procName, NULL);
if (ptaGetCount(ptad) != 4)
return (PIX *)ERROR_PTR("ptad count not 4", procName, NULL);
/* Get backwards transform from dest to src, and apply it */
getBilinearXformCoeffs(ptad, ptas, &vc);
pixd = pixBilinearSampled(pixs, vc, incolor);
FREE(vc);
return pixd;
}
static l_float32 *
Generate4PtTransformVector(l_int32 type) {
l_int32 i;
l_float32 *vc;
PTA *ptas, *ptad;
ptas = ptaCreate(4);
ptad = ptaCreate(4);
for (i = 0; i < 4; i++) {
ptaAddPt(ptas, xs[i], ys[i]);
ptaAddPt(ptad, xd[i], yd[i]);
}
if (type == PROJECTIVE)
getProjectiveXformCoeffs(ptad, ptas, &vc);
else /* BILINEAR */
getBilinearXformCoeffs(ptad, ptas, &vc);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
return vc;
}
