/*!
* \brief pixSetChromaSampling()
*
* \param[in] pix
* \param[in] sampling 1 for subsampling; 0 for no subsampling
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) The default is for 2x2 chroma subsampling because the files are
* considerably smaller and the appearance is typically satisfactory.
* To get full resolution output in the chroma channels for
* jpeg writing, call this with %sampling == 0.
* </pre>
*/
l_int32
pixSetChromaSampling(PIX *pix,
l_int32 sampling)
{
PROCNAME("pixSetChromaSampling");
if (!pix)
return ERROR_INT("pix not defined", procName, 1 );
if (sampling)
pixSetSpecial(pix, 0); /* default */
else
pixSetSpecial(pix, L_NO_CHROMA_SAMPLING_JPEG);
return 0;
}
/*!
* \brief pixConnCompIncrInit()
*
* \param[in] pixs 1 bpp
* \param[in] conn connectivity: 4 or 8
* \param[out] ppixd 32 bpp, with c.c. labelled
* \param[out] pptaa with pixel locations indexed by c.c.
* \param[out] pncc initial number of c.c.
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) This labels the connected components in a 1 bpp pix, and
* additionally sets up a ptaa that lists the locations of pixels
* in each of the components.
* (2) It can be used to initialize the output image and arrays for
* an application that maintains information about connected
* components incrementally as pixels are added.
* (3) pixs can be empty or have some foreground pixels.
* (4) The connectivity is stored in pixd->special.
* (5) Always initialize with the first pta in ptaa being empty
* and representing the background value (index 0) in the pix.
* </pre>
*/
l_int32
pixConnCompIncrInit(PIX *pixs,
l_int32 conn,
PIX **ppixd,
PTAA **pptaa,
l_int32 *pncc)
{
l_int32 empty, w, h, ncc;
PIX *pixd;
PTA *pta;
PTAA *ptaa;
PROCNAME("pixConnCompIncrInit");
if (ppixd) *ppixd = NULL;
if (pptaa) *pptaa = NULL;
if (pncc) *pncc = 0;
if (!ppixd || !pptaa || !pncc)
return ERROR_INT("&pixd, &ptaa, &ncc not all defined", procName, 1);
if (!pixs || pixGetDepth(pixs) != 1)
return ERROR_INT("pixs undefined or not 1 bpp", procName, 1);
if (conn != 4 && conn != 8)
return ERROR_INT("connectivity must be 4 or 8", procName, 1);
pixGetDimensions(pixs, &w, &h, NULL);
pixZero(pixs, &empty);
if (empty) {
*ppixd = pixCreate(w, h, 32);
pixSetSpp(*ppixd, 1);
pixSetSpecial(*ppixd, conn);
*pptaa = ptaaCreate(0);
pta = ptaCreate(1);
ptaaAddPta(*pptaa, pta, L_INSERT); /* reserve index 0 for background */
return 0;
}
/* Set up the initial labeled image and indexed pixel arrays */
if ((pixd = pixConnCompTransform(pixs, conn, 32)) == NULL)
return ERROR_INT("pixd not made", procName, 1);
pixSetSpecial(pixd, conn);
*ppixd = pixd;
if ((ptaa = ptaaIndexLabeledPixels(pixd, &ncc)) == NULL)
return ERROR_INT("ptaa not made", procName, 1);
*pptaa = ptaa;
*pncc = ncc;
return 0;
}
