struct corners* RunFastDetector9(PIX *pix,
unsigned int w,
unsigned int h) {
xy *rawcorners = (xy *) malloc(sizeof(xy));
unsigned char *im = (unsigned char*) malloc(sizeof(unsigned char) * (w*h));
void **pix_lines = pixGetLinePtrs(pix, NULL);
unsigned int x,y, num_corners;
unsigned int i = 0;
for(y=0;y<h;y++)
for(x=0;x<w;x++){
im[i] = (unsigned char) GET_DATA_BYTE(pix_lines[y],x);
i++;
}
free(pix_lines);
rawcorners = fast9_detect(im, w, h, w, 88, &num_corners);
free(im);
unsigned int mx,my;
mx = (unsigned int)w/2;
my = (unsigned int)h/2;
float skew_angle = 0.0;
struct corners *corners = ParseRawCorners(rawcorners,
num_corners,
mx,my,
skew_angle);
free(rawcorners);
return corners;
}
/*!
* wshedCreate()
*
* Input: pixs (8 bpp source)
* pixm (1 bpp 'marker' seed)
* mindepth (minimum depth; anything less is not saved)
* debugflag (1 for debug output)
* Return: WShed, or null on error
*
* Notes:
* (1) It is not necessary for the fg pixels in the seed image
* be at minima, or that they be isolated. We extract a
* single pixel from each connected component, and a seed
* anywhere in a watershed will eventually label the watershed
* when the filling level reaches it.
* (2) Set mindepth to some value to ignore noise in pixs that
* can create small local minima. Any watershed shallower
* than mindepth, even if it has a seed, will not be saved;
* It will either be incorporated in another watershed or
* eliminated.
*/
L_WSHED *
wshedCreate(PIX *pixs,
PIX *pixm,
l_int32 mindepth,
l_int32 debugflag)
{
l_int32 w, h;
L_WSHED *wshed;
PROCNAME("wshedCreate");
if (!pixs)
return (L_WSHED *)ERROR_PTR("pixs is not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (L_WSHED *)ERROR_PTR("pixs is not 8 bpp", procName, NULL);
if (!pixm)
return (L_WSHED *)ERROR_PTR("pixm is not defined", procName, NULL);
if (pixGetDepth(pixm) != 1)
return (L_WSHED *)ERROR_PTR("pixm is not 1 bpp", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
if (pixGetWidth(pixm) != w || pixGetHeight(pixm) != h)
return (L_WSHED *)ERROR_PTR("pixs/m sizes are unequal", procName, NULL);
if ((wshed = (L_WSHED *)CALLOC(1, sizeof(L_WSHED))) == NULL)
return (L_WSHED *)ERROR_PTR("wshed not made", procName, NULL);
wshed->pixs = pixClone(pixs);
wshed->pixm = pixClone(pixm);
wshed->mindepth = L_MAX(1, mindepth);
wshed->pixlab = pixCreate(w, h, 32);
pixSetAllArbitrary(wshed->pixlab, MAX_LABEL_VALUE);
wshed->pixt = pixCreate(w, h, 1);
wshed->lines8 = pixGetLinePtrs(pixs, NULL);
wshed->linem1 = pixGetLinePtrs(pixm, NULL);
wshed->linelab32 = pixGetLinePtrs(wshed->pixlab, NULL);
wshed->linet1 = pixGetLinePtrs(wshed->pixt, NULL);
wshed->debug = debugflag;
return wshed;
}
int main(int argc,
char **argv)
{
l_int32 i, j, k, w, h, w2, w4, w8, w16, w32, wpl;
l_int32 count1, count2, count3;
l_uint32 val32, val1, val2;
l_uint32 *data1, *line1, *data2, *line2;
void **lines1, **linet1, **linet2;
PIX *pixs, *pix1, *pix2;
L_REGPARAMS *rp;
if (regTestSetup(argc, argv, &rp))
return 1;
pixs = pixRead("feyn-fract.tif");
pixGetDimensions(pixs, &w, &h, NULL);
data1 = pixGetData(pixs);
wpl = pixGetWpl(pixs);
lines1 = pixGetLinePtrs(pixs, NULL);
/* Get timing for the 3 different methods */
startTimer();
for (k = 0; k < 10; k++) {
count1 = 0;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
if (GET_DATA_BIT(lines1[i], j))
count1++;
}
}
}
fprintf(stderr, "Time with line ptrs = %5.3f sec, count1 = %d\n",
stopTimer(), count1);
startTimer();
for (k = 0; k < 10; k++) {
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
for (j = 0; j < w; j++) {
if (l_getDataBit(line1, j))
count2++;
}
}
}
fprintf(stderr, "Time with l_get* = %5.3f sec, count2 = %d\n",
stopTimer(), count2);
startTimer();
for (k = 0; k < 10; k++) {
count3 = 0;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
pixGetPixel(pixs, j, i, &val32);
count3 += val32;
}
}
}
fprintf(stderr, "Time with pixGetPixel() = %5.3f sec, count3 = %d\n",
stopTimer(), count3);
pix1 = pixCreateTemplate(pixs);
linet1 = pixGetLinePtrs(pix1, NULL);
pix2 = pixCreateTemplate(pixs);
data2 = pixGetData(pix2);
linet2 = pixGetLinePtrs(pix2, NULL);
/* ------------------------------------------------- */
/* Test different methods for 1 bpp */
/* ------------------------------------------------- */
count1 = 0;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
val1 = GET_DATA_BIT(lines1[i], j);
count1 += val1;
if (val1) SET_DATA_BIT(linet1[i], j);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w; j++) {
val2 = l_getDataBit(line1, j);
count2 += val2;
if (val2) l_setDataBit(line2, j);
}
}
CompareResults(pixs, pix1, pix2, count1, count2, "1 bpp", rp);
/* ------------------------------------------------- */
/* Test different methods for 2 bpp */
/* ------------------------------------------------- */
count1 = 0;
w2 = w / 2;
for (i = 0; i < h; i++) {
for (j = 0; j < w2; j++) {
val1 = GET_DATA_DIBIT(lines1[i], j);
count1 += val1;
val1 += 0xbbbbbbbc;
SET_DATA_DIBIT(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w2; j++) {
val2 = l_getDataDibit(line1, j);
count2 += val2;
val2 += 0xbbbbbbbc;
l_setDataDibit(line2, j, val2);
}
}
CompareResults(pixs, pix1, pix2, count1, count2, "2 bpp", rp);
/* ------------------------------------------------- */
/* Test different methods for 4 bpp */
/* ------------------------------------------------- */
count1 = 0;
w4 = w / 4;
for (i = 0; i < h; i++) {
for (j = 0; j < w4; j++) {
val1 = GET_DATA_QBIT(lines1[i], j);
count1 += val1;
val1 += 0xbbbbbbb0;
SET_DATA_QBIT(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w4; j++) {
val2 = l_getDataQbit(line1, j);
count2 += val2;
val2 += 0xbbbbbbb0;
l_setDataQbit(line2, j, val2);
}
}
CompareResults(pixs, pix1, pix2, count1, count2, "4 bpp", rp);
/* ------------------------------------------------- */
/* Test different methods for 8 bpp */
/* ------------------------------------------------- */
count1 = 0;
w8 = w / 8;
for (i = 0; i < h; i++) {
for (j = 0; j < w8; j++) {
val1 = GET_DATA_BYTE(lines1[i], j);
count1 += val1;
val1 += 0xbbbbbb00;
SET_DATA_BYTE(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w8; j++) {
val2 = l_getDataByte(line1, j);
count2 += val2;
val2 += 0xbbbbbb00;
l_setDataByte(line2, j, val2);
}
}
CompareResults(pixs, pix1, pix2, count1, count2, "8 bpp", rp);
/* ------------------------------------------------- */
/* Test different methods for 16 bpp */
/* ------------------------------------------------- */
count1 = 0;
w16 = w / 16;
for (i = 0; i < h; i++) {
for (j = 0; j < w16; j++) {
val1 = GET_DATA_TWO_BYTES(lines1[i], j);
count1 += val1;
val1 += 0xbbbb0000;
SET_DATA_TWO_BYTES(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w16; j++) {
val2 = l_getDataTwoBytes(line1, j);
count2 += val2;
val2 += 0xbbbb0000;
l_setDataTwoBytes(line2, j, val2);
}
}
CompareResults(pixs, pix1, pix2, count1, count2, "16 bpp", rp);
/* ------------------------------------------------- */
/* Test different methods for 32 bpp */
/* ------------------------------------------------- */
count1 = 0;
w32 = w / 32;
for (i = 0; i < h; i++) {
for (j = 0; j < w32; j++) {
val1 = GET_DATA_FOUR_BYTES(lines1[i], j);
count1 += val1 & 0xfff;
SET_DATA_FOUR_BYTES(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w32; j++) {
val2 = l_getDataFourBytes(line1, j);
count2 += val2 & 0xfff;
l_setDataFourBytes(line2, j, val2);
}
}
CompareResults(pixs, pix1, pix2, count1, count2, "32 bpp", rp);
pixDestroy(&pixs);
pixDestroy(&pix1);
pixDestroy(&pix2);
lept_free(lines1);
lept_free(linet1);
lept_free(linet2);
return regTestCleanup(rp);
}
main(int argc,
char **argv)
{
l_int32 x, y, i, j, k, w, h, w2, w4, w8, w16, w32, wpl, nerrors;
l_int32 count1, count2, count3, ret, val1, val2;
l_uint32 val32;
l_uint32 *data, *line, *line1, *line2, *data1, *data2;
void **lines1, **linet1, **linet2;
PIX *pixs, *pixt1, *pixt2;
static char mainName[] = "lowaccess_reg";
pixs = pixRead("feyn.tif"); /* width divisible by 16 */
pixGetDimensions(pixs, &w, &h, NULL);
data = pixGetData(pixs);
wpl = pixGetWpl(pixs);
lines1 = pixGetLinePtrs(pixs, NULL);
/* Get timing for the 3 different methods */
startTimer();
for (k = 0; k < 10; k++) {
count1 = 0;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
if (GET_DATA_BIT(lines1[i], j))
count1++;
}
}
}
fprintf(stderr, "Time with line ptrs = %5.3f sec, count1 = %d\n",
stopTimer(), count1);
startTimer();
for (k = 0; k < 10; k++) {
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
if (l_getDataBit(line, j))
count2++;
}
}
}
fprintf(stderr, "Time with l_get* = %5.3f sec, count2 = %d\n",
stopTimer(), count2);
startTimer();
for (k = 0; k < 10; k++) {
count3 = 0;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
pixGetPixel(pixs, j, i, &val32);
count3 += val32;
}
}
}
fprintf(stderr, "Time with pixGetPixel() = %5.3f sec, count3 = %d\n",
stopTimer(), count3);
pixt1 = pixCreateTemplate(pixs);
data1 = pixGetData(pixt1);
linet1 = pixGetLinePtrs(pixt1, NULL);
pixt2 = pixCreateTemplate(pixs);
data2 = pixGetData(pixt2);
linet2 = pixGetLinePtrs(pixt2, NULL);
nerrors = 0;
/* Test different methods for 1 bpp */
count1 = 0;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
val1 = GET_DATA_BIT(lines1[i], j);
count1 += val1;
if (val1) SET_DATA_BIT(linet1[i], j);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w; j++) {
val2 = l_getDataBit(line, j);
count2 += val2;
if (val2) l_setDataBit(line2, j);
}
}
ret = compareResults(pixs, pixt1, pixt2, count1, count2, "1 bpp");
nerrors += ret;
/* Test different methods for 2 bpp */
count1 = 0;
w2 = w / 2;
for (i = 0; i < h; i++) {
for (j = 0; j < w2; j++) {
val1 = GET_DATA_DIBIT(lines1[i], j);
count1 += val1;
val1 += 0xbbbbbbbc;
SET_DATA_DIBIT(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w2; j++) {
val2 = l_getDataDibit(line, j);
count2 += val2;
val2 += 0xbbbbbbbc;
l_setDataDibit(line2, j, val2);
}
}
ret = compareResults(pixs, pixt1, pixt2, count1, count2, "2 bpp");
nerrors += ret;
/* Test different methods for 4 bpp */
count1 = 0;
w4 = w / 4;
for (i = 0; i < h; i++) {
for (j = 0; j < w4; j++) {
val1 = GET_DATA_QBIT(lines1[i], j);
count1 += val1;
val1 += 0xbbbbbbb0;
SET_DATA_QBIT(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w4; j++) {
val2 = l_getDataQbit(line, j);
count2 += val2;
val2 += 0xbbbbbbb0;
l_setDataQbit(line2, j, val2);
}
}
ret = compareResults(pixs, pixt1, pixt2, count1, count2, "4 bpp");
nerrors += ret;
/* Test different methods for 8 bpp */
count1 = 0;
w8 = w / 8;
for (i = 0; i < h; i++) {
for (j = 0; j < w8; j++) {
val1 = GET_DATA_BYTE(lines1[i], j);
count1 += val1;
val1 += 0xbbbbbb00;
SET_DATA_BYTE(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w8; j++) {
val2 = l_getDataByte(line, j);
count2 += val2;
val2 += 0xbbbbbb00;
l_setDataByte(line2, j, val2);
}
}
ret = compareResults(pixs, pixt1, pixt2, count1, count2, "8 bpp");
nerrors += ret;
/* Test different methods for 16 bpp */
count1 = 0;
w16 = w / 16;
for (i = 0; i < h; i++) {
for (j = 0; j < w16; j++) {
val1 = GET_DATA_TWO_BYTES(lines1[i], j);
count1 += val1;
val1 += 0xbbbb0000;
SET_DATA_TWO_BYTES(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w16; j++) {
val2 = l_getDataTwoBytes(line, j);
count2 += val2;
val2 += 0xbbbb0000;
l_setDataTwoBytes(line2, j, val2);
}
}
ret = compareResults(pixs, pixt1, pixt2, count1, count2, "16 bpp");
nerrors += ret;
/* Test different methods for 32 bpp */
count1 = 0;
w32 = w / 32;
for (i = 0; i < h; i++) {
for (j = 0; j < w32; j++) {
val1 = GET_DATA_FOUR_BYTES(lines1[i], j);
count1 += val1 & 0xfff;
SET_DATA_FOUR_BYTES(linet1[i], j, val1);
}
}
count2 = 0;
for (i = 0; i < h; i++) {
line = data + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w32; j++) {
val2 = l_getDataFourBytes(line, j);
count2 += val2 & 0xfff;
l_setDataFourBytes(line2, j, val2);
}
}
ret = compareResults(pixs, pixt1, pixt2, count1, count2, "32 bpp");
nerrors += ret;
if (!nerrors)
fprintf(stderr, "**** No errors ****\n");
else
fprintf(stderr, "**** %d errors found! ****\n", nerrors);
pixDestroy(&pixs);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
lept_free(lines1);
lept_free(linet1);
lept_free(linet2);
return 0;
}
/*!
* pixFindLargestRectangle()
*
* Input: pixs (1 bpp)
* polarity (0 within background, 1 within foreground)
* &box (<return> largest rectangle, either by area or
* by perimeter)
* debugflag (1 to output image with rectangle drawn on it)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) Why is this here? This is a simple and elegant solution to
* a problem in computational geometry that at first appears
* quite difficult: what is the largest rectangle that can
* be placed in the image, covering only pixels of one polarity
* (bg or fg)? The solution is O(n), where n is the number
* of pixels in the image, and it requires nothing more than
* using a simple recursion relation in a single sweep of the image.
* (2) In a sweep from UL to LR with left-to-right being the fast
* direction, calculate the largest white rectangle at (x, y),
* using previously calculated values at pixels #1 and #2:
* #1: (x, y - 1)
* #2: (x - 1, y)
* We also need the most recent "black" pixels that were seen
* in the current row and column.
* Consider the largest area. There are only two possibilities:
* (a) Min(w(1), horizdist) * (h(1) + 1)
* (b) Min(h(2), vertdist) * (w(2) + 1)
* where
* horizdist: the distance from the rightmost "black" pixel seen
* in the current row across to the current pixel
* vertdist: the distance from the lowest "black" pixel seen
* in the current column down to the current pixel
* and we choose the Max of (a) and (b).
* (3) To convince yourself that these recursion relations are correct,
* it helps to draw the maximum rectangles at #1 and #2.
* Then for #1, you try to extend the rectangle down one line,
* so that the height is h(1) + 1. Do you get the full
* width of #1, w(1)? It depends on where the black pixels are
* in the current row. You know the final width is bounded by w(1)
* and w(2) + 1, but the actual value depends on the distribution
* of black pixels in the current row that are at a distance
* from the current pixel that is between these limits.
* We call that value "horizdist", and the area is then given
* by the expression (a) above. Using similar reasoning for #2,
* where you attempt to extend the rectangle to the right
* by 1 pixel, you arrive at (b). The largest rectangle is
* then found by taking the Max.
*/
l_int32
pixFindLargestRectangle(PIX *pixs,
l_int32 polarity,
BOX **pbox,
const char *debugfile)
{
l_int32 i, j, w, h, d, wpls, val;
l_int32 wp, hp, w1, w2, h1, h2, wmin, hmin, area1, area2;
l_int32 xmax, ymax; /* LR corner of the largest rectangle */
l_int32 maxarea, wmax, hmax, vertdist, horizdist, prevfg;
l_int32 *lowestfg;
l_uint32 *datas, *lines;
l_uint32 **linew, **lineh;
BOX *box;
PIX *pixw, *pixh; /* keeps the width and height for the largest */
/* rectangles whose LR corner is located there. */
PROCNAME("pixFindLargestRectangle");
if (!pbox)
return ERROR_INT("&box not defined", procName, 1);
*pbox = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 1)
return ERROR_INT("pixs not 1 bpp", procName, 1);
if (polarity != 0 && polarity != 1)
return ERROR_INT("invalid polarity", procName, 1);
/* Initialize lowest "fg" seen so far for each column */
lowestfg = (l_int32 *)CALLOC(w, sizeof(l_int32));
for (i = 0; i < w; i++)
lowestfg[i] = -1;
/* The combination (val ^ polarity) is the color for which we
* are searching for the maximum rectangle. For polarity == 0,
* we search in the bg (white). */
pixw = pixCreate(w, h, 32); /* stores width */
pixh = pixCreate(w, h, 32); /* stores height */
linew = (l_uint32 **)pixGetLinePtrs(pixw, NULL);
lineh = (l_uint32 **)pixGetLinePtrs(pixh, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
maxarea = xmax = ymax = wmax = hmax = 0;
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
prevfg = -1;
for (j = 0; j < w; j++) {
val = GET_DATA_BIT(lines, j);
if ((val ^ polarity) == 0) { /* bg (0) if polarity == 0, etc. */
if (i == 0 && j == 0) {
wp = hp = 1;
}
else if (i == 0) {
wp = linew[i][j - 1] + 1;
hp = 1;
}
else if (j == 0) {
wp = 1;
hp = lineh[i - 1][j] + 1;
}
else {
/* Expand #1 prev rectangle down */
w1 = linew[i - 1][j];
h1 = lineh[i - 1][j];
horizdist = j - prevfg;
wmin = L_MIN(w1, horizdist); /* width of new rectangle */
area1 = wmin * (h1 + 1);
/* Expand #2 prev rectangle to right */
w2 = linew[i][j - 1];
h2 = lineh[i][j - 1];
vertdist = i - lowestfg[j];
hmin = L_MIN(h2, vertdist); /* height of new rectangle */
area2 = hmin * (w2 + 1);
if (area1 > area2) {
wp = wmin;
hp = h1 + 1;
}
else {
wp = w2 + 1;
hp = hmin;
}
}
}
else { /* fg (1) if polarity == 0; bg (0) if polarity == 1 */
prevfg = j;
lowestfg[j] = i;
wp = hp = 0;
}
linew[i][j] = wp;
lineh[i][j] = hp;
if (wp * hp > maxarea) {
maxarea = wp * hp;
xmax = j;
ymax = i;
wmax = wp;
hmax = hp;
}
}
}
/* Translate from LR corner to Box coords (UL corner, w, h) */
box = boxCreate(xmax - wmax + 1, ymax - hmax + 1, wmax, hmax);
*pbox = box;
if (debugfile) {
PIX *pixdb;
pixdb = pixConvertTo8(pixs, TRUE);
pixRenderHashBoxArb(pixdb, box, 6, 2, L_NEG_SLOPE_LINE, 1, 255, 0, 0);
pixWrite(debugfile, pixdb, IFF_PNG);
pixDestroy(&pixdb);
}
FREE(linew);
FREE(lineh);
FREE(lowestfg);
pixDestroy(&pixw);
pixDestroy(&pixh);
return 0;
}
/*!
* pixSearchGrayMaze()
*
* Input: pixs (1 bpp, maze)
* xi, yi (beginning point; use same initial point
* that was used to generate the maze)
* xf, yf (end point, or close to it)
* &ppixd (<optional return> maze with path illustrated, or
* if no path possible, the part of the maze
* that was searched)
* Return: pta (shortest path), or null if either no path
* exists or on error
*
* Commentary:
* Consider first a slight generalization of the binary maze
* search problem. Suppose that you can go through walls,
* but the cost is higher (say, an increment of 3 to go into
* a wall pixel rather than 1)? You're still trying to find
* the shortest path. One way to do this is with an ordered
* queue, and a simple way to visualize an ordered queue is as
* a set of stacks, each stack being marked with the distance
* of each pixel in the stack from the start. We place the
* start pixel in stack 0, pop it, and process its 4 children.
* Each pixel is given a distance that is incremented from that
* of its parent (0 in this case), depending on if it is a wall
* pixel or not. That value may be recorded on a distance map,
* according to the algorithm below. For children of the first
* pixel, those not on a wall go in stack 1, and wall
* children go in stack 3. Stack 0 being emptied, the process
* then continues with pixels being popped from stack 1.
* Here is the algorithm for each child pixel. The pixel's
* distance value, were it to be placed on a stack, is compared
* with the value for it that is on the distance map. There
* are three possible cases:
* (1) If the pixel has not yet been registered, it is pushed
* on its stack and the distance is written to the map.
* (2) If it has previously been registered with a higher distance,
* the distance on the map is relaxed to that of the
* current pixel, which is then placed on its stack.
* (3) If it has previously been registered with an equal
* or lower value, the pixel is discarded.
* The pixels are popped and processed successively from
* stack 1, and when stack 1 is empty, popping starts on stack 2.
* This continues until the destination pixel is popped off
* a stack. The minimum path is then derived from the distance map,
* going back from the end point as before. This is just Dijkstra's
* algorithm for a directed graph; here, the underlying graph
* (consisting of the pixels and four edges connecting each pixel
* to its 4-neighbor) is a special case of a directed graph, where
* each edge is bi-directional. The implementation of this generalized
* maze search is left as an exercise to the reader.
*
* Let's generalize a bit further. Suppose the "maze" is just
* a grayscale image -- think of it as an elevation map. The cost
* of moving on this surface depends on the height, or the gradient,
* or whatever you want. All that is required is that the cost
* is specified and non-negative on each link between adjacent
* pixels. Now the problem becomes: find the least cost path
* moving on this surface between two specified end points.
* For example, if the cost across an edge between two pixels
* depends on the "gradient", you can use:
* cost = 1 + L_ABS(deltaV)
* where deltaV is the difference in value between two adjacent
* pixels. If the costs are all integers, we can still use an array
* of stacks to avoid ordering the queue (e.g., by using a heap sort.)
* This is a neat problem, because you don't even have to build a
* maze -- you can can use it on any grayscale image!
*
* Rather than using an array of stacks, a more practical
* approach is to implement with a priority queue, which is
* a queue that is sorted so that the elements with the largest
* (or smallest) key values always come off first. The
* priority queue is efficiently implemented as a heap, and
* this is how we do it. Suppose you run the algorithm
* using a priority queue, doing the bookkeeping with an
* auxiliary image data structure that saves the distance of
* each pixel put on the queue as before, according to the method
* described above. We implement it as a 2-way choice by
* initializing the distance array to a large value and putting
* a pixel on the queue if its distance is less than the value
* found on the array. When you finally pop the end pixel from
* the queue, you're done, and you can trace the path backward,
* either always going downhill or using an auxiliary image to
* give you the direction to go at each step. This is implemented
* here in searchGrayMaze().
*
* Do we really have to use a sorted queue? Can we solve this
* generalized maze with an unsorted queue of pixels? (Or even
* an unsorted stack, doing a depth-first search (DFS)?)
* Consider a different algorithm for this generalized maze, where
* we travel again breadth first, but this time use a single,
* unsorted queue. An auxiliary image is used as before to
* store the distances and to determine if pixels get pushed
* on the stack or dropped. As before, we must allow pixels
* to be revisited, with relaxation of the distance if a shorter
* path arrives later. As a result, we will in general have
* multiple instances of the same pixel on the stack with different
* distances. However, because the queue is not ordered, some of
* these pixels will be popped when another instance with a lower
* distance is still on the stack. Here, we're just popping them
* in the order they go on, rather than setting up a priority
* based on minimum distance. Thus, unlike the priority queue,
* when a pixel is popped we have to check the distance map to
* see if a pixel with a lower distance has been put on the queue,
* and, if so, we discard the pixel we just popped. So the
* "while" loop looks like this:
* - pop a pixel from the queue
* - check its distance against the distance stored in the
* distance map; if larger, discard
* - otherwise, for each of its neighbors:
* - compute its distance from the start pixel
* - compare this distance with that on the distance map:
* - if the distance map value higher, relax the distance
* and push the pixel on the queue
* - if the distance map value is lower, discard the pixel
*
* How does this loop terminate? Before, with an ordered queue,
* it terminates when you pop the end pixel. But with an unordered
* queue (or stack), the first time you hit the end pixel, the
* distance is not guaranteed to be correct, because the pixels
* along the shortest path may not have yet been visited and relaxed.
* Because the shortest path can theoretically go anywhere,
* we must keep going. How do we know when to stop? Dijkstra
* uses an ordered queue to systematically remove nodes from
* further consideration. (Each time a pixel is popped, we're
* done with it; it's "finalized" in the Dijkstra sense because
* we know the shortest path to it.) However, with an unordered
* queue, the brute force answer is: stop when the queue
* (or stack) is empty, because then every pixel in the image
* has been assigned its minimum "distance" from the start pixel.
*
* This is similar to the situation when you use a stack for the
* simpler uniform-step problem: with breadth-first search (BFS)
* the pixels on the queue are automatically ordered, so you are
* done when you locate the end pixel as a neighbor of a popped pixel;
* whereas depth-first search (DFS), using a stack, requires,
* in general, a search of every accessible pixel. Further, if
* a pixel is revisited with a smaller distance, that distance is
* recorded and the pixel is put on the stack again.
*
* But surely, you ask, can't we stop sooner? What if the
* start and end pixels are very close to each other?
* OK, suppose they are, and you have very high walls and a
* long snaking level path that is actually the minimum cost.
* That long path can wind back and forth across the entire
* maze many times before ending up at the end point, which
* could be just over a wall from the start. With the unordered
* queue, you very quickly get a high distance for the end
* pixel, which will be relaxed to the minimum distance only
* after all the pixels of the path have been visited and placed
* on the queue, multiple times for many of them. So that's the
* price for not ordering the queue!
*/
PTA *
pixSearchGrayMaze(PIX *pixs,
l_int32 xi,
l_int32 yi,
l_int32 xf,
l_int32 yf,
PIX **ppixd)
{
l_int32 x, y, w, h, d;
l_uint32 val, valr, vals, rpixel, gpixel, bpixel;
void **lines8, **liner32, **linep8;
l_int32 cost, dist, distparent, sival, sivals;
MAZEEL *el, *elp;
PIX *pixd; /* optionally plot the path on this RGB version of pixs */
PIX *pixr; /* for bookkeeping, to indicate the minimum distance */
/* to pixels already visited */
PIX *pixp; /* for bookkeeping, to indicate direction to parent */
L_HEAP *lh;
PTA *pta;
PROCNAME("pixSearchGrayMaze");
if (ppixd) *ppixd = NULL;
if (!pixs)
return (PTA *)ERROR_PTR("pixs not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 8)
return (PTA *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (xi <= 0 || xi >= w)
return (PTA *)ERROR_PTR("xi not valid", procName, NULL);
if (yi <= 0 || yi >= h)
return (PTA *)ERROR_PTR("yi not valid", procName, NULL);
pixd = NULL;
pta = NULL;
pixr = pixCreate(w, h, 32);
pixSetAll(pixr); /* initialize to max value */
pixp = pixCreate(w, h, 8); /* direction to parent stored as enum val */
lines8 = pixGetLinePtrs(pixs, NULL);
linep8 = pixGetLinePtrs(pixp, NULL);
liner32 = pixGetLinePtrs(pixr, NULL);
lh = lheapCreate(0, L_SORT_INCREASING); /* always remove closest pixels */
/* Prime the heap with the first pixel */
pixGetPixel(pixs, xi, yi, &val);
el = mazeelCreate(xi, yi, 0); /* don't need direction here */
el->distance = 0;
pixGetPixel(pixs, xi, yi, &val);
el->val = val;
pixSetPixel(pixr, xi, yi, 0); /* distance is 0 */
lheapAdd(lh, el);
/* Breadth-first search with priority queue (implemented by
a heap), labeling direction to parents in pixp and minimum
distance to visited pixels in pixr. Stop when we pull
the destination point (xf, yf) off the queue. */
while (lheapGetCount(lh) > 0) {
elp = (MAZEEL *)lheapRemove(lh);
if (!elp)
return (PTA *)ERROR_PTR("heap broken!!", procName, NULL);
x = elp->x;
y = elp->y;
if (x == xf && y == yf) { /* exit condition */
FREE(elp);
break;
}
distparent = (l_int32)elp->distance;
val = elp->val;
sival = val;
if (x > 0) { /* check to west */
vals = GET_DATA_BYTE(lines8[y], x - 1);
valr = GET_DATA_FOUR_BYTES(liner32[y], x - 1);
sivals = (l_int32)vals;
cost = 1 + L_ABS(sivals - sival); /* cost to move to this pixel */
dist = distparent + cost;
if (dist < valr) { /* shortest path so far to this pixel */
SET_DATA_FOUR_BYTES(liner32[y], x - 1, dist); /* new dist */
SET_DATA_BYTE(linep8[y], x - 1, DIR_EAST); /* parent to E */
el = mazeelCreate(x - 1, y, 0);
el->val = vals;
el->distance = dist;
lheapAdd(lh, el);
}
}
if (y > 0) { /* check north */
vals = GET_DATA_BYTE(lines8[y - 1], x);
valr = GET_DATA_FOUR_BYTES(liner32[y - 1], x);
sivals = (l_int32)vals;
cost = 1 + L_ABS(sivals - sival); /* cost to move to this pixel */
dist = distparent + cost;
if (dist < valr) { /* shortest path so far to this pixel */
SET_DATA_FOUR_BYTES(liner32[y - 1], x, dist); /* new dist */
SET_DATA_BYTE(linep8[y - 1], x, DIR_SOUTH); /* parent to S */
el = mazeelCreate(x, y - 1, 0);
el->val = vals;
el->distance = dist;
lheapAdd(lh, el);
}
}
if (x < w - 1) { /* check east */
vals = GET_DATA_BYTE(lines8[y], x + 1);
valr = GET_DATA_FOUR_BYTES(liner32[y], x + 1);
sivals = (l_int32)vals;
cost = 1 + L_ABS(sivals - sival); /* cost to move to this pixel */
dist = distparent + cost;
if (dist < valr) { /* shortest path so far to this pixel */
SET_DATA_FOUR_BYTES(liner32[y], x + 1, dist); /* new dist */
SET_DATA_BYTE(linep8[y], x + 1, DIR_WEST); /* parent to W */
el = mazeelCreate(x + 1, y, 0);
el->val = vals;
el->distance = dist;
lheapAdd(lh, el);
}
}
if (y < h - 1) { /* check south */
vals = GET_DATA_BYTE(lines8[y + 1], x);
valr = GET_DATA_FOUR_BYTES(liner32[y + 1], x);
sivals = (l_int32)vals;
cost = 1 + L_ABS(sivals - sival); /* cost to move to this pixel */
dist = distparent + cost;
if (dist < valr) { /* shortest path so far to this pixel */
SET_DATA_FOUR_BYTES(liner32[y + 1], x, dist); /* new dist */
SET_DATA_BYTE(linep8[y + 1], x, DIR_NORTH); /* parent to N */
el = mazeelCreate(x, y + 1, 0);
el->val = vals;
el->distance = dist;
lheapAdd(lh, el);
}
}
FREE(elp);
}
lheapDestroy(&lh, TRUE);
if (ppixd) {
pixd = pixConvert8To32(pixs);
*ppixd = pixd;
}
composeRGBPixel(255, 0, 0, &rpixel); /* start point */
composeRGBPixel(0, 255, 0, &gpixel);
composeRGBPixel(0, 0, 255, &bpixel); /* end point */
x = xf;
y = yf;
pta = ptaCreate(0);
while (1) { /* write path onto pixd */
ptaAddPt(pta, x, y);
if (x == xi && y == yi)
break;
if (pixd)
pixSetPixel(pixd, x, y, gpixel);
pixGetPixel(pixp, x, y, &val);
if (val == DIR_NORTH)
y--;
else if (val == DIR_SOUTH)
y++;
else if (val == DIR_EAST)
x++;
else if (val == DIR_WEST)
x--;
pixGetPixel(pixr, x, y, &val);
#if DEBUG_PATH
fprintf(stderr, "(x,y) = (%d, %d); dist = %d\n", x, y, val);
#endif /* DEBUG_PATH */
}
if (pixd) {
pixSetPixel(pixd, xi, yi, rpixel);
pixSetPixel(pixd, xf, yf, bpixel);
}
pixDestroy(&pixp);
pixDestroy(&pixr);
FREE(lines8);
FREE(linep8);
FREE(liner32);
return pta;
}
/*!
* pixSearchBinaryMaze()
*
* Input: pixs (1 bpp, maze)
* xi, yi (beginning point; use same initial point
* that was used to generate the maze)
* xf, yf (end point, or close to it)
* &ppixd (<optional return> maze with path illustrated, or
* if no path possible, the part of the maze
* that was searched)
* Return: pta (shortest path), or null if either no path
* exists or on error
*
* Notes:
* (1) Because of the overhead in calling pixGetPixel() and
* pixSetPixel(), we have used raster line pointers and the
* GET_DATA* and SET_DATA* macros for many of the pix accesses.
* (2) Commentary:
* The goal is to find the shortest path between beginning and
* end points, without going through walls, and there are many
* ways to solve this problem.
* We use a queue to implement a breadth-first search. Two auxiliary
* "image" data structures can be used: one to mark the visited
* pixels and one to give the direction to the parent for each
* visited pixels. The first structure is used to avoid putting
* pixels on the queue more than once, and the second is used
* for retracing back to the origin, like the breadcrumbs in
* Hansel and Gretel. Each pixel taken off the queue is destroyed
* after it is used to locate the allowed neighbors. In fact,
* only one distance image is required, if you initialize it
* to some value that signifies "not yet visited." (We use
* a binary image for marking visited pixels because it is clearer.)
* This method for a simple search of a binary maze is implemented in
* searchBinaryMaze().
* An alternative method would store the (manhattan) distance
* from the start point with each pixel on the queue. The children
* of each pixel get a distance one larger than the parent. These
* values can be stored in an auxiliary distance map image
* that is constructed simultaneously with the search. Once the
* end point is reached, the distance map is used to backtrack
* along a minimum path. There may be several equal length
* minimum paths, any one of which can be chosen this way.
*/
PTA *
pixSearchBinaryMaze(PIX *pixs,
l_int32 xi,
l_int32 yi,
l_int32 xf,
l_int32 yf,
PIX **ppixd)
{
l_int32 i, j, x, y, w, h, d, found;
l_uint32 val, rpixel, gpixel, bpixel;
void **lines1, **linem1, **linep8, **lined32;
MAZEEL *el, *elp;
PIX *pixd; /* the shortest path written on the maze image */
PIX *pixm; /* for bookkeeping, to indicate pixels already visited */
PIX *pixp; /* for bookkeeping, to indicate direction to parent */
L_QUEUE *lq;
PTA *pta;
PROCNAME("pixSearchBinaryMaze");
if (ppixd) *ppixd = NULL;
if (!pixs)
return (PTA *)ERROR_PTR("pixs not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 1)
return (PTA *)ERROR_PTR("pixs not 1 bpp", procName, NULL);
if (xi <= 0 || xi >= w)
return (PTA *)ERROR_PTR("xi not valid", procName, NULL);
if (yi <= 0 || yi >= h)
return (PTA *)ERROR_PTR("yi not valid", procName, NULL);
pixGetPixel(pixs, xi, yi, &val);
if (val != 0)
return (PTA *)ERROR_PTR("(xi,yi) not bg pixel", procName, NULL);
pixd = NULL;
pta = NULL;
/* Find a bg pixel near input point (xf, yf) */
localSearchForBackground(pixs, &xf, &yf, 5);
#if DEBUG_MAZE
fprintf(stderr, "(xi, yi) = (%d, %d), (xf, yf) = (%d, %d)\n",
xi, yi, xf, yf);
#endif /* DEBUG_MAZE */
pixm = pixCreate(w, h, 1); /* initialized to OFF */
pixp = pixCreate(w, h, 8); /* direction to parent stored as enum val */
lines1 = pixGetLinePtrs(pixs, NULL);
linem1 = pixGetLinePtrs(pixm, NULL);
linep8 = pixGetLinePtrs(pixp, NULL);
lq = lqueueCreate(0);
/* Prime the queue with the first pixel; it is OFF */
el = mazeelCreate(xi, yi, 0); /* don't need direction here */
pixSetPixel(pixm, xi, yi, 1); /* mark visited */
lqueueAdd(lq, el);
/* Fill up the pix storing directions to parents,
* stopping when we hit the point (xf, yf) */
found = FALSE;
while (lqueueGetCount(lq) > 0) {
elp = (MAZEEL *)lqueueRemove(lq);
x = elp->x;
y = elp->y;
if (x == xf && y == yf) {
found = TRUE;
FREE(elp);
break;
}
if (x > 0) { /* check to west */
val = GET_DATA_BIT(linem1[y], x - 1);
if (val == 0) { /* not yet visited */
SET_DATA_BIT(linem1[y], x - 1); /* mark visited */
val = GET_DATA_BIT(lines1[y], x - 1);
if (val == 0) { /* bg, not a wall */
SET_DATA_BYTE(linep8[y], x - 1, DIR_EAST); /* parent E */
el = mazeelCreate(x - 1, y, 0);
lqueueAdd(lq, el);
}
}
}
if (y > 0) { /* check north */
val = GET_DATA_BIT(linem1[y - 1], x);
if (val == 0) { /* not yet visited */
SET_DATA_BIT(linem1[y - 1], x); /* mark visited */
val = GET_DATA_BIT(lines1[y - 1], x);
if (val == 0) { /* bg, not a wall */
SET_DATA_BYTE(linep8[y - 1], x, DIR_SOUTH); /* parent S */
el = mazeelCreate(x, y - 1, 0);
lqueueAdd(lq, el);
}
}
}
if (x < w - 1) { /* check east */
val = GET_DATA_BIT(linem1[y], x + 1);
if (val == 0) { /* not yet visited */
SET_DATA_BIT(linem1[y], x + 1); /* mark visited */
val = GET_DATA_BIT(lines1[y], x + 1);
if (val == 0) { /* bg, not a wall */
SET_DATA_BYTE(linep8[y], x + 1, DIR_WEST); /* parent W */
el = mazeelCreate(x + 1, y, 0);
lqueueAdd(lq, el);
}
}
}
if (y < h - 1) { /* check south */
val = GET_DATA_BIT(linem1[y + 1], x);
if (val == 0) { /* not yet visited */
SET_DATA_BIT(linem1[y + 1], x); /* mark visited */
val = GET_DATA_BIT(lines1[y + 1], x);
if (val == 0) { /* bg, not a wall */
SET_DATA_BYTE(linep8[y + 1], x, DIR_NORTH); /* parent N */
el = mazeelCreate(x, y + 1, 0);
lqueueAdd(lq, el);
}
}
}
FREE(elp);
}
lqueueDestroy(&lq, TRUE);
pixDestroy(&pixm);
FREE(linem1);
if (ppixd) {
pixd = pixUnpackBinary(pixs, 32, 1);
*ppixd = pixd;
}
composeRGBPixel(255, 0, 0, &rpixel); /* start point */
composeRGBPixel(0, 255, 0, &gpixel);
composeRGBPixel(0, 0, 255, &bpixel); /* end point */
if (!found) {
L_INFO(" No path found", procName);
if (pixd) { /* paint all visited locations */
lined32 = pixGetLinePtrs(pixd, NULL);
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
val = GET_DATA_BYTE(linep8[i], j);
if (val != 0 && pixd)
SET_DATA_FOUR_BYTES(lined32[i], j, gpixel);
}
}
FREE(lined32);
}
}
else { /* write path onto pixd */
L_INFO(" Path found", procName);
pta = ptaCreate(0);
x = xf;
y = yf;
while (1) {
ptaAddPt(pta, x, y);
if (x == xi && y == yi)
break;
if (pixd)
pixSetPixel(pixd, x, y, gpixel);
pixGetPixel(pixp, x, y, &val);
if (val == DIR_NORTH)
y--;
else if (val == DIR_SOUTH)
y++;
else if (val == DIR_EAST)
x++;
else if (val == DIR_WEST)
x--;
}
}
if (pixd) {
pixSetPixel(pixd, xi, yi, rpixel);
pixSetPixel(pixd, xf, yf, bpixel);
}
pixDestroy(&pixp);
FREE(lines1);
FREE(linep8);
return pta;
}
/*!
* pixApplyVerticalDisparity()
*
* Input: pixs (1, 8 or 32 bpp)
* fpix (vertical disparity array)
* Return: pixd (modified by fpix), or null on error
*
* Notes:
* (1) This applies the vertical disparity array to the specified
* image. For src pixels above the image, we use the pixels
* in the first raster line.
*/
PIX *
pixApplyVerticalDisparity(PIX *pixs,
FPIX *fpix)
{
l_int32 i, j, w, h, d, fw, fh, wpld, wplf, isrc, val8;
l_uint32 *datad, *lined;
l_float32 *dataf, *linef;
void **lineptrs;
PIX *pixd;
PROCNAME("pixApplyVerticalDisparity");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (!fpix)
return (PIX *)ERROR_PTR("fpix not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 1 && d != 8 && d != 32)
return (PIX *)ERROR_PTR("pix not 1, 8 or 32 bpp", procName, NULL);
fpixGetDimensions(fpix, &fw, &fh);
if (fw < w || fh < h) {
fprintf(stderr, "fw = %d, w = %d, fh = %d, h = %d\n", fw, w, fh, h);
return (PIX *)ERROR_PTR("invalid fpix size", procName, NULL);
}
pixd = pixCreateTemplate(pixs);
datad = pixGetData(pixd);
dataf = fpixGetData(fpix);
wpld = pixGetWpl(pixd);
wplf = fpixGetWpl(fpix);
if (d == 1) {
lineptrs = pixGetLinePtrs(pixs, NULL);
for (i = 0; i < h; i++) {
lined = datad + i * wpld;
linef = dataf + i * wplf;
for (j = 0; j < w; j++) {
isrc = (l_int32)(i - linef[j] + 0.5);
if (isrc < 0) isrc = 0;
if (isrc > h - 1) isrc = h - 1;
if (GET_DATA_BIT(lineptrs[isrc], j))
SET_DATA_BIT(lined, j);
}
}
}
else if (d == 8) {
lineptrs = pixGetLinePtrs(pixs, NULL);
for (i = 0; i < h; i++) {
lined = datad + i * wpld;
linef = dataf + i * wplf;
for (j = 0; j < w; j++) {
isrc = (l_int32)(i - linef[j] + 0.5);
if (isrc < 0) isrc = 0;
if (isrc > h - 1) isrc = h - 1;
val8 = GET_DATA_BYTE(lineptrs[isrc], j);
SET_DATA_BYTE(lined, j, val8);
}
}
}
else { /* d == 32 */
lineptrs = pixGetLinePtrs(pixs, NULL);
for (i = 0; i < h; i++) {
lined = datad + i * wpld;
linef = dataf + i * wplf;
for (j = 0; j < w; j++) {
isrc = (l_int32)(i - linef[j] + 0.5);
if (isrc < 0) isrc = 0;
if (isrc > h - 1) isrc = h - 1;
lined[j] = GET_DATA_FOUR_BYTES(lineptrs[isrc], j);
}
}
}
FREE(lineptrs);
return pixd;
}
/*!
* pixApplyVertDisparity()
*
* Input: dew
* pixs (1, 8 or 32 bpp)
* grayin (gray value, from 0 to 255, for pixels brought in;
* use -1 to use pixels on the boundary of pixs)
* Return: pixd (modified to remove vertical disparity), or null on error
*
* Notes:
* (1) This applies the vertical disparity array to the specified
* image. For src pixels above the image, we use the pixels
* in the first raster line.
* (2) Specify gray color for pixels brought in from the outside:
* 0 is black, 255 is white. Use -1 to select pixels from the
* boundary of the source image.
*/
static PIX *
pixApplyVertDisparity(L_DEWARP *dew,
PIX *pixs,
l_int32 grayin)
{
l_int32 i, j, w, h, d, fw, fh, wpld, wplf, isrc, val8;
l_uint32 *datad, *lined;
l_float32 *dataf, *linef;
void **lineptrs;
FPIX *fpix;
PIX *pixd;
PROCNAME("pixApplyVertDisparity");
if (!dew)
return (PIX *)ERROR_PTR("dew not defined", procName, NULL);
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 1 && d != 8 && d != 32)
return (PIX *)ERROR_PTR("pix not 1, 8 or 32 bpp", procName, NULL);
if ((fpix = dew->fullvdispar) == NULL)
return (PIX *)ERROR_PTR("fullvdispar not defined", procName, NULL);
fpixGetDimensions(fpix, &fw, &fh);
if (fw < w || fh < h) {
fprintf(stderr, "fw = %d, w = %d, fh = %d, h = %d\n", fw, w, fh, h);
return (PIX *)ERROR_PTR("invalid fpix size", procName, NULL);
}
/* Two choices for requested pixels outside pixs: (1) use pixels'
* from the boundary of pixs; use white or light gray pixels. */
pixd = pixCreateTemplate(pixs);
if (grayin >= 0)
pixSetAllGray(pixd, grayin);
datad = pixGetData(pixd);
dataf = fpixGetData(fpix);
wpld = pixGetWpl(pixd);
wplf = fpixGetWpl(fpix);
if (d == 1) {
lineptrs = pixGetLinePtrs(pixs, NULL);
for (i = 0; i < h; i++) {
lined = datad + i * wpld;
linef = dataf + i * wplf;
for (j = 0; j < w; j++) {
isrc = (l_int32)(i - linef[j] + 0.5);
if (grayin < 0) /* use value at boundary if outside */
isrc = L_MIN(L_MAX(isrc, 0), h - 1);
if (isrc >= 0 && isrc < h) { /* remains gray if outside */
if (GET_DATA_BIT(lineptrs[isrc], j))
SET_DATA_BIT(lined, j);
}
}
}
} else if (d == 8) {
lineptrs = pixGetLinePtrs(pixs, NULL);
for (i = 0; i < h; i++) {
lined = datad + i * wpld;
linef = dataf + i * wplf;
for (j = 0; j < w; j++) {
isrc = (l_int32)(i - linef[j] + 0.5);
if (grayin < 0)
isrc = L_MIN(L_MAX(isrc, 0), h - 1);
if (isrc >= 0 && isrc < h) {
val8 = GET_DATA_BYTE(lineptrs[isrc], j);
SET_DATA_BYTE(lined, j, val8);
}
}
}
} else { /* d == 32 */
lineptrs = pixGetLinePtrs(pixs, NULL);
for (i = 0; i < h; i++) {
lined = datad + i * wpld;
linef = dataf + i * wplf;
for (j = 0; j < w; j++) {
isrc = (l_int32)(i - linef[j] + 0.5);
if (grayin < 0)
isrc = L_MIN(L_MAX(isrc, 0), h - 1);
if (isrc >= 0 && isrc < h)
lined[j] = GET_DATA_FOUR_BYTES(lineptrs[isrc], j);
}
}
}
LEPT_FREE(lineptrs);
return pixd;
}
/*!
* pixRotateBySampling()
*
* Input: pixs (1, 2, 4, 8, 16, 32 bpp rgb; can be cmapped)
* xcen (x value of center of rotation)
* ycen (y value of center of rotation)
* angle (radians; clockwise is positive)
* incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
* Return: pixd, or null on error
*
* Notes:
* (1) For very small rotations, just return a clone.
* (2) Rotation brings either white or black pixels in
* from outside the image.
* (3) Colormaps are retained.
*/
PIX *
pixRotateBySampling(PIX *pixs,
l_int32 xcen,
l_int32 ycen,
l_float32 angle,
l_int32 incolor) {
l_int32 w, h, d, i, j, x, y, xdif, ydif, wm1, hm1, wpld;
l_uint32 val;
l_float32 sina, cosa;
l_uint32 *datad, *lined;
void **lines;
PIX *pixd;
PROCNAME("pixRotateBySampling");
if (!pixs)
return (PIX *) ERROR_PTR("pixs not defined", procName, NULL);
if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
return (PIX *) ERROR_PTR("invalid incolor", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 1 && d != 2 && d != 4 && d != 8 && d != 16 && d != 32)
return (PIX *) ERROR_PTR("invalid depth", procName, NULL);
if (L_ABS(angle) < MIN_ANGLE_TO_ROTATE)
return pixClone(pixs);
if ((pixd = pixCreateTemplateNoInit(pixs)) == NULL)
return (PIX *) ERROR_PTR("pixd not made", procName, NULL);
pixSetBlackOrWhite(pixd, incolor);
sina = sin(angle);
cosa = cos(angle);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
wm1 = w - 1;
hm1 = h - 1;
lines = pixGetLinePtrs(pixs, NULL);
/* Treat 1 bpp case specially */
if (d == 1) {
for (i = 0; i < h; i++) { /* scan over pixd */
lined = datad + i * wpld;
ydif = ycen - i;
for (j = 0; j < w; j++) {
xdif = xcen - j;
x = xcen + (l_int32)(-xdif * cosa - ydif * sina);
if (x < 0 || x > wm1) continue;
y = ycen + (l_int32)(-ydif * cosa + xdif * sina);
if (y < 0 || y > hm1) continue;
if (incolor == L_BRING_IN_WHITE) {
if (GET_DATA_BIT(lines[y], x))
SET_DATA_BIT(lined, j);
} else {
if (!GET_DATA_BIT(lines[y], x))
CLEAR_DATA_BIT(lined, j);
}
}
}
FREE(lines);
return pixd;
}
for (i = 0; i < h; i++) { /* scan over pixd */
lined = datad + i * wpld;
ydif = ycen - i;
for (j = 0; j < w; j++) {
xdif = xcen - j;
x = xcen + (l_int32)(-xdif * cosa - ydif * sina);
if (x < 0 || x > wm1) continue;
y = ycen + (l_int32)(-ydif * cosa + xdif * sina);
if (y < 0 || y > hm1) continue;
switch (d) {
case 8:
val = GET_DATA_BYTE(lines[y], x);
SET_DATA_BYTE(lined, j, val);
break;
case 32:
val = GET_DATA_FOUR_BYTES(lines[y], x);
SET_DATA_FOUR_BYTES(lined, j, val);
break;
case 2:
val = GET_DATA_DIBIT(lines[y], x);
SET_DATA_DIBIT(lined, j, val);
break;
case 4:
val = GET_DATA_QBIT(lines[y], x);
SET_DATA_QBIT(lined, j, val);
break;
case 16:
val = GET_DATA_TWO_BYTES(lines[y], x);
SET_DATA_TWO_BYTES(lined, j, val);
break;
default:
return (PIX *) ERROR_PTR("invalid depth", procName, NULL);
}
}
}
FREE(lines);
return pixd;
}
