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Functions
polyaprx.h File Reference
`#include "blobs.h"`
`#include "coutln.h"`

Go to the source code of this file.

## Functions

TESSLINE * | ApproximateOutline (C_OUTLINE *c_outline)
EDGEPT * | edgesteps_to_edgepts (C_OUTLINE *c_outline, EDGEPT edgepts[])
void | fix2 (EDGEPT *start, int area)
EDGEPT * | poly2 (EDGEPT *startpt, int area)
void | cutline (EDGEPT *first, EDGEPT *last, int area)

## Function Documentation

TESSLINE* ApproximateOutline | ( | C_OUTLINE * | c_outline | ) |

Definition at line 59 of file polyaprx.cpp.

{
EDGEPT *edgept; // converted steps
TBOX loop_box; // bounding box
inT32 area; // loop area
EDGEPT stack_edgepts[FASTEDGELENGTH]; // converted path
EDGEPT* edgepts = stack_edgepts;
// Use heap memory if the stack buffer is not big enough.
if (c_outline->pathlength() > FASTEDGELENGTH)
edgepts = new EDGEPT[c_outline->pathlength()];
loop_box = c_outline->bounding_box();
area = loop_box.height();
if (!poly_wide_objects_better && loop_box.width() > area)
area = loop_box.width();
area *= area;
edgept = edgesteps_to_edgepts(c_outline, edgepts);
fix2(edgepts, area);
edgept = poly2 (edgepts, area); // 2nd approximation.
EDGEPT* startpt = edgept;
EDGEPT* result = NULL;
EDGEPT* prev_result = NULL;
do {
EDGEPT* new_pt = new EDGEPT;
new_pt->pos = edgept->pos;
new_pt->prev = prev_result;
if (prev_result == NULL) {
result = new_pt;
} else {
prev_result->next = new_pt;
new_pt->prev = prev_result;
}
prev_result = new_pt;
edgept = edgept->next;
}
while (edgept != startpt);
prev_result->next = result;
result->prev = prev_result;
if (edgepts != stack_edgepts)
delete [] edgepts;
return TESSLINE::BuildFromOutlineList(result);
}

void cutline | ( | EDGEPT * | first,
|  | EDGEPT * | last,
|  | int | area
| ) |  |

Definition at line 484 of file polyaprx.cpp.

{
register EDGEPT *edge; /*current edge */
TPOINT vecsum; /*vector sum */
int vlen; /*approx length of vecsum */
TPOINT vec; /*accumulated vector */
EDGEPT *maxpoint; /*worst point */
int maxperp; /*max deviation */
register int perp; /*perp distance */
int ptcount; /*no of points */
int squaresum; /*sum of perps */
edge = first; /*start of line */
if (edge->next == last)
return; /*simple line */
/*vector sum */
vecsum.x = last->pos.x - edge->pos.x;
vecsum.y = last->pos.y - edge->pos.y;
if (vecsum.x == 0 && vecsum.y == 0) {
/*special case */
vecsum.x = -edge->prev->vec.x;
vecsum.y = -edge->prev->vec.y;
}
/*absolute value */
vlen = vecsum.x > 0 ? vecsum.x : -vecsum.x;
if (vecsum.y > vlen)
vlen = vecsum.y; /*maximum */
else if (-vecsum.y > vlen)
vlen = -vecsum.y; /*absolute value */
vec.x = edge->vec.x; /*accumulated vector */
vec.y = edge->vec.y;
maxperp = 0; /*none yet */
squaresum = ptcount = 0;
edge = edge->next; /*move to actual point */
maxpoint = edge; /*in case there isn't one */
do {
perp = CROSS (vec, vecsum); /*get perp distance */
if (perp != 0) {
perp *= perp; /*squared deviation */
}
squaresum += perp; /*sum squares */
ptcount++; /*count points */
if (poly_debug)
tprintf ("Cutline:Final perp=%d\n", perp);
if (perp > maxperp) {
maxperp = perp;
maxpoint = edge; /*find greatest deviation */
}
vec.x += edge->vec.x; /*accumulate vectors */
vec.y += edge->vec.y;
edge = edge->next;
}
while (edge != last); /*test all line */
perp = LENGTH (vecsum);
ASSERT_HOST (perp != 0);
if (maxperp < 256 * MAX_INT16) {
maxperp <<= 8;
maxperp /= perp; /*true max perp */
}
else {
maxperp /= perp;
maxperp <<= 8; /*avoid overflow */
}
if (squaresum < 256 * MAX_INT16)
/*mean squared perp */
perp = (squaresum << 8) / (perp * ptcount);
else
/*avoid overflow */
perp = (squaresum / perp << 8) / ptcount;
if (poly_debug)
tprintf ("Cutline:A=%d, max=%.2f(%.2f%%), msd=%.2f(%.2f%%)\n",
area, maxperp / 256.0, maxperp * 200.0 / area,
perp / 256.0, perp * 300.0 / area);
if (maxperp * par1 >= 10 * area || perp * par2 >= 10 * area || vlen >= 126) {
maxpoint->flags[FLAGS] |= FIXED;
/*partitions */
cutline(first, maxpoint, area);
cutline(maxpoint, last, area);
}
}

EDGEPT* edgesteps_to_edgepts | ( | C_OUTLINE * | c_outline,
|  | EDGEPT | edgepts[]
| ) |  |

Definition at line 110 of file polyaprx.cpp.

{
inT32 length; //steps in path
ICOORD pos; //current coords
inT32 stepindex; //current step
inT32 stepinc; //increment
inT32 epindex; //current EDGEPT
inT32 count; //repeated steps
ICOORD vec; //for this 8 step
ICOORD prev_vec;
inT8 epdir; //of this step
DIR128 prevdir; //prvious dir
DIR128 dir; //of this step
pos = c_outline->start_pos (); //start of loop
length = c_outline->pathlength ();
stepindex = 0;
epindex = 0;
prevdir = -1;
count = 0;
do {
dir = c_outline->step_dir (stepindex);
vec = c_outline->step (stepindex);
if (stepindex < length - 1
&& c_outline->step_dir (stepindex + 1) - dir == -32) {
dir += 128 - 16;
vec += c_outline->step (stepindex + 1);
stepinc = 2;
}
else
stepinc = 1;
if (count == 0) {
prevdir = dir;
prev_vec = vec;
}
if (prevdir.get_dir () != dir.get_dir ()) {
edgepts[epindex].pos.x = pos.x ();
edgepts[epindex].pos.y = pos.y ();
prev_vec *= count;
edgepts[epindex].vec.x = prev_vec.x ();
edgepts[epindex].vec.y = prev_vec.y ();
pos += prev_vec;
edgepts[epindex].flags[RUNLENGTH] = count;
edgepts[epindex].prev = &edgepts[epindex - 1];
edgepts[epindex].flags[FLAGS] = 0;
edgepts[epindex].next = &edgepts[epindex + 1];
prevdir += 64;
epdir = (DIR128) 0 - prevdir;
epdir >>= 4;
epdir &= 7;
edgepts[epindex].flags[DIR] = epdir;
epindex++;
prevdir = dir;
prev_vec = vec;
count = 1;
}
else
count++;
stepindex += stepinc;
}
while (stepindex < length);
edgepts[epindex].pos.x = pos.x ();
edgepts[epindex].pos.y = pos.y ();
prev_vec *= count;
edgepts[epindex].vec.x = prev_vec.x ();
edgepts[epindex].vec.y = prev_vec.y ();
pos += prev_vec;
edgepts[epindex].flags[RUNLENGTH] = count;
edgepts[epindex].flags[FLAGS] = 0;
edgepts[epindex].prev = &edgepts[epindex - 1];
edgepts[epindex].next = &edgepts[0];
prevdir += 64;
epdir = (DIR128) 0 - prevdir;
epdir >>= 4;
epdir &= 7;
edgepts[epindex].flags[DIR] = epdir;
edgepts[0].prev = &edgepts[epindex];
ASSERT_HOST (pos.x () == c_outline->start_pos ().x ()
&& pos.y () == c_outline->start_pos ().y ());
return &edgepts[0];
}

void fix2 | ( | EDGEPT * | start,
|  | int | area
| ) |  |

Definition at line 201 of file polyaprx.cpp.

{
register EDGEPT *edgept; /*current point */
register EDGEPT *edgept1;
register EDGEPT *loopstart; /*modified start of loop */
register EDGEPT *linestart; /*start of line segment */
register int dir1, dir2; /*directions of line */
register int sum1, sum2; /*lengths in dir1,dir2 */
int stopped; /*completed flag */
int fixed_count; //no of fixed points
int d01, d12, d23, gapmin;
TPOINT d01vec, d12vec, d23vec;
register EDGEPT *edgefix, *startfix;
register EDGEPT *edgefix0, *edgefix1, *edgefix2, *edgefix3;
edgept = start; /*start of loop */
while (((edgept->flags[DIR] - edgept->prev->flags[DIR] + 1) & 7) < 3
&& (dir1 =
(edgept->prev->flags[DIR] - edgept->next->flags[DIR]) & 7) != 2
&& dir1 != 6)
edgept = edgept->next; /*find suitable start */
loopstart = edgept; /*remember start */
stopped = 0; /*not finished yet */
edgept->flags[FLAGS] |= FIXED; /*fix it */
do {
linestart = edgept; /*possible start of line */
dir1 = edgept->flags[DIR]; /*first direction */
/*length of dir1 */
sum1 = edgept->flags[RUNLENGTH];
edgept = edgept->next;
dir2 = edgept->flags[DIR]; /*2nd direction */
/*length in dir2 */
sum2 = edgept->flags[RUNLENGTH];
if (((dir1 - dir2 + 1) & 7) < 3) {
while (edgept->prev->flags[DIR] == edgept->next->flags[DIR]) {
edgept = edgept->next; /*look at next */
if (edgept->flags[DIR] == dir1)
/*sum lengths */
sum1 += edgept->flags[RUNLENGTH];
else
sum2 += edgept->flags[RUNLENGTH];
}
if (edgept == loopstart)
stopped = 1; /*finished */
if (sum2 + sum1 > 2
&& linestart->prev->flags[DIR] == dir2
&& (linestart->prev->flags[RUNLENGTH] >
linestart->flags[RUNLENGTH] || sum2 > sum1)) {
/*start is back one */
linestart = linestart->prev;
linestart->flags[FLAGS] |= FIXED;
}
if (((edgept->next->flags[DIR] - edgept->flags[DIR] + 1) & 7) >= 3
|| (edgept->flags[DIR] == dir1 && sum1 >= sum2)
|| ((edgept->prev->flags[RUNLENGTH] < edgept->flags[RUNLENGTH]
|| (edgept->flags[DIR] == dir2 && sum2 >= sum1))
&& linestart->next != edgept))
edgept = edgept->next;
}
/*sharp bend */
edgept->flags[FLAGS] |= FIXED;
}
/*do whole loop */
while (edgept != loopstart && !stopped);
edgept = start;
do {
if (((edgept->flags[RUNLENGTH] >= 8) &&
(edgept->flags[DIR] != 2) && (edgept->flags[DIR] != 6)) ||
((edgept->flags[RUNLENGTH] >= 8) &&
((edgept->flags[DIR] == 2) || (edgept->flags[DIR] == 6)))) {
edgept->flags[FLAGS] |= FIXED;
edgept1 = edgept->next;
edgept1->flags[FLAGS] |= FIXED;
}
edgept = edgept->next;
}
while (edgept != start);
edgept = start;
do {
/*single fixed step */
if (edgept->flags[FLAGS] & FIXED && edgept->flags[RUNLENGTH] == 1
/*and neighours free */
&& edgept->next->flags[FLAGS] & FIXED && (edgept->prev->flags[FLAGS] & FIXED) == 0
/*same pair of dirs */
&& (edgept->next->next->flags[FLAGS] & FIXED) == 0 && edgept->prev->flags[DIR] == edgept->next->flags[DIR] && edgept->prev->prev->flags[DIR] == edgept->next->next->flags[DIR]
&& ((edgept->prev->flags[DIR] - edgept->flags[DIR] + 1) & 7) < 3) {
/*unfix it */
edgept->flags[FLAGS] &= ~FIXED;
edgept->next->flags[FLAGS] &= ~FIXED;
}
edgept = edgept->next; /*do all points */
}
while (edgept != start); /*until finished */
stopped = 0;
if (area < 450)
area = 450;
gapmin = area * fixed_dist * fixed_dist / 44000;
edgept = start;
fixed_count = 0;
do {
if (edgept->flags[FLAGS] & FIXED)
fixed_count++;
edgept = edgept->next;
}
while (edgept != start);
while ((edgept->flags[FLAGS] & FIXED) == 0)
edgept = edgept->next;
edgefix0 = edgept;
edgept = edgept->next;
while ((edgept->flags[FLAGS] & FIXED) == 0)
edgept = edgept->next;
edgefix1 = edgept;
edgept = edgept->next;
while ((edgept->flags[FLAGS] & FIXED) == 0)
edgept = edgept->next;
edgefix2 = edgept;
edgept = edgept->next;
while ((edgept->flags[FLAGS] & FIXED) == 0)
edgept = edgept->next;
edgefix3 = edgept;
startfix = edgefix2;
do {
if (fixed_count <= 3)
break; //already too few
point_diff (d12vec, edgefix1->pos, edgefix2->pos);
d12 = LENGTH (d12vec);
// TODO(rays) investigate this change:
// Only unfix a point if it is part of a low-curvature section
// of outline and the total angle change of the outlines is
// less than 90 degrees, ie the scalar product is positive.
// if (d12 <= gapmin && SCALAR(edgefix0->vec, edgefix2->vec) > 0) {
if (d12 <= gapmin) {
point_diff (d01vec, edgefix0->pos, edgefix1->pos);
d01 = LENGTH (d01vec);
point_diff (d23vec, edgefix2->pos, edgefix3->pos);
d23 = LENGTH (d23vec);
if (d01 > d23) {
edgefix2->flags[FLAGS] &= ~FIXED;
fixed_count--;
}
else {
edgefix1->flags[FLAGS] &= ~FIXED;
fixed_count--;
edgefix1 = edgefix2;
}
}
else {
edgefix0 = edgefix1;
edgefix1 = edgefix2;
}
edgefix2 = edgefix3;
edgept = edgept->next;
while ((edgept->flags[FLAGS] & FIXED) == 0) {
if (edgept == startfix)
stopped = 1;
edgept = edgept->next;
}
edgefix3 = edgept;
edgefix = edgefix2;
}
while ((edgefix != startfix) && (!stopped));
}

EDGEPT* poly2 | ( | EDGEPT * | startpt,
|  | int | area
| ) |  |

Definition at line 386 of file polyaprx.cpp.

{
register EDGEPT *edgept; /*current outline point */
EDGEPT *loopstart; /*starting point */
register EDGEPT *linestart; /*start of line */
register int edgesum; /*correction count */
if (area < 1200)
area = 1200; /*minimum value */
loopstart = NULL; /*not found it yet */
edgept = startpt; /*start of loop */
do {
/*current point fixed */
if (edgept->flags[FLAGS] & FIXED
/*and next not */
&& (edgept->next->flags[FLAGS] & FIXED) == 0) {
loopstart = edgept; /*start of repoly */
break;
}
edgept = edgept->next; /*next point */
}
while (edgept != startpt); /*until found or finished */
if (loopstart == NULL && (startpt->flags[FLAGS] & FIXED) == 0) {
/*fixed start of loop */
startpt->flags[FLAGS] |= FIXED;
loopstart = startpt; /*or start of loop */
}
if (loopstart) {
do {
edgept = loopstart; /*first to do */
do {
linestart = edgept;
edgesum = 0; /*sum of lengths */
do {
/*sum lengths */
edgesum += edgept->flags[RUNLENGTH];
edgept = edgept->next; /*move on */
}
while ((edgept->flags[FLAGS] & FIXED) == 0
&& edgept != loopstart && edgesum < 126);
if (poly_debug)
tprintf
("Poly2:starting at (%d,%d)+%d=(%d,%d),%d to (%d,%d)\n",
linestart->pos.x, linestart->pos.y, linestart->flags[DIR],
linestart->vec.x, linestart->vec.y, edgesum, edgept->pos.x,
edgept->pos.y);
/*reapproximate */
cutline(linestart, edgept, area);
while ((edgept->next->flags[FLAGS] & FIXED)
&& edgept != loopstart)
edgept = edgept->next; /*look for next non-fixed */
}
/*do all the loop */
while (edgept != loopstart);
edgesum = 0;
do {
if (edgept->flags[FLAGS] & FIXED)
edgesum++;
edgept = edgept->next;
}
//count fixed pts
while (edgept != loopstart);
if (edgesum < 3)
area /= 2; //must have 3 pts
}
while (edgesum < 3);
do {
linestart = edgept;
do {
edgept = edgept->next;
}
while ((edgept->flags[FLAGS] & FIXED) == 0);
linestart->next = edgept;
edgept->prev = linestart;
linestart->vec.x = edgept->pos.x - linestart->pos.x;
linestart->vec.y = edgept->pos.y - linestart->pos.y;
}
while (edgept != loopstart);
}
else
edgept = startpt; /*start of loop */
loopstart = edgept; /*new start */
return loopstart; /*correct exit */
}