void fractal::draw_border( bool is_active ) {
color_t color = is_active ? v->get_color(0, 255, 0) // green color
: v->get_color(96, 128, 96); // green-gray color
// top border
drawing_area area0( off_x-1, off_y-1, size_x+2, 1, dm );
for (int i=-1; i<size_x+1; ++i)
area0.put_pixel(color);
// bottom border
drawing_area area1( off_x-1, off_y+size_y, size_x+2, 1, dm );
for (int i=-1; i<size_x+1; ++i)
area1.put_pixel(color);
// left border
drawing_area area2( off_x-1, off_y, 1, size_y+2, dm );
for (int i=0; i<size_y; ++i)
area2.set_pixel(0, i, color);
// right border
drawing_area area3( size_x+off_x, off_y, 1, size_y+2, dm );
for (int i=0; i<size_y; ++i)
area3.set_pixel(0, i, color);
}
/*------------------------- AFFINE CONVEX EROSION -------------------------*/
static void aceros(DPoint* in, int size,
std::vector<DPoint>& out, double area_sz) {
// deal with singular cases (less than 2 points)
if(size<2)
return;
// test if the curve is closed
DPoint* pmax = in+size;
bool is_closed = (*in==pmax[-1]);
if(is_closed)
--pmax;
// deal with singular cases (2 or 3 points, closed)
if(size<4 && is_closed)
return;
// return input if segment or area_sz=0
if(size==2 || area_sz==0.) {
while(in!=pmax)
out.push_back(*in++);
return;
}
// compute total area
double tot_area = area_pol(in, in+1, pmax-1);
tot_area = ABS(tot_area);
// check extinction
if (is_closed) {
if(area_sz>=tot_area/2.1) // theoretically: 2.0
return;
} else if(area_sz>=tot_area) {
out.push_back(*in);
out.push_back(pmax[-1]);
return;
}
if(!is_closed)
out.push_back(*in);
DPoint *p=in, *p0=p, *q0=in+1, *p1=in+1, *q1=in+2;
double cur_area=0.0;
bool okp=false, okq=false;
do { // MAIN LOOP: compute the middle points of significative chords
if(cur_area<=area_sz) {
double inc_area = area3(q0, q1, p0);
if(cur_area+inc_area>=area_sz) { // compute middle point
double lambda = double((area_sz-cur_area)/inc_area);
out.push_back(.5*(*p0+(1-lambda)**q0+lambda**q1));
}
if(cur_area+inc_area-area3(p0,p1,q1)>area_sz) {
cur_area -= area3(p0, p1, q0);
p0 = p1++;
if(is_closed && p1==pmax)
p1 -= size-1;
if(p0==p)
okp = true;
}
else {
cur_area += inc_area;
q0 = q1++;
if(is_closed && q1==pmax)
q1 -= size-1;
if(q0==p+1)
okq = true;
}
} else {
double inc_area = area3(p0, p1, q0);
if(cur_area-inc_area<=area_sz) { // compute middle point
double lambda = double((cur_area-area_sz)/inc_area);
out.push_back(.5*(*q0+(1-lambda)**p0+lambda**p1));
}
if(!is_closed && q1!=pmax &&
cur_area-inc_area+area3(p1, q0, q1)<area_sz) {
cur_area += area3(p0, q0, q1);
q0 = q1++;
if(is_closed && q1==pmax)
q1 -= size-1;
if(q0==p+1)
okq = true;
} else {
cur_area -= inc_area;
p0 = p1++;
if(is_closed && p1==pmax)
p1 -= size-1;
if(p0==p)
okp = true;
}
}
// more precise computation of cur_area if needed
if(p1==q0)
cur_area = 0.0;
DPoint* p2 = p1+1;
if(is_closed && p2==pmax)
p2 -= size-1;
if(p2==q0)
cur_area = area3(p0, p1, q0);
} while(!(is_closed? (okp&&okq): ((q0+1==pmax&&cur_area<=area_sz))));
// add last point to output
out.push_back(is_closed? out.front(): pmax[-1]);
}
