boost::tuple<double, int, int>
detect_slope(boost::gil::rgb8_image_t const& source)
{
boost::gil::rgb8c_view_t::xy_locator src_loc = boost::gil::const_view(source).xy_at(0, 0);
int const w = source.width();
int const h = source.height();
int x = -1;
int y = source.height() - 1;
for (int i = y + 1; x < 0 && i > 0; --i, --y) {
for (int xx = 0; xx < source.width(); ++xx) {
if (is_border_mark(src_loc(xx, y)) &&
((xx > 0 && y > 0 && is_border_mark(src_loc(xx-1, y-1))) ||
( y > 0 && is_border_mark(src_loc(xx, y-1))) ||
(xx+1 < w && y > 0 && is_border_mark(src_loc(xx+1, y-1))))) {
std::string msg = (boost::format("(%d, %d)") % xx % y).str();
::MessageBox(NULL, multi_to_wide(msg).c_str(), L"slope-bottom was detected", MB_OK);
while (is_border_mark(src_loc(xx+1, y))) ++xx;
x = xx;
break;
}
}
}
std::vector<boost::gil::point2<int> > points;
if (x <= source.width() / 2) {
collect_slope_points_right(source, x, y, std::back_inserter(points));
}
else {
collect_slope_points_left(source, x, y, std::back_inserter(points));
}
double slope, intercept;
boost::tie(slope, intercept) = linear_interpolate(points.begin(), points.end());
return boost::make_tuple(slope, x, y);
}
pixel_t bilinear_sampler_t::sample( int x, int y, float t, float s) const
{
float it = 1.0f - t;
float is = 1.0f - s;
const_image_view_t::xy_locator src_loc( src_.xy_at( x - src_area_.min.x, y - src_area_.min.y));
pixel_t a( *src_loc);
pixel_t b( src_loc[tr_]);
pixel_t top( (a[0]*it) + (b[0]*t), (a[1]*it) + (b[1]*t), (a[2]*it) + (b[2]*t), (a[3]*it) + (b[3]*t));
a = src_loc[bl_];
b = src_loc[br_];
pixel_t bot( (a[0]*it + b[0]*t), (a[1]*it) + (b[1]*t), (a[2]*it) + (b[2]*t), (a[3]*it) + (b[3]*t));
return pixel_t( (top[0]*is) + (bot[0]*s), (top[1]*is) + (bot[1]*s), (top[2]*is) + (bot[2]*s), (top[3]*is) + (bot[3]*s));
}
void
collect_slope_points_right(boost::gil::rgb8_image_t const& source, int x, int y, Output out)
{
boost::gil::rgb8c_view_t::xy_locator src_loc = boost::gil::const_view(source).xy_at(0, 0);
int const w = source.width();
int const h = source.height();
typedef typename Output::container_type::value_type point_type;
*out++ = point_type(x, y);
for (; x < source.width(); ++x) {
int yy = source.height() - 1;
for (int i = yy + 1; i > 0; --i, --yy) {
if (is_border_mark(src_loc(x, yy)))
break;
}
if (y - 1 <= yy && yy <= y + 1) {
*out++ = point_type(x, yy);
if (yy == y - 1) y = yy;
}
}
}
