// Normalize in-place using the DENORM.
void TESSLINE::Normalize(const DENORM& denorm) {
EDGEPT* pt = loop;
do {
denorm.LocalNormTransform(pt->pos, &pt->pos);
pt = pt->next;
} while (pt != loop);
SetupFromPos();
}
// Extracts Tesseract features and appends them to the features vector.
// Startpt to lastpt, inclusive, MUST have the same src_outline member,
// which may be nullptr. The vector from lastpt to its next is included in
// the feature extraction. Hidden edges should be excluded by the caller.
// If force_poly is true, the features will be extracted from the polygonal
// approximation even if more accurate data is available.
static void ExtractFeaturesFromRun(
const EDGEPT* startpt, const EDGEPT* lastpt,
const DENORM& denorm, double feature_length, bool force_poly,
GenericVector<INT_FEATURE_STRUCT>* features) {
const EDGEPT* endpt = lastpt->next;
const C_OUTLINE* outline = startpt->src_outline;
if (outline != nullptr && !force_poly) {
// Detailed information is available. We have to normalize only from
// the root_denorm to denorm.
const DENORM* root_denorm = denorm.RootDenorm();
int total_features = 0;
// Get the features from the outline.
int step_length = outline->pathlength();
int start_index = startpt->start_step;
// pos is the integer coordinates of the binary image steps.
ICOORD pos = outline->position_at_index(start_index);
// We use an end_index that allows us to use a positive increment, but that
// may be beyond the bounds of the outline steps/ due to wrap-around, to
// so we use % step_length everywhere, except for start_index.
int end_index = lastpt->start_step + lastpt->step_count;
if (end_index <= start_index)
end_index += step_length;
LLSQ prev_points;
LLSQ prev_dirs;
FCOORD prev_normed_pos = outline->sub_pixel_pos_at_index(pos, start_index);
denorm.NormTransform(root_denorm, prev_normed_pos, &prev_normed_pos);
LLSQ points;
LLSQ dirs;
FCOORD normed_pos(0.0f, 0.0f);
int index = GatherPoints(outline, feature_length, denorm, root_denorm,
start_index, end_index, &pos, &normed_pos,
&points, &dirs);
while (index <= end_index) {
// At each iteration we nominally have 3 accumulated sets of points and
// dirs: prev_points/dirs, points/dirs, next_points/dirs and sum them
// into sum_points/dirs, but we don't necessarily get any features out,
// so if that is the case, we keep accumulating instead of rotating the
// accumulators.
LLSQ next_points;
LLSQ next_dirs;
FCOORD next_normed_pos(0.0f, 0.0f);
index = GatherPoints(outline, feature_length, denorm, root_denorm,
index, end_index, &pos, &next_normed_pos,
&next_points, &next_dirs);
LLSQ sum_points(prev_points);
// TODO(rays) find out why it is better to use just dirs and next_dirs
// in sum_dirs, instead of using prev_dirs as well.
LLSQ sum_dirs(dirs);
sum_points.add(points);
sum_points.add(next_points);
sum_dirs.add(next_dirs);
bool made_features = false;
// If we have some points, we can try making some features.
if (sum_points.count() > 0) {
// We have gone far enough from the start. Make a feature and restart.
FCOORD fit_pt = sum_points.mean_point();
FCOORD fit_vector = MeanDirectionVector(sum_points, sum_dirs,
prev_normed_pos, normed_pos);
// The segment to which we fit features is the line passing through
// fit_pt in direction of fit_vector that starts nearest to
// prev_normed_pos and ends nearest to normed_pos.
FCOORD start_pos = prev_normed_pos.nearest_pt_on_line(fit_pt,
fit_vector);
FCOORD end_pos = normed_pos.nearest_pt_on_line(fit_pt, fit_vector);
// Possible correction to match the adjacent polygon segment.
if (total_features == 0 && startpt != endpt) {
FCOORD poly_pos(startpt->pos.x, startpt->pos.y);
denorm.LocalNormTransform(poly_pos, &start_pos);
}
if (index > end_index && startpt != endpt) {
FCOORD poly_pos(endpt->pos.x, endpt->pos.y);
denorm.LocalNormTransform(poly_pos, &end_pos);
}
int num_features = ComputeFeatures(start_pos, end_pos, feature_length,
features);
if (num_features > 0) {
// We made some features so shuffle the accumulators.
prev_points = points;
prev_dirs = dirs;
prev_normed_pos = normed_pos;
points = next_points;
dirs = next_dirs;
made_features = true;
total_features += num_features;
}
// The end of the next set becomes the end next time around.
normed_pos = next_normed_pos;
}
if (!made_features) {
// We didn't make any features, so keep the prev accumulators and
// add the next ones into the current.
points.add(next_points);
dirs.add(next_dirs);
}
}
} else {
// There is no outline, so we are forced to use the polygonal approximation.
const EDGEPT* pt = startpt;
do {
FCOORD start_pos(pt->pos.x, pt->pos.y);
FCOORD end_pos(pt->next->pos.x, pt->next->pos.y);
denorm.LocalNormTransform(start_pos, &start_pos);
denorm.LocalNormTransform(end_pos, &end_pos);
ComputeFeatures(start_pos, end_pos, feature_length, features);
} while ((pt = pt->next) != endpt);
}
}