// Fits splines to the textlines, or creates fake QSPLINES from the straight
// baselines that are already on the TO_ROWs.
// As a side-effect, computes the xheights of the rows and the block.
// Although x-height estimation is conceptually separate, it is part of
// detecting perspective distortion and therefore baseline fitting.
void BaselineBlock::FitBaselineSplines(bool enable_splines,
bool show_final_rows,
Textord* textord) {
double gradient = tan(skew_angle_);
FCOORD rotation(1.0f, 0.0f);
if (enable_splines) {
textord->make_spline_rows(block_, gradient, show_final_rows);
} else {
// Make a fake spline from the existing line.
TBOX block_box= block_->block->bounding_box();
TO_ROW_IT row_it = block_->get_rows();
for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) {
TO_ROW* row = row_it.data();
inT32 xstarts[2] = { block_box.left(), block_box.right() };
double coeffs[3] = { 0.0, row->line_m(), row->line_c() };
row->baseline = QSPLINE(1, xstarts, coeffs);
textord->compute_row_xheight(row, block_->block->classify_rotation(),
row->line_m(), block_->line_size);
}
}
textord->compute_block_xheight(block_, gradient);
block_->block->set_xheight(block_->xheight);
if (textord_restore_underlines) // fix underlines
restore_underlined_blobs(block_);
}
void tweak_row_baseline(ROW *row,
double blshift_maxshift,
double blshift_xfraction) {
TBOX blob_box; //bounding box
C_BLOB *blob; //current blob
WERD *word; //current word
inT32 blob_count; //no of blobs
inT32 src_index; //source segment
inT32 dest_index; //destination segment
inT32 *xstarts; //spline segments
double *coeffs; //spline coeffs
float ydiff; //baseline error
float x_centre; //centre of blob
//words of row
WERD_IT word_it = row->word_list ();
C_BLOB_IT blob_it; //blob iterator
blob_count = 0;
for (word_it.mark_cycle_pt (); !word_it.cycled_list (); word_it.forward ()) {
word = word_it.data (); //current word
//get total blobs
blob_count += word->cblob_list ()->length ();
}
if (blob_count == 0)
return;
xstarts =
(inT32 *) alloc_mem ((blob_count + row->baseline.segments + 1) *
sizeof (inT32));
coeffs =
(double *) alloc_mem ((blob_count + row->baseline.segments) * 3 *
sizeof (double));
src_index = 0;
dest_index = 0;
xstarts[0] = row->baseline.xcoords[0];
for (word_it.mark_cycle_pt (); !word_it.cycled_list (); word_it.forward ()) {
word = word_it.data (); //current word
//blobs in word
blob_it.set_to_list (word->cblob_list ());
for (blob_it.mark_cycle_pt (); !blob_it.cycled_list ();
blob_it.forward ()) {
blob = blob_it.data ();
blob_box = blob->bounding_box ();
x_centre = (blob_box.left () + blob_box.right ()) / 2.0;
ydiff = blob_box.bottom () - row->base_line (x_centre);
if (ydiff < 0)
ydiff = -ydiff / row->x_height ();
else
ydiff = ydiff / row->x_height ();
if (ydiff < blshift_maxshift
&& blob_box.height () / row->x_height () > blshift_xfraction) {
if (xstarts[dest_index] >= x_centre)
xstarts[dest_index] = blob_box.left ();
coeffs[dest_index * 3] = 0;
coeffs[dest_index * 3 + 1] = 0;
coeffs[dest_index * 3 + 2] = blob_box.bottom ();
//shift it
dest_index++;
xstarts[dest_index] = blob_box.right () + 1;
}
else {
if (xstarts[dest_index] <= x_centre) {
while (row->baseline.xcoords[src_index + 1] <= x_centre
&& src_index < row->baseline.segments - 1) {
if (row->baseline.xcoords[src_index + 1] >
xstarts[dest_index]) {
coeffs[dest_index * 3] =
row->baseline.quadratics[src_index].a;
coeffs[dest_index * 3 + 1] =
row->baseline.quadratics[src_index].b;
coeffs[dest_index * 3 + 2] =
row->baseline.quadratics[src_index].c;
dest_index++;
xstarts[dest_index] =
row->baseline.xcoords[src_index + 1];
}
src_index++;
}
coeffs[dest_index * 3] =
row->baseline.quadratics[src_index].a;
coeffs[dest_index * 3 + 1] =
row->baseline.quadratics[src_index].b;
coeffs[dest_index * 3 + 2] =
row->baseline.quadratics[src_index].c;
dest_index++;
xstarts[dest_index] = row->baseline.xcoords[src_index + 1];
}
}
}
}
while (src_index < row->baseline.segments
&& row->baseline.xcoords[src_index + 1] <= xstarts[dest_index])
src_index++;
while (src_index < row->baseline.segments) {
coeffs[dest_index * 3] = row->baseline.quadratics[src_index].a;
coeffs[dest_index * 3 + 1] = row->baseline.quadratics[src_index].b;
coeffs[dest_index * 3 + 2] = row->baseline.quadratics[src_index].c;
dest_index++;
src_index++;
xstarts[dest_index] = row->baseline.xcoords[src_index];
}
//turn to spline
row->baseline = QSPLINE (dest_index, xstarts, coeffs);
free_mem(xstarts);
free_mem(coeffs);
}
