DenysMedvid/pdf2htmlEX
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improve text optimization

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This commit is contained in:
Lu Wang 2013-04-03 14:04:39 +08:00
parent 1803111023
commit 3f962b5a9c
2 changed files with 97 additions and 78 deletions
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171
src/HTMLRenderer/TextLineBuffer.cc
View File

@ -68,6 +68,9 @@ void HTMLRenderer::TextLineBuffer::flush(void)
*/
if(text.empty()) return;
while((!states.empty()) && (states.back().start_idx >= text.size()))
states.pop_back();
if(states.empty() || (states[0].start_idx != 0))
{
cerr << "Warning: text without a style! Must be a bug in pdf2htmlEX" << endl;
@ -83,54 +86,47 @@ void HTMLRenderer::TextLineBuffer::flush(void)
max_ascent = max<double>(max_ascent, s.font_info->ascent * s.draw_font_size);
}
// append a dummy state for convenience
states.resize(states.size() + 1);
states.back().start_idx = text.size();
for(auto iter = states.begin(); iter != states.end(); ++iter)
iter->hash();
// append a dummy offset for convenience
offsets.push_back(Offset({text.size(), 0}));
ostream & out = renderer->f_pages.fs;
long long hid = renderer->height_manager.install(max_ascent);
long long lid = renderer->left_manager .install(x);
long long bid = renderer->bottom_manager.install(y);
{
long long hid = renderer->height_manager.install(max_ascent);
long long lid = renderer->left_manager .install(x);
long long bid = renderer->bottom_manager.install(y);
out << "<div class=\"" << CSS::LINE_CN
<< " " << CSS::TRANSFORM_MATRIX_CN << tm_id
<< " " << CSS::LEFT_CN << lid
<< " " << CSS::HEIGHT_CN << hid
<< " " << CSS::BOTTOM_CN << bid
<< "\">";
auto cur_state_iter = states.begin();
auto cur_offset_iter = offsets.begin();
//accumulated horizontal offset;
double dx = 0;
out << "<div class=\"" << CSS::LINE_CN
<< " " << CSS::TRANSFORM_MATRIX_CN << tm_id
<< " " << CSS::LEFT_CN << lid
<< " " << CSS::HEIGHT_CN << hid
<< " " << CSS::BOTTOM_CN << bid
<< "\">";
}
stack.clear();
stack.push_back(nullptr);
//accumulated horizontal offset;
double dx = 0;
// whenever a negative offset appears, we should not pop out that <span>
// otherwise the effect of negative margin-left would disappear
size_t last_text_pos_with_negative_offset = 0;
size_t cur_text_idx = 0;
while(cur_text_idx < text.size())
auto cur_offset_iter = offsets.begin();
for(auto state_iter2 = states.begin(), state_iter1 = state_iter2++;
state_iter1 != states.end();
++state_iter1, ++state_iter2)
{
// TODO: a new state may consume an offset with proper 'margin-left'
if(cur_text_idx >= cur_state_iter->start_idx)
{
// export current state, find a closest parent
{
// greedy
int best_cost = State::ID_COUNT;
// we have a nullptr at the beginning, so no need to check for rend
for(auto iter = stack.rbegin(); *iter; ++iter)
{
int cost = cur_state_iter->diff(**iter);
int cost = state_iter1->diff(**iter);
if(cost < best_cost)
{
while(stack.back() != *iter)
@ -148,61 +144,72 @@ void HTMLRenderer::TextLineBuffer::flush(void)
if((*iter)->start_idx <= last_text_pos_with_negative_offset)
break;
}
cur_state_iter->begin(out, stack.back());
stack.push_back(&*cur_state_iter);
++ cur_state_iter;
state_iter1->begin(out, stack.back());
stack.push_back(&*state_iter1);
}
if(cur_text_idx >= cur_offset_iter->start_idx)
{
double target = cur_offset_iter->width + dx;
double actual_offset = 0;
size_t text_idx2 = (state_iter2 == states.end()) ? text.size() : state_iter2->start_idx;
if(abs(target) <= renderer->param->h_eps)
while(true)
{
if((cur_offset_iter != offsets.end()) && (cur_offset_iter->start_idx <= cur_text_idx))
{
actual_offset = 0;
if(cur_offset_iter->start_idx > text_idx2)
break;
double target = cur_offset_iter->width + dx;
double actual_offset = 0;
if(abs(target) <= renderer->param->h_eps)
{
actual_offset = 0;
}
else
{
bool done = false;
if(!(state_iter1->hash_umask & State::umask_by_id(State::WORD_SPACE_ID)))
{
double space_off = state_iter1->single_space_offset();
if(abs(target - space_off) <= renderer->param->h_eps)
{
Unicode u = ' ';
outputUnicodes(out, &u, 1);
actual_offset = space_off;
done = true;
}
}
if(!done)
{
long long wid = renderer->whitespace_manager.install(target, &actual_offset);
if(!equal(actual_offset, 0))
{
if(is_positive(-actual_offset))
last_text_pos_with_negative_offset = cur_text_idx;
double threshold = state_iter1->em_size() * (renderer->param->space_threshold);
out << "<span class=\"" << CSS::WHITESPACE_CN
<< ' ' << CSS::WHITESPACE_CN << wid << "\">" << (target > (threshold - EPS) ? " " : "") << "</span>";
}
}
}
dx = target - actual_offset;
++ cur_offset_iter;
}
else
{
bool done = false;
auto cur_state = stack.back();
if(!(cur_state->hash_umask & State::umask_by_id(State::WORD_SPACE_ID)))
{
double space_off = cur_state->single_space_offset();
if(abs(target - space_off) <= renderer->param->h_eps)
{
Unicode u = ' ';
outputUnicodes(out, &u, 1);
actual_offset = space_off;
done = true;
}
}
if(cur_text_idx >= text_idx2)
break;
if(!done)
{
long long wid = renderer->whitespace_manager.install(target, &actual_offset);
if(!equal(actual_offset, 0))
{
if(is_positive(-actual_offset))
last_text_pos_with_negative_offset = cur_text_idx;
double threshold = cur_state->em_size() * (renderer->param->space_threshold);
out << "<span class=\"" << CSS::WHITESPACE_CN
<< ' ' << CSS::WHITESPACE_CN << wid << "\">" << (target > (threshold - EPS) ? " " : "") << "</span>";
}
}
size_t next_text_idx = text_idx2;
if((cur_offset_iter != offsets.end()) && (cur_offset_iter->start_idx) < next_text_idx)
next_text_idx = cur_offset_iter->start_idx;
outputUnicodes(out, (&text.front()) + cur_text_idx, next_text_idx - cur_text_idx);
cur_text_idx = next_text_idx;
}
dx = target - actual_offset;
++ cur_offset_iter;
}
size_t next_text_idx = min<size_t>(cur_state_iter->start_idx, cur_offset_iter->start_idx);
outputUnicodes(out, (&text.front()) + cur_text_idx, next_text_idx - cur_text_idx);
cur_text_idx = next_text_idx;
}
// we have a nullptr in the bottom
@ -235,13 +242,18 @@ void HTMLRenderer::TextLineBuffer::set_state (State & state)
state.word_space = renderer->word_space_manager.get_actual_value();
}
void HTMLRenderer::TextLineBuffer::optimize(void)
void HTMLRenderer::TextLineBuffer::optimize()
{
if(!(renderer->param->optimize_text))
return;
assert(!states.empty());
// for optimization, we need accurate values
auto & ws_manager = renderer->word_space_manager;
double old_ws_eps = ws_manager.get_eps();
ws_manager.set_eps(EPS);
auto offset_iter = offsets.begin();
std::map<double, int> width_map;
@ -269,11 +281,11 @@ void HTMLRenderer::TextLineBuffer::optimize(void)
// collect widths
width_map.clear();
while((offset_iter != offsets.end()) && (offset_iter->start_idx < text_idx1))
while((offset_iter != offsets.end()) && (offset_iter->start_idx <= text_idx1))
++ offset_iter;
double threshold = (state_iter1->em_size()) * (renderer->param->space_threshold);
for(; (offset_iter != offsets.end()) && (offset_iter->start_idx < text_idx2); ++offset_iter)
for(; (offset_iter != offsets.end()) && (offset_iter->start_idx <= text_idx2); ++offset_iter)
{
double target = offset_iter->width;
// we don't want to add spaces for tiny gaps, or even negative shifts
@ -313,10 +325,13 @@ void HTMLRenderer::TextLineBuffer::optimize(void)
state_iter1->word_space = 0;
double new_word_space = most_used_width - state_iter1->single_space_offset();
// install new word_space
state_iter1->ids[State::WORD_SPACE_ID] = renderer->word_space_manager.install(new_word_space, &(state_iter1->word_space));
state_iter1->ids[State::WORD_SPACE_ID] = ws_manager.install(new_word_space, &(state_iter1->word_space));
// mark that the word_space is not free
state_iter1->hash_umask &= (~word_space_umask);
}
// restore old eps
ws_manager.set_eps(old_ws_eps);
}
// this state will be converted to a child node of the node of prev_state

4
src/util/StateManager.h
View File

@ -36,6 +36,10 @@ public:
this->eps = eps;
}
double get_eps (void) const {
return eps;
}
// usually called at the beginning of a page
void reset(void) {
cur_value = imp->default_value();