mirror of
https://github.com/pdf2htmlEX/pdf2htmlEX.git
synced 2024-12-22 13:00:08 +00:00
improve text optimization
This commit is contained in:
Lu Wang
parent
1803111023
commit
3f962b5a9c
@ -68,6 +68,9 @@ void HTMLRenderer::TextLineBuffer::flush(void)
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*/
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if(text.empty()) return;
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while((!states.empty()) && (states.back().start_idx >= text.size()))
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states.pop_back();
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if(states.empty() || (states[0].start_idx != 0))
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{
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cerr << "Warning: text without a style! Must be a bug in pdf2htmlEX" << endl;
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@ -83,54 +86,47 @@ void HTMLRenderer::TextLineBuffer::flush(void)
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max_ascent = max<double>(max_ascent, s.font_info->ascent * s.draw_font_size);
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}
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// append a dummy state for convenience
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states.resize(states.size() + 1);
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states.back().start_idx = text.size();
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for(auto iter = states.begin(); iter != states.end(); ++iter)
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iter->hash();
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// append a dummy offset for convenience
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offsets.push_back(Offset({text.size(), 0}));
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ostream & out = renderer->f_pages.fs;
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long long hid = renderer->height_manager.install(max_ascent);
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long long lid = renderer->left_manager .install(x);
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long long bid = renderer->bottom_manager.install(y);
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{
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long long hid = renderer->height_manager.install(max_ascent);
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long long lid = renderer->left_manager .install(x);
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long long bid = renderer->bottom_manager.install(y);
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out << "<div class=\"" << CSS::LINE_CN
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<< " " << CSS::TRANSFORM_MATRIX_CN << tm_id
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<< " " << CSS::LEFT_CN << lid
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<< " " << CSS::HEIGHT_CN << hid
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<< " " << CSS::BOTTOM_CN << bid
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<< "\">";
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auto cur_state_iter = states.begin();
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auto cur_offset_iter = offsets.begin();
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//accumulated horizontal offset;
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double dx = 0;
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out << "<div class=\"" << CSS::LINE_CN
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<< " " << CSS::TRANSFORM_MATRIX_CN << tm_id
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<< " " << CSS::LEFT_CN << lid
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<< " " << CSS::HEIGHT_CN << hid
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<< " " << CSS::BOTTOM_CN << bid
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<< "\">";
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}
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stack.clear();
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stack.push_back(nullptr);
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//accumulated horizontal offset;
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double dx = 0;
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// whenever a negative offset appears, we should not pop out that <span>
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// otherwise the effect of negative margin-left would disappear
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size_t last_text_pos_with_negative_offset = 0;
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size_t cur_text_idx = 0;
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while(cur_text_idx < text.size())
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auto cur_offset_iter = offsets.begin();
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for(auto state_iter2 = states.begin(), state_iter1 = state_iter2++;
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state_iter1 != states.end();
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++state_iter1, ++state_iter2)
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{
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// TODO: a new state may consume an offset with proper 'margin-left'
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if(cur_text_idx >= cur_state_iter->start_idx)
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{
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// export current state, find a closest parent
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{
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// greedy
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int best_cost = State::ID_COUNT;
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// we have a nullptr at the beginning, so no need to check for rend
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for(auto iter = stack.rbegin(); *iter; ++iter)
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{
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int cost = cur_state_iter->diff(**iter);
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int cost = state_iter1->diff(**iter);
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if(cost < best_cost)
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{
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while(stack.back() != *iter)
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@ -148,61 +144,72 @@ void HTMLRenderer::TextLineBuffer::flush(void)
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if((*iter)->start_idx <= last_text_pos_with_negative_offset)
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break;
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}
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cur_state_iter->begin(out, stack.back());
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stack.push_back(&*cur_state_iter);
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++ cur_state_iter;
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state_iter1->begin(out, stack.back());
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stack.push_back(&*state_iter1);
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}
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if(cur_text_idx >= cur_offset_iter->start_idx)
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{
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double target = cur_offset_iter->width + dx;
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double actual_offset = 0;
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size_t text_idx2 = (state_iter2 == states.end()) ? text.size() : state_iter2->start_idx;
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if(abs(target) <= renderer->param->h_eps)
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while(true)
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{
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if((cur_offset_iter != offsets.end()) && (cur_offset_iter->start_idx <= cur_text_idx))
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{
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actual_offset = 0;
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if(cur_offset_iter->start_idx > text_idx2)
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break;
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double target = cur_offset_iter->width + dx;
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double actual_offset = 0;
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if(abs(target) <= renderer->param->h_eps)
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{
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actual_offset = 0;
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}
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else
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{
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bool done = false;
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if(!(state_iter1->hash_umask & State::umask_by_id(State::WORD_SPACE_ID)))
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{
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double space_off = state_iter1->single_space_offset();
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if(abs(target - space_off) <= renderer->param->h_eps)
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{
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Unicode u = ' ';
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outputUnicodes(out, &u, 1);
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actual_offset = space_off;
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done = true;
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}
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}
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if(!done)
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{
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long long wid = renderer->whitespace_manager.install(target, &actual_offset);
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if(!equal(actual_offset, 0))
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{
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if(is_positive(-actual_offset))
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last_text_pos_with_negative_offset = cur_text_idx;
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double threshold = state_iter1->em_size() * (renderer->param->space_threshold);
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out << "<span class=\"" << CSS::WHITESPACE_CN
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<< ' ' << CSS::WHITESPACE_CN << wid << "\">" << (target > (threshold - EPS) ? " " : "") << "</span>";
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}
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}
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}
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dx = target - actual_offset;
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++ cur_offset_iter;
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}
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else
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{
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bool done = false;
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auto cur_state = stack.back();
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if(!(cur_state->hash_umask & State::umask_by_id(State::WORD_SPACE_ID)))
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{
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double space_off = cur_state->single_space_offset();
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if(abs(target - space_off) <= renderer->param->h_eps)
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{
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Unicode u = ' ';
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outputUnicodes(out, &u, 1);
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actual_offset = space_off;
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done = true;
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}
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}
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if(cur_text_idx >= text_idx2)
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break;
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if(!done)
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{
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long long wid = renderer->whitespace_manager.install(target, &actual_offset);
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if(!equal(actual_offset, 0))
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{
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if(is_positive(-actual_offset))
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last_text_pos_with_negative_offset = cur_text_idx;
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double threshold = cur_state->em_size() * (renderer->param->space_threshold);
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out << "<span class=\"" << CSS::WHITESPACE_CN
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<< ' ' << CSS::WHITESPACE_CN << wid << "\">" << (target > (threshold - EPS) ? " " : "") << "</span>";
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}
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}
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size_t next_text_idx = text_idx2;
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if((cur_offset_iter != offsets.end()) && (cur_offset_iter->start_idx) < next_text_idx)
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next_text_idx = cur_offset_iter->start_idx;
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outputUnicodes(out, (&text.front()) + cur_text_idx, next_text_idx - cur_text_idx);
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cur_text_idx = next_text_idx;
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}
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dx = target - actual_offset;
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++ cur_offset_iter;
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}
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size_t next_text_idx = min<size_t>(cur_state_iter->start_idx, cur_offset_iter->start_idx);
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outputUnicodes(out, (&text.front()) + cur_text_idx, next_text_idx - cur_text_idx);
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cur_text_idx = next_text_idx;
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}
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// we have a nullptr in the bottom
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@ -235,13 +242,18 @@ void HTMLRenderer::TextLineBuffer::set_state (State & state)
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state.word_space = renderer->word_space_manager.get_actual_value();
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}
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void HTMLRenderer::TextLineBuffer::optimize(void)
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void HTMLRenderer::TextLineBuffer::optimize()
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{
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if(!(renderer->param->optimize_text))
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return;
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assert(!states.empty());
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// for optimization, we need accurate values
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auto & ws_manager = renderer->word_space_manager;
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double old_ws_eps = ws_manager.get_eps();
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ws_manager.set_eps(EPS);
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auto offset_iter = offsets.begin();
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std::map<double, int> width_map;
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@ -269,11 +281,11 @@ void HTMLRenderer::TextLineBuffer::optimize(void)
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// collect widths
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width_map.clear();
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while((offset_iter != offsets.end()) && (offset_iter->start_idx < text_idx1))
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while((offset_iter != offsets.end()) && (offset_iter->start_idx <= text_idx1))
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++ offset_iter;
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double threshold = (state_iter1->em_size()) * (renderer->param->space_threshold);
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for(; (offset_iter != offsets.end()) && (offset_iter->start_idx < text_idx2); ++offset_iter)
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for(; (offset_iter != offsets.end()) && (offset_iter->start_idx <= text_idx2); ++offset_iter)
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{
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double target = offset_iter->width;
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// we don't want to add spaces for tiny gaps, or even negative shifts
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@ -313,10 +325,13 @@ void HTMLRenderer::TextLineBuffer::optimize(void)
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state_iter1->word_space = 0;
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double new_word_space = most_used_width - state_iter1->single_space_offset();
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// install new word_space
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state_iter1->ids[State::WORD_SPACE_ID] = renderer->word_space_manager.install(new_word_space, &(state_iter1->word_space));
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state_iter1->ids[State::WORD_SPACE_ID] = ws_manager.install(new_word_space, &(state_iter1->word_space));
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// mark that the word_space is not free
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state_iter1->hash_umask &= (~word_space_umask);
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}
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// restore old eps
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ws_manager.set_eps(old_ws_eps);
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}
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// this state will be converted to a child node of the node of prev_state
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@ -36,6 +36,10 @@ public:
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this->eps = eps;
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}
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double get_eps (void) const {
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return eps;
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}
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// usually called at the beginning of a page
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void reset(void) {
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cur_value = imp->default_value();
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