Justified label control

label.cpp

#include <FL/Fl_Box.H>

class TextLabel: public Fl_Box {
	LayoutEngine engine;
	std::string text;
	
public:
	TextLabel( std::string& text, uint32_t x, uint32_t y, uint32_t height, uint32_t width) 
		: text(text)
		, Fl_Box( x, y, width, height, text.c_str())
	{
		// Empty constructor.
	}
	
	void draw() override {
		uint32_t height = fl_height() * 1.3, i = 0;
		uint32_t top = y() + height, start = x();
		
		uint32_t space = (fl_width(" ") * 1.24),
				 width = w(),
				 left = x();
		
		Fl_Font faceName(fl_font());
		Fl_Fontsize faceSize(fl_size());
		
		fl_font(labelfont(), labelsize());
		auto document = engine.parse(text);
		
		fl_color(FL_BLACK);
		
		uint32_t pxBoxWidth(((x() + width) * 2) + space), pTextWidth = 0;
		uint32_t pCalcWidth(((fl_width(" ") / 1.5) * width) + ( (int) ( width / 1.5 ) - 2 ));
		
		typedef std::vector<std::pair<uint32_t, std::string>> StringList;
		
		std::vector<std::pair<uint32_t, StringList>> collection;
		StringList item;
		
		for (std::string word : document.content) {
			uint32_t pTextLength = fl_width(word.c_str()),
					 id = item.size() + 1;
			
			if ( start + ( fl_width(word.c_str()) + space ) >= pCalcWidth ) {
				start = left;
				item.push_back(std::make_pair( id, word ));
				
				collection.push_back(std::make_pair( collection.size(), item ));
				item.clear();
			}
			else {
				start += fl_width(word.c_str()) + space;
				item.push_back(std::make_pair( id, word ));
			}
		}
		
		for ( std::pair<uint32_t, StringList> iterator : collection ) {
			uint32_t spaceLeft(pCalcWidth),
					 calcSlice(pCalcWidth / iterator.second.size()),
					 textWidth( 0 );
			
			start = left;
			
			for (std::pair<uint32_t, std::string> entry: iterator.second ) {
				uint32_t textLength(fl_width(entry.second.c_str()));
				
				if (textLength > textWidth) {
					textWidth = textLength + space;
				}
			}
			
			for (std::pair<uint32_t, std::string> entry: iterator.second ) {
				if ((spaceLeft - calcSlice) > 0) {
					spaceLeft -= calcSlice;
				}
				
				fl_draw( entry.second.c_str(), start, top );
				uint32_t pCalcSpace = pCalcWidth / iterator.second.size();
				
				printf("Free space: %s = %d/%d = %d ( %d, %d )\n",
					entry.second, pCalcWidth, iterator.second.size(), pCalcSpace, 
					spaceLeft, calcSlice );
				
				start += textWidth;
			}
			
			top += height;
		}
		
		fl_font(faceName, faceSize);
	}
};