wip: extend selection start and end positions to coincide with highlight

At the moment this often extends the selection to due overlapping
character boxes. They probably need to be shrunk such that there is no
overlap, which may not always be possible.

RTL support is not implemented either.

pdf_viewer/document.cpp

@@ -80,7 +80,7 @@ void Document::fill_highlight_rects(fz_context* ctx, fz_document* doc_) {
 		std::vector<fz_rect> highlight_rects;
 		std::vector<fz_rect> merged_rects;
 		std::wstring highlight_text;
-		get_text_selection(ctx, highlight.selection_begin, highlight.selection_end, true, highlight_rects, highlight_text, doc_);
+		get_text_selection(ctx, highlight.selection_begin, highlight.selection_end, false, highlight_rects, highlight_text, doc_);
 		merge_selected_character_rects(highlight_rects, merged_rects);
 
 		if (i < highlights.size()) {

pdf_viewer/document_view.cpp

@@ -307,7 +307,13 @@ void DocumentView::add_highlight(AbsoluteDocumentPos selection_begin, AbsoluteDo
 		get_text_selection(selection_begin, selection_end, is_word_selection, selected_characters, selected_text);
 		merge_selected_character_rects(selected_characters, merged_characters);
 		if (selected_text.size() > 0) {
-			current_document->add_highlight(selected_text, merged_characters, selection_begin, selection_end, type);
+			const fz_rect& selection_rect = std::reduce(merged_characters.begin(), merged_characters.end(), merged_characters.at(0),
+					[] (const fz_rect& pos1, const fz_rect& pos2)->fz_rect {
+				const fz_rect& pos_tl = (pos1.y0 <= pos2.y0 && pos1.x0 <= pos2.x0) ? pos1 : pos2;
+				const fz_rect& pos_br = (pos1.y1 >= pos2.y1 && pos1.x1 >= pos2.x1) ? pos1 : pos2;
+				return { pos_tl.x0, pos_tl.y0, pos_br.x1, pos_br.y1 };
+			});
+			current_document->add_highlight(selected_text, merged_characters, { selection_rect.x0, selection_rect.y0 }, { selection_rect.x1, selection_rect.y1 }, type);
 		}
 	}
 }