Implement jump list

Every time a jump occurs its origin is saved. You can then move through
those saved positions, e.g. to return to the table of contents after
having read a section.

doc/katarakt.txt

@@ -89,6 +89,8 @@ KEY BINDINGS
 	Focus next/previous search hit that is currently not visible
 *u*, *i* ::
 	Rotate pages left/right
+*\^o*, *^i*, *Alt-Left*, *Alt-Right* ::
+	Move backward/forward through the jump list. Entries are added automatically when jumping
 
 VARIABLES
 ---------

share/katarakt.ini

@@ -47,6 +47,8 @@ previous_invisible_hit=Ctrl+Shift+N
 focus_goto=Ctrl+G
 rotate_left=U
 rotate_right=I
+jump_back=Ctrl+O, Alt+Left
+jump_forward=Ctrl+I, Alt+Right
 toggle_fullscreen=F
 close_search=Esc
 reload=R

src/canvas.cpp

@@ -27,6 +27,8 @@ Canvas::Canvas(Viewer *v, QWidget *parent) :
 		valid(true) {
 	setFocusPolicy(Qt::StrongFocus);
 
+	clear_jumps();
+
 	// load config options
 	CFG *config = CFG::get_instance();
 
@@ -80,6 +82,8 @@ Canvas::Canvas(Viewer *v, QWidget *parent) :
 	add_action("focus_goto", SLOT(focus_goto()));
 	add_action("rotate_left", SLOT(rotate_left()));
 	add_action("rotate_right", SLOT(rotate_right()));
+	add_action("jump_back", SLOT(jump_back()));
+	add_action("jump_forward", SLOT(jump_forward()));
 
 	// prints the string representation of a key
 //	cerr << QKeySequence(Qt::Key_Equal).toString().toUtf8().constData() << endl;
@@ -117,6 +121,55 @@ void Canvas::add_action(const char *action, const char *slot) {
 	}
 }
 
+void Canvas::store_jump(int page) {
+	map<int,list<int>::iterator>::iterator it = jump_map.find(page);
+	if (it != jump_map.end()) {
+		jumplist.erase(it->second);
+	}
+	jumplist.push_back(page);
+	jump_map[page] = --jumplist.end();
+	cur_jump_pos = jumplist.end();
+
+//	cerr << "jumplist: ";
+//	for (list<int>::iterator it = jumplist.begin(); it != jumplist.end(); ++it) {
+//		if (it == cur_jump_pos) {
+//			cerr << "*";
+//		}
+//		cerr << *it << " ";
+//	}
+//	cerr << endl;
+}
+
+void Canvas::clear_jumps() {
+	jumplist.clear();
+	jump_map.clear();
+	cur_jump_pos = jumplist.end();
+}
+
+void Canvas::jump_back() {
+	if (cur_jump_pos == jumplist.begin()) {
+		return;
+	}
+	if (cur_jump_pos == jumplist.end()) {
+		store_jump(cur_layout->get_page());
+		--cur_jump_pos;
+	}
+	--cur_jump_pos;
+	if (cur_layout->scroll_page(*cur_jump_pos, false)) {
+		update();
+	}
+}
+
+void Canvas::jump_forward() {
+	if (cur_jump_pos == jumplist.end() || cur_jump_pos == --jumplist.end()) {
+		return;
+	}
+	++cur_jump_pos;
+	if (cur_layout->scroll_page(*cur_jump_pos, false)) {
+		update();
+	}
+}
+
 const Layout *Canvas::get_layout() const {
 	return cur_layout;
 }
@@ -162,7 +215,9 @@ void Canvas::mousePressEvent(QMouseEvent *event) {
 void Canvas::mouseReleaseEvent(QMouseEvent *event) {
 	if (event->button() == Qt::LeftButton) {
 		if (mx_down == event->x() && my_down == event->y()) {
+			int page = cur_layout->get_page();
 			if (cur_layout->click_mouse(mx_down, my_down)) {
+				store_jump(page); // store old position if a clicked link moved the view
 				update();
 			}
 		}
@@ -258,13 +313,17 @@ void Canvas::page_down() {
 }
 
 void Canvas::page_first() {
+	int page = cur_layout->get_page();
 	if (cur_layout->scroll_page(-1, false)) {
+		store_jump(page);
 		update();
 	}
 }
 
 void Canvas::page_last() {
+	int page = cur_layout->get_page();
 	if (cur_layout->scroll_page(viewer->get_res()->get_page_count(), false)) {
+		store_jump(page);
 		update();
 	}
 }
@@ -393,7 +452,9 @@ void Canvas::search() {
 
 void Canvas::next_hit() {
 	if (cur_layout->get_search_visible()) {
+		int page = cur_layout->get_page();
 		if (cur_layout->advance_hit()) {
+			store_jump(page);
 			update();
 		}
 	}
@@ -401,7 +462,9 @@ void Canvas::next_hit() {
 
 void Canvas::previous_hit() {
 	if (cur_layout->get_search_visible()) {
+		int page = cur_layout->get_page();
 		if (cur_layout->advance_hit(false)) {
+			store_jump(page);
 			update();
 		}
 	}
@@ -409,7 +472,9 @@ void Canvas::previous_hit() {
 
 void Canvas::next_invisible_hit() {
 	if (cur_layout->get_search_visible()) {
+		int page = cur_layout->get_page();
 		if (cur_layout->advance_invisible_hit()) {
+			store_jump(page);
 			update();
 		}
 	}
@@ -417,7 +482,9 @@ void Canvas::next_invisible_hit() {
 
 void Canvas::previous_invisible_hit() {
 	if (cur_layout->get_search_visible()) {
+		int page = cur_layout->get_page();
 		if (cur_layout->advance_invisible_hit(false)) {
+			store_jump(page);
 			update();
 		}
 	}
@@ -452,9 +519,11 @@ void Canvas::page_rendered(int page) {
 }
 
 void Canvas::goto_page() {
+	int old_page = cur_layout->get_page();
 	int page = goto_line->text().toInt() - 1;
 	goto_line->hide();
 	if (cur_layout->scroll_page(page, false)) {
+		store_jump(old_page);
 		update();
 	}
 }

src/canvas.h

@@ -28,6 +28,9 @@ public:
 	bool is_valid() const;
 	void reload(bool clamp);
 
+	void store_jump(int page);
+	void clear_jumps();
+
 	const Layout *get_layout() const;
 
 protected:
@@ -78,6 +81,8 @@ private slots:
 	void focus_goto();
 	void rotate_left();
 	void rotate_right();
+	void jump_back();
+	void jump_forward();
 
 private:
 	void add_action(const char *action, const char *slot);
@@ -90,6 +95,10 @@ private:
 
 	GotoLine *goto_line;
 
+	std::list<int> jumplist;
+	std::map<int,std::list<int>::iterator> jump_map;
+	std::list<int>::iterator cur_jump_pos;
+
 	int mx, my;
 	int mx_down, my_down;
 

src/config.cpp

@@ -66,6 +66,8 @@ CFG::CFG() :
 	keys["focus_goto"] = QStringList() << "Ctrl+G";
 	keys["rotate_left"] = QStringList() << "U";
 	keys["rotate_right"] = QStringList() << "I";
+	keys["jump_back"] = QStringList() << "Ctrl+O" << "Alt+Left";
+	keys["jump_forward"] = QStringList() << "Ctrl+I" << "Alt+Right";
 	// viewer keys
 	keys["toggle_fullscreen"] = QStringList() << "F";
 	keys["close_search"] = QStringList() << "Esc";

src/search.cpp

@@ -247,6 +247,7 @@ void SearchBar::set_text() {
 
 	worker->stop = true;
 	search_mutex.unlock();
+	viewer->get_canvas()->store_jump(start_page);
 	viewer->get_canvas()->setFocus(Qt::OtherFocusReason);
 }
 

src/viewer.cpp

@@ -207,6 +207,10 @@ void Viewer::open() {
 			}
 		}
 #endif
+
+		// clear the jumplist - it's not useful in a different file
+		canvas->clear_jumps();
+
 		setWindowTitle(QString::fromUtf8("%1 \u2014 katarakt").arg(info.fileName()));
 		reload();
 	}