genode/repos/demo/src/app/scout/navbar.cc

/*
 * \brief   Document navigation element
 * \date    2005-11-23
 * \author  Norman Feske <norman.feske@genode-labs.com>
 */

/*
 * Copyright (C) 2005-2017 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU Affero General Public License version 3.
 */

#include "elements.h"
#include "widgets.h"
#include "styles.h"
#include "browser.h"

using namespace Scout;


/**
 * Configuration
 */
enum {
	ARROW_H = 64,   /* height of arrow gfx */
	ARROW_W = 64,   /* width  of arrow gfx */
};


Generic_icon *Navbar::next_icon;
Generic_icon *Navbar::prev_icon;


class Linkicon_event_handler : public Event_handler
{
	private:

		/*
		 * Noncopyable
		 */
		Linkicon_event_handler(Linkicon_event_handler const &);
		Linkicon_event_handler &operator = (Linkicon_event_handler const &);

		Anchor *_dst    = nullptr;
		Navbar *_navbar = nullptr;

	public:

		/**
		 * Constructor
		 */
		Linkicon_event_handler() { }

		/**
		 * Assign link destination
		 */
		void destination(Navbar *navbar, Anchor *dst)
		{
			_dst    = dst;
			_navbar = navbar;
		}

		/**
		 * Event handler interface
		 */
		void handle_event(Event const &ev) override
		{
			if (ev.type != Event::PRESS || !_navbar) return;

			/* lookup browser, in which the link token resides */
			Browser *b = 0;
			for (Element *e = _navbar; e && !b; e = e->parent())
				b = dynamic_cast<Browser *>(e);

			if (!b || !_dst) return;

			_navbar->curr(0);
			b->go_to(_dst);
			_navbar->fade_to(100, 2);
		}
};


static Linkicon_event_handler next_ev_handler;
static Linkicon_event_handler prev_ev_handler;


Navbar::Navbar()
{
	_flags.bottom = 1;

	next_ev_handler.destination(0, 0);
	prev_ev_handler.destination(0, 0);
}


void Navbar::next_link(const char *title, Anchor *dst)
{
	_next_title = new Block(Block::RIGHT);
	_next_anchor = dst;
	_next_title->append_plaintext(title, &navbar_style);
	append(_next_title);
	next_ev_handler.destination(0, 0);
}


void Navbar::prev_link(const char *title, Anchor *dst)
{
	_prev_title = new Block(Block::LEFT);
	_prev_anchor = dst;
	_prev_title->append_plaintext(title, &navbar_style);
	append(_prev_title);
	prev_ev_handler.destination(0, 0);
}


void Navbar::format_fixed_width(int w)
{
	const int padx = 10;  /* free space in the center */

	/* format labels */
	int text_w = w/2 - ARROW_W - padx;
	if (_next_title) _next_title->format_fixed_width(text_w);
	if (_prev_title) _prev_title->format_fixed_width(text_w);

	/* determine right-alignment offset for right label */
	int next_dx = _next_title ? text_w - _next_title->min_size().w() : 0;

	/* determine bounding box of navbar */
	unsigned h = ARROW_H;
	if (_next_title) h = max(h, _next_title->min_size().h());
	if (_prev_title) h = max(h, _prev_title->min_size().h());
	h += 16;

	/* assign icons to this navbar instance */
	next_icon->parent(this);
	prev_icon->parent(this);

	next_ev_handler.destination(this, _next_anchor);
	prev_ev_handler.destination(this, _prev_anchor);

	next_icon->event_handler(&next_ev_handler);
	prev_icon->event_handler(&prev_ev_handler);

	/* place icons */
	int ypos = (h - ARROW_H)/2;
	next_icon->geometry(Rect(Point(w - 64, ypos), Area(ARROW_W, ARROW_H)));
	prev_icon->geometry(Rect(Point(0,      ypos), Area(ARROW_W, ARROW_H)));

	/* place labels */
	if (_next_title) {
		ypos = (h - _next_title->min_size().h())/2 + 1;
		_next_title->geometry(Rect(Point(w/2 + padx + next_dx, ypos),
		                           Area(text_w, _next_title->min_size().h())));
	}
	if (_prev_title) {
		ypos = (h - _prev_title->min_size().h())/2 + 1;
		_prev_title->geometry(Rect(Point(ARROW_W, ypos),
		                           Area(text_w, _prev_title->min_size().h())));
	}

	_min_size = Scout::Area(w, h);
}


void Navbar::draw(Canvas_base &canvas, Point abs_position)
{
	int cx1 = canvas.clip().x1(), cy1 = canvas.clip().y1();
	int cx2 = canvas.clip().x2(), cy2 = canvas.clip().y2();

	/* shrink clipping area to text area (cut too long words) */
	int nx1 = max(cx1, _position.x() + abs_position.x() + ARROW_W);
	int ny1 = max(cy1, _position.y() + abs_position.y());
	int nx2 = min(cx2, nx1 + (int)_size.w() - 2*ARROW_W);
	int ny2 = min(cy2, ny1 + (int)_size.h());

	canvas.clip(Rect(Point(nx1, ny1), Area(nx2 - nx1 + 1, ny2 - ny1 + 1)));
	Parent_element::draw(canvas, abs_position);
	canvas.clip(Rect(Point(cx1, cy1), Area(cx2 - cx1 + 1, cy2 - cy1 + 1)));

	if (_prev_title) prev_icon->draw(canvas, abs_position + _position);
	if (_next_title) next_icon->draw(canvas, abs_position + _position);
}


Element *Navbar::find(Point position)
{
	Element *res;

	position = position - _position;

	if (_prev_title && (res = prev_icon->find(position))) return res;
	if (_next_title && (res = next_icon->find(position))) return res;

	return Parent_element::find(position);
}


int Navbar::on_tick()
{
	/* call on_tick function of the fader */
	if (::Fader::on_tick() == 0) return 0;

	prev_icon->alpha(_curr_value);
	next_icon->alpha(_curr_value);
	navbar_style.color = Color(0, 0, 0, _curr_value);

	refresh();
	return 1;
}