pixscroller.cc

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/*
    Copyright (C) 2005 Paul Davis
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id$
*/
#include <iostream>
#include <algorithm>
#include <cmath>

#include <gtkmm.h>

#include "gtkmm2ext/pixscroller.h"
#include "gtkmm2ext/keyboard.h"

using namespace std;
using namespace Gtk;
using namespace Gtkmm2ext;

PixScroller::PixScroller (Adjustment& a, 
                          Glib::RefPtr<Gdk::Pixbuf> s,
                          Glib::RefPtr<Gdk::Pixbuf> r)
        : adj (a),
          rail (r),
          slider (s)
{
        Cairo::Format format;

        dragging = false;
        add_events (Gdk::BUTTON_PRESS_MASK|Gdk::BUTTON_RELEASE_MASK|Gdk::POINTER_MOTION_MASK|Gdk::SCROLL_MASK);

        adj.signal_value_changed().connect (mem_fun (*this, &PixScroller::adjustment_changed));
        default_value = adj.get_value();

        sliderrect.set_width(slider->get_width());
        sliderrect.set_height(slider->get_height());
        railrect.set_width(rail->get_width());
        railrect.set_height(rail->get_height());

        railrect.set_y(sliderrect.get_height() / 2);
        sliderrect.set_x(0);

        overall_height = railrect.get_height() + sliderrect.get_height();

        sliderrect.set_y((int) rint ((overall_height - sliderrect.get_height()) * (adj.get_upper() - adj.get_value())));
        railrect.set_x((sliderrect.get_width() / 2) - 2);

        if (rail->get_has_alpha()) {
                format = Cairo::FORMAT_ARGB32;
        } else {
                format = Cairo::FORMAT_RGB24;
        }
        rail_surface = Cairo::ImageSurface::create  (format, rail->get_width(), rail->get_height());
        rail_context = Cairo::Context::create (rail_surface);
        Gdk::Cairo::set_source_pixbuf (rail_context, rail, 0.0, 0.0);
        rail_context->paint();        

        if (slider->get_has_alpha()) {
                format = Cairo::FORMAT_ARGB32;
        } else {
                format = Cairo::FORMAT_RGB24;
        }
        slider_surface = Cairo::ImageSurface::create  (format, slider->get_width(), slider->get_height());
        slider_context = Cairo::Context::create (slider_surface);
        Gdk::Cairo::set_source_pixbuf (slider_context, slider, 0.0, 0.0);
        slider_context->paint();        
}

void
PixScroller::on_size_request (GtkRequisition* requisition)
{
        requisition->width = sliderrect.get_width();
        requisition->height = overall_height;
}

bool
PixScroller::on_expose_event (GdkEventExpose* ev)
{
        GdkRectangle intersect;
        Glib::RefPtr<Gdk::Window> win (get_window());
        Cairo::RefPtr<Cairo::Context> context = get_window()->create_cairo_context();
        
        if (gdk_rectangle_intersect (railrect.gobj(), &ev->area, &intersect)) {

                context->save();
                context->rectangle (intersect.x, intersect.y, intersect.width, intersect.height);
                context->clip();
                context->set_source (rail_surface, intersect.x - railrect.get_x(), intersect.y - railrect.get_y());
                context->rectangle (intersect.x, intersect.y, intersect.width, intersect.height);
                context->clip();
                context->paint();
                context->restore();
        }
        
        if (gdk_rectangle_intersect (sliderrect.gobj(), &ev->area, &intersect)) {

                context->save();
                context->rectangle (intersect.x, intersect.y, intersect.width, intersect.height);
                context->clip();
                context->set_source (rail_surface, intersect.x - sliderrect.get_x(), intersect.y - sliderrect.get_y());
                context->rectangle (intersect.x, intersect.y, intersect.width, intersect.height);
                context->clip();
                context->paint();
                context->restore();
        }

        return true;
}

bool
PixScroller::on_button_press_event (GdkEventButton* ev)
{
        switch (ev->button) {
        case 1:
                if (!(ev->state & Keyboard::TertiaryModifier)) {
                        add_modal_grab();
                        grab_y = ev->y;
                        grab_start = ev->y;
                        grab_window = ev->window;
                        dragging = true;
                }
                break;
        default:
                break;
        } 
                               

        return false;
}

bool
PixScroller::on_button_release_event (GdkEventButton* ev)
{
        double scale;
        
        if (ev->state & Keyboard::PrimaryModifier) {
                if (ev->state & Keyboard::SecondaryModifier) {
                        scale = 0.05;
                } else {
                        scale = 0.1;
                }
        } else {
                scale = 1.0;
        }

        switch (ev->button) {
        case 1:
                if (dragging) {
                        remove_modal_grab();
                        dragging = false;

                        if (ev->y == grab_start) {
                                /* no motion - just a click */
                                double fract;

                                if (ev->y < sliderrect.get_height()/2) {
                                        /* near the top */
                                        fract = 1.0;
                                } else {
                                        fract = 1.0 - (ev->y - sliderrect.get_height()/2) / railrect.get_height();
                                }

                                fract = min (1.0, fract);
                                fract = max (0.0, fract);

                                adj.set_value (scale * fract * (adj.get_upper() - adj.get_lower()));
                        }
                } else {
                        if (ev->state & Keyboard::TertiaryModifier) {
                                adj.set_value (default_value);
                                cerr << "default value = " << default_value << endl;
                        }
                }
                break;
        default:
                break;
        }
        return false;
}

bool
PixScroller::on_scroll_event (GdkEventScroll* ev)
{
        double scale;
        
        if (ev->state & Keyboard::PrimaryModifier) {
                if (ev->state & Keyboard::SecondaryModifier) {
                        scale = 0.05;
                } else {
                        scale = 0.1;
                }
        } else {
                scale = 0.5;
        }

        switch (ev->direction) {

        case GDK_SCROLL_UP:
                /* wheel up */
                adj.set_value (adj.get_value() + (adj.get_page_increment() * scale));
                break;
        case GDK_SCROLL_DOWN:
                /* wheel down */
                adj.set_value (adj.get_value() - (adj.get_page_increment() * scale));
                break;
        default:
                break;
        }
        return false;
}

bool
PixScroller::on_motion_notify_event (GdkEventMotion* ev)
{
        if (dragging) {
                double fract;
                double delta;
                double scale;

                if (ev->window != grab_window) {
                        grab_y = ev->y;
                        grab_window = ev->window;
                        return true;
                }
                
                if (ev->state & Keyboard::PrimaryModifier) {
                        if (ev->state & Keyboard::SecondaryModifier) {
                                scale = 0.05;
                        } else {
                                scale = 0.1;
                        }
                } else {
                        scale = 1.0;
                }

                delta = ev->y - grab_y;
                grab_y = ev->y;

                fract = (delta / railrect.get_height());

                fract = min (1.0, fract);
                fract = max (-1.0, fract);
                
                fract = -fract;

                adj.set_value (adj.get_value() + scale * fract * (adj.get_upper() - adj.get_lower()));
        }

        return true;
}

void
PixScroller::adjustment_changed ()
{
        int y = (int) rint ((overall_height - sliderrect.get_height()) * (adj.get_upper() - adj.get_value()));

        if (y != sliderrect.get_y()) {
                sliderrect.set_y(y);
                queue_draw ();
        }
}