scroomer.cc

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/*
    Copyright (C) 2008 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.

*/

#include <iostream>

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

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

Scroomer::Scroomer(Gtk::Adjustment& adjustment)
        : adj(adjustment)
        , handle_size(0)
        , grab_comp(None)
{
        position[TopBase] = 0;
        position[Handle1] = 0;
        position[Slider] = 0;
        position[Handle2] = 0;
        position[BottomBase] = 0;
        position[Total] = 0;

        add_events (Gdk::BUTTON_PRESS_MASK |
                    Gdk::BUTTON_RELEASE_MASK |
                    Gdk::POINTER_MOTION_MASK |
                    Gdk::SCROLL_MASK);

        adjustment.signal_value_changed().connect (mem_fun (*this, &Scroomer::adjustment_changed));
        //adjustment.signal_changed().connect (mem_fun (*this, &Scroomer::adjustment_changed));
}

Scroomer::~Scroomer()
{
}

bool
Scroomer::on_motion_notify_event (GdkEventMotion* ev)
{
        double range = adj.get_upper() - adj.get_lower();
        double pixel2val = range / get_height();
        double val_at_pointer = ((get_height() - ev->y) * pixel2val) + adj.get_lower();
        double delta_y = ev->y - grab_y;
        double half_min_page = min_page_size / 2;
        double fract = delta_y / position[Total];
        double scale, temp, zoom;
        double val, page;

        if (grab_comp == None || grab_comp == Total) {
                return true;
        }

        if (ev->window != grab_window) {
                grab_y = ev->y;
                grab_window = ev->window;
                return true;
        }

        if (ev->y < 0 || ev->y > get_height ()) {
                return true;
        }

        grab_y = ev->y;

        if (ev->state & Keyboard::PrimaryModifier) {
                if (ev->state & Keyboard::SecondaryModifier) {
                        scale = 0.05;
                } else {
                        scale = 0.1;
                }
        } else {
                scale = 1.0;
        }

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

        switch (grab_comp) {
        case TopBase:
        case BottomBase:
                unzoomed_val += scale * fract * range;
                unzoomed_val = min(unzoomed_val, adj.get_upper() - unzoomed_page);
                unzoomed_val = max(unzoomed_val, adj.get_lower());
                break;
        case Slider:
                unzoomed_val += scale * fract * range;
                unzoomed_val = min(unzoomed_val, adj.get_upper() - unzoomed_page);
                unzoomed_val = max(unzoomed_val, adj.get_lower());
                break;
        case Handle1:

                unzoomed_page += scale * fract * range;
                unzoomed_page = min(unzoomed_page, adj.get_upper() - unzoomed_val);
                unzoomed_page = max(unzoomed_page, min_page_size);
                
                if (pinch){
                        temp = unzoomed_val + unzoomed_page;
                        unzoomed_val -= scale * fract * range * 0.5;
                        unzoomed_val = min(unzoomed_val, temp - min_page_size);
                        unzoomed_val = max(unzoomed_val, adj.get_lower());
                }
                
                break;
        case Handle2:
                temp = unzoomed_val + unzoomed_page;
                unzoomed_val += scale * fract * range;
                unzoomed_val = min(unzoomed_val, temp - min_page_size);
                unzoomed_val = max(unzoomed_val, adj.get_lower());
                
                unzoomed_page = temp - unzoomed_val;
                
                if (pinch){
                        
                        unzoomed_page -= scale * fract * range;
                }
                
                unzoomed_page = min(unzoomed_page, adj.get_upper() - unzoomed_val);             
                unzoomed_page = max(unzoomed_page, min_page_size);
                break;
        default:
                break;
        }

        /* Then we handle zoom, which is dragging horizontally. We zoom around the area that is
         * the current y pointer value, not from the area that was the start of the drag.
         * We don't start doing zoom until we are at least one scroomer width outside the scroomer's
         * area.
         */
        
        if (ev->x > (get_width() * 2)) {
                zoom = ev->x - get_width();
                
                double higher = unzoomed_val + unzoomed_page - half_min_page - val_at_pointer;
                double lower = val_at_pointer - (unzoomed_val + half_min_page);

                higher *= zoom / 128;
                lower *= zoom / 128;

                val = unzoomed_val + lower;
                page = unzoomed_page - higher - lower;

                page = max(page, min_page_size);

                if (lower < 0) {
                        val = max(val, val_at_pointer - half_min_page);
                } else if (lower > 0) {
                        val = min(val, val_at_pointer - half_min_page);
                }

                val = min(val, adj.get_upper() - min_page_size);
                page = min(page, adj.get_upper() - val);
        } else if (ev->x < 0) {
                /* on zoom out increase the page size as well as moving the range towards the mouse pos*/
                /*zoom = abs(ev->x);

                double higher = unzoomed_val + unzoomed_page - half_min_page - val_at_pointer;
                double lower = val_at_pointer - (unzoomed_val + half_min_page);

                higher *= zoom / 128;
                lower *= zoom / 128;

                val = unzoomed_val + lower;
                page = unzoomed_page - higher - lower;

                page = max(page, min_page_size);

                if (lower < 0) {
                        val = max(val, val_at_pointer - half_min_page);
                }
                else if (lower > 0) {
                        val = min(val, val_at_pointer - half_min_page);
                }

                val = min(val, adj.get_upper() - min_page_size);
                page = min(page, adj.get_upper() - val);*/

                val = unzoomed_val;
                page = unzoomed_page;
        } else {
                val = unzoomed_val;
                page = unzoomed_page;
        }

        /* Round these values to stop the scroomer handlers quivering about during drags */
        adj.set_page_size (rint (page));
        adj.set_value (rint (val));
        adj.value_changed();
        
        return true;
}

bool
Scroomer::on_scroll_event (GdkEventScroll* ev)
{
        switch (ev->direction) {
        case GDK_SCROLL_UP:
                adj.set_value (min (adj.get_value() + adj.get_page_size() / 10.0, adj.get_upper() - adj.get_page_size()));
                break;
        case GDK_SCROLL_DOWN:
                adj.set_value (adj.get_value() - adj.get_page_size() / 10.0);
                break;
        default:
                return false;
        }

        return true;
}

bool
Scroomer::on_button_press_event (GdkEventButton* ev)
{
        if (ev->button == 1 || ev->button == 3) {
                Component comp = point_in(ev->y);

                if (comp == Total || comp == None) {
                        return false;
                }

                add_modal_grab();
                grab_comp = comp;
                grab_y = ev->y;
                unzoomed_val = adj.get_value();
                unzoomed_page = adj.get_page_size();
                grab_window = ev->window;
                
                if (ev->button == 3){
                        pinch = true;
                } else {
                        pinch = false;
                }

                DragStarting (); /* EMIT SIGNAL */
        }
        
        if (ev->type == GDK_2BUTTON_PRESS && ev->button == 1) {
                DoubleClicked();
        }

        return true;
}

bool
Scroomer::on_button_release_event (GdkEventButton* ev)
{
        if (grab_comp == None || grab_comp == Total) {
                return true;
        }

        if (ev->window != grab_window) {
                grab_y = ev->y;
                grab_window = ev->window;
                return true;
        }

        if (ev->button != 1 && ev->button != 3) {
                return true;
        }

        switch (grab_comp) {
        case TopBase:
                break;
        case Handle1:
                break;
        case Slider:
                break;
        case Handle2:
                break;
        case BottomBase:
                break;
        default:
                break;
        }
        
        grab_comp = None;

        remove_modal_grab();
        DragFinishing (); /* EMIT SIGNAL */
        return true;
}

void
Scroomer::on_size_allocate (Allocation& a)
{
        Gtk::DrawingArea::on_size_allocate(a);

        position[Total] = a.get_height();
        set_min_page_size(min_page_size);
        update();
}

void
Scroomer::set_comp_rect(GdkRectangle& r, Component c) const
{
        int index = (int) c;

        switch (c) {
        case None:
                return;
        case Total:
                r.y = 0;
                r.height = position[Total];
                break;
        default:
                r.y = position[index];
                r.height = position[index+1] - position[index];
                break;
        }
}

Scroomer::Component
Scroomer::point_in(double point) const
{
        for (int i = 0; i < Total; ++i) {
                if (position[i+1] >= point) {
                        return (Component) i;
                }
        }

        return None;
}

void
Scroomer::set_min_page_size(double ps)
{
        double coeff = ((double)position[Total]) / (adj.get_upper() - adj.get_lower());

        min_page_size = ps;
        handle_size = (int) floor((ps * coeff) / 2);
}

void
Scroomer::update()
{
        double range = adj.get_upper() - adj.get_lower();
        //double value = adj.get_value() - adj.get_lower();
        int height = position[Total];
        double coeff = ((double) height) / range;

        /* save the old positions to calculate update regions later*/
        for (int i = Handle1; i < Total; ++i) {
                old_pos[i] = position[i];
        }

        position[BottomBase] = (int) floor(height - (adj.get_value() * coeff));
        position[Handle2] = position[BottomBase] - handle_size;

        position[Handle1] = (int) floor(height - ((adj.get_value() + adj.get_page_size()) * coeff));
        position[Slider] = position[Handle1] + handle_size;
}

void
Scroomer::adjustment_changed()
{
        //cerr << floor(adj.get_value()) << " " << floor(adj.get_value() + adj.get_page_size()) << endl;
        Gdk::Rectangle rect;
        Glib::RefPtr<Gdk::Window> win = get_window();

        update();

        if (!win) {
                return;
        }

        rect.set_x(0);
        rect.set_width(get_width());

        if (position[Handle1] < old_pos[Handle1]) {
                rect.set_y(position[Handle1]);
                rect.set_height(old_pos[Slider] - position[Handle1]);
                win->invalidate_rect(rect, false);
        } else if (position[Handle1] > old_pos[Handle1]) {
                rect.set_y(old_pos[Handle1]);
                rect.set_height(position[Slider] - old_pos[Handle1]);
                win->invalidate_rect(rect, false);
        }

        if (position[Handle2] < old_pos[Handle2]) {
                rect.set_y(position[Handle2]);
                rect.set_height(old_pos[BottomBase] - position[Handle2]);
                win->invalidate_rect(rect, false);
        } else if (position[Handle2] > old_pos[Handle2]) {
                rect.set_y(old_pos[Handle2]);
                rect.set_height(position[BottomBase] - old_pos[Handle2]);
                win->invalidate_rect(rect, false);
        }
}