pageview.cpp

/*
License: GPL-2
  An electronic filing cabinet: scan, print, stack, arrange
 Copyright (C) 2009 Simon Glass, chch-kiwi@users.sourceforge.net
 .
 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

X-Comment: On Debian GNU/Linux systems, the complete text of the GNU General
 Public License can be found in the /usr/share/common-licenses/GPL file.
*/


#include <QDebug>
#include <QScrollBar>
#include <QWheelEvent>

#include "desktopmodel.h"
#include "pagedelegate.h"
#include "pageview.h"



Pageview::Pageview (QWidget *parent)
      : QListView (parent)
   {
   setViewMode (IconMode);

   setWrapping (true);
   setFlow (LeftToRight);

   // the user cannot have free movement, but this makes the destination cursor look nice
   setMovement (Free);
   setResizeMode (Adjust);
   setLayoutMode (SinglePass);
   setUniformItemSizes (true);
   setSelectionRectVisible (true);
   setHorizontalScrollMode (QAbstractItemView::ScrollPerPixel);
   setVerticalScrollMode (QAbstractItemView::ScrollPerPixel);

   setEditTriggers (QAbstractItemView::EditKeyPressed);
   setStyleSheet ("QListView { background : lightgray }");

   _autoscroll = true;  // the user has not scrolled yet
   _ignore_scroll = false;
   }


Pageview::~Pageview ()
   {
   }


void Pageview::currentChanged (const QModelIndex &index, const QModelIndex &previous)
   {
   UNUSED (previous);
   emit showInfo (index);
   }


void Pageview::allowMove (bool allow)
   {
   setSelectionMode (ExtendedSelection);
   setDropIndicatorShown (false);
   setDragDropMode (allow ? InternalMove : NoDragDrop);
   setDragEnabled (allow);
   }


void Pageview::wheelEvent (QWheelEvent *e)
   {
   int new_scale = _scale_down;

   int step = 1, jump = new_scale;
   while (jump >= 12)
      {
      step *= 2;
      jump /= 2;
      }

   if (e->modifiers () & Qt::ControlModifier)
      {
//printf ("delta %d\n", e->delta ());
      if (e->angleDelta ().y() < 0)
         new_scale += step;
      else if (e->angleDelta ().y() > 0 && new_scale > step)
         new_scale -= step;
      else
         e->ignore ();

      if (new_scale > 224)
         new_scale = 224;
      if (new_scale != _scale_down)
         emit signalNewScale (new_scale);
      }
   else
      QListView::wheelEvent (e);
   }


void Pageview::setScale (int scale_down)
   {
   _scale_down = scale_down;
   }


void Pageview::selectPage (QModelIndex ind)
   {
   QItemSelectionModel *sel = selectionModel ();

   sel->select (QItemSelection (ind, ind),
      QItemSelectionModel::Clear | QItemSelectionModel::Select);
   scrollTo (ind);
   }


void Pageview::scrollToEnd (bool ifAtEnd)
   {
//    QScrollBar *vs = verticalScrollBar ();

//    qDebug () << "scrollToEnd" << _autoscroll;
   if (!ifAtEnd || _autoscroll)
      {
      _ignore_scroll = true;
      // doesn't seem to work, perhaps because the window extent hasn't been updated yet
//       vs->setValue (vs->maximum ());

      // so use this instead
      scrollTo (model ()->index (model ()->rowCount (QModelIndex ()) - 1, 0, QModelIndex ()));
      _ignore_scroll = false;
      }
   }


void Pageview::scrollContentsBy (int dx, int dy)
   {
   /* if we caused the scroll, then don't worry. Otherwise the user is trying
      to adjust the scrollbars, so if they are not at the bottom, we turn off
      autoscroll */
   if (!_ignore_scroll)
      {
      QScrollBar *vs = verticalScrollBar ();

      _autoscroll = vs->value () == vs->maximum ();
//       qDebug () << "autoscroll" << _autoscroll;
      }
   QListView::scrollContentsBy (dx, dy);
   }


void Pageview::slotPagePartChanged (const QModelIndex &index,
      const QImage &image, int scaled_linenum)
   {
   const Pagedelegate *del = (Pagedelegate *)itemDelegate ();
   QStyleOptionViewItem option = getViewOptions ();

   int hvalue = horizontalScrollBar()->value();
   int vvalue = verticalScrollBar()->value();

   QRect rect = rectForIndex (index);
   QRect part_rect;
   option.rect = rect;
   del->getPagePart (option, index, scaled_linenum, image.height (), part_rect);

   part_rect.translate (-hvalue, -vvalue);

   QWidget *vp = viewport ();
//    qDebug () << "repaint" << part_rect;
//    part_rect.setHeight (part_rect.height () - 1);   // leave blank line (for testing!)
//    vp->repaint (part_rect);
   vp->update (part_rect);
   }


void Pageview::updateGeometries (void)
   {
   QScrollBar *vs = verticalScrollBar ();
   QScrollBar *hs = horizontalScrollBar ();

   QListView::updateGeometries ();
   vs->setSingleStep (30);
   hs->setSingleStep (30);
   }