splitter_handle.cpp

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/*
 * Copyright (c) 2012, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <QEvent>
#include <QMouseEvent>
#include <QPaintEvent>
#include <QPainter>
#include <QTreeView>

#include "rviz/properties/splitter_handle.h"

namespace rviz
{

SplitterHandle::SplitterHandle( QTreeView* parent )
  : QWidget( parent )
  , parent_( parent )
  , first_column_size_ratio_( 0.5f )
  , color_( 128, 128, 128, 64 )
{
  setCursor( Qt::SplitHCursor );
  updateGeometry();
  parent_->installEventFilter( this );
}

bool SplitterHandle::eventFilter( QObject* event_target, QEvent* event )
{
  if( event_target == parent_ && (event->type() == QEvent::Resize ||
                                  event->type() == QEvent::Paint))
  {
    updateGeometry();
  }
  return false; // Return false regardless so resize event also does its normal job.
}

void SplitterHandle::updateGeometry()
{
  int w = 7;
  int content_width = parent_->contentsRect().width();
  int new_column_width = int( first_column_size_ratio_ * content_width );
  if ( new_column_width != parent_->columnWidth(0) ) {
    parent_->setColumnWidth( 0, new_column_width );
    parent_->setColumnWidth( 1, content_width - new_column_width );
  }
  int new_x = new_column_width - w / 2 + parent_->columnViewportPosition(0);
  if ( new_x != x() || parent_->height() != height() )
    setGeometry( new_x, 0, w, parent_->height() );
}

void SplitterHandle::setRatio( float ratio )
{
  first_column_size_ratio_ = ratio;
  updateGeometry();
}

float SplitterHandle::getRatio()
{
  return first_column_size_ratio_;
}

void SplitterHandle::mousePressEvent( QMouseEvent* event )
{
  if( event->button() == Qt::LeftButton )
  {
    // position of mouse press inside this QWidget
    x_press_offset_ = event->x();
  }
}

void SplitterHandle::mouseMoveEvent( QMouseEvent* event )
{
  int padding = 55;

  if( event->buttons() & Qt::LeftButton )
  {
    QPoint pos_rel_parent = parent_->mapFromGlobal( event->globalPos() );

    int new_x = pos_rel_parent.x() - x_press_offset_ - parent_->columnViewportPosition(0);

    if( new_x > parent_->width() - width() - padding )
    {
      new_x = parent_->width() - width() - padding;
    }

    if( new_x < padding )
    {
      new_x = padding;
    }

    if( new_x != x() )
    {
      int new_column_width = new_x + width() / 2 - parent_->contentsRect().x();
      first_column_size_ratio_ = new_column_width / (float) parent_->contentsRect().width();
      updateGeometry();
    }
  }
}

void SplitterHandle::paintEvent( QPaintEvent* event )
{
  QPainter painter( this );
  painter.setPen( color_ );
  painter.drawLine( 1+width() / 2, 0, 1+width() / 2, height() );
}

} // end namespace rviz