#include <QPainter>
  #include "VHistoWidget.h"
  #include <iostream>
  
  using namespace cv;
  using namespace std;
  
  VHistoWidget::VHistoWidget(int scale, int width, int height, int paletteHeight, QWidget *parent)
    : QWidget(parent),
      m_width(width),
      m_height(height),
      m_paletteHeight(paletteHeight),
      m_scale(scale)
  {
    setFixedSize(m_width, m_height + m_paletteHeight + 1);
  }
  
  ///////////
  // slots //
  ///////////
  
  void VHistoWidget::setHisto(const Mat &vHisto)
  {
    m_vHisto = vHisto;
    update();
  }
  
  void VHistoWidget::setScale(int scale)
  {
    m_scale = scale;
    update();
  }
  
  void VHistoWidget::paintEvent(QPaintEvent *event)
  {
    Q_UNUSED(event);
    float binWidth = static_cast<float>(m_width) / m_vHisto.rows;
  
    QPainter painter(this);
    painter.fillRect(0, 0, m_width, m_height, QBrush(Qt::white));
    float vNormFac = 256.0 / m_vHisto.rows;
  
    for (int i = 1; i <= m_vHisto.rows; i++) {
      QRectF rectangle(QPointF((i-1) * binWidth,
  			     m_height * (1 - m_scale * m_vHisto.at<float>(i-1))),
  		     QPointF(i * binWidth,
  			     m_height));
      painter.fillRect(rectangle, QBrush(Qt::black));
  
      QRectF palette(QPointF((i-1) * binWidth, m_height + 1),
  		   QPointF(i * binWidth, m_height + 1 + m_paletteHeight));
      QColor vLevel(qRound((i-1) * vNormFac), qRound((i-1) * vNormFac), qRound((i-1) * vNormFac));
      painter.fillRect(palette, vLevel);
    }
  }