histogram_view.cpp

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#include "histogram_view.h"
#include <assert.h>
#include <cmath>

using namespace Shared;

namespace Statistics {

HistogramView::HistogramView(Store * store, BannerView * bannerView) :
  CurveView(store, nullptr, bannerView, nullptr),
  m_store(store),
  m_labels{},
  m_highlightedBarStart(NAN),
  m_highlightedBarEnd(NAN)
{
}

void HistogramView::reload() {
  CurveView::reload();
  float pixelLowerBound = floatToPixel(Axis::Horizontal, m_highlightedBarStart)-2;
  float pixelUpperBound = floatToPixel(Axis::Horizontal, m_highlightedBarEnd)+2;
  /* We deliberately do not mark as dirty the frame of the banner view to avoid
   *unpleasant blinking of the drawing of the banner view. */
  KDRect dirtyZone(KDRect(pixelLowerBound, 0, pixelUpperBound-pixelLowerBound,
    bounds().height()-m_bannerView->bounds().height()));
  markRectAsDirty(dirtyZone);
}

void HistogramView::drawRect(KDContext * ctx, KDRect rect) const {
  ctx->fillRect(rect, KDColorWhite);
  drawAxes(ctx, rect, Axis::Horizontal);
  drawLabels(ctx, rect, Axis::Horizontal, false);
  /* We memoize the total size to avoid recomputing it in double precision at
   * every call to EvaluateHistogramAtAbscissa() */
  float totalSize = m_store->sumOfColumn(1);
  if (isMainViewSelected()) {
    drawHistogram(ctx, rect, EvaluateHistogramAtAbscissa, m_store, &totalSize, m_store->firstDrawnBarAbscissa(), m_store->barWidth(), true, Palette::Select, Palette::YellowDark, m_highlightedBarStart, m_highlightedBarEnd);
  } else {
    drawHistogram(ctx, rect, EvaluateHistogramAtAbscissa, m_store, &totalSize, m_store->firstDrawnBarAbscissa(), m_store->barWidth(), true, Palette::GreyMiddle, Palette::YellowDark);
  }
}

void HistogramView::setHighlight(float start, float end) {
  if (m_highlightedBarStart != start || m_highlightedBarEnd != end) {
    reload();
    m_highlightedBarStart = start;
    m_highlightedBarEnd = end;
    reload();
  }
}

char * HistogramView::label(Axis axis, int index) const {
  if (axis == Axis::Vertical) {
    return nullptr;
  }
  return (char *)m_labels[index];
}

float HistogramView::EvaluateHistogramAtAbscissa(float abscissa, void * model, void * context) {
  Store * store = (Store *)model;
  float * totalSize = (float *)context;
  return store->heightOfBarAtValue(abscissa)/(*totalSize);
}

}