Graph Gallery

 // Copyright (C) 2023 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

 #include "highlightseries.h"

 const float darkRedPos = 1.f;
 const float redPos = 0.8f;
 const float yellowPos = 0.6f;
 const float greenPos = 0.4f;
 const float darkGreenPos = 0.2f;

 HighlightSeries::HighlightSeries()
 {
     setDrawMode(QSurface3DSeries::DrawSurface);
     setFlatShadingEnabled(true);
     setVisible(false);
 }

 HighlightSeries::~HighlightSeries() {}

 void HighlightSeries::setTopographicSeries(TopographicSeries *series)
 {
     m_topographicSeries = series;
     m_srcWidth = m_topographicSeries->dataProxy()->array().at(0).size();
     m_srcHeight = m_topographicSeries->dataProxy()->array().size();

     QObject::connect(m_topographicSeries,
                      &QSurface3DSeries::selectedPointChanged,
                      this,
                      &HighlightSeries::handlePositionChange);
 }

 void HighlightSeries::handlePositionChange(const QPoint &position)
 {
     m_position = position;

     if (position == invalidSelectionPosition()) {
         setVisible(false);
         return;
     }

     int halfWidth = m_width / 2;
     int halfHeight = m_height / 2;

     int startX = position.x() - halfWidth;
     if (startX < 0)
         startX = 0;
     int endX = position.x() + halfWidth;
     if (endX > (m_srcWidth - 1))
         endX = m_srcWidth - 1;
     int startZ = position.y() - halfHeight;
     if (startZ < 0)
         startZ = 0;
     int endZ = position.y() + halfHeight;
     if (endZ > (m_srcHeight - 1))
         endZ = m_srcHeight - 1;

     QSurfaceDataProxy *srcProxy = m_topographicSeries->dataProxy();
     const QSurfaceDataArray &srcArray = srcProxy->array();

     QSurfaceDataArray dataArray;
     dataArray.reserve(endZ - startZ);
     for (int i = startZ; i < endZ; ++i) {
         QSurfaceDataRow newRow;
         newRow.reserve(endX - startX);
         QSurfaceDataRow srcRow = srcArray.at(i);
         for (int j = startX; j < endX; ++j) {
             QVector3D pos = srcRow.at(j).position();
             pos.setY(pos.y() + m_heightAdjustment);
             newRow.append(QSurfaceDataItem(pos));
         }
         dataArray.append(newRow);
     }

     dataProxy()->resetArray(dataArray);
     setVisible(true);
 }

 void HighlightSeries::handleGradientChange(float value)
 {
     float ratio = m_minHeight / value;

     QLinearGradient gr;
     gr.setColorAt(0.f, Qt::black);
     gr.setColorAt(darkGreenPos * ratio, Qt::darkGreen);
     gr.setColorAt(greenPos * ratio, Qt::green);
     gr.setColorAt(yellowPos * ratio, Qt::yellow);
     gr.setColorAt(redPos * ratio, Qt::red);
     gr.setColorAt(darkRedPos * ratio, Qt::darkRed);

     setBaseGradient(gr);
     setColorStyle(Q3DTheme::ColorStyle::RangeGradient);

     handleZoomChange(ratio);
 }

 void HighlightSeries::handleZoomChange(float zoom)
 {
     m_heightAdjustment = (1.2f - zoom) * 10.f;
 }