XmlLutReader.h

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// SPDX-FileCopyrightText: Copyright (c) OpenGeoSys Community (opengeosys.org)
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <QFile>
#include <QtXml/QDomDocument>
 
#include "BaseLib/Logging.h"
 
#include "Applications/DataHolderLib/ColorLookupTable.h"
 
 
namespace FileIO
{

class XmlLutReader
{
public:
    static bool readFromFile(const QString &fileName, DataHolderLib::ColorLookupTable &lut)
    {
        QFile file(fileName);
        if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        {
            ERR("XmlLutReader::readFromFile(): Can't open xml-file {:s}.",
                fileName.toStdString());
            return false;
        }
 
        QDomDocument doc("ColorMap");
        doc.setContent(&file);
        QDomElement docElement = doc.documentElement();
        if (docElement.nodeName().compare("ColorMap"))
        {
            ERR("XmlLutReader::readFromFile(): Unexpected XML root.");
            file.close();
            return false;
        }
 
        if (docElement.hasAttribute("interpolation"))
        {
            if (docElement.attribute("interpolation").compare("Linear") == 0)
                lut.setInterpolationType(DataHolderLib::LUTType::LINEAR);
            else if (docElement.attribute("interpolation").compare("Exponential") == 0)
                lut.setInterpolationType(DataHolderLib::LUTType::EXPONENTIAL);
            else
                lut.setInterpolationType(DataHolderLib::LUTType::NONE);
        }
        else // default
            lut.setInterpolationType(DataHolderLib::LUTType::NONE);
 
        QDomElement point = docElement.firstChildElement();
        double range[2] = { point.attribute("x").toDouble(), point.attribute("x").toDouble() };
 
        while (!point.isNull())
        {
            if ((point.nodeName().compare("Point") == 0 )
                && point.hasAttribute("x")
                && point.hasAttribute("r")
                && point.hasAttribute("g")
                && point.hasAttribute("b"))
            {
                double value = point.attribute("x").toDouble();
                unsigned char r = static_cast<int>(255 * point.attribute("r").toDouble());
                unsigned char g = static_cast<int>(255 * point.attribute("g").toDouble());
                unsigned char b = static_cast<int>(255 * point.attribute("b").toDouble());
                unsigned char o = static_cast<int>(255 * (point.hasAttribute("o") ? point.attribute("o").toDouble() : 1));
 
                if (value < range[0])
                    range[0] = value;
                if (value > range[1])
                    range[1] = value;
 
                DataHolderLib::Color color = DataHolderLib::createColor(r, g, b, o);
                lut.setColor(value, color);
            }
            point = point.nextSiblingElement();
        }
 
        lut.setTableRange(range[0], range[1]);
 
        file.close();
        return true;
    };
 
 
};
 
}  // namespace FileIO