CPP File

#include "Gradient.h"
#include <QVector>
#include <QApplication>
#include <QtCore>

Gradient::Gradient(QVector<StopColor> gradient)
{
    this->setSizePolicy(
                QSizePolicy::MinimumExpanding,
                QSizePolicy::MinimumExpanding
                );

    if (gradient.isEmpty())
    {
        m_gradient = gradient;
    }
    else
    {
        // self._gradient = [
        //     (0.0, '#000000'),
        //     (1.0, '#ffffff'),
        // ]
    }

    this->m_handle_w = 10;
    this->m_handle_h = 10;
    this->m_drag_position = 0;
}

void Gradient::paintEvent(QPaintEvent *e)
{
    QPainter painter(this);
    int width = painter.device()->width();
    int height = painter.device()->height();

    // Draw the linear horizontal gradient.

    QLinearGradient gradient(0, 0, width, 0);

    for (StopColor &StopColor : m_gradient)
    {
        gradient.setColorAt(StopColor.stop, QColor(StopColor.color));
    }

    QRect rect(0, 0, width, height);
    painter.fillRect(rect, gradient);

    QPen pen;

    int y = painter.device()->height() / 2;

    // Draw the stop handles.
    for (StopColor &StopColor : m_gradient)
    {
        pen.setColor(QColor(Qt::white));
        painter.setPen(pen);

        painter.drawLine(StopColor.stop * width, y - this->m_handle_h, StopColor.stop * width, y + this->m_handle_h);

        pen.setColor(QColor(Qt::red));
        painter.setPen(pen);

        QRect rect(
                    StopColor.stop * width - this->m_handle_h/2,
                    y - this->m_handle_h/2,
                    this->m_handle_w,
                    this->m_handle_h
                    );
        painter.drawRect(rect);
    }
    painter.end();
}

void Gradient::_sort_gradient()
{
    std::sort(this->m_gradient.begin(), this->m_gradient.end());
}

void Gradient::_constrain_gradient()
{
    for (StopColor &stopColor : this->m_gradient)
        stopColor.stop = std::max(0.0, std::min(1.0, stopColor.stop));
}

void Gradient::setGradient(QVector<StopColor> gradient)
{
    // assert all([0.0 <= stop <= 1.0 for stop, _ in gradient])
    this->m_gradient = gradient;
    this->_constrain_gradient();
    this->_sort_gradient();
    //emit this->gradientChanged();
}