#include "qimageview.h"
#include <cmath>
QImageView::QImageView(QWidget *parent): QGraphicsView(parent)
{
    // 隐藏水平/竖直滚动条
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    //QPainter::Antialiasing //绘图抗锯齿
    //QPainter::TextAntialiasing //绘制的字体抗锯齿
    setRenderHints(QPainter::Antialiasing);
    //设置背景笔刷
    setBackgroundBrush(BackgroundColor);

}
void QImageView::drawBackground(QPainter *painter, const QRectF &r)
{
    QGraphicsView::drawBackground(painter, r);
    auto drawGrid = [&](double gridStep) {
        QRect windowRect = rect();
        QPointF tl = mapToScene(windowRect.topLeft());
        QPointF br = mapToScene(windowRect.bottomRight());
        double left = std::floor(tl.x() / gridStep - 0.5);
        double right = std::floor(br.x() / gridStep + 1.0);
        double bottom = std::floor(tl.y() / gridStep - 0.5);
        double top = std::floor(br.y() / gridStep + 1.0);
        // vertical lines
        for (int xi = int(left); xi <= int(right); ++xi)
        {
            QLineF line(xi * gridStep, bottom * gridStep, xi * gridStep, top * gridStep);
            painter->drawLine(line);
        }
        // horizontal lines
        for (int yi = int(bottom); yi <= int(top); ++yi)
        {
            QLineF line(left * gridStep, yi * gridStep, right * gridStep, yi * gridStep);
            painter->drawLine(line);
        }
    };

    QPen pfine(FineGridColor, 1.0);
    painter->setPen(pfine);
    drawGrid(15);
    QPen p(CoarseGridColor, 1.0);
    painter->setPen(p);
    drawGrid(150);
}