我对 Qt 没有太多经验,并且在使用QPainter
. 我正在尝试制作一个简单的图形小部件,它接受多个点并创建一个QVector
of QPoints
,然后使用这个向量来绘制一个多边形。但是,我的实现现在没有出现任何内容。我相当确定我已将小部件正确添加到窗口中,因为我可以看到它应该占据的空白空间。这使我相信问题出在图形小部件中。任何帮助表示赞赏。
标题:
//graph.h
#ifndef GRAPH_H
#define GRAPH_H
#include <QWidget>
#include <QPainter>
#include <QVector>
class Graph : public QWidget
{
Q_OBJECT
public:
Graph(QWidget *parent = 0);
QSize minimumSizeHint() const;
QSize maximumSizeHint() const;
QSize sizeHint() const;
void addPoint(int w, int h);
void clearPoints();
void drawGraph();
protected:
void paintEvent(QPaintEvent *event);
private:
QPen pen;
QBrush brush;
QPixmap pixmap;
QVector<QPoint> points;
};
#endif // GRAPH_H
来源:
//graph.cpp
#include "graph.h"
Graph::Graph(QWidget *parent)
: QWidget(parent)
{
points.resize(0);
setBackgroundRole(QPalette::Base);
setAutoFillBackground(true);
}
void Graph::paintEvent(QPaintEvent *event)
{
QPainter painter(this);
painter.setPen(QPen(Qt::NoPen));
painter.setBrush(QBrush(Qt::green, Qt::SolidPattern));
painter.setRenderHint(QPainter::Antialiasing, true);
painter.drawPolygon(points);
}
QSize Graph::minimumSizeHint() const
{
return sizeHint();
}
QSize Graph::maximumSizeHint() const
{
return sizeHint();
}
QSize Graph::sizeHint() const
{
return QSize(500, 200);
}
void Graph::addPoint(int w, int h)
{
points.append(QPoint(w*2, h*2));
}
void Graph::clearPoints()
{
points.clear();
}
void Graph::drawGraph() {
points.prepend(QPoint(0,0)); //The base points of the graph
points.append(QPoint(500,0));
update();
points.clear();
}