Qt：在widget的外部进行绘制带有坐标轴的图像
=====================================Widget.h=====================================
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
namespace Ui {
class Widget;
}
class Widget : public QWidget {
Q_OBJECT
public:
Widget(QWidget *parent = 0 );
~Widget();
protected:
virtual void changeEvent(QEvent *e);
virtual bool eventFilter(QObject *watched, QEvent *e);
void paintOnWidget(QWidget *w);
private:
Ui::Widget *ui;
};
#endif // WIDGET_H
=====================================Widget.cpp=====================================
#include "Widget.h"
#include "ui_Widget.h"
#include <QtGui/QPainter>
Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) {
ui->setupUi(this );
ui->widget->installEventFilter(this );
}
Widget::~Widget() {
delete ui;
}
void Widget::changeEvent(QEvent *e) {
QWidget::changeEvent(e);
switch (e->type()) {
case QEvent::LanguageChange:
ui->retranslateUi(this );
break ;
default:
break ;
}
}
bool Widget::eventFilter(QObject *watched, QEvent *e) {
if (watched == ui->widget) {
if (e->type() == QEvent::Paint) {
paintOnWidget(ui->widget);
return true ;
}
}
return QWidget::eventFilter(watched, e);
}
void Widget::paintOnWidget(QWidget *w) {
QPainter painter(w);
QFontMetrics metrics = painter.fontMetrics();
int textHeight = metrics.ascent() + metrics.descent();
int leftWidth = metrics.width(tr("9000" )) + 5 ;
int rightWidth = metrics.width(tr("( 日 )" ));
int width = w->size().width() - leftWidth - rightWidth;
int height = w->size().height() - 3 * textHeight;
// 绘制外框
painter.drawRect(0 , 0 , w->size().width() -1 , w->size().height() - 1 );
// 移动坐标系
//painter.translate(inset * 2, ui->yearWidget->size().height() - inset);
painter.translate(leftWidth, 1.75 * textHeight + height);
int totalCount = 9000 ; // 默认每年收入 9000 件衣服
int count = 10 ; // 分成 10 成
float deltaX = width / 12.0f ; // x 坐标上每分的宽度
float deltaY = (float )height / count; // y 坐标上每分的宽度
// 画横坐标
painter.drawLine(0 , 0 , width, 0 );
for (int i = 1 ; i <= 12 ; ++i) {
QString month = tr("%1 月 " ).arg(i);
int stringWidth = metrics.width(month);
// 绘制坐标刻度
painter.drawLine(deltaX * i, 0 , deltaX * i, 4 );
// 绘制坐标处的月
int monthX = deltaX * (i - 1 ) + ((deltaX - stringWidth) / 2 );
painter.drawText(monthX, textHeight, month);
}
// 画纵坐标
painter.drawLine(0 , 0 , 0 , -height);
painter.drawText(-metrics.width(tr("( 件 )" )),
-(deltaY * count + textHeight / 2 + metrics.descent()),
tr("( 件 )" ));
for (int i = 1 ; i <= count; ++i) {
QString value = QString("%1" ).arg(i * totalCount / count);
int stringWidth = metrics.width(value);
// 绘制坐标刻度
painter.drawLine(-4 , -i * deltaY, 0 , -i * deltaY);
// 绘制坐标值
//painter.drawText(-stringWidth - 4, -i * deltaY + stringHeight / 2, value);
painter.drawText(-stringWidth - 4 , -(deltaY * i + textHeight / 2 - metrics.ascent()), value);
}
// // 绘制每个月收到的服饰
// painter.setBrush(Qt::BDiagPattern);
// for (int i = 0; i < yearList.size(); ++i) {
// painter.setPen(Qt::black);
// int fineryCount = yearList.at(i); // 第 i + 1个月收到的服饰件数
// int h = fineryCount / (float)totalCount * height;
// painter.drawRect(deltaX * i + 2, 0, deltaX - 4, -h);
//
// // 绘制收到的服饰件数
// QString fineryString = QString("%1").arg(fineryCount);
// int stringWidth = metrics.width(fineryString);
//
// if (h > height) {
// h = height;
// }
//
// painter.setPen(Qt::red);
// //painter.drawText(deltaX * i + (deltaX - stringWidth) / 2, -(h + metrics.descent()), fineryString);
// }
}