学步园

main.cpp

#include <QtGui/QApplication><br /> #include "analogclock.h"</p> <p>Q_DECL_EXPORT int main(int argc, char *argv[])<br /> {<br /> QApplication theApp(argc, argv);</p> <p> AnalogClock clock;<br /> clock.show();</p> <p> return theApp.exec();<br /> }<br />
analogclock.h

#ifndef ANALOGCLOCK_H<br /> #define ANALOGCLOCK_H</p> <p>#include <QWidget></p> <p>class AnalogClock : public QWidget<br /> {<br /> Q_OBJECT<br /> public:<br /> explicit AnalogClock(QWidget *parent = 0);</p> <p>signals:</p> <p>public slots:</p> <p>protected:<br /> void paintEvent(QPaintEvent *event);<br /> };</p> <p>#endif // ANALOGCLOCK_H void paintEvent(QPaintEvent *event);<br />

analogclock.cpp

#include <QtGui><br /> #include "analogclock.h"</p> <p>AnalogClock::AnalogClock(QWidget *parent) :<br /> QWidget(parent)<br /> {<br /> QTimer* timer = new QTimer(this);<br /> connect(timer, SIGNAL(timeout()), this, SLOT(update()));<br /> timer->start(1000);<br /> setWindowTitle(tr("Analog Clock"));<br /> resize(200, 200);</p> <p>}</p> <p>void AnalogClock::paintEvent(QPaintEvent *)<br /> {<br /> // 时针和分针的点坐标<br /> //画的是三角形，所以需要三个点的坐标<br /> static const QPoint hourHand[3] = {<br /> QPoint(7, 8),<br /> QPoint(-7, 8),<br /> QPoint(0, -30)<br /> };<br /> static const QPoint minuteHand[3] = {<br /> QPoint(7, 8),<br /> QPoint(-7, 8),<br /> QPoint(0, -60)<br /> };</p> <p> static const QPoint secondHand[3] = {<br /> QPoint(4, 8),<br /> QPoint(-4, 8),<br /> QPoint(0, -100)<br /> };</p> <p> /* 设置时针和分针的颜色 */<br /> QColor hourColor(127, 0, 127);<br /> QColor minuteColor(0, 127, 127, 191);<br /> QColor secondColor(0, 100, 100);</p> <p> /* QT自带函数，返回两个数的最小值 */<br /> int side = qMin(width(), height());</p> <p> /* 获取当前时间 */<br /> QTime time = QTime::currentTime();</p> <p> /*<br /> 在this这个可绘画设备上创建一个绘画者<br /> 设置渲染，用反锯齿效果<br /> 用一个重载函数转换一下坐标系<br /> 缩放一下这个坐标系<br /> */<br /> //The QPainter class performs low-level painting on widgets and other paint devices.<br /> QPainter painter(this);</p> <p> //Sets the given render hint on the painter if on is true; otherwise clears the render hint<br /> //Renderhints are used to specify flags to QPainter that may or may not be respected by any given engine.<br /> painter.setRenderHint(QPainter::Antialiasing);</p> <p> //Translates the coordinate system by the given offset<br /> painter.translate(width()/2, height()/2);</p> <p> //Scales the coordinate system by (sx, sy).<br /> painter.scale(side/200.0, side/200.0);</p> <p> /* 用一个重载函数设置一下画笔的类型，NoPen就是没有线<br /> 再用一个重载函数设置一下笔刷的颜色，用默认类型<br /> */<br /> //Sets the painter's pen to be the given pen.<br /> //The pen defines how to draw lines and outlines, and it also defines the text color.<br /> painter.setPen(Qt::NoPen);</p> <p> //sets the painter's brush to the given brush.<br /> //The painter's brush defines how shapes are filled.<br /> painter.setBrush(hourColor);</p> <p> //Saves the current painter state (pushes the state onto a stack).<br /> //A save() must be followed by a corresponding restore(); the end() function unwinds the stack.<br /> painter.save(); //保存当前的绘画者状态</p> <p> //用给出的角度旋转坐标系<br /> //Rotates the coordinate system the given angle clockwise.<br /> painter.rotate(30.0*((time.hour()+time.minute()/60.0)));</p> <p> //用线把点连起来<br /> //Draws the convex polygon defined by the first pointCount points in the array points using the current pen.<br /> //The first point is implicitly connected to the last point, and the polygon is filled with the current brush().<br /> painter.drawConvexPolygon(hourHand, 3);</p> <p> //恢复当前的绘画者状态<br /> //Restores the current painter state (pops a saved state off the stack).<br /> painter.restore();</p> <p> painter.setPen(hourColor);</p> <p> /* 画代表小时的线 */<br /> for (int i = 0; i < 12; ++i) {<br /> //Draws a line from (x1, y1) to (x2, y2) and sets the current pen position to (x2, y2).<br /> painter.drawLine(88, 0, 96, 0);<br /> painter.rotate(30.0);<br /> }</p> <p> //下面画分钟的过程是上面的重复，只是分针的颜色用到了透明度<br /> painter.setPen(Qt::NoPen);<br /> painter.setBrush(minuteColor);<br /> painter.save();<br /> painter.rotate(6.0*(time.minute()+time.second()/60.0));<br /> painter.drawConvexPolygon(minuteHand, 3);<br /> painter.restore();<br /> painter.setPen(minuteColor);</p> <p> /* 画代表分钟的线 */<br /> for (int j = 0; j < 60; ++j) {<br /> if((j % 5) != 0) {<br /> painter.drawLine(92, 0, 96,0);<br /> }<br /> painter.rotate(6.0);<br /> }</p> <p> //下面画秒针的过程是上面的重复<br /> painter.setPen(Qt::NoPen);<br /> painter.setBrush(secondColor);<br /> painter.save();<br /> painter.rotate(6.0*(time.second()));<br /> painter.drawConvexPolygon(secondHand, 3);<br /> painter.restore();<br /> painter.setPen(minuteColor);<br /> }<br />