用Qt写的屏幕绘图软件

?用Qt写的屏幕绘图软件 [问题点数：40分，无满意结帖，结帖人songhuirong1]

songhuirong1
songhuirong1
等级：
结帖率：100%
楼主 发表于： 2012-05-08 09:18:03
首先感谢各位热心朋友的帮助，不久前我在论坛里发帖提问过如何用Qt来写一个屏幕绘图的软件，在各位热心朋友的帮助下，我完成了这个小程序。现在将源码供出和大家一同分享，共同探讨。在此申明，这个软件只为学习Qt而写，所以并不完善，请各位多多指教。
首先介绍下，使用方法：
1、切换画笔：
Ctrl+R：红色画笔
Ctrl+G：绿色画笔
Ctrl+B：蓝色画笔
2、形状切换：
B：画直线
C：画曲线
R：画矩形
E：画圆形
注意：以上键不区分大小写
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以下是源码部分：
1、drawonscreen.h
#ifndef DRAWONSCREEN_H
#define DRAWONSCREEN_H

#include
#include

class DrawOnScreen : public QMainWindow
{
Q_OBJECT

public:
DrawOnScreen(QWidget *parent = 0);
~DrawOnScreen();

void drawBaseLine(QPainter *painter);
void drawCurve(QPainter *painter);
void drawRectangle(QPainter *painter);
void drawEllip(QPainter *painter);
protected:
void paintEvent(QPaintEvent *event);
void resizeEvent(QResizeEvent *event);
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void mouseReleaseEvent(QMouseEvent*event);
void keyPressEvent(QKeyEvent *event);
private:
enum DrawShape{BASELINE, CURVE, RECT, ELLIPSE} drawShape;
bool isDrawLine;
bool isDrawCurve;
bool isDrawRect;
bool isDrawEllipse;
QPixmap pixmap;
QPixmap screenPixmap;
QPointF startPoint;
QPointF endPoint;
QPen pen;
QCursor cursor;
};

#endif // DRAWONSCREEN_H

2、drawonscreen.cpp
#include
#include "drawonscreen.h"

DrawOnScreen::DrawOnScreen(QWidget *parent)
: QMainWindow(parent)
{
drawShape = BASELINE;
pen = QPen(Qt::green, 5);
cursor = QCursor(QPixmap(":/sunsong/images/green.png"));
setCursor(cursor);
isDrawLine = false;
isDrawCurve = false;
isDrawRect = false;
isDrawEllipse = false;
showFullScreen();
}

DrawOnScreen::~DrawOnScreen()
{

}

void DrawOnScreen::paintEvent(QPaintEvent *event)
{
pixmap = pixmap.grabWindow(QApplication::desktop()->winId(), 0, 0, -1, -1);
QPainter painter(&pixmap);
painter.setRenderHints(QPainter::Antialiasing, true);
painter.setPen(pen);

switch(drawShape)
{
case BASELINE:
drawBaseLine(&painter);
break;
case CURVE:
drawCurve(&painter);
break;
case RECT:
drawRectangle(&painter);
break;
case ELLIPSE:
drawEllip(&painter);
break;
default:
break;
}

QPainter p(this);
p.drawPi

xmap(rect(), pixmap);
isDrawLine = false;
isDrawCurve = false;
isDrawRect = false;
isDrawEllipse = false;
}

void DrawOnScreen::resizeEvent(QResizeEvent *event)
{
pixmap = QPixmap(size());
screenPixmap = QPixmap(size());
}

void DrawOnScreen::drawBaseLine(QPainter *painter)
{
if(isDrawLine)
{
painter->drawPixmap(rect(), screenPixmap);
painter->drawLine(startPoint, endPoint);
}
}

void DrawOnScreen::drawCurve(QPainter *painter)
{
if(isDrawCurve)
painter->drawLine(startPoint, endPoint);
}

void DrawOnScreen::drawRectangle(QPainter *painter)
{
if(isDrawRect)
{
QRectF rectf = QRectF(startPoint, endPoint);
painter->drawPixmap(rect(), screenPixmap);
painter->drawRect(rectf);
}
}

void DrawOnScreen::drawEllip(QPainter *painter)
{
if(isDrawEllipse)
{
QRectF rectf = QRectF(startPoint, endPoint);
painter->drawPixmap(rect(), screenPixmap);
painter->drawEllipse(rectf);
}
}

void DrawOnScreen::mousePressEvent(QMouseEvent *event)
{
if(event->button() == Qt::LeftButton)
{
startPoint = event->posF();
screenPixmap = pixmap;
}
}

void DrawOnScreen::mouseMoveEvent(QMouseEvent *event)
{
if(event->buttons() & Qt::LeftButton)
{
endPoint = event->posF();

switch(drawShape)
{
case BASELINE:
isDrawLine = true;
repaint();
break;
case CURVE:
isDrawCurve = true;
repaint();
startPoint = endPoint;
break;
case RECT:
isDrawRect = true;
repaint();
break;
case ELLIPSE:
isDrawEllipse = true;
repaint();
break;
default:
break;
}
}
}

void DrawOnScreen::mouseReleaseEvent(QMouseEvent*event)
{
if(event->button() == Qt::LeftButton)
{
endPoint = event->posF();
isDrawLine = true;
isDrawCurve = true;
isDrawRect = true;
isDrawEllipse = true;
repaint();
}
}

void DrawOnScreen::keyPressEvent(QKeyEvent *event)
{
switch(event->key())
{
case Qt::Key_B:
{
if(event->modifiers() & Qt::ControlModifier)
{
pen.setColor(Qt::blue);
cursor = QCursor(QPixmap(":/sunsong/images/blue.png"));
setCursor(cursor);
}
else
drawShape = BASELINE;
}
break;
case Qt::Key_C:
drawShape = CURVE;
break;
case Qt::Key_R:
{
if(event->modifiers() & Qt::ControlModifier)
{
pen.setColor(Qt::red);
cursor = QCursor(QPixmap(":/sunsong/images/red.png"));
setCursor(cursor);
}

else
drawShape = RECT;
}
break;
case Qt::Key_E:
drawShape = ELLIPSE;
break;
case Qt::Key_G:
{
if(event->modifiers() & Qt::ControlModifier)
{
pen.setColor(Qt::green);
cursor = QCursor(QPixmap(":/sunsong/images/green.png"));
setCursor(cursor);
}
}
break;
default:
break;
}
}

3、main.cpp
#include
#include "drawonscreen.h"

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
DrawOnScreen w;
w.show();
return a.exec();
}