一、可按比例拖拽窗体大小的无边框窗口
前几天接到一个需求，就是视频广播的窗体画面要可以拖拽，修改成了可以拖拽全屏的窗口之后，又有一个问题：视频画面也被拉伸了。
由于视频画面是有比例的，所以我们最好也能保证窗口画面也保持一定的比例，所以这里我就改了一下之前的无边框窗口方案如下：
优点：改造过的无边框方案，可以让无边框的窗体变换大小的时候保持一定比例，保证窗体中的画面不变形
缺点：1.不够自由，不能自由拖动
2.如果拖动的是左边，因为拖动事件实际上是先变换大小后修改坐标，那么右边就会有明显抖动
3.因为要检测当前的鼠标状态，所以是挺浪费系统资源的，较差的机型上可能会有一些意想不到的问题。
.h文件下：
enum {
TOPLEFT = 11,
TOP = 12,
TOPRIGHT = 13,
LEFT = 21,
CENTER = 22,
RIGHT = 23,
BUTTOMLEFT = 31,
BUTTOM = 32,
BUTTOMRIGHT = 33
};
#define FRAMESHAPE 15
const double default_rate = 4.00 / 3.00; //画面比例参数
public:
int CalCursorCol(QPoint pt); //计算鼠标X的位置
int CalCursorPos(QPoint pt, int colPos); //计算鼠标的位置
void setCursorShape(int CalPos); //设置鼠标对应位置的形状
protected:
void mouseMoveEvent(QMouseEvent *event);
void mousePressEvent(QMouseEvent *event);
void mouseReleaseEvent(QMouseEvent *event);
private:
int m_iCalCursorPos;
bool m_bLeftPress;
QRect m_rtPreGeometry;
QPoint m_ptViewMousePos;
.cpp文件：
//注，要在构造函数写上setMouseTracking(true)，要从表面的控件->控件的父控件 ->...->this都要写上
void Mengban::mouseMoveEvent(QMouseEvent * event)
{
//窗体不是最大的话就改变鼠标的形状
if (Qt::WindowMaximized != windowState())
{
setCursorShape(CalCursorPos(event->pos(), CalCursorCol(event->pos())));
}
//获取当前的点，这个点是全局的
QPoint ptCurrentPos = QCursor::pos();
//计算出移动的位置，当前点 - 鼠标左键按下的点
QPoint ptMoveSize = ptCurrentPos - m_ptViewMousePos;
QRect rtTempGeometry = m_rtPreGeometry;
if (m_bLeftPress)
{
switch (m_iCalCursorPos)
{
//case TOPLEFT:
// rtTempGeometry.setTopLeft(m_rtPreGeometry.topLeft() + ptMoveSize);
// break;
case TOP:
rtTempGeometry.setTop(m_rtPreGeometry.top() + ptMoveSize.y());
rtTempGeometry.setRight(this->x() + this->height() * default_rate);
break;
//case TOPRIGHT:
// rtTempGeometry.setTopRight(m_rtPreGeometry.topRight() + ptMoveSize);
// break;
case LEFT:
rtTempGeometry.setLeft(m_rtPreGeometry.left() + ptMoveSize.x());
rtTempGeometry.setTop(this->y() - this->width() / default_rate + this->height());
break;
case RIGHT:
rtTempGeometry.setRight(m_rtPreGeometry.right() + ptMoveSize.x());
rtTempGeometry.setBottom(this->y() + this->width() / default_rate);
break;
//case BUTTOMLEFT:
// rtTempGeometry.setBottomLeft(m_rtPreGeometry.bottomLeft() + ptMoveSize);
// break;
case BUTTOM:
rtTempGeometry.setBottom(m_rtPreGeometry.bottom() + ptMoveSize.y());
rtTempGeometry.setLeft(this->x() - this->height() * default_rate+this->width());
break;
//case BUTTOMRIGHT:
// rtTempGeometry.setBottomRight(m_rtPreGeometry.bottomRight() + ptMoveSize);
// break;
case CENTER:
rtTempGeometry.moveTo(rtTempGeometry.x() + ptMoveSize.x(), rtTempGeometry.y() + ptMoveSize.y());
default:
break;
}
//移动窗体，如果比最小窗体大，就移动
if (rtTempGeometry.width() >= 360 && rtTempGeometry.height() >= 270)
setGeometry(rtTempGeometry);
}
}
void Mengban::mousePressEvent(QMouseEvent * event)
{
m_iCalCursorPos = CalCursorPos(event->pos(), CalCursorCol(event->pos()));
if (event->button() == Qt::LeftButton /*&& Qt::WindowMaximized != windowState()*/)
{
//if (m_iCalCursorPos != CENTER)
//{
m_bLeftPress = true;
//}
}
m_rtPreGeometry = geometry();
m_ptViewMousePos = event->globalPos();
}
void Mengban::mouseReleaseEvent(QMouseEvent * event)
{
m_bLeftPress = false;
QApplication::restoreOverrideCursor();
}
int Mengban::CalCursorCol(QPoint pt)
{
return (pt.x() < FRAMESHAPE ? 1 : ((pt.x() > this->width() - FRAMESHAPE) ? 3 : 2));
}
int Mengban::CalCursorPos(QPoint pt, int colPos)
{
return ((pt.y() < FRAMESHAPE ? 10 : ((pt.y() > this->height() - FRAMESHAPE) ? 30 : 20)) + colPos);
}
void Mengban::setCursorShape(int CalPos)
{
Qt::CursorShape cursor;
switch (CalPos)
{
//case TOPLEFT:
//case BUTTOMRIGHT:
// cursor = Qt::SizeFDiagCursor;
// break;
//case TOPRIGHT:
//case BUTTOMLEFT:
// cursor = Qt::SizeBDiagCursor;
// break;
case TOP:
case BUTTOM:
cursor = Qt::SizeVerCursor;
break;
case LEFT:
case RIGHT:
cursor = Qt::SizeHorCursor;
break;
default:
cursor = Qt::ArrowCursor;
break;
}
//qDebug() << "fresh!!";
//qDebug() << "current cursor" << cursor;
this->setCursor(cursor);
}
二、可拖拽大小的windows系统方案：
这个方案拖拽窗体大小是通过系统api实现的，具体怎么实现的我也不是很清楚，之后有时间系统看一下windows高级编程再回来聊聊这个技术点。这里只谈优缺点
优点:
1.windows自带api，效率更高，消耗资源更少
2.没有限制，自由拖拽大小（当然了，窗体会受到最大最小窗口大小的限制）
3.代码简单，分析方便
缺点：
1.不可修改，这部分就像个黑盒，native只是告诉你现在修改的时候那个地方是锚点，仅此而已，基本上没法修改，当然了，我什么都不知道 :<
2.因为是windows的api，所以该功能仅限windows平台
#ifndef MBASEWIDGET_H
#define MBASEWIDGET_H
#include <QtWidgets/QWidget>
#include "windows.h"
class MBaseWidget : public QWidget
{
Q_OBJECT
public:
MBaseWidget(QWidget *parent);
~MBaseWidget();
void setMarginWidth(const int &); //设置鼠标可以在界面边缘多大范围内拖动改变界面大小
void serResizable(bool); //设置是否可以拖动改变大小
protected:
bool nativeEvent(const QByteArray & eventType, void * message, long * result);
private:
int m_iMarginWidth;
bool m_bCanResize;
};
#endif // MBASEWIDGET_H
#include "MBaseWidget.h"
#include "windowsx.h"
MBaseWidget::MBaseWidget(QWidget *parent)
: QWidget(parent)
{
m_iMarginWidth = 3;
m_bCanResize = true;
setWindowFlags(Qt::FramelessWindowHint);
}
MBaseWidget::~MBaseWidget()
{
}
void MBaseWidget::setMarginWidth(const int &iWidth)
{
m_iMarginWidth = iWidth;
}
void MBaseWidget::serResizable(bool bCanResize)
{
m_bCanResize = bCanResize;
}
bool MBaseWidget::nativeEvent(const QByteArray &eventType, void *message, long *result)
{
if (!m_bCanResize)
{
return QWidget::nativeEvent(eventType,message,result);
}
MSG* msg = (MSG*)message;
switch(msg->message)
{
case WM_NCHITTEST:
int xPos = GET_X_LPARAM(msg->lParam) - this->frameGeometry().x();
int yPos = GET_Y_LPARAM(msg->lParam) - this->frameGeometry().y();
if(xPos < m_iMarginWidth && yPos<m_iMarginWidth) //左上角
*result = HTTOPLEFT;
else if(xPos>=width()-m_iMarginWidth&&yPos<m_iMarginWidth) //右上角
*result = HTTOPRIGHT;
else if(xPos<m_iMarginWidth&&yPos>=height()-m_iMarginWidth) //左下角
*result = HTBOTTOMLEFT;
else if(xPos>=width()-m_iMarginWidth&&yPos>=height()-m_iMarginWidth)//右下角
*result = HTBOTTOMRIGHT;
else if(xPos < m_iMarginWidth) //左边
*result = HTLEFT;
else if(xPos>=width()-m_iMarginWidth) //右边
*result = HTRIGHT;
else if(yPos<m_iMarginWidth) //上边
*result = HTTOP;
else if(yPos>=height()-m_iMarginWidth) //下边
*result = HTBOTTOM;
else //其他部分不做处理，返回false，留给其他事件处理器处理
return false;
return true;
}
return false; //此处返回false，留给其他事件处理器处理
}
三、之前用的老的frameless方案：
最开始在网上找的frameless的方案，没什么好说的，详情见一个关于如何将widget变成一个像商用软件那样 不可拖拽大小、没有开启、关闭等按钮的固定窗口
讲道理，我发现莫名其妙的其实在这里就包含了前两种写法，但是我莫名其妙地一点都没用过。所以说抄代码也要看源码啊
内容如下：
在程序中定义Padding 为2，并同时定义枚举类型。
#define PADDING 2
enum Direction { UP=0, DOWN=1, LEFT, RIGHT, LEFTTOP, LEFTBOTTOM, RIGHTBOTTOM, RIGHTTOP, NONE };
在.cpp中设置当前窗口
this->setWindowFlags(Qt::FramelessWindowHint); //取消标题栏
// 去掉标题栏,去掉工具栏，窗口置顶
setWindowFlags(Qt::FramelessWindowHint | Qt::Tool | Qt::WindowStaysOnTopHint);
setWindowOpacity(0.7); //设置窗体透明度
重写mouseMoveEvent,mousePressEvent,mouseReleaseEvent
MainWindow.h
public:
void region(const QPoint ¤tGlobalPoint); //鼠标的位置,改变光标
protected:
//鼠标按下移动及释放事件
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void mouseReleaseEvent(QMouseEvent *event);
private:
QPoint m_movePoint; //鼠标的位置
bool isLeftPressDown; // 判断左键是否按下
Direction dir; // 窗口大小改变时，记录改变方向 MainWindow.cpp
void MainWindow::region(const QPoint ¤tGlobalPoint)
{
// 获取窗体在屏幕上的位置区域，topLeft为坐上角点，rightButton为右下角点
QRect rect = this->rect();
QPoint topLeft = this->mapToGlobal(rect.topLeft()); //将左上角的(0,0)转化为全局坐标
QPoint rightButton = this->mapToGlobal(rect.bottomRight());
int x = currentGlobalPoint.x(); //当前鼠标的坐标
int y = currentGlobalPoint.y();
if(((topLeft.x() + PADDING >= x) && (topLeft.x() <= x))
&& ((topLeft.y() + PADDING >= y) && (topLeft.y() <= y)))
{
// 左上角
dir = LEFTTOP;
this->setCursor(QCursor(Qt::SizeFDiagCursor)); // 设置光标形状
}else if(((x >= rightButton.x() - PADDING) && (x <= rightButton.x()))
&& ((y >= rightButton.y() - PADDING) && (y <= rightButton.y())))
{
// 右下角
dir = RIGHTBOTTOM;
this->setCursor(QCursor(Qt::SizeFDiagCursor));
}else if(((x <= topLeft.x() + PADDING) && (x >= topLeft.x()))
&& ((y >= rightButton.y() - PADDING) && (y <= rightButton.y())))
{
//左下角
dir = LEFTBOTTOM;
this->setCursor(QCursor(Qt::SizeBDiagCursor));
}else if(((x <= rightButton.x()) && (x >= rightButton.x() - PADDING))
&& ((y >= topLeft.y()) && (y <= topLeft.y() + PADDING)))
{
// 右上角
dir = RIGHTTOP;
this->setCursor(QCursor(Qt::SizeBDiagCursor));
}else if((x <= topLeft.x() + PADDING) && (x >= topLeft.x()))
{
// 左边
dir = LEFT;
this->setCursor(QCursor(Qt::SizeHorCursor));
}else if((x <= rightButton.x()) && (x >= rightButton.x() - PADDING))
{
// 右边
dir = RIGHT;
this->setCursor(QCursor(Qt::SizeHorCursor));
}else if((y >= topLeft.y()) && (y <= topLeft.y() + PADDING))
{
// 上边
dir = UP;
this->setCursor(QCursor(Qt::SizeVerCursor));
}else if((y <= rightButton.y()) && (y >= rightButton.y() - PADDING))
{
// 下边
dir = DOWN;
this->setCursor(QCursor(Qt::SizeVerCursor));
}else
{
// 默认
dir = NONE;
this->setCursor(QCursor(Qt::ArrowCursor));
} }
//三个鼠标事件的重写 //鼠标按下事件
void MainWindow::mousePressEvent(QMouseEvent *event)
{
switch(event->button())
{
case Qt::LeftButton:
isLeftPressDown = true;
if(dir != NONE)
{
this->mouseGrabber(); //返回当前抓取鼠标输入的窗口
}
else
{
m_movePoint = event->globalPos() - this->frameGeometry().topLeft();
//globalPos()鼠标位置，topLeft()窗口左上角的位置
}
break;
case Qt::RightButton:
this->setWindowState(Qt::WindowMinimized);
break;
default:
MainWindow::mousePressEvent(event);
} }
//鼠标移动事件 void MainWindow::mouseMoveEvent(QMouseEvent *event) { QPoint globalPoint = event->globalPos(); //鼠标全局坐标
QRect rect = this->rect(); //rect == QRect(0,0 1280x720)
QPoint topLeft = mapToGlobal(rect.topLeft());
QPoint bottomRight = mapToGlobal(rect.bottomRight());
if (this->windowState() != Qt::WindowMaximized)
{
if(!isLeftPressDown) //没有按下左键时
{
this->region(globalPoint); //窗口大小的改变——判断鼠标位置，改变光标形状
}
else
{
if(dir != NONE)
{
QRect newRect(topLeft, bottomRight); //定义一个矩形 拖动后最大1000*1618
switch(dir)
{
case LEFT:
if(bottomRight.x() - globalPoint.x() <= this->minimumWidth())
{
newRect.setLeft(topLeft.x()); //小于界面的最小宽度时，设置为左上角横坐标为窗口x
//只改变左边界
}
else
{
newRect.setLeft(globalPoint.x());
}
break;
case RIGHT:
newRect.setWidth(globalPoint.x() - topLeft.x()); //只能改变右边界
break;
case UP:
if(bottomRight.y() - globalPoint.y() <= this->minimumHeight())
{
newRect.setY(topLeft.y());
}
else
{
newRect.setY(globalPoint.y());
}
break;
case DOWN:
newRect.setHeight(globalPoint.y() - topLeft.y());
break;
case LEFTTOP:
if(bottomRight.x() - globalPoint.x() <= this->minimumWidth())
{
newRect.setX(topLeft.x());
}
else
{
newRect.setX(globalPoint.x());
}
if(bottomRight.y() - globalPoint.y() <= this->minimumHeight())
{
newRect.setY(topLeft.y());
}
else
{
newRect.setY(globalPoint.y());
}
break;
case RIGHTTOP:
if (globalPoint.x() - topLeft.x() >= this->minimumWidth())
{
newRect.setWidth(globalPoint.x() - topLeft.x());
}
else
{
newRect.setWidth(bottomRight.x() - topLeft.x());
}
if (bottomRight.y() - globalPoint.y() >= this->minimumHeight())
{
newRect.setY(globalPoint.y());
}
else
{
newRect.setY(topLeft.y());
}
break;
case LEFTBOTTOM:
if (bottomRight.x() - globalPoint.x() >= this->minimumWidth())
{
newRect.setX(globalPoint.x());
}
else
{
newRect.setX(topLeft.x());
}
if (globalPoint.y() - topLeft.y() >= this->minimumHeight())
{
newRect.setHeight(globalPoint.y() - topLeft.y());
}
else
{
newRect.setHeight(bottomRight.y() - topLeft.y());
}
break;
case RIGHTBOTTOM:
newRect.setWidth(globalPoint.x() - topLeft.x());
newRect.setHeight(globalPoint.y() - topLeft.y());
break;
default:
break;
}
this->setGeometry(newRect);
}
else
{
move(event->globalPos() - m_movePoint); //移动窗口
event->accept();
}
}
} }
//鼠标释放事件
void MainWindow::mouseReleaseEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton)
{
isLeftPressDown = false;
if (dir != NONE)
{
this->releaseMouse(); //释放鼠标抓取
this->setCursor(QCursor(Qt::ArrowCursor));
dir = NONE; //热心网友指正
}
} } 法2： 重写nativeEvent事件： MainWindow.h
protected:
bool nativeEvent(const QByteArray &eventType, void *message, long *result); MainWindow.cpp
bool MainWindow::nativeEvent(const QByteArray &eventType, void *message, long *result)
{
MSG* msg = (MSG*)message;
switch(msg->message)
{
case WM_NCHITTEST:
int xPos = GET_X_LPARAM(msg->lParam) - this->frameGeometry().x();
int yPos = GET_Y_LPARAM(msg->lParam) - this->frameGeometry().y();
if(this->childAt(xPos,yPos) == 0)
{
*result = HTCAPTION;
}else{
return false;
}
if(xPos > 0 && xPos < 8)
*result = HTLEFT;
if(xPos > (this->width() - 8) && xPos < (this->width() - 0))
*result = HTRIGHT;
if(yPos > 0 && yPos < 8)
*result = HTTOP;
if(yPos > (this->height() - 8) && yPos < (this->height() - 0))
*result = HTBOTTOM;
if(xPos > 18 && xPos < 22 && yPos > 18 && yPos < 22)
*result = HTTOPLEFT;
if(xPos > (this->width() - 22) && xPos < (this->width() - 18) && yPos > 18 && yPos < 22)
*result = HTTOPRIGHT;
if(xPos > 18 && xPos < 22 && yPos > (this->height() - 22) && yPos < (this->height() - 18))
*result = HTBOTTOMLEFT;
if(xPos > (this->width() - 22) && xPos < (this->width() - 18) && yPos > (this->height() - 22) && yPos < (this->height() - 18))
*result = HTBOTTOMRIGHT;
return true;
}
return false;
}