Qt之自定义界面（窗体缩放-跨平台终极版）
简述
通过上一节内容，我们实现了窗体的缩放，功能很不错，但是很遗憾-不支持跨平台！如果对于多平台来说，这是一个硬伤，所以，我们急需要一个能够支持跨平台的实现方案。
在网上看到过很多不同的实现方式，多多少少会存在一些问题-要么融合度太高、要么不能很好地进行移动、缩放。基于前人的分享与总结，最后，我花了很长时间来完善。独乐乐不如众乐乐，既然纯开源-那就全部分享出来。
- 简述
- 效果
- 窗体缩放
- 实现
- 接口说明
- 使用方式
- 平台支持
效果
窗体缩放
实现
frameless_helper.h
#ifndef FRAMELESS_HELPER_H
#define FRAMELESS_HELPER_H
#include frameless_helper.cpp
FramelessHelperPrivate类
/*****
* FramelessHelperPrivate
* 存储界面对应的数据集合，以及是否可移动、可缩放属性
*****/
class FramelessHelperPrivate
{
public:
QHash m_widgetDataHash;
bool m_bWidgetMovable : true;
bool m_bWidgetResizable : true;
bool m_bRubberBandOnResize : true;
bool m_bRubberBandOnMove : true;
}; CursorPosCalculator类
/*****
* CursorPosCalculator
* 计算鼠标是否位于左、上、右、下、左上角、左下角、右上角、右下角
*****/
class CursorPosCalculator
{
public:
explicit CursorPosCalculator();
void reset();
void recalculate(const QPoint &globalMousePos, const QRect &frameRect);
public:
bool m_bOnEdges : true;
bool m_bOnLeftEdge : true;
bool m_bOnRightEdge : true;
bool m_bOnTopEdge : true;
bool m_bOnBottomEdge : true;
bool m_bOnTopLeftEdge : true;
bool m_bOnBottomLeftEdge : true;
bool m_bOnTopRightEdge : true;
bool m_bOnBottomRightEdge : true;
static int m_nBorderWidth;
static int m_nTitleHeight;
};int CursorPosCalculator::m_nBorderWidth = 5;
int CursorPosCalculator::m_nTitleHeight = 30;
/***** CursorPosCalculator *****/
CursorPosCalculator::CursorPosCalculator()
{
reset();
}
void CursorPosCalculator::reset()
{
m_bOnEdges = false;
m_bOnLeftEdge = false;
m_bOnRightEdge = false;
m_bOnTopEdge = false;
m_bOnBottomEdge = false;
m_bOnTopLeftEdge = false;
m_bOnBottomLeftEdge = false;
m_bOnTopRightEdge = false;
m_bOnBottomRightEdge = false;
}
void CursorPosCalculator::recalculate(const QPoint &gMousePos, const QRect &frameRect)
{
int globalMouseX = gMousePos.x();
int globalMouseY = gMousePos.y();
int frameX = frameRect.x();
int frameY = frameRect.y();
int frameWidth = frameRect.width();
int frameHeight = frameRect.height();
m_bOnLeftEdge = (globalMouseX >= frameX &&
globalMouseX <= frameX + m_nBorderWidth );
m_bOnRightEdge = (globalMouseX >= frameX + frameWidth - m_nBorderWidth &&
globalMouseX <= frameX + frameWidth);
m_bOnTopEdge = (globalMouseY >= frameY &&
globalMouseY <= frameY + m_nBorderWidth );
m_bOnBottomEdge = (globalMouseY >= frameY + frameHeight - m_nBorderWidth &&
globalMouseY <= frameY + frameHeight);
m_bOnTopLeftEdge = m_bOnTopEdge && m_bOnLeftEdge;
m_bOnBottomLeftEdge = m_bOnBottomEdge && m_bOnLeftEdge;
m_bOnTopRightEdge = m_bOnTopEdge && m_bOnRightEdge;
m_bOnBottomRightEdge = m_bOnBottomEdge && m_bOnRightEdge;
m_bOnEdges = m_bOnLeftEdge || m_bOnRightEdge || m_bOnTopEdge || m_bOnBottomEdge;
}WidgetData类
/*****
* WidgetData
* 更新鼠标样式、移动窗体、缩放窗体
*****/
class WidgetData
{
public:
explicit WidgetData(FramelessHelperPrivate *d, QWidget *pTopLevelWidget);
~WidgetData();
QWidget* widget();
// 处理鼠标事件-划过、按下、释放、移动
void handleWidgetEvent(QEvent *event);
// 更新橡皮筋状态
void updateRubberBandStatus();
private:
// 更新鼠标样式
void updateCursorShape(const QPoint &gMousePos);
// 重置窗体大小
void resizeWidget(const QPoint &gMousePos);
// 移动窗体
void moveWidget(const QPoint &gMousePos);
// 处理鼠标按下
void handleMousePressEvent(QMouseEvent *event);
// 处理鼠标释放
void handleMouseReleaseEvent(QMouseEvent *event);
// 处理鼠标移动
void handleMouseMoveEvent(QMouseEvent *event);
// 处理鼠标离开
void handleLeaveEvent(QEvent *event);
// 处理鼠标进入
void handleHoverMoveEvent(QHoverEvent *event);
private:
FramelessHelperPrivate *d;
QRubberBand *m_pRubberBand;
QWidget *m_pWidget;
QPoint m_ptDragPos;
CursorPosCalculator m_pressedMousePos;
CursorPosCalculator m_moveMousePos;
bool m_bLeftButtonPressed;
bool m_bCursorShapeChanged;
bool m_bLeftButtonTitlePressed;
Qt::WindowFlags m_windowFlags;
};/***** WidgetData *****/
WidgetData::WidgetData(FramelessHelperPrivate *_d, QWidget *pTopLevelWidget)
{
d = _d;
m_pWidget = pTopLevelWidget;
m_bLeftButtonPressed = false;
m_bCursorShapeChanged = false;
m_bLeftButtonTitlePressed = false;
m_pRubberBand = NULL;
m_windowFlags = m_pWidget->windowFlags();
m_pWidget->setMouseTracking(true);
m_pWidget->setAttribute(Qt::WA_Hover, true);
updateRubberBandStatus();
}
WidgetData::~WidgetData()
{
m_pWidget->setMouseTracking(false);
m_pWidget->setWindowFlags(m_windowFlags);
m_pWidget->setAttribute(Qt::WA_Hover, false);
delete m_pRubberBand;
m_pRubberBand = NULL;
}
QWidget* WidgetData::widget()
{
return m_pWidget;
}
void WidgetData::handleWidgetEvent(QEvent *event)
{
switch (event->type())
{
default:
break;
case QEvent::MouseButtonPress:
handleMousePressEvent(static_cast(event));
break;
case QEvent::MouseButtonRelease:
handleMouseReleaseEvent(static_cast(event));
break;
case QEvent::MouseMove:
handleMouseMoveEvent(static_cast(event));
break;
case QEvent::Leave:
handleLeaveEvent(static_cast(event));
break;
case QEvent::HoverMove:
handleHoverMoveEvent(static_cast(event));
break;
}
}
void WidgetData::updateRubberBandStatus()
{
if (d->m_bRubberBandOnMove || d->m_bRubberBandOnResize)
{
if (NULL == m_pRubberBand)
m_pRubberBand = new QRubberBand(QRubberBand::Rectangle);
}
else
{
delete m_pRubberBand;
m_pRubberBand = NULL;
}
}
void WidgetData::updateCursorShape(const QPoint &gMousePos)
{
if (m_pWidget->isFullScreen() || m_pWidget->isMaximized())
{
if (m_bCursorShapeChanged)
{
m_pWidget->unsetCursor();
}
return;
}
m_moveMousePos.recalculate(gMousePos, m_pWidget->frameGeometry());
if(m_moveMousePos.m_bOnTopLeftEdge || m_moveMousePos.m_bOnBottomRightEdge)
{
m_pWidget->setCursor( Qt::SizeFDiagCursor );
m_bCursorShapeChanged = true;
}
else if(m_moveMousePos.m_bOnTopRightEdge || m_moveMousePos.m_bOnBottomLeftEdge)
{
m_pWidget->setCursor( Qt::SizeBDiagCursor );
m_bCursorShapeChanged = true;
}
else if(m_moveMousePos.m_bOnLeftEdge || m_moveMousePos.m_bOnRightEdge)
{
m_pWidget->setCursor( Qt::SizeHorCursor );
m_bCursorShapeChanged = true;
}
else if(m_moveMousePos.m_bOnTopEdge || m_moveMousePos.m_bOnBottomEdge)
{
m_pWidget->setCursor( Qt::SizeVerCursor );
m_bCursorShapeChanged = true;
}
else
{
if (m_bCursorShapeChanged)
{
m_pWidget->unsetCursor();
m_bCursorShapeChanged = false;
}
}
}
void WidgetData::resizeWidget(const QPoint &gMousePos)
{
QRect origRect;
if (d->m_bRubberBandOnResize)
origRect = m_pRubberBand->frameGeometry();
else
origRect = m_pWidget->frameGeometry();
int left = origRect.left();
int top = origRect.top();
int right = origRect.right();
int bottom = origRect.bottom();
origRect.getCoords(&left, &top, &right, &bottom);
int minWidth = m_pWidget->minimumWidth();
int minHeight = m_pWidget->minimumHeight();
if (m_pressedMousePos.m_bOnTopLeftEdge)
{
left = gMousePos.x();
top = gMousePos.y();
}
else if (m_pressedMousePos.m_bOnBottomLeftEdge)
{
left = gMousePos.x();
bottom = gMousePos.y();
}
else if (m_pressedMousePos.m_bOnTopRightEdge)
{
right = gMousePos.x();
top = gMousePos.y();
}
else if (m_pressedMousePos.m_bOnBottomRightEdge)
{
right = gMousePos.x();
bottom = gMousePos.y();
}
else if (m_pressedMousePos.m_bOnLeftEdge)
{
left = gMousePos.x();
}
else if (m_pressedMousePos.m_bOnRightEdge)
{
right = gMousePos.x();
}
else if (m_pressedMousePos.m_bOnTopEdge)
{
top = gMousePos.y();
}
else if (m_pressedMousePos.m_bOnBottomEdge)
{
bottom = gMousePos.y();
}
QRect newRect(QPoint(left, top), QPoint(right, bottom));
if (newRect.isValid())
{
if (minWidth > newRect.width())
{
if (left != origRect.left())
newRect.setLeft(origRect.left());
else
newRect.setRight(origRect.right());
}
if (minHeight > newRect.height())
{
if (top != origRect.top())
newRect.setTop(origRect.top());
else
newRect.setBottom(origRect.bottom());
}
if (d->m_bRubberBandOnResize)
{
m_pRubberBand->setGeometry(newRect);
}
else
{
m_pWidget->setGeometry(newRect);
}
}
}
void WidgetData::moveWidget(const QPoint& gMousePos)
{
if (d->m_bRubberBandOnMove)
{
m_pRubberBand->move(gMousePos - m_ptDragPos);
}
else
{
m_pWidget->move(gMousePos - m_ptDragPos);
}
}
void WidgetData::handleMousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton)
{
m_bLeftButtonPressed = true;
m_bLeftButtonTitlePressed = event->pos().y() < m_moveMousePos.m_nTitleHeight;
QRect frameRect = m_pWidget->frameGeometry();
m_pressedMousePos.recalculate(event->globalPos(), frameRect);
m_ptDragPos = event->globalPos() - frameRect.topLeft();
if (m_pressedMousePos.m_bOnEdges)
{
if (d->m_bRubberBandOnResize)
{
m_pRubberBand->setGeometry(frameRect);
m_pRubberBand->show();
}
}
else if (d->m_bRubberBandOnMove)
{
m_pRubberBand->setGeometry(frameRect);
m_pRubberBand->show();
}
}
}
void WidgetData::handleMouseReleaseEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton)
{
m_bLeftButtonPressed = false;
m_bLeftButtonTitlePressed = false;
m_pressedMousePos.reset();
if (m_pRubberBand && m_pRubberBand->isVisible())
{
m_pRubberBand->hide();
m_pWidget->setGeometry(m_pRubberBand->geometry());
}
}
}
void WidgetData::handleMouseMoveEvent(QMouseEvent *event)
{
if (m_bLeftButtonPressed)
{
if (d->m_bWidgetResizable && m_pressedMousePos.m_bOnEdges)
{
resizeWidget(event->globalPos());
}
else if (d->m_bWidgetMovable && m_bLeftButtonTitlePressed)
{
moveWidget(event->globalPos());
}
}
else if (d->m_bWidgetResizable)
{
updateCursorShape(event->globalPos());
}
}
void WidgetData::handleLeaveEvent(QEvent *event)
{
Q_UNUSED(event)
if (!m_bLeftButtonPressed)
{
m_pWidget->unsetCursor();
}
}
void WidgetData::handleHoverMoveEvent(QHoverEvent *event)
{
if (d->m_bWidgetResizable)
{
updateCursorShape(m_pWidget->mapToGlobal(event->pos()));
}
} FramelessHelper类
#include keys = d->m_widgetDataHash.keys();
int size = keys.size();
for (int i = 0; i < size; ++i)
{
delete d->m_widgetDataHash.take(keys[i]);
}
delete d;
}
bool FramelessHelper::eventFilter(QObject *obj, QEvent *event)
{
switch (event->type())
{
case QEvent::MouseMove:
case QEvent::HoverMove:
case QEvent::MouseButtonPress:
case QEvent::MouseButtonRelease:
case QEvent::Leave:
{
WidgetData *data = d->m_widgetDataHash.value(static_cast(obj));
if (data)
{
data->handleWidgetEvent(event);
return true;
}
}
}
return QObject::eventFilter(obj, event);
}
void FramelessHelper::activateOn(QWidget *topLevelWidget)
{
if (!d->m_widgetDataHash.contains(topLevelWidget))
{
WidgetData *data = new WidgetData(d, topLevelWidget);
d->m_widgetDataHash.insert(topLevelWidget, data);
topLevelWidget->installEventFilter(this);
}
}
void FramelessHelper::removeFrom(QWidget *topLevelWidget)
{
WidgetData *data = d->m_widgetDataHash.take(topLevelWidget);
if (data)
{
topLevelWidget->removeEventFilter(this);
delete data;
}
}
void FramelessHelper::setRubberBandOnMove(bool movable)
{
d->m_bRubberBandOnMove = movable;
QList list = d->m_widgetDataHash.values();
foreach (WidgetData *data, list)
{
data->updateRubberBandStatus();
}
}
void FramelessHelper::setWidgetMovable(bool movable)
{
d->m_bWidgetMovable = movable;
}
void FramelessHelper::setWidgetResizable(bool resizable)
{
d->m_bWidgetResizable = resizable;
}
void FramelessHelper::setRubberBandOnResize(bool resizable)
{
d->m_bRubberBandOnResize = resizable;
QList list = d->m_widgetDataHash.values();
foreach (WidgetData *data, list)
{
data->updateRubberBandStatus();
}
}
void FramelessHelper::setBorderWidth(uint width)
{
if (width > 0)
{
CursorPosCalculator::m_nBorderWidth = width;
}
}
void FramelessHelper::setTitleHeight(uint height)
{
if (height > 0)
{
CursorPosCalculator::m_nTitleHeight = height;
}
}
bool FramelessHelper::widgetMovable()
{
return d->m_bWidgetMovable;
}
bool FramelessHelper::widgetResizable()
{
return d->m_bWidgetResizable;
}
bool FramelessHelper::rubberBandOnMove()
{
return d->m_bRubberBandOnMove;
}
bool FramelessHelper::rubberBandOnResisze()
{
return d->m_bRubberBandOnResize;
}
uint FramelessHelper::borderWidth()
{
return CursorPosCalculator::m_nBorderWidth;
}
uint FramelessHelper::titleHeight()
{
return CursorPosCalculator::m_nTitleHeight;
} 接口说明
-
FramelessHelperPrivate
存储界面对应的数据集合，以及是否可移动、可缩放属性
-
CursorPosCalculator
计算鼠标是否位于左、上、右、下、左上角、左下角、右上角、右下角
-
WidgetData
更新鼠标样式、移动窗体、缩放窗体
-
FramelessHelper
激活窗体、移除窗体、设置窗体移动、窗体缩放、橡皮筋移动、橡皮筋缩放、边框的宽度、标题栏高度等
代码很多，我就不详细解答了，里面主要的接口我都添加了注释。其它接口的命名也是比较规范的-见名知义。
使用方式
这里的this指的是要处理的窗体。
FramelessHelper *pHelper = new FramelessHelper(this);
pHelper->activateOn(this); //激活当前窗体
pHelper->setTitleHeight(m_pTitleBar->height()); //设置窗体的标题栏高度
pHelper->setWidgetMovable(true); //设置窗体可移动
pHelper->setWidgetResizable(true); //设置窗体可缩放
pHelper->setRubberBandOnMove(true); //设置橡皮筋效果-可移动
pHelper->setRubberBandOnResize(true); //设置橡皮筋效果-可缩放平台支持
因为使用的是纯Qt实现，所以支持跨平台！Win7、Win10、Redhat7.0已测试通过，其它平台尚未测试，有需要的童鞋可自行实验。