QtQuick实现的涂鸦板

#include "PaintedItem.h" #include <QPainter> #include <QPen> #include <QBrush> #include <QColor> #include <QDebug> PaintedItem::PaintedItem(QQuickItem *parent) : QQuickPaintedItem(parent) , m_element(0) , m_bEnabled(true) , m_bPressed(false) , m_bMoved(false) , m_pen(Qt::black) { setAcceptedMouseButtons(Qt::LeftButton); } PaintedItem::~PaintedItem() { purgePaintElements(); } void PaintedItem::clear() { purgePaintElements(); update(); } void PaintedItem::undo() { if(m_elements.size()) { delete m_elements.takeLast(); update(); } } void PaintedItem::paint(QPainter *painter) { painter->setRenderHint(QPainter::Antialiasing); int size = m_elements.size(); ElementGroup *element; for(int i = 0; i < size; ++i) { element = m_elements.at(i); painter->setPen(element->m_pen); painter->drawLines(element->m_lines); } } void PaintedItem::mousePressEvent(QMouseEvent *event) { m_bMoved = false; if(!m_bEnabled || !(event->button() & acceptedMouseButtons())) { QQuickPaintedItem::mousePressEvent(event); } else { //qDebug() << "mouse pressed"; m_bPressed = true; m_element = new ElementGroup(m_pen); m_elements.append(m_element); m_lastPoint = event->localPos(); event->setAccepted(true); } } void PaintedItem::mouseMoveEvent(QMouseEvent *event) { if(!m_bEnabled || !m_bPressed || !m_element) { QQuickPaintedItem::mousePressEvent(event); } else { //qDebug() << "mouse move"; m_element->m_lines.append(QLineF(m_lastPoint, event->localPos())); m_lastPoint = event->localPos(); update(); } } void PaintedItem::mouseReleaseEvent(QMouseEvent *event) { if(!m_element || !m_bEnabled || !(event->button() & acceptedMouseButtons())) { QQuickPaintedItem::mousePressEvent(event); } else { //qDebug() << "mouse released"; m_bPressed = false; m_bMoved = false; m_element->m_lines.append(QLineF(m_lastPoint, event->localPos())); update(); } } void PaintedItem::purgePaintElements() { int size = m_elements.size(); if(size > 0) { for(int i = 0; i < size; ++i) { delete m_elements.at(i); } m_elements.clear(); } m_element = 0; }