基于QtQGraphicsView的简单作图软件.zip_QT实现橡皮檫功能资源-CSDN文库

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h：386个

cpp：100个

png：35个

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《基于Qt QGraphicsView的简单作图软件开发详解》在软件开发领域，图形用户界面（GUI）的设计与实现是至关重要的部分。QT框架以其强大的功能和跨平台特性，成为许多开发者首选的C++ GUI库。本篇文章将深入探讨如何利用Qt的QGraphicsView组件创建一个简单的作图软件——EasyCanvas。 Qt是一个开源的C++库，它提供了丰富的工具和类，用于构建高效、美观的图形界面。QGraphicsView是Qt图形视图框架的一部分，它允许开发者在窗口中展示复杂的2D图形场景，包括自定义的图形元素。通过QGraphicsView，我们可以实现对场景中的对象进行缩放、旋转、拖动等操作，非常适合用于创建绘图应用。在EasyCanvas项目中，我们首先需要设置一个QGraphicsView实例作为主窗口，并与QGraphicsScene关联。QGraphicsScene是图形对象的容器，它可以包含各种QGraphicsItem，如线条、矩形、椭圆、文本等。在EasyCanvas中，用户可以自由绘制这些基本形状，因此我们需要继承QGraphicsItem，创建自定义的图形类，如`CustomLine`、`CustomRectangle`等。对于每个自定义图形类，我们需要重写关键方法，如`boundingRect()`来定义图形的边界，`paint()`来绘制图形，以及`shape()`来生成图形的蒙版，以便支持鼠标交互。同时，还需要实现`mousePressEvent()`、`mouseMoveEvent()`和`mouseReleaseEvent()`来处理用户的点击和拖动行为，使用户能够动态绘制和调整图形。在EasyCanvas中，颜色选择和线条样式也是必不可少的功能。我们可以添加颜色选择器控件，如QColorDialog，让用户选择绘制的颜色；并通过设置QPen的宽度和风格，改变线条的样式。此外，为了提供撤销/重做功能，可以使用QStack来保存用户的每一步操作，当用户触发撤销或重做时，根据栈的状态恢复或重复前一步操作。在QGraphicsView中，我们还可以实现图形的缩放和平移功能。通过重载QGraphicsView的`wheelEvent()`方法，可以实现滚轮缩放，而`dragMoveEvent()`和`dragEnterEvent()`则可以用来处理鼠标拖动时的平移操作。为了保存和加载用户的作品，EasyCanvas可以集成QFile对话框，让用户选择文件进行读写。数据序列化是关键，我们可以利用QDataStream将QGraphicsScene中的所有图形对象及其属性保存到文件，读取时再反序列化回场景。为了提高用户体验，EasyCanvas可能还需要添加一些辅助功能，如网格线辅助定位，橡皮擦功能，以及选择和移动多个图形的工具。这些功能的实现同样基于QGraphicsView提供的接口和事件机制。基于Qt的QGraphicsView组件为我们提供了强大的2D图形绘制能力，使得开发如EasyCanvas这样的简单作图软件变得轻松可行。通过熟练掌握QGraphicsView的用法，开发者可以创建出更多功能丰富、交互性强的图形应用程序。在实践中不断探索和优化，Qt的潜力将得到充分挖掘，为软件开发带来无限可能。

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基于Qt QGraphicsView的简单作图软件.zip （578个子文件）

UICanvasItemBase.cpp 18KB

MainWindow.cpp 16KB

UICanvasItemManager.cpp 16KB

CustomDialog.cpp 12KB

SQLCore.cpp 11KB

UICustomColorWidget.cpp 11KB

UICanvasOperators.cpp 11KB

PythonWrapCore.cpp 9KB

CustomTestWidget.cpp 8KB

UICustomColorCircle.cpp 8KB

UICanvasView.cpp 7KB

UICanvasTextItem.cpp 7KB

UICanvasAudioItem.cpp 7KB

UINodeTreeViewModel.cpp 7KB

GlobalHotKeyManager.cpp 6KB

UISchemeManagerWidget.cpp 6KB

AudioPlayerThread.cpp 6KB

AudioDecodec.cpp 6KB

UICustomColorSliderItem.cpp 5KB

UICanvasEllipseItem.cpp 4KB

CanvasSchemeManager.cpp 4KB

UICanvasRectItem.cpp 4KB

UICustomGroupControl.cpp 4KB

UINodeTreeView.cpp 4KB

UICanvasPathItem.cpp 4KB

NDAttributeBase.cpp 4KB

NDNodeBase.cpp 4KB

UndoCmdCore.cpp 3KB

UICanvasScene.cpp 3KB

UICustomDoubleControl.cpp 3KB

UICustomOrientationControl.cpp 3KB

UICustomColorControl.cpp 3KB

UICustomSwitchWidget.cpp 3KB

UICustomIntControl.cpp 3KB

UICanvasImageItem.cpp 3KB

UICustomPostionWidget.cpp 3KB

UICustomCombineControlBase.cpp 3KB

UICustomLineEdit.cpp 3KB

UICustomImageViewer.cpp 3KB

UICustomLeftItemWidget.cpp 3KB

UIAttrTextControl.cpp 3KB

UINodeAttrControl.cpp 3KB

UINodeItem.cpp 3KB

UICustomColorViewWidget.cpp 2KB

UICustomCustomColorOperator.cpp 2KB

UISchemeManagerDialog.cpp 2KB

ItemAttributeChangedCmd.cpp 2KB

UICustomColorSlider.cpp 2KB

UINodeTreeDelegate.cpp 2KB

CustomStyleConfig.cpp 2KB

NDTextNode.cpp 2KB

UICustomPostionControl.cpp 2KB

UICustomLeftWidget.cpp 2KB

UICustomComboBoxControl.cpp 2KB

main.cpp 2KB

NDAttributeGroup.cpp 2KB

UIAttrFloatControl.cpp 2KB

UIAttrIntControl.cpp 1KB

UICustomLeftTabsControl.cpp 1KB

UICustomLineEditControl.cpp 1KB

UINodeTreeWidget.cpp 1KB

UIAttrColorControl.cpp 1KB

AudioPlayer.cpp 1KB

UIAttrBoolControl.cpp 1KB

UINodeSortFilterProxyModel.cpp 1KB

ItemDeleteCmd.cpp 1KB

UICustomSwitchControl.cpp 939B

ItemCreateCmd.cpp 921B

UICustonColorDialog.cpp 876B

NDStringAttribute.cpp 867B

NDAttributeData.cpp 861B

ItemPasteCmd.cpp 762B

ItemChangeNameCmd.cpp 746B

GlobalHotKeyFilter.cpp 679B

UIAttributWidget.cpp 670B

UICustomTextEditTagControl.cpp 641B

Utils.cpp 585B

CustomWidget.cpp 578B

UICustomTimeEditControl.cpp 557B

NDPostionAttribute.cpp 541B

UICustomDateEditControl.cpp 528B

GlobalHotKeyInfo.cpp 522B

UICustomTextEdit.cpp 520B

NDRealAttribute.cpp 519B

UICustomFontComboBoxControl.cpp 496B

NDIntAttribute.cpp 485B

NDNodeManager.cpp 445B

UIAboutMeDialog.cpp 429B

UICustomDoubleSpinBox.cpp 426B

UICustomIntSpinBox.cpp 393B

UICustomComboBox.cpp 306B

UICustomDateEdit.cpp 277B

NDColorAttribute.cpp 256B

RALLBlockSignal.cpp 216B

NDBoolAttribute.cpp 213B

UICustomCalendarWidget.cpp 191B

CustomMainWindow.cpp 162B

UICustomTimeEdit.cpp 155B

pythonwrap.cpp 54B

AudioData.cpp 24B

共 578 条

#include "UICanvasItemBase.h" #include "Utils.h" #include <QPainter> #include <QGraphicsSceneMouseEvent> #include <QDebug> #include <QGraphicsView> #include <QGraphicsScene> #include <QVector2D> #include <QVector3D> #include <cmath> #include <math.h> #include <QJsonObject> #include <QApplication> #include "NDNodeBase.h" #include "NDAttributeBase.h" #include "NDRealAttribute.h" #include "NDIntAttribute.h" #include "RALLBlockSignal.h" #include "UICanvasItemManager.h" #include "UICanvasView.h" QImage UICanvasItemBase::m_closeIcon; QImage UICanvasItemBase::m_resizeIcon; QImage UICanvasItemBase::m_rotateIcon; UICanvasItemBase::UICanvasItemBase(QGraphicsItem* parentItem) :QGraphicsItem(parentItem) , m_cPenColor(255, 0, 0) , m_cBrushColor(200, 100, 100) { this->setFlag(QGraphicsItem::ItemIsSelectable, true); this->setFlag(QGraphicsItem::ItemSendsGeometryChanges, true); initIcon(); // 初始化基本属性 initNodeBase(); // 获取中心位置 m_size = QSize(100, 100); QPointF centerPos = g_currentCanvasManager->getCurrentCanvasView()->getCenterPos(); this->setPos(centerPos); } UICanvasItemBase::~UICanvasItemBase() { } void UICanvasItemBase::setItemResizeable(bool resizeable) { m_isResizeable = resizeable; } NDNodeBase* UICanvasItemBase::getCurrentNode(void) const { return m_pNode; } void UICanvasItemBase::setItemResizeRatio(bool resizeRation, qreal rationValue) { m_isRatioScale = resizeRation; m_ratioValue = rationValue; } QRectF UICanvasItemBase::boundingRect() const { QRectF rectF = getCustomRect(); if (!this->isSelected()) return rectF; rectF.adjust(-m_nInterval, -m_nInterval, m_nInterval, m_nInterval); rectF.adjust(-m_nEllipseWidth, -m_nEllipseWidth, m_nEllipseWidth, m_nEllipseWidth); return rectF; } void UICanvasItemBase::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget) { painter->setRenderHint(QPainter::Antialiasing, true); painter->setRenderHint(QPainter::SmoothPixmapTransform, true); painter->setRenderHint(QPainter::TextAntialiasing, true); // 自定义绘制 customPaint(painter, option, widget); if (!this->isSelected()) return; // 设置画笔 QPen pen; pen.setWidth(m_nPenWidth); pen.setColor(m_cPenColor); pen.setStyle(Qt::DashLine); painter->setPen(pen); QRectF itemRect = this->getCustomRect(); // 绘制轮廓线 QRectF outLintRect = itemRect.adjusted(-m_nInterval, -m_nInterval, m_nInterval, m_nInterval); painter->drawRect(outLintRect); painter->setPen(Qt::NoPen); painter->setBrush(m_cBrushColor); // 绘制控制点 painter->drawEllipse(outLintRect.topRight(), m_nEllipseWidth, m_nEllipseWidth); if (!m_closePixmap.isNull()) painter->drawPixmap(QRect(outLintRect.topRight().x() - m_nEllipseWidth / 2, \ outLintRect.topRight().y() - m_nEllipseWidth / 2, \ m_nEllipseWidth, m_nEllipseWidth), m_closePixmap); painter->drawEllipse(outLintRect.bottomLeft(), m_nEllipseWidth, m_nEllipseWidth); if (!m_rotatePixmap.isNull()) painter->drawPixmap(QRect(outLintRect.bottomLeft().x() - m_nEllipseWidth / 2, \ outLintRect.bottomLeft().y() - m_nEllipseWidth / 2, \ m_nEllipseWidth, m_nEllipseWidth), m_rotatePixmap); if (m_isResizeable) { painter->drawEllipse(outLintRect.bottomRight(), m_nEllipseWidth, m_nEllipseWidth); if (!m_resizePixmap.isNull()) painter->drawPixmap(QRect(outLintRect.bottomRight().x() - m_nEllipseWidth / 2, \ outLintRect.bottomRight().y() - m_nEllipseWidth / 2, \ m_nEllipseWidth, m_nEllipseWidth), m_resizePixmap); } } QPainterPath UICanvasItemBase::shape() const { QPainterPath path; path.addRect(boundingRect()); return path; } void UICanvasItemBase::mousePressEvent(QGraphicsSceneMouseEvent* event) { QRectF itemRect = this->getCustomRect(); QRectF outLintRect = itemRect.adjusted(-m_nInterval, -m_nInterval, m_nInterval, m_nInterval); // 获取当前模式 QPointF pos = event->pos(); QPointF scenePos = event->scenePos(); if (itemRect.contains(pos)) m_itemOper = t_move; else if (g_utilTool->getDistance(pos, outLintRect.topRight()) <= m_nEllipseWidth) { g_currentCanvasManager->deleteCanvasItem(m_pNode); return; } else if (g_utilTool->getDistance(pos, outLintRect.bottomLeft()) <= m_nEllipseWidth) m_itemOper = t_rotate; else if (g_utilTool->getDistance(pos, outLintRect.bottomRight()) <= m_nEllipseWidth) m_itemOper = t_resize; // 保存当前的一些信息 m_pos = pos; m_pressedPos = scenePos; m_startPos = this->pos(); m_startRotate = m_rotate; m_startSize = m_size; return QGraphicsItem::mousePressEvent(event); } void UICanvasItemBase::mouseMoveEvent(QGraphicsSceneMouseEvent* event) { // 获取场景坐标和本地坐标 QPointF scenePos = event->scenePos(); QPointF pos = event->pos(); if (m_itemOper == t_move) { // 处理移动 mouseMoveMoveOperator(scenePos, pos); } else if (m_itemOper == t_resize) { // 处理更改大小 mouseMoveResizeOperator(scenePos, pos); } else if (m_itemOper == t_rotate) { // 处理旋转 mouseMoveRotateOperator(scenePos, pos); } return QGraphicsItem::mouseMoveEvent(event); } void UICanvasItemBase::mouseReleaseEvent(QGraphicsSceneMouseEvent* event) { // 获取场景坐标和本地坐标 QPointF scenePos = event->scenePos(); QPointF pos = event->pos(); if (m_itemOper == t_move) { // 处理移动 mouseReleaseMoveOperator(scenePos, pos); } else if (m_itemOper == t_resize) { // 处理更改大小 mouseReleaseResizeOperator(scenePos, pos); } else if (m_itemOper == t_rotate) { // 处理旋转 mouseReleaseRotateOperator(scenePos, pos); } m_itemOper = t_none; return QGraphicsItem::mouseReleaseEvent(event); } QVariant UICanvasItemBase::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant& value) { if (change == QGraphicsItem::ItemSelectedChange) prepareGeometryChange(); else if (change == QGraphicsItem::ItemPositionHasChanged) { updateAttribute(); } return QGraphicsItem::itemChange(change, value); } void UICanvasItemBase::mouseMoveMoveOperator(const QPointF& scenePos, const QPointF& loacalPos) { qreal xInterval = scenePos.x() - m_pressedPos.x(); qreal yInterval = scenePos.y() - m_pressedPos.y(); this->setPos(m_startPos + QPointF(xInterval, yInterval)); this->update(); } void UICanvasItemBase::mouseMoveResizeOperator(const QPointF& scenePos, const QPointF& loacalPos) { if (!m_isResizeable) return; qreal ratio = m_ratioValue; qreal itemWidth = abs(loacalPos.x()) * 2 - m_nInterval - m_nEllipseWidth; qreal itemHeight = abs(loacalPos.y()) * 2 - m_nInterval - m_nEllipseWidth; if (m_isRatioScale) itemHeight = itemWidth * 1.0 / ratio; // 设置图片的最小大小为10 if (itemWidth < 10 || itemHeight < 10) return; m_size = QSize(itemWidth, itemHeight); m_pWidthAttribute->setValue(m_size.width()); m_pHeightAttribute->setValue(m_size.height()); this->update(); } void UICanvasItemBase::mouseMoveRotateOperator(const QPointF& scenePos, const QPointF& loacalPos) { // 获取并设置为单位向量 QVector2D startVec(m_pos.x() - 0, m_pos.y() - 0); startVec.normalize(); QVector2D endVec(loacalPos.x() - 0, loacalPos.y() - 0); endVec.normalize(); // 单位向量点乘，计算角度 qreal dotValue = QVector2D::dotProduct(startVec, endVec); if (dotValue > 1.0) dotValue = 1.0; else if (dotValue < -1.0) dotValue = -1.0; dotValue = qAcos(dotValue);

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