QT-可拖拉绘图工具
- 一、演示效果
- 二、关键程序
- 三、下载链接
一、演示效果
二、关键程序
#include "diagramscene.h"
#include "arrow.h"
#include <QTextCursor>
#include <QGraphicsSceneMouseEvent>
#include <QDebug>
QPen const DiagramScene::penForLines = QPen(QBrush(QColor(Qt::black)), 2, Qt::PenStyle::DashLine);
DiagramScene::DiagramScene(QMenu *itemMenu, QObject *parent)
: QGraphicsScene(parent)
{
myItemMenu = itemMenu;
myMode = MoveItem;
myItemType = DiagramItem::Step;
line = nullptr;
textItem = nullptr;
myItemColor = Qt::white;
myTextColor = Qt::black;
myLineColor = Qt::black;
}
void DiagramScene::setLineColor(const QColor &color)
{
myLineColor = color;
foreach (QGraphicsItem* p, selectedItems()) {
if (p->type() == Arrow::Type) {
Arrow* item = qgraphicsitem_cast<Arrow*>(p);
item->setColor(myLineColor);
update();
}
}
}
void DiagramScene::setTextColor(const QColor &color)
{
myTextColor = color;
foreach (QGraphicsItem* p, selectedItems()) {
if (p->type() == DiagramTextItem::Type) {
DiagramTextItem* item = qgraphicsitem_cast<DiagramTextItem*>(p);
item->setDefaultTextColor(myTextColor);
}
}
}
//! [2]
//! [3]
void DiagramScene::setItemColor(const QColor &color)
{
myItemColor = color;
foreach (QGraphicsItem* p, selectedItems()) {
if (p->type() == DiagramItem::Type) {
DiagramItem* item = qgraphicsitem_cast<DiagramItem*>(p);
item->setBrush(myItemColor);
}
}
}
void DiagramScene::setFont(const QFont &font)
{
myFont = font;
foreach (QGraphicsItem* p, selectedItems()) {
if (p->type() == DiagramTextItem::Type) {
DiagramTextItem* item = qgraphicsitem_cast<DiagramTextItem*>(p);
item->setFont(myFont);
}
}
}
void DiagramScene::deleteItems(QList<QGraphicsItem*> const& items) {
qDebug() << "delete items" << items;
QList<QGraphicsItem*> diagramItems;
foreach (QGraphicsItem *item, items) {
if (item->type() == Arrow::Type) {
removeItem(item);
Arrow *arrow = qgraphicsitem_cast<Arrow *>(item);
arrow->startItem()->removeArrow(arrow);
arrow->endItem()->removeArrow(arrow);
delete item;
} else diagramItems.append(item);
}
foreach (QGraphicsItem *item, diagramItems) {
if (item->type() == DiagramItem::Type)
qgraphicsitem_cast<DiagramItem *>(item)->removeArrows();
removeItem(item);
delete item;
}
}
//! [4]
void DiagramScene::setMode(Mode mode)
{
myMode = mode;
}
void DiagramScene::setItemType(DiagramItem::DiagramType type)
{
myItemType = type;
}
//! [5]
void DiagramScene::editorLostFocus(DiagramTextItem *item)
{
QTextCursor cursor = item->textCursor();
cursor.clearSelection();
item->setTextCursor(cursor);
if (item->toPlainText().isEmpty()) {
removeItem(item);
item->deleteLater();
} else {
if (item->contentIsUpdated()) {
qDebug() << "content update ---";
emit textChanged();
}
}
}
void DiagramScene::mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent)
{
if (mouseEvent->button() != Qt::LeftButton)
return;
DiagramItem *item;
switch (myMode) {
case InsertItem:
item = new DiagramItem(myItemType, myItemMenu);
item->setBrush(myItemColor);
addItem(item);
item->setPos(mouseEvent->scenePos());
qDebug() << "insert item at: " << mouseEvent->scenePos();
qDebug() << "\ttype: " << myItemType << " color: " << myItemColor;
emit itemInserted(item);
hasItemSelected = itemAt(mouseEvent->scenePos(), QTransform()) != nullptr;
break;
case InsertLine:
if (itemAt(mouseEvent->scenePos(), QTransform()) == nullptr) break;
line = new QGraphicsLineItem(QLineF(mouseEvent->scenePos(),
mouseEvent->scenePos()));
line->setPen(QPen(myLineColor, 2));
addItem(line);
break;
case InsertText:
textItem = new DiagramTextItem();
textItem->setFont(myFont);
textItem->setTextInteractionFlags(Qt::TextEditorInteraction);
textItem->setZValue(1000.0);
connect(textItem, SIGNAL(lostFocus(DiagramTextItem*)),
this, SLOT(editorLostFocus(DiagramTextItem*)));
connect(textItem, SIGNAL(selectedChange(QGraphicsItem*)),
this, SIGNAL(itemSelected(QGraphicsItem*)));
addItem(textItem);
textItem->setDefaultTextColor(myTextColor);
textItem->setPos(mouseEvent->scenePos());
emit textInserted(textItem);
qDebug() << "text inserted at" << textItem->scenePos();
break;
default:
hasItemSelected = itemAt(mouseEvent->scenePos(), QTransform()) != nullptr;
}
QGraphicsScene::mousePressEvent(mouseEvent);
}
void DiagramScene::mouseMoveEvent(QGraphicsSceneMouseEvent *mouseEvent) {
if (myMode == InsertLine && line != nullptr) {
QLineF newLine(line->line().p1(), mouseEvent->scenePos());
line->setLine(newLine);
} else if (myMode == MoveItem) {
if (hasItemSelected)
mouseDraggingMoveEvent(mouseEvent);
QGraphicsScene::mouseMoveEvent(mouseEvent);
}
}
void DiagramScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent) {
hasItemSelected = false;
// leave sticky mode
horizontalStickyMode = false;
verticalStickyMode = false;
foreach(QGraphicsItem* p, selectedItems())
p->setFlag(QGraphicsItem::ItemIsMovable);
clearOrthogonalLines();
if (line != nullptr && myMode == InsertLine) {
QList<QGraphicsItem *> startItems = items(line->line().p1());
if (startItems.count() && startItems.first() == line)
startItems.removeFirst();
QList<QGraphicsItem *> endItems = items(line->line().p2());
if (endItems.count() && endItems.first() == line)
endItems.removeFirst();
removeItem(line);
delete line;
if (startItems.count() > 0 && endItems.count() > 0 &&
startItems.first()->type() == DiagramItem::Type &&
endItems.first()->type() == DiagramItem::Type &&
startItems.first() != endItems.first()) {
DiagramItem *startItem = qgraphicsitem_cast<DiagramItem *>(startItems.first());
DiagramItem *endItem = qgraphicsitem_cast<DiagramItem *>(endItems.first());
Arrow *arrow = new Arrow(startItem, endItem);
arrow->setColor(myLineColor);
startItem->addArrow(arrow);
endItem->addArrow(arrow);
arrow->setZValue(-1000.0);
addItem(arrow);
arrow->updatePosition();
emit arrowInserted();
}
}
line = nullptr;
QGraphicsScene::mouseReleaseEvent(mouseEvent);
}
void DiagramScene::wheelEvent(QGraphicsSceneWheelEvent* wheelEvent) {
// ctrl key is being pressed
if ((wheelEvent->modifiers() & Qt::KeyboardModifier::ControlModifier) != 0) {
emit scaleChanging(wheelEvent->delta());
wheelEvent->accept();
} else {
QGraphicsScene::wheelEvent(wheelEvent);
}
}
void DiagramScene::mouseDraggingMoveEvent(QGraphicsSceneMouseEvent* event) {
clearOrthogonalLines();
if ((event->buttons() & Qt::LeftButton) != 0 && selectedItems().size() == 1) {
QGraphicsItem* itemUnderCursor = selectedItems().first();
QPointF curCenter = itemUnderCursor->scenePos();
QPointF const& mousePos = event->scenePos();
foreach(QGraphicsItem* p, items()) {
if (p->type() != DiagramItem::Type || p == itemUnderCursor) continue;
DiagramItem* item = qgraphicsitem_cast<DiagramItem*>(p);
QPointF const& objPoint = item->scenePos();
LineAttr lineAttr;
tryEnteringStickyMode(itemUnderCursor, objPoint, mousePos);
if ((lineAttr = getPointsRelationship(objPoint, curCenter)) != Other) {
if ((lineAttr & Horizontal) != 0) {
QGraphicsLineItem* newHLine = new QGraphicsLineItem();
newHLine->setLine(QLineF(QPointF(0, objPoint.y()),
QPointF(sceneRect().width(), objPoint.y())));
newHLine->setPen(penForLines);
orthogonalLines.append(newHLine);
}
if ((lineAttr & Vertical) != 0) {
QGraphicsLineItem* newVLine = new QGraphicsLineItem();
newVLine->setLine(QLineF(QPointF(objPoint.x(), 0),
QPointF(objPoint.x(), sceneRect().height())));
newVLine->setPen(penForLines);
orthogonalLines.append(newVLine);
}
}
}
tryLeavingStickyMode(itemUnderCursor, mousePos);
}
foreach(QGraphicsLineItem* p, orthogonalLines) {
addItem(p);
}
}
void DiagramScene::clearOrthogonalLines() {
foreach(QGraphicsLineItem* p, orthogonalLines) {
removeItem(p);
delete p;
}
orthogonalLines.clear();
}
bool DiagramScene::closeEnough(qreal x, qreal y, qreal delta) {
return std::abs(x - y) < delta;
}
DiagramScene::LineAttr DiagramScene::getPointsRelationship(const QPointF& p1,
const QPointF& p2) {
int ret = Other;
ret |= closeEnough(p1.x(), p2.x(), Delta) ? Vertical : Other;
ret |= closeEnough(p1.y(), p2.y(), Delta) ? Horizontal : Other;
return static_cast<DiagramScene::LineAttr>(ret);
}
void DiagramScene::tryEnteringStickyMode(QGraphicsItem* item, const QPointF& target,
const QPointF& mousePos) {
QPointF const& itemPos = item->scenePos();
if (!verticalStickyMode) {
if (closeEnough(itemPos.x(), target.x(), stickyDistance)) { // enter stickyMode
verticalStickyMode = true;
verticalStickPoint = mousePos;
item->setFlag(QGraphicsItem::ItemIsMovable, false);
item->setPos(QPointF(target.x(), itemPos.y()));
}
}
if (!horizontalStickyMode) {
if (closeEnough(itemPos.y(), target.y(), stickyDistance)) {
horizontalStickyMode = true;
horizontalStickPoint = mousePos;
item->setFlag(QGraphicsItem::ItemIsMovable, false);
item->setPos(QPointF(itemPos.x(), target.y()));
}
}
}
void DiagramScene::tryLeavingStickyMode(QGraphicsItem* item, const QPointF& mousePos) {
if (verticalStickyMode) { // already in stickyMode, item should be able to move vertically
item->moveBy(0, mousePos.y() - verticalStickPoint.y());
verticalStickPoint.setY(mousePos.y());
// when to exit stickyMode?
if (!closeEnough(mousePos.x(), verticalStickPoint.x(), stickyDistance)) {
verticalStickyMode = false;
item->setFlag(QGraphicsItem::ItemIsMovable, true);
}
}
if (horizontalStickyMode) {
item->moveBy(mousePos.x() - horizontalStickPoint.x(), 0);
horizontalStickPoint.setX(mousePos.x());
if (!closeEnough(mousePos.y(), horizontalStickPoint.y(), stickyDistance)) {
horizontalStickyMode = false;
item->setFlag(QGraphicsItem::ItemIsMovable, true);
}
}
}
三、下载链接
https://download.csdn.net/download/u013083044/88640602