I am extending QGraphicsItem to be added to a extended QGraphicsSene. when I added the extended item to the scene and the scene to the graphics view in the normal way it shows the image but when I added the image as follows it does not show. could some one please check this out and tell me the issue.
header
#ifndef IMAGEMAP_H
#define IMAGEMAP_H
#include <QGraphicsItem>
#include <QGraphicsScene>
class ScanImage : public QGraphicsItem
{
public:
ScanImage(const QString imgsrc);
~ScanImage();
void setImageSource(const QString is);
QString imageSource();
QRectF boundingRect() const;
void paint( QPainter *painter,
const QStyleOptionGraphicsItem *option,
QWidget *widget);
protected:
void mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent);
private:
QString imgsrc;
};
class ImageHolder : public QGraphicsScene
{
public:
ImageHolder();
~ImageHolder();
protected:
void mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent);
void mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent);
private:
QRectF selectedRect;
};
#endif //
source
#include "imagemap.h"
#include "QtGui"
ScanImage::ScanImage(const QString is)
{
imgsrc=is;
update();
}
ScanImage::~ScanImage()
{
}
ImageHolder::ImageHolder()
{
setSceneRect(0.0,0.0,512.0,512.0);
ScanImage im("2.jpg");
im.setZValue(1.0);
im.setVisible(true);
addItem(&im);
}
ImageHolder::~ImageHolder()
{
}
void ScanImage::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
qDebug() <<event->pos();
}
void ImageHolder::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
qDebug() <<event->scenePos().rx();
selectedRect.setTopLeft(event->scenePos());
}
void ImageHolder::mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent)
{
qDebug() <<mouseEvent->scenePos().ry();
selectedRect.setBottomRight(mouseEvent->scenePos());
addRect ( selectedRect);
}
QRectF ScanImage::boundingRect() const
{
return QRectF(0.0, 0.0, 512.0, 512.0);
}
void ScanImage::paint( QPainter* painter,
const QStyleOptionGraphicsItem*,
QWidget* )
{
QRectF target(0.0, 0.0, 512.0, 512.0);
QRectF source(0.0, 0.0, 512.0, 512.0);
painter->drawImage(target, QImage(imgsrc),source);
}
void ScanImage::setImageSource(QString is)
{
imgsrc = is;
}
QString ScanImage::imageSource()
{
return imgsrc;
}
main
int main(int argv, char* argc[])
{
QApplication app(argv,argc);
ImageHolder scene;
QGraphicsView view(&scene);
view.resize(512,512);
view.show();
return app.exec();
}
You are adding a QGraphicsItem allocated as a local variable on the QGraphicsScene constructor's stack. Once the constructor is finished, the objects on its stack are automatically deallocated (i.e. deleted) and in your case removed from the scene. Use new operator to create the item.
Related
I have a specific string on a QLineEdit, this string is passed to a QListView via QPushButton. Those strings are choices of a QComboBox and they are very specific:
1) "[ INFO] Minimum Distance: 5",
2) "[ INFO] Minimum Distance: 10" and
3) "[ INFO] Minimum Distance: 15"
Here a perfectly working minimal verifiable example if you need to test it.
Currently I can successfully change the color of the QGraphicsView but by clicking or double-clicking on the QString entered in the QListView.
The problem: How can I detect the specific QString content inside a QListView in order to change the background color of a QGraphicsView?
What I mean I don't want to click or double-click on the entry of the QListView but I would like the QListView to see that there is a string "[ INFO] Minimum Distance: 5" and therefore change the color of the QGraphicsView automatically without me clicking or double-clicking on the QListView entry.
After I "Go to slot" my choices are the following below:
Below the MVE working code, you can copy /paste on your machine and it will work:
mainwindow.h
#include <QMainWindow>
#include <QGraphicsView>
#include <QGraphicsScene>
#include <QGraphicsTextItem>
#include <QStringListModel>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
void changeColorDetection();
void updateListView();
void updateListView(const QString & message);
private slots:
void on_pushButton_clicked();
void on_listView_entered(const QModelIndex &index);
void on_listView_activated(const QModelIndex &index);
private:
Ui::MainWindow *ui;
QGraphicsView *mView;
QGraphicsScene *mScene;
QGraphicsTextItem *mText;
StringList *newString;
QStringListModel *model;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
mView = new QGraphicsView();
mScene = new QGraphicsScene();
ui->graphicsView->setScene(mScene);
QFont font;
font.setPixelSize(10);
font.setBold(false);
font.setFamily("Calibri");
mText = new QGraphicsTextItem;
mText->setPos(150,70);
mScene->addText(tr("Boat outside alarm area"))->setDefaultTextColor(Qt::black);
model = new QStringListModel();
ui->listView->setModel(model);
ui->listView->setEditTriggers(QAbstractItemView::NoEditTriggers);
emptyIndex();
connect(ui->listView, SIGNAL(loggingUpdated()), this, SLOT(updateListView(const QString &)));
connect(ui->graphicsView, SIGNAL(clicked(const QModelIndex &)), this, SLOT(on_listView_activated(const QModelIndex &index)));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::updateListView(const QString & message)
{
if(model->insertRow(model->rowCount())) {
QModelIndex index = model->index(model->rowCount() - 1, 0);
model->setData(index, message);
ui->listView->scrollTo(index);
}
}
void MainWindow::on_pushButton_clicked()
{
QString str = ui->lineEdit->text();
model->insertRow(model->rowCount());
QModelIndex index = model->index(model->rowCount()-1);
model->setData(index, str);
ui->listView->scrollToBottom();
}
void MainWindow::on_comboBox_currentIndexChanged(const QString &arg1)
{
QString list = ui->comboBox->currentText();
ui->lineEdit->setText(list);
Q_UNUSED(arg1)
}
void MainWindow::on_listView_activated(const QModelIndex &index)
{
QStringList allStrings = model->stringList();
QString last = allStrings.last();
if(last.startsWith("[ INFO] Minimum Distance: 5"))
{
ui->graphicsView->setBackgroundBrush(QColor(Qt::red));
}
else if(last.startsWith("[ INFO] Minimum Distance: 10"))
{
ui->graphicsView->setBackgroundBrush(QColor(Qt::yellow));
}
else if(last.startsWith("[ INFO] Minimum Distance: 15"))
{
ui->graphicsView->setBackgroundBrush(QColor(Qt::green));
}
Q_UNUSED(index)
}
EDIT 2
mainwindow.h
#include <QMainWindow>
#include <QGraphicsView>
#include <QGraphicsScene>
#include <QGraphicsTextItem>
#include <QStringListModel>
#include "listview.h"
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
public slots:
void setGraphicViewColor(QColor c);
private:
Ui::MainWindow *ui;
QGraphicsView *mView;
QGraphicsScene *mScene;
QGraphicsTextItem *mText;
QStringListModel *model;
ListView *myListView;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
mView = new QGraphicsView();
mScene = new QGraphicsScene();
ui->graphicsView->setScene(mScene);
QFont font;
font.setPixelSize(10);
font.setBold(false);
font.setFamily("Calibri");
mText = new QGraphicsTextItem;
mText->setPos(150,70);
mScene->addText(tr("Boat outside alarm area"))->setDefaultTextColor(Qt::black);
model = new QStringListModel();
ui->listView->setModel(model);
ui->listView->setEditTriggers(QAbstractItemView::NoEditTriggers);
connect(ui->listView, SIGNAL(changeColor(QColor)), this, SLOT(setGraphicViewColor(QColor)));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::setGraphicViewColor(QColor c)
{
qDebug() << "Update your graphicsView backgroundBrush" << c;
ui->graphicsView->setBackgroundBrush(Qt::green);
}
listview.h
#ifndef LISTVIEW_H
#define LISTVIEW_H
#include <QListView>
#include <QStringListModel>
class ListView : public QListView
{
Q_OBJECT
public:
ListView(QWidget *parent = nullptr);
signals:
void changeColor(QColor c);
protected:
void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles = QVector<int>()) override;
};
#endif // LISTVIEW_H
listview.cpp
#include "listview.h"
ListView::ListView(QWidget *parent)
: QListView(parent)
{}
void ListView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles)
{
QListView::dataChanged(topLeft, bottomRight, roles);
/**
* Assuming that you have just one item changed
* So topLeft == bottomRight
*/
if (topLeft.row() == model()->rowCount()-1){
QString last = topLeft.data().toString();
if(last.startsWith("[ INFO] Minimum Distance: 5")) {
emit changeColor(Qt::red);
} else if(last.startsWith("[ INFO] Minimum Distance: 10")) {
emit changeColor(Qt::yellow);
} else if(last.startsWith("[ INFO] Minimum Distance: 15")) {
emit changeColor(Qt::green);
}
}
}
Below the error and a screenshot of the ui that does not detect the change event:
The output of the .ui:
What I have done so far:
I have been doinf a lot of research about this problem and came across this source which was useful but could not solve the problem, but in addition it seems to use a QModelIndex and I am not sure this is exactly what I need for this small project.
Also I read this source which was useful to establish and capture the specific and unique string but in terms of changing colors I could not solve that.
Thank you very much for pointing in the right direction for solving this issue.
If I well understand, you want to change the backgroundBrush of your graphicsView if the last item of your QStringListModel starts with your specific strings.
To detect this, you can subclass QListView:
listview.h:
#ifndef LISTVIEW_H
#define LISTVIEW_H
#include <QListView>
#include <QStringListModel>
class ListView : public QListView
{
Q_OBJECT
public:
ListView(QWidget *parent = nullptr);
signals:
void changeColor(QColor c);
protected:
void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles = QVector<int>()) override;
};
#endif // LISTVIEW_H
listview.cpp:
#include "listview.h"
ListView::ListView(QWidget *parent)
: QListView(parent)
{
}
void ListView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles)
{
QListView::dataChanged(topLeft, bottomRight, roles);
/**
* Assuming that you have just one item changed
* So topLeft == bottomRight
*/
if (topLeft.row() == model()->rowCount()-1){
QString last = topLeft.data().toString();
if(last.startsWith("[ INFO] Minimum Distance: 5")) {
emit changeColor(Qt::red);
} else if(last.startsWith("[ INFO] Minimum Distance: 10")) {
emit changeColor(Qt::yellow);
} else if(last.startsWith("[ INFO] Minimum Distance: 15")) {
emit changeColor(Qt::green);
}
}
}
Now you have all what you need, but you need to add a slot to connect the signal of your custom ListView with your QGraphicsView::brush
// Add this in your mainwindows.h
public slots:
void setGraphicViewColor(QColor c);
// This in the ctor of your MainWindow:
connect(ui->listView, SIGNAL(changeColor(QColor)), this, SLOT(setGraphicViewColor(QColor)));
// And the implementation of your custom slot in mainwindows.cpp
void MainWindow::setGraphicViewColor(QColor c)
{
qDebug() << "Update your graphicsView backgroundBrush" << c;
//ui->graphicsView->setBackgroundBrush(c);
}
I'm trying to create a program in which you can connect points together with lines. I instantiate QGraphicsEllipseItem into a QGraphicsScene and I use HoverEnterEvent and HoverLeaveEvent to change the color and the size of the ellipses when the mouse is over them. To draw a temporary line between the point clicked and the mouse cursor I have to use MouseMoveEvent into the scene. However, when I do that, the HoverEvents of the items don't work anymore ! How can I use both MouseMoveEvent of the scene and HoverEvents of the items ?
void GraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent)
{
for (int i = 0; i < pointList.size(); ++i) {
if (pointList[i]->over == 1){
pointList[i]->press();
lineActivated=true;
tempLine.setLine(pointList[i]->x(),pointList[i]->y(),pointList[i]->x(),pointList[i]->y());
}
}
}
void GraphicsScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
if(lineActivated){
const QPointF pos = event->scenePos();
tempLine.setP2(pos);
}
}
void Point::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
{
pen.setColor(Qt::green);
pen.setWidth(2);
this->setPen(pen);
over=true;
qDebug("enter");
update();
}
void Point::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
if(isClicked==false){
pen.setColor(Qt::lightGray);
pen.setWidth(1);
over=false;
this->setPen(pen);
qDebug("leave");
update();
}
}
By default QGraphicsScene::mouseMoveEvent sends the necessary information to handle the hover event of the items but override that method you eliminate that behavior. The solution is to call the parent method.
#include <QtWidgets>
class GraphicsScene: public QGraphicsScene{
public:
using QGraphicsScene::QGraphicsScene;
protected:
void mousePressEvent(QGraphicsSceneMouseEvent *event){
if(!m_lineitem){
m_lineitem = new QGraphicsLineItem;
addItem(m_lineitem);
}
QLineF l(event->scenePos(), event->scenePos());
m_lineitem->setLine(l);
QGraphicsScene::mousePressEvent(event);
}
void mouseMoveEvent(QGraphicsSceneMouseEvent *event){
if(m_lineitem){
QLineF l(m_lineitem->line().p1(), event->scenePos());
m_lineitem->setLine(l);
}
QGraphicsScene::mouseMoveEvent(event);
}
private:
QGraphicsLineItem *m_lineitem = nullptr;
};
class Point: public QGraphicsEllipseItem{
public:
Point(QGraphicsItem *parent=nullptr): QGraphicsEllipseItem(parent){
setRect(QRectF(-5, -5, 10, 10));
QPen pen;
pen.setColor(Qt::lightGray);
pen.setWidth(1);
setPen(pen);
setAcceptHoverEvents(true);
}
protected:
void hoverEnterEvent(QGraphicsSceneHoverEvent *event){
QPen pen;
pen.setColor(Qt::green);
pen.setWidth(2);
setPen(pen);
QGraphicsEllipseItem::hoverEnterEvent(event);
}
void hoverLeaveEvent(QGraphicsSceneHoverEvent *event){
QPen pen;
pen.setColor(Qt::lightGray);
pen.setWidth(1);
setPen(pen);
QGraphicsEllipseItem::hoverLeaveEvent(event);
}
};
int main(int argc, char *argv[]){
QApplication a(argc, argv);
GraphicsScene *scene = new GraphicsScene;
QGraphicsView w(scene);
w.setRenderHint(QPainter::Antialiasing, true);
w.fitInView(QRectF(0, 0, 100, 100), Qt::KeepAspectRatio);
for(const QPointF & p: {QPointF(10.0, 10.0), QPointF(90.0, 20.0), QPointF(30.0, 40.0)}){
Point *it = new Point();
scene->addItem(it);
it->setPos(p);
}
w.resize(640, 480);
w.show();
return a.exec();
}
i have graphic view(QGraphics view) setted scene(QGraphic scene) i am dropping objects on scene its working fine, i have to assign parameter for dropped object by dragging parameter from parameter list .i have implemented drag drop events of object.but when i am dragging parameter from param list non- acceptance symbol on object.how to assign param to object by dropping ? Any other suggestions and examples are welcome where i can get ideas to implementation.
image of gui
speedometer.cpp
#include <QMimeData>
SpeedoMeter::SpeedoMeter( QWidget *parent ):
QwtDial( parent ),
d_label( "km/h" )
{
setAcceptDrops(true);
}
void SpeedoMeter::dragEnterEvent(QDragEnterEvent *event)
{
if (event->mimeData()->hasFormat(paramlistMimeType()))
{
qDebug()<<"dragenter event in speedo" ;
event->accept();
}
}
void SpeedoMeter::dragMoveEvent(QDragMoveEvent *event)
{
if (event->mimeData()->hasFormat(paramlistMimeType()))
{
qDebug()<<"dragmove event in speedo" ;
event->acceptProposedAction();
}
}
void SpeedoMeter::dropEvent(QDropEvent *event)
{
if (event->mimeData()->hasFormat(paramlistMimeType()))
{
qDebug()<<"dragmove event in speedo" ;
event->accept();
}
}
The following example shows how to implement the logic to accept the drag-and-drop:
speedometer.h
#ifndef SPEEDOMETER_H
#define SPEEDOMETER_H
#include <qwt_dial.h>
class SpeedoMeter : public QwtDial
{
public:
SpeedoMeter(QWidget *parent=nullptr);
protected:
void dragEnterEvent(QDragEnterEvent *event);
void dropEvent(QDropEvent *event);
void dragMoveEvent(QDragMoveEvent *event);
void paintEvent(QPaintEvent *event);
private:
QString d_label;
};
#endif // SPEEDOMETER_H
speedometer.cpp
#include "speedometer.h"
#include <qwt_dial_needle.h>
#include <QDragEnterEvent>
#include <QMimeData>
#include <QPainter>
SpeedoMeter::SpeedoMeter(QWidget *parent):
QwtDial(parent),
d_label( "km/h" )
{
setAcceptDrops(true);
QwtDialSimpleNeedle *nd = new QwtDialSimpleNeedle(QwtDialSimpleNeedle::Arrow, Qt::white, Qt::red);
setNeedle(nd);
setValue(80);
}
void SpeedoMeter::dragEnterEvent(QDragEnterEvent *event)
{
if(event->mimeData()->hasFormat("application/x-qabstractitemmodeldatalist"))
event->acceptProposedAction();
}
void SpeedoMeter::dropEvent(QDropEvent *event)
{
const QMimeData *mimedata = event->mimeData();
if(mimedata->hasFormat("application/x-qabstractitemmodeldatalist")){
QString text;
// https://stackoverflow.com/questions/1723989/how-to-decode-application-x-qabstractitemmodeldatalist-in-qt-for-drag-and-drop
QByteArray encoded = mimedata->data("application/x-qabstractitemmodeldatalist");
QDataStream stream(&encoded, QIODevice::ReadOnly);
while (!stream.atEnd()) {
int row, col;
QMap<int, QVariant> roleDataMap;
stream >> row >> col >> roleDataMap;
if(roleDataMap.contains(Qt::DisplayRole)){
text = roleDataMap[Qt::DisplayRole].toString();
break;
}
}
// your text
d_label = text;
update();
}
}
void SpeedoMeter::dragMoveEvent(QDragMoveEvent *event)
{
if(event->mimeData()->hasFormat("application/x-qabstractitemmodeldatalist"))
event->accept();
}
void SpeedoMeter::paintEvent(QPaintEvent *event)
{
// https://stackoverflow.com/questions/43904204/qwt-dial-show-unit
QwtDial::paintEvent(event);
QPainter painter(this);
painter.setPen(Qt::black);
QFont font;
font.setPointSize(11);
painter.setFont(font);
QString text = QString("%1 %2").arg(value()).arg(d_label);
QPoint c = rect().center();
QSize Size = painter.fontMetrics().size(Qt::TextSingleLine, text);
painter.drawText(QPointF(c.x() -Size.width()/2, c.y() + 2.5*Size.height()), text);
}
main.cpp
#include "speedometer.h"
#include <QApplication>
#include <QGraphicsView>
#include <QHBoxLayout>
#include <QListWidget>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QWidget w;
QHBoxLayout *layout = new QHBoxLayout(&w);
QListWidget listWidget;
listWidget.setDragDropMode(QAbstractItemView::DragOnly);
listWidget.addItems({"km/h", "ft/s", "m/s", "miles/h"});
QGraphicsView view;
QGraphicsScene scene;
view.setScene(&scene);
SpeedoMeter speed;
scene.addWidget(&speed);
layout->addWidget(&listWidget);
layout->addWidget(&view);
w.show();
return a.exec();
}
In the following link you can find the complete example.
I have a QGraphicsSvgItem subclass where I would like to modify the svg color. I want to use for that QGraphicsColorizeEffect, and it works great.
My items also have a custom selection rectangle, highlighted - similar to other item types.
When I apply the colorize effect, the highlight also turns to the same color...
I have tried to setEnabled(false); in paint but it seems to have no effect.
sample code:
file mysvg.h
#ifndef MYSVG_H
#define MYSVG_H
#include <QGraphicsSvgItem>
#include <QGraphicsColorizeEffect>
class MySvg : public QGraphicsSvgItem
{
public:
MySvg();
~MySvg();
virtual void paint(QPainter* painter,
const QStyleOptionGraphicsItem* option,
QWidget* widget = NULL);
private:
QGraphicsColorizeEffect* m_effect;
void drawSelectionRectangle(QPainter* painter, const QStyleOptionGraphicsItem* option, const QRectF& rectangle);
};
#endif // MYSVG_H
file mysvg.cpp
#include <QStyleOptionGraphicsItem>
#include <QStyle>
#include <QPainterPath>
#include <QPainter>
#include <QFileDialog>
#include <QSvgRenderer>
MySvg::MySvg()
{
m_effect = new QGraphicsColorizeEffect();
m_effect->setColor(Qt::red);
setGraphicsEffect(m_effect);
setFlags(QGraphicsItem::ItemIsMovable |
QGraphicsItem::ItemIsFocusable |
QGraphicsItem::ItemIsSelectable);
QString filename = QFileDialog::getOpenFileName(0, tr("Open Svg File"),
QString(), tr("Svg files (*.svg *.svgz)"));
setSharedRenderer(new QSvgRenderer(filename));
}
MySvg::~MySvg()
{
delete renderer();
delete m_effect;
}
void MySvg::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
QStyleOptionGraphicsItem opt(*option);
opt.state = QStyle::State_None;
QGraphicsSvgItem::paint(painter, &opt, widget);
//m_effect->setEnabled(false); // no effect though seemed logical
QRectF rectangle = boundingRect();
if (option->state & (QStyle::State_Selected))
drawSelectionRectangle(painter, option, rectangle);
//m_effect->setEnabled(true);
}
void MySvg::drawSelectionRectangle(QPainter *painter, const QStyleOptionGraphicsItem *option, const QRectF &rectangle)
{
painter->setPen(QPen(option->palette.windowText(), 0, Qt::DotLine));
painter->setBrush(QColor(255, 188, 0, 50));
painter->drawRect(rectangle);
}
file main.cpp
#include <QApplication>
#include <QGraphicsView>
#include "mysvg.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QGraphicsScene s;
QGraphicsView view;
view.setScene(&s);
s.setSceneRect(-50, -50, 500, 650);
view.show();
MySvg* svg = new MySvg();
s.addItem(svg);
return app.exec();
}
file mysvg.pro
QT += core gui svg
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = mysvg
TEMPLATE = app
SOURCES += main.cpp \
mysvg.cpp
HEADERS += mysvg.h
I have considered making a QGraphicsSvgItem a private member of the MySvg item - but the MySvg item has to do a lot of other things, and I don't know what to do with the renderer (who would own it...) - if I can figure out how to make a QGraphicsSvgItem subclass a member of the MySvg class, I can apply the colorize to the member and perform all other operations on the MySvg item...
Please help me figure a way to apply color to the svg, but not other drawing portion of the item.
Edit - I have tried to add a member item to the class and apply the colorize effect to the member - but it doesn't apply the colorize effect at all... The svg loads with all original colors.
Here is the code containing a member item:
new mysvg.h
class SvgMember : public QGraphicsSvgItem
{
public:
SvgMember (const QByteArray &content, const QColor& c);
~SvgMember ();
private:
QGraphicsColorizeEffect* m_effect;
};
class MySvg : public QGraphicsItem
{
public:
MySvg();
~MySvg();
virtual void paint(QPainter* painter,
const QStyleOptionGraphicsItem* option,
QWidget* widget = NULL);
virtual QRectF boundingRect() const;
virtual QPainterPath shape() const;
private:
void drawSelectionRectangle(QPainter* painter, const QStyleOptionGraphicsItem* option, const QRectF& rectangle);
SvgMember * m_member;
};
new mysvg.cpp
MySvg::MySvg()
{
setFlags(QGraphicsItem::ItemIsMovable |
QGraphicsItem::ItemIsFocusable |
QGraphicsItem::ItemIsSelectable);
QString filename = QFileDialog::getOpenFileName(0, QObject::tr("Open Svg File"),
QString(), QObject::tr("Svg files (*.svg *.svgz)"));
QFile f(filename);
f.open(QFile::ReadOnly | QFile::Text);
QByteArray svgContents = f.readAll();
f.close();
m_member = new SvgMember (svgContents, Qt::red);
}
MySvg::~MySvg()
{
delete m_member;
}
void MySvg::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
QStyleOptionGraphicsItem opt(*option);
opt.state = QStyle::State_None;
m_member->paint(painter, &opt, widget);
QRectF rectangle = boundingRect();
if (option->state & (QStyle::State_Selected))
drawSelectionRectangle(painter, option, rectangle);
}
/*! \brief reimplemented to use member rectangle */
QRectF MySvg::boundingRect() const
{
return m_member->boundingRect();
}
/*! \brief reimplemented to use member shape */
QPainterPath MySvg::shape() const
{
return m_member->shape();
}
void MySvg::drawSelectionRectangle(QPainter *painter, const QStyleOptionGraphicsItem *option, const QRectF &rectangle)
{
painter->setPen(QPen(option->palette.windowText(), 0, Qt::DotLine));
painter->setBrush(QColor(255, 188, 0, 50));
painter->drawRect(rectangle);
}
SvgMember ::SvgMember (const QByteArray &content, const QColor &c)
{
m_effect = new QGraphicsColorizeEffect();
setGraphicsEffect(m_effect);
m_effect->setColor(c);
setSharedRenderer(new QSvgRenderer(content));
}
SvgMember ::~SvgMember ()
{
delete renderer();
delete m_effect;
}
What can I do to apply the colorize effect to the svg - but not to the selection rectangle ?
The effect is a feature of the base class QGraphicsItem. It is applied to the entire graphics item and all its children. So, everything that is painted inside the item is affected by its effect.
The selection rectangle should be painted outside of the SVG item object.
It can be achieved by enclosing QGraphicsSvgItem by the composite class QGraphicsItemGroup.
When a QGraphicsItem is added to QGraphicsItemGroup it becomes reparented. Thus the item is destroyed when the group object is destroyed. So, it is not needed to delete it manually. QGraphicsItem takes ownership of effect, so it is not needed to delete the effect object.
The following class MyGraphicsItemGroup works as you expect.
Implementation "mygraphicsitemgroup.cpp"
#include "mygraphicsitemgroup.h"
#include <QGraphicsColorizeEffect>
#include <QGraphicsSvgItem>
#include <QStyleOptionGraphicsItem>
#include <QPainter>
#include <QFileDialog>
MyGraphicsItemGroup::MyGraphicsItemGroup()
{
setFlags(QGraphicsItem::ItemIsMovable |
QGraphicsItem::ItemIsFocusable |
QGraphicsItem::ItemIsSelectable);
QString filename = QFileDialog::getOpenFileName(0,
QObject::tr("Open Svg File"), QString(),
QObject::tr("Svg files (*.svg *.svgz)"));
QGraphicsColorizeEffect *effect = new QGraphicsColorizeEffect();
effect->setColor(Qt::red);
QGraphicsSvgItem *svg = new QGraphicsSvgItem(filename);
svg->setGraphicsEffect(effect);
addToGroup(svg);
}
void MyGraphicsItemGroup::paint(QPainter* painter,
const QStyleOptionGraphicsItem* option, QWidget* widget)
{
QStyleOptionGraphicsItem opt(*option);
opt.state = QStyle::State_None;
QGraphicsItemGroup::paint(painter, &opt, widget);
QRectF rectangle = boundingRect();
if (option->state & QStyle::State_Selected)
drawSelectionRectangle(painter, option, rectangle);
}
void MyGraphicsItemGroup::drawSelectionRectangle(QPainter *painter,
const QStyleOptionGraphicsItem *option, const QRectF &rectangle)
{
painter->setPen(QPen(option->palette.windowText(), 0, Qt::DotLine));
painter->setBrush(QColor(255, 188, 0, 50));
painter->drawRect(rectangle);
}
Header "mygraphicsitemgroup.h"
#ifndef MYGRAPHICSITEMGROUP_H
#define MYGRAPHICSITEMGROUP_H
#include <QGraphicsItemGroup>
class MyGraphicsItemGroup : public QGraphicsItemGroup
{
public:
MyGraphicsItemGroup();
virtual void paint(QPainter* painter,
const QStyleOptionGraphicsItem* option, QWidget* widget);
void drawSelectionRectangle(QPainter *painter,
const QStyleOptionGraphicsItem *option, const QRectF &rectangle);
};
#endif // MYGRAPHICSITEMGROUP_H
I am implenting copy paste operation in QGraphicsView to different entites like circle, point, ellipse etc. Applied copy operation but unable to get how to apply paste operation for it. Please help me out solve the problem. My slot for copy appears as follows:
cadgraphicsscene.cpp
void CadGraphicsScene::copy()
{
selectItems();
}
void CadGraphicsScene::selectItems()
{
// refresh record of selected items and their starting positions
selectedItems.clear();
foreach (QGraphicsItem *item, itemList)
{
if (item->isSelected())
{
if (dynamic_cast<QGraphicsItem *>(item))
{
selectedItems.append(qMakePair(
dynamic_cast<QGraphicsItem *>(item),
item->scenePos()));
}
}
}
}
cadgraphicsscene.h
#ifndef CADGRAPHICSSCENE_H
#define CADGRAPHICSSCENE_H
#include <QGraphicsScene>
#include <QXmlStreamWriter>
#include <QUndoStack>
#include "cadcommandadd.h"
#include "cadcommanddelete.h"
#include "cadcommandmove.h"
class CadGraphicsScene : public QGraphicsScene
{
Q_OBJECT
public:
explicit CadGraphicsScene(QObject *parent, QUndoStack *);
enum Mode { NoMode, PointMode, LineMode, CircleMode, EllipseMode, TextMode };
QFont font() const
{
return myFont;
}
QColor textColor() const
{
return myTextColor;
}
void setTextColor(const QColor &color);
void setFont(const QFont &font);
void deleteItems();
void copy();
void writeStream(QXmlStreamWriter *stream);
void readStream(QXmlStreamReader *stream);
public slots:
void setMode(Mode mode);
void selectItems();
void editorLostFocus(mText *item);
protected:
void mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent);
void mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent);
void setFlags();
void areItemsSelectable(bool);
signals:
void textInserted(QGraphicsTextItem *item);
void itemSelected(QGraphicsItem *item);
private:
Mode entityMode;
QUndoStack *mUndoStack;
bool mFirstClick;
bool mSecondClick;
bool mThirdClick;
bool mPaintFlag;
QVector<QPointF> stuff;
QPointF start_p, mid_p, end_p, move_p, check_p;
QPen paintpen, linePen;
QList<QGraphicsItem *> itemList;
Point *pointItem;
Line *lineItem;
Circle *circleItem;
Ellipse *ellipseItem;
mText *textItem;
QColor myTextColor;
QFont myFont;
typedef QPair<QGraphicsItem *, QPointF> itemPos;
QList<itemPos> selectedItems;
};
#endif // CADGRAPHICSSCENE_H