I try to build chart demo using Qwt and C++. I've added the following code to button click handler:
QwtPlot *plot = new QwtPlot(QwtText("Demo"));
plot->setGeometry(0, 0, 100, 100);
QwtPlotCurve curve("Sine");
QVector<double> xs;
QVector<double> ys;
for (double x = 0; x < 100; x++)
{
xs.append(x);
ys.append(sin(x));
}
QwtPointArrayData *series = new QwtPointArrayData(xs, ys);
curve.setData(series);
curve.attach(plot);
plot->show();
QLayout *lay = ui->centralWidget->layout();
lay->addWidget(plot);
and it segfaults at addWidget(plot);.
What am I doing wrong?
The layout of centralWidget is probably NULL or you haven't initialized the ui (e.g. calling setUp()). Check the first case with if(lay == NULL) and the second by looking at your code.
If the first case is correct have a look at your UI file in QDesigner and add a layout.
Related
I am creating dynamic list of charts and pushing them into ui.verticalLayout->addWidget(chartView,Qt::AlignCenter); But as more items i add - than smaller they become, because of fitting to the size of vertical layout. I was trying to find more information about adding to list or smth like that - but didn't realized nothing related with charts. Here is code:
for (int i = 0; i < 5; i++) {
QPieSeries* serie_pie = new QPieSeries();
double free_serie = 1.33;
double used_serie = 3.1;
serie_pie->append("Free", free_serie);
serie_pie->append("Used", used_serie);
QChart* chart_for_pie = new QChart();
chart_for_pie->addSeries(serie_pie);
chart_for_pie->setMargins(QMargins(0, 0, 0, 0));
chart_for_pie->legend()->setAlignment(Qt::AlignRight);
QChartView* chartView = new QChartView(chart_for_pie);
chart_for_pie->setBackgroundVisible(false);
chartView->setRenderHint(QPainter::Antialiasing);
ui.verticalLayout->addWidget(chartView,Qt::AlignCenter);// add into another place :)
}
Thanks for any help.
QChart inherits by QGraphicsWidget. So you can try to use
1) QGraphicsWidget::resize(qreal w, qreal h)
or
2) QGraphicsWidget::resize(const QSizeF &size)
And one more for beauty QGraphicsLayoutItem::setGeometry(const QRectF &rect)
https://doc.qt.io/qt-5/qgraphicswidget.html
If you want to try resize QChartView
try it:
1) QWidget::setMinimumSize(int minw, int minh)
2) QWidget::setMaximumSize(int maxw, int maxh)
https://doc.qt.io/qt-5/qwidget.html#setMaximumSize-1
Create a QScrollArea and add your charts to that
Situation:
I wrote a bar plot using QtCharts, QChartView, QChart, QBarSeries, QBarSet, QValueAxis and QCategoryAxis and it works fine.
Problem:
When i resize the window or use QRubberbandon the plot, it crashes.
What i tried:
Every other plot i wrote is not affected by that problem, including the ones using QStackedBarSeries. The Problem also occured in another program i wrote in the same situation.
Code - Head:
int D_Plot::Plot_Stat_Multi_MeanMedian(
QChartView *pChartView,
vector<vector<double> > *vv_SetSta,
bool pl_mean,
bool pl_sd,
bool pl_median,
bool pl_adm,
QString name_title,
QString name_categories,
QString name_y)
Code - Body:
//Chart
QChart *chart = new QChart();
chart->setTitle(name_title);
//Sets
QBarSet set_mean("Mean");
QBarSet set_sdev("Standard Deviation");
QBarSet set_medi("Median");
QBarSet set_aadm("Average Absolute Deviation from Median");
//Categories
QStringList categories;
//Series
QBarSeries *series = new QBarSeries();
for(unsigned int set = 0; set < vv_SetSta->size(); set++)
{
if(pl_mean) set_mean.append((*vv_SetSta)[set][c_STAT_MEAN_ARITMETIC]);
if(pl_sd) set_sdev.append((*vv_SetSta)[set][c_STAT_STAN_DEV_SAMPLE]);
if(pl_median) set_medi.append((*vv_SetSta)[set][c_STAT_MEDIAN]);
if(pl_adm) set_aadm.append((*vv_SetSta)[set][c_STAT_ABS_DEV_MED]);
categories.append(QString::number(set));
}
if(pl_mean) series->append(&set_mean);
if(pl_sd) series->append(&set_sdev);
if(pl_median) series->append(&set_medi);
if(pl_adm) series->append(&set_aadm);
chart->addSeries(series);
//Axis
QBarCategoryAxis *X_axis = new QBarCategoryAxis();
X_axis->append(categories);
X_axis->setTitleText(name_categories);
chart->setAxisX(X_axis, series);
QValueAxis *Y_axis = new QValueAxis();
Y_axis->setTitleText(name_y);
chart->setAxisY(Y_axis, series);
//Showing
pChartView->setChart(chart);
return ER_Okay;
You are creating your QBarSet objects locally (i.e. not via the new operator) and passing a pointer to these sets to the QBarSet::append method which AFAIK takes ownership if the objects pointed to i.e feels obliged to de-allocate them when going out of scope. This is bound to fail with locally allocated objects.
I have a QGridLayout inside a center widget, which contains a supposedly fixed-sized widget (referred to as inner widget) that also has a QGridLayout filled with buttons. Inner widget's size is determined by how many buttons are there in the grid, and is supposed to be an exact fit (no spacing between the buttons, FixedSize policy applied in buttons' constructor), and all buttons have their sizes and policies set in the constructor. Now, if I don't put inner widget into a layout of any kind, it works just fine, I get nice square buttons. But if I put inner widget into a grid layout, all buttons suddenly change their sizes, and widget also doesn't seem like keeping its size. Why?
Edit: MyButtonTable:
MyButtonTable::MyButtonTable(QWidget *parent) : QWidget(parent), array()
{
size_x = 2;
size_y = 2;
QGridLayout* layout = new QGridLayout();
for(size_t x = 0; x < size_x; x++) {
this->array.push_back(std::vector<MyRightClickButton*>());
}
for(size_t x = 0; x < size_x; x++) {
for(size_t y = 0; y < size_y; y++) {
this->array[x].push_back(new button_t());
QObject::connect(array[x][y], SIGNAL(rightClicked()), this, SLOT(internalRightClick()));
QObject::connect(array[x][y], SIGNAL(clicked()), this, SLOT(internalClick()));
layout->addWidget(array[x][y], x, y);
}
}
layout->setSpacing(0);
layout->setContentsMargins(0,0,0,0);
this->setLayout(layout);
this->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
this->setMinimumSize(QSize(0,0));
this->resize(QSize(10*size_y,10*size_x));
}
MyRightClickButton(QWidget *parent = 0):QPushButton(parent) {
marked = false;
this->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
this->setMinimumSize(QSize(0,0));
this->resize(QSize(10,10));
}
A layout manager is used to arrange child widgets in them. The arrangement designates each layout manager. Layout managers adjust the size of their child widgets based on the resize policies. Even if you are setting a fixed size for a child widget, using resize() or setGeometry(), they will be resized by the layout manager, if you did not set the resize policy of the child widget.
For example
widget->setFixedSize (100, 100);
widget->setSizePolicy (QSizePolicy::Fixed, QSizePolicy::Fixed);
This is how it should be done.
I am using Qt and C++ to add some features to a freeware called: EASYPAINT.
I had to add a more intuitive method in which the users can see the actual width directly from the tool instead of changing numbers. ( just like in the new windows paint , where you can actually see the line thickness and not pixels.)
I am using a QComboBox. My question is (look at the code first), instead of having 20 (penSizeList->addItem), I know we can have addItems.... But what about the icon. for each Item, will I have to search for 20 different line thickness.png and add them? Or is there another method I can use?
And also, how can I get rid of the string in addItem, and only keep an image or icon in the QComboBox.
QComboBox *penSizeList = new QComboBox();
penSizeList->setIconSize(QSize(100,100));
penSizeList->setStatusTip("Pen Size");
QIcon ONEpxIcon(":/media/actions-icons/clear-gray.png");
QIcon THREEpxIcon(":/media/instruments-icons/canvas-lines1.png");
penSizeList->addItem(ONEpxIcon,"1px");
penSizeList->addItem(THREEpxIcon,"2px");
penSizeList->addItem(THREEpxIcon,"3px");
penSizeList->addItem(THREEpxIcon,"4px");
penSizeList->addItem(THREEpxIcon,"5px");
penSizeList->addItem(THREEpxIcon,"6px");
penSizeList->addItem(THREEpxIcon,"7px");
penSizeList->addItem(THREEpxIcon,"8px");
penSizeList->addItem(THREEpxIcon,"9px");
penSizeList->addItem(THREEpxIcon,"10px");
penSizeList->addItem(THREEpxIcon,"11px");
penSizeList->addItem(THREEpxIcon,"12px");
penSizeList->addItem(THREEpxIcon,"13px");
penSizeList->addItem(THREEpxIcon,"14px");
penSizeList->addItem(THREEpxIcon,"15px");
penSizeList->addItem(THREEpxIcon,"16px");
penSizeList->addItem(THREEpxIcon,"17px");
penSizeList->addItem(THREEpxIcon,"18px");
penSizeList->addItem(THREEpxIcon,"19px");
penSizeList->addItem(THREEpxIcon,"20px");
connect(penSizeList,SIGNAL(activated(int)), this, SLOT(penValueChanged(int)));
Try to do this in loop.
penSizeList->addItem(ONEpxIcon,"1px");
for(int i = 2; i < 21 ; i++)
{
penSizeList->addItem(THREEpxIcon,QString("%1px").arg(i));
}
Or if you have different icons for each line:
for(int i = 1; i < 21 ; i++)
{
penSizeList->addItem(QIcon(QString("iconLine%1.png").arg(i)),QString("%1px").arg(i));
}
If you want only icons, set empty string:
penSizeList->addItem(icon,"");
If you want full image then you should set this image as background. For example:
QPixmap pxmap("G:/2/qt.jpg");
QStandardItemModel *md = new QStandardItemModel;
QStandardItem *iii = new QStandardItem;
iii->setBackground(QBrush(Qt::red));
iii->setText("ss");
QStandardItem *iiii = new QStandardItem;
iiii->setBackground(QBrush(pxmap));
iiii->setText("ss");
md->setItem(1,0,iii);
md->setItem(0,0,iiii);
ui->comboBox->setModel(md);
Hi guys I have to dynamically create push buttons depending on user inputs, therefore if user gives a large input number the widget containing the push buttons has to have the ability to scroll up and down. For this reason I am using QScrollArea. I generate the template in Qt designer and the UIC generates the code for me after which I add in my part which should handle dynamic creation of push buttons. However, I can not seem to get the vertical scroll bars to appear. Here is the relevant part of the code.
verticalWidget = new QWidget(FWHMWorkflowDialog);
verticalWidget->setObjectName(QString::fromUtf8("verticalWidget"));
verticalWidget->setMinimumSize(QSize(150, 0));
verticalWidget->setMaximumSize(QSize(150, 16777215));
verticalLayout_5 = new QVBoxLayout(verticalWidget);
verticalLayout_5->setObjectName(QString::fromUtf8("verticalLayout_5"));
scrollArea = new QScrollArea(verticalWidget);
scrollArea->setObjectName(QString::fromUtf8("scrollArea"));
scrollArea->setMaximumSize(QSize(150, 16777215));
scrollArea->setWidgetResizable(true);
scrollAreaWidgetContents = new QWidget();
scrollAreaWidgetContents->setObjectName(QString::fromUtf8("scrollAreaWidgetContents"));
scrollAreaWidgetContents->setGeometry(QRect(0, 0, 130, 432));
numberOfSlices = numberSlices;
for (int i = 0; i < numberOfSlices; i++)
{
QWidget *horizontalWidget = new QWidget(scrollAreaWidgetContents);
horizontalWidget->setMaximumSize(150,40);
horizontalWidget->setGeometry(QRect(0, i*40, 150, 40));
hWidgetList.push_back(horizontalWidget);
QHBoxLayout *hLayout = new QHBoxLayout(horizontalWidget);
hLayoutList.push_back(hLayout);
hLayout->setSizeConstraint(QLayout::SetMinimumSize);
hLayout->setContentsMargins(-1, 1, -1, 1);
QPushButton *pushButton = new QPushButton(horizontalWidget);
pushButtonList.push_back(pushButton);
QString temp = QString("m_sliceButton").arg(i);
pushButtonList[i]->setObjectName(temp);
pushButtonList[i]->setGeometry(QRect(10, 20+i*40, 98, 27));
hLayout->addWidget(pushButton);
QCheckBox *checkBox = new QCheckBox(horizontalWidget);
checkBoxList.push_back(checkBox);
temp = QString("m_checkBox").arg(i);
checkBoxList[i]->setObjectName(temp);
checkBoxList[i]->setEnabled(true);
checkBoxList[i]->setGeometry(QRect(110, 20+i*40, 21, 22));
hLayout->addWidget(checkBox);
}
scrollArea->setWidget(scrollAreaWidgetContents);
//scrollArea->setWidgetResizable(true);
verticalLayout_5->addWidget(scrollArea);
The output window always looks like the following.
In this example the input by the user is 25 however you can see that the 21st button is cut off and 4 other buttons are not visible.
The size window problem occurring after scroll functionality started working.
You need to add your horizontalWidget to a vertical widget like so:
QVBoxLayout* vLayout = new QVBoxLayout();
for (int i = 0; i < numberOfSlices; i++)
{
QWidget *horizontalWidget = new QWidget();
vLayout->addWidget(horizontalWidget);
....
}
scrollAreaWidgetContents->setLayout(vLayout);
You second problem looks like it comes from this line:
scrollArea = new QScrollArea(verticalWidget);
You're adding scrollArea directly to verticalWidget, but to get it to lay out the way you want you need to put it in a layout. Try the following instead:
QVBoxLayout* l = new QVBoxLayout();
l->addWidget(sliceLabel); // or whatever you call it
l->addWidget(scrollArea);
l->addWidget(clearButton); // again, your name here
verticalWidget->setLayout(l);
Try playing around with the QScrollBarPolicy.
http://doc.qt.digia.com/qt/qabstractscrollarea.html#horizontalScrollBarPolicy-prop
I'm guessing that the default behavior isn't working because there is something strange going on with layouts.